Nickel or chrome which is better. The marriage of the coating is shiny nickel-chrome. For copper and its alloys

05.11.2019

I agree, but there is still formaldehyde.

this is normal
Perhaps I misunderstand the terms, I called this additive a leveler for the reason that its action in the electrolyte allows you to increase the class of surface cleanliness. Compared to galvanizing electrolytes, there are also brighteners, but I have never heard of zinc levelers.

The principle of operation of any brightening additive is microlevelling. That is, at the microcrystalline level, the coating is deposited in the depressions faster than on the protrusions, which actually corresponds to your photo. Another aspect is macro alignment. This alignment in dimensions is an order of magnitude greater than the dimensions of interatomic distances. Macro leveling is not always accompanied by shine. For example, cyanide copper levels well, but the shine is not strong.
From the very beginning of work with this system of brighteners after cleaning with activated carbon, the content of the wetting agent is slightly reduced and a small veil is visible on the Hull cell at medium current densities. Adding 100-150 ml of wetting agent per 1000 l (initial charge 2 ml/l) removes the veil.

This is fine. The wetting agent is adsorbed on coal better than all other additives. I have seen many cases where, after light charcoal treatment for brighteners, there was no need to correct, and there was not enough wetting agent. The veil formed with a lack of wetting agent differs in the form and nature of the formation from the defect according to your photo.
I think they determine additives by liquid chromatography, in any case, in the Atotekh technical instructions for one of their galvanizing processes, HPLC is recommended for determining the content of additives (however, at the level of equipment of most domestic galvanizers, this is more like an evil mockery).

All these cunning devices (-ohafs, -meters) are all good when we are dealing with a pure electrolyte that works strictly according to the regulations. Another thing is when the electrolyte is dirty and / or treated with peroxide. In general, the easiest and most direct way to spoil the electrolyte is to treat it with peroxide. Peroxide does not completely oxidize all organic matter. Some of the organic matter is partially oxidized, then partially reduced at the anode. And these processes continue cyclically, giving more and more new organic derivatives. Therefore, no one knows how many organic compounds actually become in such a bath and what is their effect on the main organic components, and there is no point in trying to calculate.
That is, you determined the amount of the main organic matter using a graph. What's next? How to quantitatively take into account the influence of secondary organics? Therefore, no matter how tricky the device is, anyway, the surest method is the poke method using the Hull cell and / or a curved cathode. Peroxide for nickel is such a "hook" from which it is difficult to get off. Because if you poured peroxide once, then the products of partial oxidation / reduction will constantly accumulate and transform (quickly or slowly, but constantly). As a result, peroxide will have to be added at regular intervals. Well, if you yourself are to blame for using peroxide (do not follow the degreasing, washing, do not wash the bags, etc.). But, if you do everything right, and the addition of peroxide is included in the regulations, then it's like buying a new car, in the engine of which, according to the instructions, you need to add 1 liter of oil per 500 km.
yes, you can right in the bath
I agree, but if once a week it is dumped into treatment plants, then it needs to be diluted every 50 times, otherwise the electrocoagulator will not clean up. Could you tell me, please, how often, on average, do your clients change this activation bath?

Once a week, we rarely change anything other than washing baths. It may have to be changed once a month, maybe once every six months. There is little hexavalent chromium. You can manually restore hexavalent chromium bisulfite and then drain into the main drains.
Unfortunately, we are also not as close to civilization as we would like. We try to convince to change the chemical degreasing every six months, but cyanide electro-degreasing saves us.

Do you do coatings for European auto brands? As far as I know, if the German shop covers, for example, for a BMW conveyor, then on Friday evening all the surface preparation and washing baths are drained. Everything up to galvanic baths. Penalties for downtime and marriage when working for the assembly line are very high.
Regarding NFDS, if you don’t change it once a week or a maximum of two, then there’s no point in taking a bath. There are such small concentrations that everything will go away with the details by the end of the week you will get dirty water.

Yes, but from our practice, the bath is changed no more than once a month (as a rule, less often). More precisely, they change upon the fact of the occurrence of problems.
Honestly, I don’t know what to answer, because no one has ever corrected it. Its working concentration is only 2.6 g/l. I don't think there is anything accumulating there, try it if there is a problem with the amount of sewage.

I don't think so either. But our bathroom is being renovated. They correct because they don't change as often as Yefim's.

Thanks for the answer, I have not seen such a radical approach to peroxide treatment - thanks again for that. As for the wetting agent - yes, the problem is not in it, I remember writing - there are no spots on nickel when removing chrome. And yes, when undercorrected with a wetting agent, the borders of the spots are blurry, but here they are literally "minted".

Chromium is a refractory, very hard metal with extraordinary resistance to corrosion. These unique qualities provided him with such a high demand in industry and construction.

The consumer is most often familiar not with chrome products, but with objects coated with a thin layer of metal. The dazzling mirror shine of such a coating is attractive in itself, but it also has a purely practical significance. Chrome is resistant to corrosion and is able to protect alloys and metals from rust.

And today we will answer questions about whether chromium is a metal or non-metal, and if it is a metal, then which one: black or non-ferrous, heavy or light. We will also tell you in what form chromium occurs in nature, and what are the differences between chromium and other similar metals.

To begin with, let's talk about what chromium looks like, what metals it contains, and what is the peculiarity of such a substance. Chromium is a typical silver-bluish metal, heavy, exceeds in density, and also belongs to the category of refractory - its melting and boiling points are very high.

The element chromium is placed in the secondary subgroup of the 6th group in the 4th period. It is close in properties to molybdenum and tungsten, although it also has noticeable differences. The latter most often exhibit only the highest oxidation state, while chromium exhibits a valency of two, three, and six. This means that the element forms many different compounds.

It was the compounds that gave the name to the element itself - from the Greek paint, color. The fact is that its salts and oxides are painted in a wide variety of bright colors.

This video will tell you what chrome is:

Features and differences compared to other metals

In the study of metal, two properties of a substance aroused the greatest interest: hardness and refractoriness. Chromium is one of the hardest metals - it ranks fifth and is inferior to uranium, iridium, tungsten and beryllium. However, this quality turned out to be unclaimed, since the metal had properties that were more important for industry.

Chromium melts at 1907 C. It is inferior to tungsten or molybdenum in this indicator, but still belongs to refractory substances. True, impurities strongly influence its melting point.

Like many corrosion-resistant metals, chromium forms a thin and very dense oxide film in air. The latter covers the access of oxygen, nitrogen and moisture to the substance, which makes it invulnerable. The peculiarity is that he transfers this quality to his alloy with: in the presence of an element, the potential of the a-phase of iron increases and, as a result, steel in air is also covered with a dense oxide film. This is the secret to the durability of stainless steel.
Being a refractory substance, the metal also increases the melting point of the alloy. Heat-resistant and heat-resistant steels necessarily include a proportion of chromium, and sometimes very large - up to 60%. The addition of both and chromium has an even stronger effect.
Chromium forms alloys with its brothers in the group - molybdenum and tungsten. They are used for coating parts where particularly high wear resistance at high temperatures is required.

The advantages and disadvantages of chromium are described below.

Chrome as metal (photo)

Advantages

Like any other substance, metal has its advantages and disadvantages, and their combination determines its use.

An unconditional plus of the substance is corrosion resistance and the ability to transfer this property to its alloys. Chromium stainless steels are of great importance because they have solved a number of problems in the construction of ships, submarines, building frames and so on at once.
Corrosion resistance is provided in another way - they cover the object with a thin layer of metal. The popularity of this method is very high, today there are at least a dozen ways of chrome plating in different conditions and for different results.
The chromium layer creates a bright mirror shine, so chrome plating is used not only to protect the alloy from corrosion, but also to obtain an aesthetic appearance. Moreover, modern chromium plating methods make it possible to create a coating on any material - not only on metal, but also on plastic and ceramics.
Obtaining heat-resistant steel with the addition of chromium should also be attributed to the advantages of the substance. There are many areas where metal parts must work at high temperatures, and iron itself does not have such resistance to stress at temperature.
Of all the refractory substances, it is the most resistant to acids and bases.
The advantage of the substance can be considered its prevalence - 0.02% in the earth's crust, and a relatively simple method of extraction and production. Of course, it requires energy consumption, but it cannot be compared with a complex one, for example.

disadvantages

The disadvantages include qualities that do not allow full use of all the properties of chromium.

First of all, this is a strong dependence of physical, and not only chemical properties on impurities. Even the melting point of the metal was difficult to establish, since in the presence of an insignificant fraction of nitrogen or carbon, the indicator changed noticeably.
Despite the higher electrical conductivity compared to, chromium is much less used in electrical engineering and its cost is quite high. It is much more difficult to make something from it: the high melting point and hardness significantly limit the application.
Pure chromium is a malleable metal, containing impurities becomes very hard. To obtain at least a relatively ductile metal, it has to be subjected to additional processing, which, of course, increases the cost of manufacturing.

metal structure

The chromium crystal has a body-centered cubic lattice, a=0.28845 nm. Above a temperature of 1830 C, a modification with a face-centered cubic lattice can be obtained.

At a temperature of +38 C, a second-order phase transition is recorded with an increase in volume. In this case, the crystal lattice of the substance does not change, but its magnetic properties become completely different. Up to this temperature - the Neel point, chromium exhibits the properties of an antiferromagnet, that is, it is a substance that is almost impossible to magnetize. Above the Neel point, the metal becomes a typical paramagnet, that is, it exhibits magnetic properties in the presence of a magnetic field.

Properties and characteristics

Under normal conditions, the metal is quite inert - both due to the oxide film and simply by its nature. However, when the temperature rises, it reacts with simple substances, and with acids, and with bases. Its compounds are very diverse and are used very widely. The physical characteristics of the metal, as mentioned, strongly depend on the amount of impurities. In practice, they deal with chromium with a purity of up to 99.5%. are:

melting temperature- 1907 C. This value serves as the boundary between refractory and ordinary substances;
boiling temperature- 2671 C;
Mohs hardness – 5;
electrical conductivity– 9 106 1/(Ohm m). According to this indicator, chromium is second only to silver and gold;
resistivity–127 (Ohm mm2)/m;
thermal conductivity substances is 93.7 W / (m K);
specific heat–45 J/(g K).

The thermophysical characteristics of the substance are somewhat anomalous. At the Neel point, where the volume of the metal changes, its coefficient of thermal expansion sharply increases and continues to grow with increasing temperature. The thermal conductivity also behaves abnormally - it drops at the Neel point and decreases when heated.

The element is among the necessary: in the human body, chromium ions are participants in carbohydrate metabolism and the process of regulating insulin release. The daily dose is 50-200 mcg.

Chromium is non-toxic, although in the form of a metal powder it can cause irritation to the mucous membranes. Its trivalent compounds are also relatively safe and are even used in the food and sports industries. But hexavalent for humans are poison, cause severe damage to the respiratory tract and gastrointestinal tract.

We will talk further about the production and price of chromium metal per kg today.

This video will show if the finish is chrome:

Production

In a large number of different minerals - often accompanies and. However, its content is insufficient to be of industrial importance. Only rocks containing at least 40% of the element are promising, so there are few minerals suitable for extraction, mainly chromium iron ore or chromite.

The mineral is mined by the mine and quarry method, depending on the depth of occurrence. And since the ore initially contains a large proportion of the metal, it is almost never enriched, which, accordingly, simplifies and reduces the cost of the production process.

About 70% of the mined metal is used for alloying steel. Moreover, it is often used not in its pure form, but in the form of ferrochrome. The latter can be obtained directly in a shaft electric furnace or a blast furnace - this is how carbon ferrochromium is obtained. If a low carbon compound is required, the aluminothermic method is used.

This method produces both pure chromium and ferrochrome. To do this, a charge is loaded into the smelting shaft, including chromium iron ore, chromium oxide, sodium nitrate and. The first portion, the ignition mixture, is ignited, and the rest of the charge is loaded into the melt. At the end, a flux is added - lime, to facilitate the extraction of chromium. Melting takes about 20 minutes. After some cooling, the shaft is tilted, slag is released, returned to its original position and tilted again, now both chromium and slag are removed into the mold. After cooling, the resulting block is separated.
Another method is also used - metallothermic melting. It is carried out in an electric furnace in a rotating shaft. The charge here is divided into 3 parts, each differs in composition. This method allows you to extract more chromium, but, most importantly, it reduces consumption.
If it is required to obtain a chemically pure metal, they resort to a laboratory method: crystals are planted by electrolysis of chromate solutions.

The cost of chromium metal per 1 kg fluctuates markedly, since it depends on the volume of rolled metal produced - the main consumer of the element. In January 2017, 1 ton of metal was valued at $7,655.

Application

Chrome plating

Chrome plating can be divided into 2 categories:

functional- its purpose is to prevent corrosion of the product. The layer thickness is greater here, so the chrome plating process takes longer - sometimes up to 24 hours. In addition to the fact that the chromium layer will prevent rusting, it significantly increases the wear resistance of the part;
decorative- Chrome creates a mirror-shiny surface. Car enthusiasts and motorcycle racers rarely turn down the opportunity to decorate their car with chrome parts. The decorative coating layer is much thinner - up to 0.0005 mm.

Chrome plating is actively used in modern construction and in the manufacture of furniture. Mirrored fittings, bathroom and kitchen accessories, kitchen utensils, furniture parts - chrome-plated products are extremely popular. And since, thanks to the modern chromium plating method, a coating can be created on literally any object, several atypical methods of application have also appeared. So, for example, chrome-plated plumbing cannot be attributed to trivial solutions.

Chrome is a metal with very unusual properties, and its qualities are in demand in the industry. For the most part, its alloys and compounds are of interest, which only increases the importance of the metal for the national economy.

The video below will tell about the removal of chrome from metal:

Chrome and Nickel

In their purest form, these cousins» are found only as coatings, and the first nickel-plated things date back to the 19th century. Chrome began to be used later. However, the bulk of their extraction is spent by industry not at all on coatings, but for the production of alloyed steel - stainless, heat-resistant, chemically passive, etc.

Nickel acquired its melodious name a long time ago: in medieval Europe, sometimes they came across an ore very similar to iron, with an unpleasant exception - it was not possible to smelt metal from it under any circumstances.

Of course, the fiasco was attributed to the machinations of malicious kobold dwarfs (hence - cobalt) and devils (in Western Europe one of the common names for the devil is Nick). Then, when it turned out that the ore did not contain iron at all, but a completely different metal, it was named in memory of past delusions.

Nickel plating has gained its greatest popularity among household utensils - from kerosene lamps and samovars to beds and bicycles (the automotive world joined later) - due to its durability and nobility of appearance. It is quite resistant to water in all its manifestations, but only on condition that the film is applied neatly and correctly, otherwise we will see a common picture of surface ulceration with multiple cavities and shells of various shapes and sizes - from microscopic to the size of a grain of rice. This happens when the subject long time kept damp. The ubiquitous moisture, penetrating to iron through pores invisible to the eye, forms local centers of corrosion. If the damage is not catastrophic, it is enough to gently grind the product with fine finishing sandpaper (the so-called “micron” or “zero”) and somehow preserve the result. You can rub the surface with machine oil from time to time or cover it with a thin layer of durable colorless varnish (preferably tsapon) - it all depends on specific situation. Unprotected metal stored in room conditions, of course, it will no longer be covered with a rash, but the exposed iron will darken, which will not happen with oil or varnish.

A less radical way is to soak the object in kerosene. The latter, having a strong alkaline reaction and amazing penetrating power, will gently dissolve the rust at its place of residence.

When the nickel film has peeled off in a continuous patch, which is not uncommon due to poor-quality preparation of the base, it remains to carry the product to the nearest factory or car repair shop, where there is a working galvanizing section.

A good nickel plating, although retaining its original integrity, fades over time, twitching with a bluish haze. In this case, it is simply polished, although the former brilliance usually cannot be returned. Older manuals recommend removing blue and dull deposits with a 1:1 solution of sulfuric acid in alcohol, but this is too much. You can see an example of the restoration of a nickel-plated object (kerosene lamp) on one of the colored inserts.

Chrome is much harder than nickel, and its films are stronger, do not tarnish, but pitting finds food here too. The methods of dealing with it are similar.

The presented training courses are to help beginners who love decorative chrome plating of chemical plating. The purpose of the training courses is to fill the gap of systematized knowledge on the topic of decorative chromium plating by chemical plating and make this technology more accessible to beginners. The presented texts, photos and videos are the author's personal experience, which does not claim to be professional. The author of the training courses is not responsible for possible injuries, burns and poisoning associated with the use of hazardous chemicals such as concentrated acids, alkalis, ammonia. Therefore, do not neglect protective equipment and care when handling reagents.

Decorative chrome plating, chemical plating, all these terms and processes were not known to me not so long ago. Dear friend, since you are on this site, it means that you are also hooked on this topic and you are looking for answers to questions. Questions that haunt you ... How to make any thing with a mirror shine? However, the answers are very close, just sit back and carefully look at the contents of this page. In fact, this is a technology of mirror silvering by spraying. This is also called chemical silver plating. So, there is no talk of real chrome plating, but the name has taken root and is misleading. When I started collecting information on this topic, I was faced with the fact that there is a lot of information on the topic of decorative chrome plating, but to my amazement, nothing specific. All around, yes. Here are a lot of videos where garage craftsmen, as well as pros selling equipment, are happy to demonstrate the process of transforming a nondescript detail into a product sparkling with a mirror. But step by step, all the technology, no one lays out for nothing, inflating a big, big secret out of it ... There are many questions, but the answers are paid ...

After reading a mountain of sites and textbooks, a mess formed in my head, probably, like many others, faced with such a task. So that a clear picture appeared in my head, I decided to immediately practice. It is clear that without chemistry, you will not learn how to chemistry, so I began to search and bypass the offices that sell chemistry. First of all, I asked the price for silver nitrate, since this is the most expensive component. Decide on a supplier. For bought on the list of chemicals, dishes and other necessary utensils. The question arose how to try without equipment. The solution is simple - manual household sprayers. The search and experiments began to create a miracle solution of silvering and application technology. And then one interesting detail about the preparation of chemistry emerged ... All the available information posted on the Internet is a copy of the materials of mainly Soviet textbooks on the topic of chemical metallization ...

Draining a fair amount of silver (respectively, money) to the ground in the process of unsuccessful experiments. Came for a pretty good recipe. In other words, everything is in order. This is the end of the lyrical introduction and the beginning of a short course on how to make a thing a mirror. I will not ship the theory, I will leave it for independent study. There is a lot of this goodness on the Internet. Let's get straight to the point. Short, concise, to the point. I will show you on the example of silvering a glass cup.

Technology of chemical metallization with silver, sputtering method

To get the first experience of silver coating on the surface, by spraying, you should learn the technology. And to put it simply - the sequence of actions.

I will list them:
1. preparation of solutions
2. surface preparation
3.surface activation
4. plating

I will give a brief overview of the above points. To get the big picture in my head. Let's take a closer look at the lessons of the same name.

Preparation of solutions

To prepare solutions you will need:

stannous chloride
Hydrochloric acid
Nitrate silver
Sodium hydroxide
Ammonia
Glucose
Formalin
Distilled water

We buy chemicals in stores or warehouses of medical equipment.

From the equipment you will need:

Measuring cup for 1 liter
Measuring cup for 200 - 250 ml.
100 ml bottles - 3 pcs.
Disposable syringes for 5, 20 and 50 cubes
Disposable cups 50 ml
Disposable knives and spoons
Electronic scales, measuring up to 200 gr.

We buy equipment in household goods and pharmacies.

You can start preparing solutions with a solution of tin dichloride. Required to activate the surface. For this we take:
1. Stannous chloride
2. Hydrochloric acid
3. Distilled water

The next solution is "silver". We take:
1. Nitrate silver
2. Sodium hydroxide
3. Ammonia
4. Distilled water

Surface preparation

To prepare the surface, it must be degreased. To do this, you can prepare a simple degreasing solution, consisting of:
1. Sodium hydroxide
2. and water temperature 40-60 degrees

The surface should be carefully wiped with a sponge moistened with a degreasing solution. Then wash off the solution with distilled water, wiping, but with another sponge. A sign of good degreasing is the wettability of the surface with water. That is, watering with water, the entire surface should be covered with a water film. If there are dry islands, silver will not stick there.

Surface activation

In order for the metallization reaction to take place precisely on the surface, and not in the sink, it is necessary to activate it, as they say. That is, to help the silver stick to the surface. It is for this that we take a solution of tin dichloride. The time of the procedure is very important here. Water the part with a solution of stannous chloride for one minute. Then pour with distilled water - three minutes. This is a very important stage and non-observance of the surface treatment time leads to marriage, that is, to a waste of time, effort and money. Watering should be as even as possible so that all areas of the surface are equally moistened.

Metallization

This is the most interesting stage of obtaining a mirror film of silver on the surface. Actually for the sake of this, the whole idea. To do this, you need only a silver solution and a reducing agent solution. This will require some skill, which comes with experience. It is necessary to spray so that the solutions mix on the surface and nothing else. And sprayed in equal amounts by volume. Having reached such accuracy, we get an ideal mirror, without defects.

In addition, you should be aware that the mirror film not durable and in order for it to retain its properties, it should be protected with a layer of transparent or tinted varnish. But that's a completely different story.

The process of decorative chrome plating can be repeated even at home in the bathroom without buying expensive equipment with minimal cost. You can learn more about the technology by studying the email course Technology of decorative chrome plating and trying it in practice, it will allow you to decide whether it is worth moving further in this direction.

What does the email course "Technology of decorative chrome plating" consist of?

Chemistry and equipment.
Recipes and preparation of solutions for silvering.
Surface preparation for silver application.
Metallization

This knowledge and skills cost me more than 40 thousand rubles and several months of time. The information is provided to you free of charge, in a concise form and to the point, in the form of 5 short lessons. In order to receive an email course, leave a request by filling out the form located above, under the video. Enter your real name and email address, then click the "Submit Application" button. After that, you will be taken to a page with instructions to confirm your application. Read it carefully and then go to your mailbox. You should receive an email confirming your application. Click on the confirmation link, and almost immediately you will receive the first letter of the Decorative Chrome Technology course, where you will receive comprehensive information on how to start using the technology.

Chrome, Nickel, Blued? Chrome and nickel difference

Nickel - Chemist's Handbook 21

from "Corrosion Theory and Corrosion-Resistant Structural Alloys"

Pure nickel as a structural material is now used to a limited extent. From the chemical industry, it is almost completely replaced by corrosion-resistant steels. Occasionally, nickel is used in some industrial and laboratory installations, mainly due to its extremely high resistance to alkalis. Nickel is widely used for protective and decorative (mainly electroplated) coatings on iron and steel, as well as copper alloys (in order to increase their stability in atmospheric conditions). There is also information about the use of nickel-clad iron in the chemical industry. Nickel is slightly more electronegative than copper (see Table 2), but it is noticeably more positive than iron, chromium, zinc, or aluminum. The equilibrium potential of nickel is -0.25 V, the stationary potential is 0.5 N. Na l-0.02 V. Unlike copper, nickel has a noticeable tendency to pass into a passive state (see Chapter II). These circumstances largely determine the corrosion characteristics of nickel. In oxidizing environments, nickel alloys with chromium additives are more easily passivated and acquire corrosion resistance in more acidic oxidizing environments compared to pure nickel. It is also worth emphasizing the excellent resistance of nickel to alkalis of all concentrations and temperatures. Nickel, along with silver, is considered one of the the best materials for melting alkalis. Nickel can also impart this property to a large extent to high-nickel steels and cast irons. Nickel is very stable in solutions of many salts, in sea water and other natural waters, and in a number of organic media. Therefore, it still finds some use in the food industry. Under atmospheric conditions, nickel is quite stable, although it tarnishes somewhat. However, if a significant amount of SO2 is present in the atmosphere, then more noticeable atmospheric corrosion of nickel is observed. The most widely used of copper-nickel alloys, in addition to the cupronickel-type alloy, is an alloy based on nickel with copper of the monel type, containing about 30% Cu and 3-4% Fe + Mn, and sometimes also a little Al and Si. This alloy, in comparison with pure copper and nickel, has an increased resistance to non-oxidizing acids (phosphoric, sulfuric and hydrochloric and even medium concentrations of HF), as well as in solutions of salts and many organic acids. The corrosion resistance of monel, as well as copper and nickel, decreases markedly with increasing aeration of the medium or the access of oxidizing agents. These alloys are characterized by increased anti-corrosion, high mechanical and technological properties and relatively high strength. They are well rolled, cast, processed by pressure and cutting. In the rolled condition Ov 600-700 MPa and 6=40-45%. These alloys are a good structural material for some chemical apparatus operating in low concentrations of h3SO4 and HC1, as well as in acetic and phosphoric acids. It should also be noted that the Monel-K alloy, which is close in terms of corrosion characteristics, has a composition, % 66 Ni 29 u 0.9 Fe 2.7 Al 0.4 Mn 0.5 Si 0.15. It is characteristic of this alloy that it undergoes hardening during aging. In this state, it has high (for non-ferrous metals) mechanical properties av=1000 MPa at 6=20%. Monel-K is used for the manufacture of machine parts with a significant power load, for example, parts centrifugal pumps, as well as for bolts, if it is impossible to use steel due to its insufficient resistance or the danger of hydrogenation. The scarcity of the initial components - nickel and copper greatly limits the distribution of alloys based on them. Alloying nickel with molybdenum (over 15%) gives the alloy a very high resistance to non-oxidizing acids (see Fig. 86). The widest practical use find alloys of a similar type, the composition of which (% by weight) is given below. The composition of Hastelloy C, in addition, sometimes includes 3-5% W. All these three alloys are also quite stable in most organic media, alkalis, marine and fresh water. Along with high chemical resistance, they have great strength and are a valuable material for chemical machine and air industry. They can be obtained in the form of strips, plates, pipes, wires, they are able to be welded, cast. Their use is limited by high cost and some technological difficulties (forging, rolling). Nickel-chromium alloys (nichromes) are heat-resistant and highly heat-resistant and acid-resistant material. LiCr alloys containing no more than 35% Cr are solid solutions based on the y-lattice of nickel (austenite). Since chromium and the chromium-rich a-phase with the usual content of interstitial impurities (C, N, O) are very brittle, the content of 35% Cr should be recognized as the limit for obtaining ductile alloys. However, alloys containing more than 30% Cr, in practice, are still too hard, and their processing, even at elevated temperatures, is difficult. It has been established that the purer the alloy in terms of other impurities, mainly interstitial impurities (C, N, O), the higher the chromium content is permissible without fear of worsening the possibility of technological processing of the alloy. If it is necessary to obtain very plastic nichromes (for example, for drawing wire 0.01-0.3 mm), the chromium content in silave usually does not exceed 20%. Alloys containing 25-30% (sometimes up to 33%) Cr are used for the manufacture of thick wire and strips. They are characterized by maximum heat resistance, along with high heat resistance and an extremely slow grain growth rate at elevated operating temperatures. Therefore, nichromes, unlike heat-resistant alloys of the Fe-Cr-A1 system (limped), do not noticeably lose their plasticity after working at high temperatures. In order to partial replacement nickel, improve machinability and technological properties at high temperatures, sometimes up to 25-30% Fe or more (ferro-chromiums) are introduced into these alloys. phosphorus and even carbon are considered harmful impurities reducing the ductility of the alloy. The presence of not more than 0.02-0.03% 5, 0.05% P in the best grades of vacuum melting nichrome up to 0.04-0.07 and in ordinary technical nichrome up to 0.2-0.3% C. Manganese used as a deoxidizer, in addition, it contributes to grain refinement during primary crystallization and can be allowed in alloys such as nichrome up to 2% (sometimes higher). The aluminum content is usually not higher than 0.2% (in special alloys up to 1.2%), silicon is not higher than 1%, molybdenum is sometimes specially introduced into nichrome (in an amount of 1-3, and sometimes up to 6-7%) to increase corrosion resistance to chloride ions, as well as heat resistance.

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Chrome, Nickel, Blued?

People's Commissar 02-05-2011 13:01

If the topic is in the wrong section, then please move it to the right one, because I did not find a suitable one.

Gentlemen of the forum, tell me who is in the know. I'm going to get a Flaubert 4mm Cuno Melcher Magnum revolver. There is a choice: Chrome, Nickel, Burnished. Since the search on the Internet did not give results, I decided to turn to knowledgeable people: which is better to take??? What are the pros and cons, which is more durable and corrosion resistant ???

P.S.: The difference in price is not scary, only quality is of interest.

Groz 02-05-2011 15:16

This is not for wearing, my IMHO is blued. The front cut of the drum will not be so hemorrhagic to clean. But stainless steel is better for wearing.

Idalgo 02-05-2011 17:26

I'm for nerd.

Foxbat 03-05-2011 12:53

The nickel is nice, but it's still a plating, and soft. In addition, by itself it does not protect against corrosion, it is porous. If it is not made quite right, it will rust, which is very noticeable on the mass of cheap edged weapons of the late 19th and early 20th centuries, when they were addicted. Black spots of corrosion appear on it, especially if it is damaged.

No matter how you throw it, you can’t imagine better stainless steel!

By the way, chrome is a very rare coating for weapons, I have never seen it on a mass scale (I’m not saying that it doesn’t happen, I just haven’t seen it), only on an expensive sports one.

vovikas 05/03/2011 14:34quote: By the way, chrome is a very rare coating for weapons, I have never seen it on a mass scale (I’m not saying that it doesn’t happen, I just haven’t seen it), only on an expensive sports one. wah! I have my neshchyasny tanfogle 1911 in chrome (corrected - it was written in nickel). matte. but. it would be better to be in "no way". scratched coating after a police check - yes, well, his nafik. accidentally put "no" - again scratches. so my conclusion is only black or stainless steel, but this is not accessible to everyone at a price (I'm talking about stainless, kneshna) ... filin 03-05-2011 15:36 quote: chrome is a very rare coating for weapons Here we are again "ahead of the rest "... A huge amount was covered with chrome anyhow. It is quite common to cover with black chrome. Now both expensive and medium-priced hunting weapons are covered with black chrome. As for pistols - Izhmekh quite often sins with white chrome. It looks clumsy. And if still put on a chrome-plated PM a "golden" fuse, trigger, trigger and slide delay (sputtering with titanium nitride) - it turns out a gypsy's dream ... vovikas 03-05-2011 15:42quote: it turns out a gypsy's dream ... that's just "for the gypsies" nada!!! I serve a gypsy camp (in the line of technical equipment, don’t think it’s wrong). and their baron goes to shoot at our shooting range. a perfectly adequate man. and squints with the right eye at my 92nd Beretta, black, no frills! almost all sets of "gold" parts for the PM went there. People's Commissar 03-05-2011 19:25

Today I specified: there is nickel, blued. Chromed versions of this model do not exist, consequently, the choice is narrowed: Blued or nickel-plated?

03-05-2011 19:37

2ts don't bother. according to anyone, this is not steel, but silumin, and therefore everything else is just coloring.

quas 05/03/2011 20:16quote:Originally posted by filin:so almost all sets of "gold" parts for PM went there. Very practical cover, durable. :-)zav.hoz 04-05-2011 16:58

If you choose from nickel-plated and "blued" according to silumin, then definitely take nickel. "Burning" is peeling off once or twice. But chrome - it would be much more serious. I have a 1911 (steel) frame that has a matte Hard-Chrome finish - looks good, does not scratch and almost does not get dirty.

filin 05/04/2011 18:00quote: But chrome - it would have been much more serious. It depends on who does it. , which M.T. Kalashnikov called "punches". Marxist 04-05-2011 21:54

Chrome coating is inherently porous, and the porosity is highly dependent on the modes (the faster the coating is, the worse it is if sclerosis does not fail). Porosity is unimportant, for example, in hydraulic equipment (all the same, everything is in oil), but it is critical in weapons, where any aggressive muck accumulates in micro-techinka. Moreover, it rusts under the chrome, at first it is not visible, and when it comes out, it is too late to drink Borzh. Because expensive weapons (trunks anyway) are usually not chrome plated, but are either made entirely of stainless steel or traditional materials. And nickel plating must be distinguished between electrochemical (electroplating, like chromium) and chemical - smoother (there is no increase in current density on microroughnesses and growth of coating material on them), possibly not porous (I will not say), can be done at home.

People's Commissar 05-05-2011 22:08quote: If you choose from nickel-plated and blued according to silumin, then definitely take nickel. "Burning" is peeling off once or twice. But chrome - it would be much more serious. I have a 1911 (steel) frame that has a matte Hard-Chrome finish - looks good, does not scratch and almost does not get dirty.

No, not silumin (except for the drum).

vovikas 05-05-2011 22:37quote: No way, not silumin oh-oh! ok lumin!!! Idalgo 05-05-2011 23:03

Nerzhu need to take. Ideal for a revolver.

05-05-2011 23:13

Yes, no nerves in this version! kuno does nothing of the sort. alpha does. but only in serious calibers. so take black and tint as you wear.

Idalgo 05-05-2011 23:24quote:Originally posted by vovikas:yes, no nerves in this version! Spraying nah.vovikas 05-05-2011 23:27quote: Then of course .. blued, it is not blued. paint or something else is applied to the alloy. it's not steel!map 05-05-2011 23:33

I am for a slingshot ... with blued steel balls ...

It is not for nothing that slingshots were banned in Germany, and Flauberts were left ...

zav.hoz 05-05-2011 23:49quote:Originally posted by map:Slingshots were banned in Germany for a reason. When was it banned? At masses, I seemed to see them, although I was not at all interested.

And as for aluminum - the coating is most likely oxidation, it different colors do. It is not erased by hand, but with a screwdriver or a rusty carnation - for one or two!

Idalgo 05-05-2011 23:55

Well, nah, such happiness, if you don’t even bury gun blue. You do what you want, but I wouldn't take it.

gotmog 06-05-2011 10:53

If the alloy is aluminum, then the black coating is most likely obtained by anodizing. There, depending on the composition of the electrolyte, it is possible to obtain the desired color, in addition, the oxide film obtained during anodization is easily colored even with aniline dyes. May fade in places over time. Oxidized aluminum is usually gray-green in color. Nickel plating is chemically very strong, but thinner than electrolytic. But to cover something with black chrome - this is fucked up how to have sex - too capricious process. Among other things, the coating on aluminum alloys can be applied by gas-plasma spraying, and here the composition of the coating is limited only by the imagination of the "sprayers"

Idalgo 05/06/2011 12:03 pm quote: Originally posted by DIDI: He just didn't see the "correct gypsy" Beretta. Fuck.. give me two!!! Paul! Can you send yours for engraving? I want, Schaub like a gypsy baron!!! People's Commissar 06-05-2011 13:09

so, I take black (either blued, or some other crap). Thanks everyone for the info.

Dear admins, do not close the topic yet, because there are no similar topics on the Hansa, and if anyone needs anything, let them discuss it here, thank you in advance.

map 06-05-2011 19:59

[B] When was it banned? At masses, I seemed to see them, although I was not at all interested.

Two or three weeks ago, there was information on TV: a Lufthansa pilot was sentenced to 1.5 years for importing two slingshots and ammunition of steel balls to them into Germany ...

4erepaha 07-05-2011 16:05

Two or three weeks ago, there was information on TV: a Lufthansa pilot was sentenced to 1.5 years for importing two slingshots and ammunition of steel balls to them into Germany ...)