Restoration of rusty metal. How to prevent rust on metal? What is rust remover

In connection with the appearance of a certain gas, causing an instant burning cough. This article is the identification of this gas. The article is replete with formulas; the number of formulas is due to the non-triviality of both the electrolysis process itself and the rust itself. Chemists and chemists, help bring the article to full compliance with reality; it is your duty to take care of the "little" brothers in the event of a chemical hazard.

Let there be iron Fe 0:
- if there was no water on Earth, then oxygen would fly in - and made oxide: 2Fe + O 2 \u003d 2FeO (black). The oxide oxidizes further: 4FeO + O 2 = 2Fe 2 O 3 (red-brown). FeO 2 does not exist, these are schoolchildren's inventions; but Fe 3 O 4 (black) is quite real, but artificial: the supply of superheated steam to iron or the reduction of Fe 2 O 3 with hydrogen at a temperature of about 600 degrees;
- but there is water on Earth - as a result, both iron and iron oxides tend to turn into the base Fe (OH) 2 (white ?!. It quickly darkens in the air - is it not a point below): 2Fe + 2H 2 O + O 2 \u003d 2Fe(OH) 2 , 2FeO + H 2 O = 2Fe(OH) 2 ;
- further even worse: there is electricity on Earth - all these substances tend to turn into the base Fe (OH) 3 (brown) due to the presence of moisture and potential difference (galvanic couple). 8Fe(OH) 2 + 4H 2 O + 2O 2 = 8Fe(OH) 3 , Fe 2 O 3 + 3H 2 O = 2Fe(OH) 3 (slowly). That is, if iron is stored in a dry apartment, it rusts slowly, but holds on; increase the humidity or wet it - it will become worse, and stick it into the ground - it will be very bad.

Preparing a solution for electrolysis is also an interesting process:
- first, the analysis of the available substances for the preparation of solutions is carried out. Why soda ash and water? Soda ash Na 2 CO 3 contains Na metal, which is much to the left of hydrogen in a number of electrical potentials - which means that during electrolysis the metal will not be reduced at the cathode (in solution, but not in melt), and water will decompose into hydrogen and oxygen (in solution). There are only 3 variants of the reaction of the solution: metals much to the left of hydrogen are not reduced, weakly to the left of hydrogen they are reduced with the release of H 2 and O 2, to the right of hydrogen they are simply reduced at the cathode. Here it is, the process of copper plating of the surface of parts in a CuSo 4 solution, galvanizing in ZnCl 2, nickel plating in NiSO 4 + NiCl 2, etc.;
- to dilute soda ash in water stands in calm, slowly and without breathing. Do not tear the package with your hands, but cut it with scissors. After that, the scissors must be put in the water. Any of the four types of soda (food, soda, washing, caustic soda) takes moisture from the air; its shelf life, in fact, is determined by the time of accumulation of moisture and clumping. That is, in a glass jar, the shelf life is eternity. Also, any soda generates a sodium hydroxide solution when mixed with water and electrolysis, differing only in the concentration of NaOH;
- soda ash is mixed with water, the solution becomes bluish in color. It would seem that a chemical reaction has taken place - but not: as in the case of table salt and water, the solution does not have a chemical reaction, but only a physical one: the dissolution of a solid in a liquid solvent (water). You can drink this solution and get mild to moderate poisoning - nothing fatal. Or evaporate and get soda ash back.

The choice of anode and cathode is a whole undertaking:
- it is advisable to choose the anode as a solid inert material (so that it does not collapse, including from oxygen, and does not participate in chemical reactions) - that is why stainless steel acts as it (I read heresy on the Internet, I almost got poisoned);
- it is pure iron that is the cathode, otherwise rust will act as an excessively high resistance of the electrical circuit. To place the iron to be purified completely into the solution, you need to solder or screw it to some other iron. Otherwise, the metal of the iron holder itself will take part in the solution as a non-inert material and as a section of the circuit with the least resistance (parallel connection of metals);
- not yet specified, but there should be a dependence of the flowing current and electrolysis rate on the surface area of the anode and cathode. That is, one M5x30 stainless steel bolt may not be enough to quickly remove rust from a car door (to realize the full potential of electrolysis).

Let's take an inert anode and cathode as an example: considering the electrolysis of only a blue solution. As soon as voltage is applied, the solution begins to transform to the final one: Na 2 CO 3 + 4H 2 O \u003d 2NaOH + H 2 CO 3 + 2H 2 + O 2. NaOH - sodium hydroxide - mad alkali, caustic soda, Freddy Krueger in a nightmare: the slightest contact of this dry substance with wet surfaces (skin, lungs, eyes, etc.) causes hellish pain and fast irreversible (but recoverable with a mild degree of burn ) damage. Fortunately, sodium hydroxide is dissolved in carbonic acid H 2 CO 3 and water; when the water is completely evaporated by hydrogen at the cathode and oxygen at the anode, the maximum concentration of NaOH in carbonic acid is formed. It is absolutely impossible to drink or smell this solution, it is also impossible to poke your fingers (the longer the electrolysis, the more it burns). You can clean the pipes with it, while understanding its high chemical activity: if the pipes are plastic, you can hold them for 2 hours, but if they are metal (grounded, by the way) - the pipes will start to eat: Fe + 2NaOH + 2H 2 O \u003d Na 2 + H 2 , Fe + H 2 CO 3 \u003d FeCO 3 + H 2.

This is the first of the possible causes of suffocating "gas", a physical and chemical process: saturation of air with a solution of concentrated sodium hydroxide in carbonic acid (boiling bubbles of oxygen and hydrogen as carriers). In the books of the 19th century, carbonic acid is used as a poisonous substance (in large quantities). That is why drivers installing a battery in a car get damaged by sulfuric acid (in fact, the same electrolysis): in the process of overcurrent to a highly discharged battery (the car has no current limit), the electrolyte boils for a short time, sulfuric acid comes out together with oxygen and hydrogen in the cabin. If the room is made completely airtight, due to the oxygen-hydrogen mixture (explosive gas), you can get a good blow with the destruction of the room. The video shows broads in miniature: under the action of molten copper, water decomposes into hydrogen and oxygen, and metal is more than 1100 degrees (I can imagine how the room completely filled with it stinks) ... About the symptoms of NaOH inhalation: caustic, burning sensation, sore throat, cough, shortness of breath, shortness of breath ; symptoms may be delayed. Feels like it fits perfectly.
...at the same time, Vladimir Vernadsky writes that life on Earth without carbonic acid dissolved in water is impossible.

We replace the cathode with a rusty piece of iron. A whole series of funny chemical reactions begins (and here it is, borscht!):
- rust Fe (OH) 3 and Fe (OH) 2, as bases, begin to react with carbonic acid (released at the cathode), obtaining siderite (red-brown): 2Fe (OH) 3 + 3H 2 CO 3 \u003d 6H 2 O + Fe 2 (CO3) 3, Fe (OH) 2 + H 2 CO 3 \u003d FeCO 3 + 2 (H 2 O). Iron oxides do not participate in the reaction with carbonic acid, because. there is no strong heating, and the acid is weak. Also, electrolysis does not restore iron at the cathode, because. these bases are not a solution, but the anode is not iron;
- caustic soda, as a base, does not react with bases. Necessary conditions for Fe(OH) 2 (amphoteric hydroxide): NaOH>50% + boiling in nitrogen atmosphere (Fe(OH) 2 + 2NaOH = Na2). Necessary conditions for Fe (OH) 3 (amphoteric hydroxide): fusion (Fe (OH) 3 + NaOH \u003d NaFeO 2 + 2H 2 O). Necessary conditions for FeO: 400-500 degrees (FeO + 4NaOH \u003d 2H 2 O + Na 4 FeO 3). Or maybe there is a reaction with FeO? FeO + 4NaOH = Na 4 FeO 3 + 2H 2 O - but only at a temperature of 400-500 degrees. Okay, maybe the sodium hydroxide removes some of the iron - and the rust just falls off? But here is a bummer: Fe + 2NaOH + 2H 2 O \u003d Na 2 + H 2 - but when boiling in a nitrogen atmosphere. What the hell is a solution of caustic soda without electrolysis removes rust? But he does not remove it in any way (I poured out exactly a transparent solution of caustic soda from "Auchan"). It removes grease, and in my case, with a piece of matiz, it dissolved the paint and primer (the resistance of the primer to NaOH is in its performance characteristics) - which exposed a clean iron surface, the rust simply disappeared. Conclusion: soda ash is needed only to obtain acid by electrolysis, which cleans the metal, taking rust on itself at an accelerated pace; sodium hydroxide seems to be out of business (but will react with debris in the cathode, cleaning it).

About foreign substances after electrolysis:
- the solution changed its color, became "dirty": with reacted bases Fe(OH) 3 , Fe(OH) 2 ;
- black plaque on the gland. First thought: iron carbide Fe 3 C (triiron carbide, cementite), insoluble in acids and oxygen. But the conditions are not the same: to obtain it, you need to apply a temperature of 2000 degrees; and in chemical reactions there is no free carbon to attach to iron. The second thought: one of the iron hydrides (saturation of iron with hydrogen) - but this is also not true: the conditions for obtaining are not the same. And then it came up: iron oxide FeO, the basic oxide does not react with either acid or caustic soda; and also Fe 2 O 3 . And amphoteric hydroxides are layers above the basic oxides, protecting the metal from further penetration of oxygen (they do not dissolve in water, they prevent the access of water and air to FeO). You can put the cleaned parts in citric acid: Fe 2 O 3 + C 6 H 8 O 7 \u003d 2FeO + 6CO + 2H 2 O + 2H 2 (special attention to the release of carbon monoxide and the fact that acid and metal eat on contact) - and FeO is removed with a conventional brush. And if you heat the highest oxide in carbon monoxide and do not burn out, then it will restore iron: Fe 2 O 3 + 3CO \u003d 2Fe + 3CO 2;
- white flakes in solution: some salts that are insoluble during electrolysis either in water or in acid;
- other substances: iron is initially "dirty", water is not initially distilled, dissolution of the anode.

The second of the possible causes of suffocating "gas" is a physical and chemical process: iron, as a rule, is not pure - with galvanization, a primer and other third-party substances; and water - with minerals, sulfates, etc. Their reaction during electrolysis is unpredictable, anything can be released into the air. However, my piece was so small (0.5x100x5) and the tap water (weakly mineralized) is unlikely to be the cause. Also, the idea of the presence of foreign substances in the soda ash itself has disappeared: only it is indicated on the packaging in the composition.

The third possible cause of asphyxiating gas is a chemical process. If the cathode is restored, then the anode is bound to be destroyed by oxidation, if not inert. Stainless steel contains about 18% chromium. And this chromium, when destroyed, enters the air in the form of hexavalent chromium or its oxide (CrO 3 , chromic anhydride, reddish - further we will talk about it), a strong poison and a carcinogen with a delayed catalysis of lung cancer. The lethal dose is 0.08g/kg. Ignites gasoline at room temperature. Released when welding stainless steel. The horror is that it has the same symptoms as sodium hydroxide when inhaled; and sodium hydroxide already seems like a harmless animal. Judging by the description of cases of at least bronchial asthma, you need to work as a roofer for 9 years, breathing this poison; however, a clear delayed effect is described - that is, it can shoot both 5 and 15 years after a single poisoning.

How to check if chrome stood out from stainless steel (where - the question remains). The bolt after the reaction became more shiny than the same bolt from the same batch - a bad sign. As it turned out, stainless steel is such as long as chromium oxide exists in the form of a protective coating. If chromium oxide was destroyed by oxidation during electrolysis, then such a bolt will rust more intensively (free iron will react, and then chromium in the composition of untouched stainless steel will oxidize to CrO). Therefore, he created all the conditions for the rusting of two bolts: salt water and a solution temperature of 60-80 degrees. Stainless steel grade A2 12X18H9 (X18H9): it contains 17-19% chromium (and in stainless iron-nickel alloys, chromium is even higher, up to ~ 35%). One of the bolts turned red in several places, all places - in the contact zone of the stainless steel with the solution! The reddest one is along the line of contact with the solution.

And my happiness was that the current strength was then only 0.15A during electrolysis, the kitchen was closed and the window in it was open. It was clearly imprinted in my mind: to exclude stainless steel from electrolysis or to do it in an open area and at a distance (there is no stainless steel without chromium, this is its alloying element). Because stainless steel is NOT an inert anode during electrolysis: it dissolves and releases poisonous chromium oxide; sofa chemists, kill yourself against the wall until someone dies from your advice! The question remains, in what form, how much and where; but taking into account the release of pure oxygen at the anode, CrO is already precisely oxidized to the intermediate oxide Cr 3 O 2 (also poisonous, MPC 0.01 mg / m 3), and then to the higher oxide CrO 3: 2Cr 2 O 3 + 3O 2 \u003d 4CrO3. The latter remains an assumption (the necessary alkaline environment is present, but whether strong heating is needed for this reaction), but it is better to play it safe. Even blood and urine tests for chromium are difficult to do (they are not in the price lists, not even in the extended general blood test).

Inert electrode - graphite. It is necessary to go to the trolleybus depot, take pictures of the discarded brushes. Because even on aliexpress for 250 rubles per pin. And this is the cheapest of the inert electrodes.

And here is 1 more real example when a sofa electronics led to material losses. And to the right knowledge, really. As in this article. The benefits of sofa idle talk? - hardly, they sow chaos; and have to clean up after them.

I tend to the first reason for the suffocating "gas": the evaporation of a solution of sodium hydroxide in carbonic acid into the air. Because with chromium oxides, it is hose masks with mechanical air supply that are used - I would have suffocated in my miserable RPG-67, but it was noticeably easier to breathe in it at the very epicenter.
How to check for chromium oxide in the air? Start the process of water decomposition in a pure solution of soda ash on a graphite anode (pick out from a pencil, but not every pencil contains a pure graphite rod) and an iron cathode. And take a chance to inhale the air in the kitchen again after 2.5 hours. Is it logical? Almost: the symptoms of caustic soda and hexavalent chromium oxide are identical - the presence of caustic soda in the air will not prove the absence of hexavalent chromium vapor. However, the absence of odor without stainless steel will clearly give the result of the presence of hexavalent chromium. I checked, there was a smell - a phrase with hope "hooray! I breathed caustic soda, not hexavalent chromium!" can be broken into jokes.

What else was forgotten:
- how do acid and alkali exist together in one vessel? In theory, salt and water should appear. There is a very subtle point here, which can only be understood experimentally (did not check). If all the water is decomposed during electrolysis and the solution is isolated from salts in the precipitate - option 2: either a solution of caustic soda or caustic soda with carbonic acid will remain. If the latter is in the composition, the release of salt under normal conditions and the precipitation of ... soda ash will begin: 2NaOH + H 2 CO 3 \u003d Na 2 CO 3 + 2H 2 O. The problem is that it will dissolve in water right there - sorry, the taste cannot be tasted and compared with the original solution: suddenly the caustic soda has not completely reacted;
- Does carbonic acid interact with iron itself? The question is serious, because. the formation of carbonic acid occurs precisely at the cathode. You can check by creating a more concentrated solution and doing electrolysis until a thin piece of metal is completely dissolved (did not check). Electrolysis is seen as a more gentle rust removal method than acid pickling;
What are the symptoms of inhaling explosive gas? No + no smell, no color;
- Do caustic soda and carbonic acid react with plastic? Make identical electrolysis in plastic and glass containers and compare the turbidity of the solution and the transparency of the surface of the container (did not check on glass). Plastic - became less transparent in places of contact with the solution. However, these turned out to be salts, easily scraped off with a finger. So, food plastic does not react with the solution. Glass is used to store concentrated alkalis and acids.

If you inhale a lot of burning gas, regardless of whether it is NaOH or CrO 3, you need to take "unithiol" or a similar drug. And the general rule applies: no matter what poisoning occurs, no matter what strength and origin it may be, drink plenty of water in the next 1-2 days, if the kidneys allow. Task: remove the toxin from the body, and if this is not done by vomiting or expectoration, give additional opportunities to do this to the liver and urinary system.

The most annoying thing is that this is all the 9th grade school curriculum. Damn, I'm 31 years old - and I won't pass the exam ...

Electrolysis is interesting in that it turns back time:
- a solution of NaOH and H 2 CO 3 under normal conditions will lead to the formation of soda ash, while electrolysis inverts this reaction;
- iron in natural conditions is oxidized, and is restored during electrolysis;
- hydrogen and oxygen tend to combine in any way: mix with air, burn and become water, absorb or react with something; electrolysis, on the contrary, generates gases of various substances in their pure form.
The local time machine, nothing else: returns the position of the molecules of substances to their original state.

According to the reaction formulas, a solution of powdered sodium hydroxide is more dangerous when it is created and electrolyzed, but more effective in certain situations:
- for inert electrodes: NaOH + 2H 2 O = NaOH + 2H 2 + O 2 (the solution is a source of pure hydrogen and oxygen without impurities);
- reacts more intensively with organic materials, there is no carbonic acid (fast and cheap degreaser);
- if iron is taken as an anode, it will begin to dissolve at the anode and be reduced at the cathode, thickening the iron layer on the cathode in the absence of carbonic acid. This is a method of restoring the cathode material or coating it with another metal when there is no solution with the desired metal at hand. Rust removal, according to experimenters, also goes faster if iron is made the anode in the case of soda ash;
- but the concentration of NaOH in the air during evaporation will be higher (you still need to decide which is more dangerous: carbonic acid with caustic soda or moisture with caustic soda).

Earlier I wrote about education that a lot of time is wasted in school and university. This article does not change this opinion, because an ordinary person will not need matan, organic chemistry or quantum physics in life (only at work, and when I needed matan 10 years later, I learned it again, I didn’t remember anything at all). But inorganic chemistry, electrical engineering, physical laws, Russian and foreign languages - this is what should be a priority (still introduce the psychology of the interaction of the sexes and the foundations of scientific atheism). Here, I did not study at the Faculty of Electronics; and then bam, locked up - and Visio learned to use, and MultiSim and some of the designations of the elements learned, etc. Even if I studied at the Faculty of Psychology, the result would be the same: I got stuck in life - bit into it - figured it out. But if at school the emphasis on natural sciences and languages \u200b\u200bis been strengthened (and they explained to young people why it was strengthened), life would be easier. Both at school and at the institute in chemistry: they talked about electrolysis (theory without practice), but about the toxicity of vapors - no.

Finally, an example of obtaining pure gases (using inert electrodes): 2LiCl + 2H 2 O = H 2 + Cl 2 + 2LiOH. That is, first we poison ourselves with the purest chlorine, and then we explode with hydrogen (again, to the issue of the safety of the emitted substances). If there was a CuSO 4 solution, and the iron-metal cathode would drop out of the base and leave an oxygen-containing acid residue SO4 2-, it does not participate in the reactions. If the acid residue did not contain oxygen, it would decompose into simple substances (which can be seen in the example of C 1 - , which is released as Cl 2).

(added 05/24/2016) If you need to boil NaOH with rust for their mutual reaction - why not? Nitrogen in the air is 80%. The effectiveness of rust removal will increase significantly, but then this process must definitely be done outdoors.

About metal hydrogenation (increase in brittleness): I did not find any formulas and adequate opinions on this topic. If possible, I will set up the electrolysis of the metal for several days, adding a reagent, and then I will knock with a hammer.

(added 05/27/2016) Graphite can be removed from a used salt battery. If it stubbornly resists disassembly, deform it in a vice.

(added 06/10/2016) Metal hydrogenation: H + + e - = H ads. H ads + H ads \u003d H 2, where ADS is adsorption. If a metal can, under the necessary conditions, dissolve hydrogen in itself (what a number!) - then it dissolves it in itself. The conditions for the occurrence of iron have not been found, but for steel they are described in the book of Schrader A.V. "Influence of Hydrogen on Chemical and Petroleum Equipment". In Figure 58, page 108, there is a graph of the brand 12X18H10T: at a pressure comparable to atmospheric pressure and a temperature of 300-900 degrees: 30-68 cm 3 / kg. Figure 59 shows dependencies for other steel grades. The general formula for steel hydrogenation is: K s = K 0 e -∆H/2RT, where K 0 is the pre-exponential factor 1011l/mol s, ∆H is the heat of dissolution of steel ~1793K), R is the universal gas constant 8.3144598J/(mol ·K), T - medium temperature. As a result, at room temperature 300K we have K s = 843 l/mol. The number is not correct, you need to double-check the parameters.

(added 06/12/2016) If caustic soda does not interact with metals without high temperature, it is a safe (for metal) degreaser for pallets, pans and other things (iron, copper, stainless steel - but not aluminum, teflon, titanium, zinc).

With hydrogenation - clarifications. The pre-exponential factor K 0 lies in the range 2.75-1011l/mol·s, this is not a constant value. Calculating it for stainless steel: 10 13 C m 2/3, where C m is the atomic density of steel. The atomic density of stainless steel is 8 10 22 at / cm 3 - K 0 \u003d 37132710668902231139280610806.786 at. / cm 3 \u003d - and then everything is stuck.

If you look closely at the Schrader graphs, you can make an approximate conclusion about the hydrogenation of steel in OH (reducing the temperature by 2 times slows down the process by 1.5 times): approximately 5.93 cm 3 / kg at 18.75 degrees Celsius - but the time of penetration into the metal of such a volume is not indicated. In the book by Sukhotin A.M., Zotikov V.S. "Chemical resistance of materials. Handbook" on page 95 in table 8 shows the effect of hydrogen on the long-term strength of steels. It makes it possible to understand that the hydrogenation of steels with hydrogen at a pressure of 150-460 atmospheres changes the ultimate strength by a maximum of 1.5 times in the interval of 1000-10000 hours. Therefore, it is not necessary to consider the hydrogenation of steels during electrolysis in well as a destructive factor.

(added 06/17/2016) A good way to disassemble the battery: do not flatten the case, but open it like a tulip bud. From the positive input, piece by piece, bend down the parts of the cylinder - the positive input is removed, the graphite rod is exposed - and smoothly unscrewed with pliers.

(added 06/22/2016) The simplest batteries for disassembly are Ashanov's. And then in some models there are 8 circles of plastic to fix the graphite rod - it becomes difficult to pull it out, it starts to crumble.

(added 07/05/2016) Surprise: a graphite rod is destroyed much faster than an anode made of metal: in just a few hours. Using stainless steel as an anode is the best solution, if we forget about toxicity. The conclusion from this whole story is simple: electrolysis should be carried out only in the open air. If there is an open balcony in this role, do not open the windows, but pass the wires through the rubber door seal (just press the wires with the door). Taking into account the current during electrolysis up to 8A (Internet opinion) and up to 1.5A (my experience), as well as the maximum voltage of the PC PSU 24V, the wire must be rated for 24V / 11A - this is any wire in insulation with a cross section of 0.5mm 2.

Now about iron oxide on an already machined part. There are parts that are difficult to crawl into to erase black plaque (or an object under restoration, when you can’t rub the surface with an iron brush). When analyzing chemical processes, I came across a method for removing it with citric acid and tried it. Indeed, it also works with FeO - the plaque disappeared / crumbled for 4 hours at room temperature, and the solution turned green. But this method is considered less sparing, because. acid and metal eats up (cannot be overexposed, constant monitoring). Plus, a final rinse with a soda solution is required: either the acid residue will eat up the metal in air, and an undesirable coating will be obtained (an awl on soap). And you need to be careful: if as much as 6CO is released with Fe 2 O 3, then what is released with FeO is difficult to predict (organic acid). It is assumed that FeO + C 6 H 8 O 7 \u003d H 2 O + FeC 6 H 6 O 7 (formation of iron citrate) - but I also release gas (3Fe + 2C 6 H 8 O 7 → Fe 3 (C 6 H 5 O 7) 2 + 3H 2). They also write that citric acid decomposes in light and temperature - I can’t find the correct reaction in any way.

(added 07/06/2016) I tried citric acid on a thick layer of rust on nails - it dissolved in 29 hours. As expected: citric acid is suitable for the purification of metal. To clean thick rust: apply a high concentration of citric acid, high temperature (up to boiling), frequent stirring - to speed up the process, which is inconvenient.

A solution of soda ash after electrolysis, in practice, is difficult to regenerate. It is not clear: add water or add soda. The addition of table salt as a catalyst killed the solution completely + the graphite anode collapsed in just an hour.

Total: coarse rust is removed by electrolysis, FeO is pickled with citric acid, the part is washed with soda solution - and almost pure iron is obtained. Gas during reaction with citric acid - CO 2 (decarboxylation of citric acid), a darkish coating on iron - iron citrate (cleans easily-medium, does not perform any protective functions, soluble in warm water).

In theory, these methods of removing oxides are ideal for recovering coins. Unless weaker proportions of reagents are needed for a lower solution concentration and lower currents.

(added 07/09/2016) Conducted experiments with graphite. It is during the electrolysis of soda ash that it collapses extremely quickly. Graphite is carbon, when dissolved at the time of electrolysis, it can react with steel and precipitate iron carbide Fe 3 C. The condition of 2000 degrees is not met, however, electrolysis is not NU.

(added 07/10/2016) When electrolyzing soda ash using graphite rods, the voltage cannot be increased above 12V. A lower value may be needed - keep an eye on the graphite breakdown time at your voltage.

(added 07/17/2016) Discovered the local rust removal method.

(added 07/25/2016) Instead of citric acid, you can use oxalic acid.

(added 07/29/2016) Steel grades A2, A4 and others are written in English letters: imported and from the word "austenitic".

(added 10/11/2016) It turns out that there is another type of rust: iron metahydroxide FeO(OH). It is formed when iron is buried in the ground; in the Caucasus, this method of rusting strip iron was used to saturate it with carbon. After 10-15 years, the resulting high-carbon steel became sabers.

Rescuing old tools will require patience, durable abrasives, and good eyesight.

The Forgotten One has a strange power of attraction. He beckons, attracts. Take it in your hands, and the next thing you will do is scrape off a layer of rust with your thumbnail, trying to make out the name of the manufacturer of this tool.

You vaguely remember how he fell into your hands: either they took it at a sale, or he gave it to his father-in-law, or maybe a compassionate neighbor left it as a keepsake during the move, just so as not to throw it away ...

"Everybody Has Those Little Lost Jewels", - once said my friend, an excellent carpenter, who gravitates towards collecting motley tools, looking thoughtfully at a rusty hammer lying in the corner of my balcony. Planes, chisels, chisels, hammers, pliers and a whole heap of rare and strange devices for working with materials of different hardness from different countries and eras decorated his workshop.

But here's what's interesting: all these production tools were in perfect condition, there was not even rust on them, and sharpening, if any, was like a new tool. They waited for their turn to work, their oiled sides gleaming, each in his place. It always surprised me. How does he keep such old instruments in such great order...? Decided to find out his secret.

“Restoring them is quite easy,” said a friend, “but, unfortunately, I’m leaving early tomorrow morning on a business trip, so I won’t have time to tell all the subtleties. You better read about it somewhere on the Internet. There are a lot of good ways to find it."

And indeed, I found it. I will give excerpts from one such article in this material. In my opinion, it will turn out to be a good instruction for the practical restoration of old instruments that have long been abandoned to the mercy of fate.

“We took a bunch of old instruments with us and went to the studio (a former church in North Salem, New York) to put them in order. We realized that all it takes is some basic chemistry and a bit of effort to salvage tools that look like they've been on the ocean floor for centuries.", - this was the beginning of an article on the restoration of old rusty trash. But is it really rubbish?

The round head of this figured hammer (in the title photo) looked deader than dead. But as soon as the rust was removed from the metal, the steel touched by rust was polished to a shine, a thin layer of machine oil was applied to the metal and a new handle was added to the hammer, as life completely returned to this thin tool for elegant work.

Method for cleaning a large area of rust. Rusty, wobbly table saw

A 1980s Craftsman table saw bought at a church auction for $80

A metal cutting machine that will stand in an unheated garage, shop or barn will rust sooner or later. Condensation settles precisely on steel and cast iron parts, as they are colder than the surrounding air.

Rust makes it difficult for a piece of plywood to slide across a table that should be smooth and non-abrasive. Because of it, it becomes more difficult to expose the blade or adjust its slope. Bought at a church auction for $80, this 1980s Craftsman table is about to get a second life. Here's how to revive it.

First of all, the saw table was removed from the bed. After that, she was loaded into a Ford F-150 and taken to a warm workshop for further work.

INSTRUMENTS ARE tarnished, and when they are tarnished, they are put aside, and when they are put aside, they begin to rust.

The good news was that the motor ended up with two capacitors, one to start the motor spinning and the other to provide the extra push to start the winding. So more reliable. The electric motor itself, the motor shaft and pulley were in good shape. Before starting the rust work, all dirt, sawdust and cobwebs were removed from the nooks and cavities of the saw.

The work for which everything was started has begun.

For this the rusty surface was first moistened with kerosene- he acted as a solvent and coolant (cutting fluid). Leaving him alone for an hour, they returned with a drill.

To clean off rust, an abrasive nylon brush with aluminum oxide at 240 grit was clamped into the cams of the drill. At low speeds of about 500 (the drill must be with an adjustable speed of rotation), moving back and forth, the brush easily cleaned the rust without damaging the metal surface.

Be prepared for the fact that the removed parts may not fall back into place. This is exactly what happened with the wings that extend the table top - it was not possible to align them with the plane of the table top. They had to be gently tapped until they were in the grooves in the desired position. The main thing here is not to rush.

Don't forget to put all parts back when reassembling. In the case of the saw, we are talking about an electric motor, a new saw blade and other small elements that have been put in their rightful places.

Rust removal method is not for everyone: hydrolysis in the fight against rust from video blogger Mizantrop

How to fix corroded hand tools

Any metal tool can be cleaned from rust and oxides. It doesn't even matter how much rust has penetrated the metal structure.

Here is an example:

To restore a pile of hammer heads and a pair of axes, first remove everything unnecessary from them. The half-rotted parts of the handles and the old handles will no longer be needed. Usually, in order to remove the handle, it is most convenient, holding a hammer or hatchet in a vice, to knock out the rest of the handle with an object of a suitable diameter. Or split the rotten with a sharp object.

Corrosion can be removed with white vinegar. Place the metal to be worked in a plastic container, pour enough white vinegar to submerge the parts.

Leave the parts for several hours or days, depending on the degree of oxidation.

In the second step of cleaning, you will need steel wool. Please note that iron wool has eight grades of abrasiveness: from the most gentle - 0000 # to the most rough - 4 #. The thicker the rust layer, the coarser you should use, ideally reducing the abrasiveness as the rust is removed.

When there is no more rust left, thoroughly rinse the blanks in clean water to wash off traces of vinegar, finally wiping the parts dry.

Surface scratched during rust removal can be sanded down with 100 grit abrasive on a sanding disc.

Finally, the instruments were wiped down with mineral spirits, primed with an anti-corrosion metal primer, and painted with glossy alkyd enamel.

The cutting edges of the axes were sharpened by hand on a series of waterstones used for woodworking tools.

The assembly process was completed by installing the handles and then jamming them.

Restoring a not very rusty knife

Is it possible to restore precision rusted instruments?

The restoration of any composite precision instrument must begin with a thorough disassembly.

For example, the planer in the photo above. Please note that not all parts are rusted. This means that we separate the wheat from the chaff and work only with those details where there is.

Most of the rust was removed with a hand wire brush. Then the metal was sanded with 60 grit coarse sandpaper, then polished with 1000 grit sandpaper.

To make fine polishing less hassle, stick sandpaper on a flat surface and, changing the ends of the part, begin to run it over the paper until the desired shine and evenness appears. As a lubricant, you can drop a couple of drops of mineral alcohol.

PRECISION INSTRUMENTS REQUIRE A CAREFUL APPROACH TO RECOVERY AND ADJUSTMENT

Sharpening the planer knife and polishing the handles complete the restoration work.

Top class restoration

Often come across rusty iron products, crumble in the hands. How to restore iron? How to restore the found rusty iron thing?

Found an interesting method of conservation, the restoration of rusty iron. I will use it soon.

Even if the found object looks more like a large piece of solid rust, do not despair. There is a way to bring the found treasure back to life. This is the restoration of iron in a carbon environment. This is a very simple method available to everyone.
For restoration, you will need an iron box with a bolted lid, crushed charcoal (on which we fry kebabs) and a rustic oven.
So, in order. The find, first of all, must be preserved in the form in which it was discovered with pieces of earth, if you dug it up, and rust. It is not necessary to try to "forcibly" clean it from the earth or from exfoliating rust mechanically or in any other way.
If you fished an item out of a pond, wrap it in bandages like a mummy. This will prevent the metal from flaking as it dries.
In an iron box, let's call it a "reactor", crushed charcoal is poured so that our iron objects do not come into contact with the walls of the reactor. The reactor is completely filled with coal, closed with a lid and placed in a melted oven on a pillow of orange coals and overlaid with firewood on all sides. Pay attention to the temperature regime, the "reactor" should be red-hot.
After about 2 hours, it is necessary to remove the “reactor” from the oven and allow it to cool completely. Please note that only completely dried items are loaded into the reactor.
After the reactor, the objects are cleaned in NaOH alkali (for example, Krot pipe cleaner) and washed in acidified water. If necessary, the restoration procedure in the reactor can be repeated several times.

The method consists in the reduction of rust, that is, iron oxide Fe2O3 to free iron in a carbon medium. Sergey Dmitriev spoke about this method.
http://www.clubklad.ru/blog/article/2399/

FAQ (Frequently Asked Questions)
What is the crystalline form of iron?
I see three possible options (attention, all these are hypotheses and IMHO):
1. Near the core of the find, iron atoms can be very close to each other. After the oxygen atom is detached, the iron atoms are more likely to connect with each other than remain free, since the former is a more stable state, and the outer levels of electrons are in an excited state, which contributes to the formation of new bonds.
2. Near the core of the find, there are such sections of the iron crystal lattices, in which only a part of the bonds are replaced by oxygen atoms. Such fragments cannot be called metallic iron, since they have the properties of an oxide and do not have strength. It is enough to take away oxygen atoms from such lattices so that the former bonds are restored in them and they turn again into metallic iron.
3. Combination of the two previous options.
How will the surface of powdered iron be formed?
Powdered iron will not form a surface, since its very formation is an alternative to crystallization. Apparently, it is formed where the iron atoms are far enough apart to join together in a lattice. Powdered iron will be removed by further cleaning. Near the core of the artifact, the density of iron atoms is much higher. In this region, crystallization of iron is possible if the necessary conditions are present.
Why is the steel not tempered?
At these temperatures, many steel grades must be tempered.
Why is steel not tempered if the encyclopedia says that tempering occurs at such temperatures (depending on the brand)?
I don't have an exact answer to this question. I can put forward only three hypotheses.
1. The first hypothesis refers only to the correctness of the question. Released compared to what state? Compared to factory hardened or compared to pre-process? It makes no sense to compare archaeological iron with factory hardening, because as a result of fatigue and corrosion, this hardening weakens, sometimes to brittleness. Compared to the state of the object before the process, the strength increases significantly. The fact is that at such temperatures there is a refreshment of broken bonds in the cr. steel lattices and recrystallization occurs. Therefore, the object becomes significantly stronger than before the process. So, according to this hypothesis, steel is not tempered because it has lost its original hardening. There is nothing to release, but it becomes stronger, as recrystallization occurs.
2. Another hypothesis. Suppose steel is tempered. At the same time, under these conditions, a process called carburization occurs, that is, surface saturation with carbon, which leads to an increase in strength. Two conflicting processes end up with strength sufficient to withstand some loads, possibly less than factory strength.
3. Third hypothesis. Those steel grades with which experiments were carried out are tempered at higher temperatures than 800C.
Does the heat treatment method you presented allow you to get rid of chlorides?
Ferric chlorides and ferrous sulfates decompose at such temperatures, except for FeCl2. The procedure for removing harmful salts must be carried out, but only at the stage described above.
Why do you call your iron box a reactor?
Because it's a chemical reaction
Is it appropriate to use the term "recovery" for your method?
It is appropriate, because it is based on reactions to detach oxygen atoms, and these are reduction reactions.
Is it appropriate to use the term "restoration" for your method?
It is appropriate, because as a result it is possible to obtain the previous dimensions, shape and movement of mechanisms.

In every house, among household utensils, interior items, there are materials, tools or parts made of metal. They are practical, wear-resistant, but sooner or later they corrode. How to prevent this process? How to treat metal so that it does not rust?

There are several methods that allow you to extend the life of iron parts and objects. The most effective way is chemical treatment. These include inhibitor compounds that coat metal objects with a thin film. It is she who allows you to protect the product from destruction. Such drugs are often used for preventive purposes.

Consider the main methods to prevent corrosion:

mechanical removal of rust;
chemical treatment;
anti-corrosion agents;
folk remedies for rust.

mechanical cleaning

To perform mechanical treatment against corrosion by hand, you must purchase a metal brush or coarse abrasive paper. Items can be processed dry or wet. In the first version, the usual scraping of rust occurs, and in the second, the skin is wetted in a solution of white spirit or kerosene.

It is also possible to carry out mechanical cleaning of rusting materials using hardware, such as:

Bulgarian.

Sander.

Electric drill with a metal brush attachment.

Sandblasting machine.

Of course, you can clean the surface more thoroughly by hand. But it is used in small areas. Hardware materials will speed up the workflow, but they can also harm details. During processing, a large layer of metal will be removed. The best option that will carefully remove corrosion is a sandblaster. Such equipment has its own small drawback - high cost.

When processing objects with sandblasting equipment, the metal surface does not grind off, but retains its structure. A powerful sand jet gently removes rust.

Chemical treatment

Chemicals are divided into two groups:

Acids (the most popular orthophosphoric);
Rust converters.

Acids are often used to mean common solvents. Some of them have an orthophosphorus composition, which allows you to restore rusting material. The way to use the acid is quite simple: wipe the iron or metal from dust with a damp cloth, then remove the remaining moisture, apply a thin layer of acid with a silicone brush on the object.

The substance will react with the damaged surface, leave it for 30 minutes. When the part is cleaned, wipe the treated area with a dry cloth. Wear protective clothing before using chemical rust removers. In the course of work, take care that the composition does not get on your exposed skin.

Orthophosphoric acid has a number of advantages over other compounds. It gently acts on metal objects, removes rust and prevents the appearance of new areas of infection.

Rust converters are applied to the entire metal surface, while forming a protective layer that will further prevent corrosion of the entire object. After the composition dries, you can open it with paint or varnish. Today, a large number of converters are produced in the construction industry, the most popular of them are:

Rust modifier Berner. Designed for processing bolts and nuts that cannot be dismantled.

Rust neutralizer VSN-1. Used in small areas. Neutralizes rusty spots, forming a gray film that can be easily wiped off with a dry cloth.

Aerosol "Zincor". The degreasing composition allows you to restore objects that are in rust, forms a protective film on the surface.

It is a fast acting gel that does not run and removes any type of corrosion.

Converter SF-1. Used for cast iron, galvanized, aluminum surfaces. Removes rust, protects the material after processing, extends its service life up to 10 years.

Most of the anti-corrosion agents consist of toxic chemical compounds. Make sure you have a respirator. So you protect the mucous membrane of the respiratory tract from irritation.

The use of anti-corrosion compounds

Rocket Chemical, one of the leading chemical companies, offers a wide range of anti-corrosion products. But the most effective line of five substances is considered:

long acting inhibitor. Metal products treated with the substance can be outdoors all year round. At the same time, they are protected from any weather influences that provoke a corrosive process.

Protective lithium grease. The material is applied to the surface to protect and prevent rusting. It is recommended for application on door hinges, chains, cables, rack and pinion mechanisms. Forms a protective film that is not washed off by precipitation.

Waterproof silicone grease. Due to its silicone composition, the lubricant is applied to metal surfaces with elements of plastic, vinyl and rubber. Dries quickly to form a thin, sheer, non-tacky finish.

Rust spray. The drug is used to treat hard-to-reach places, designed for deep penetration, protects products from the reappearance of rust. Widely used for anti-corrosion treatment of threaded connections and bolts.

A solution that removes corrosive stains. The composition of the solution includes non-toxic substances. It can be used both for processing building materials and various kitchen utensils. How to make a knife not rust? Feel free to process it with a solution, leave it for 5 hours, then wash it well with a detergent. And the knife is ready for use again.

In the video: rust destroyer WD-40.

Folk remedies

What to do if you are allergic to chemicals, but you need to clean the rust from metal objects? Do not despair, there are many folk remedies that are in no way inferior to factory preparations:

Cilit is a cleaner for plaque and rust in the bathroom and kitchen. This gel is often applied to faucets, faucets, if the knife is rusting or other metal appliances. It is also used to remove corrosion from any iron and metal products. But it should be remembered that its chemical composition can corrode the paint.
A solution of kerosene and paraffin. It must be prepared in a ratio of 10:1. Leave to brew for a day. After we process the objects damaged by rust, leave for 12 hours. Finally, clean the treated area with a dry cloth. This method is suitable for building materials and tools.
Coca Cola against rust. Its alkaline composition corrodes corrosive stains. To do this, immerse the item in a container with a drink or dampen a rag. Leave for a day, then rinse the item under running water.

As you can see, nothing is impossible. Therefore, choose a more acceptable option for yourself in order to return the original look to metal products.