What is the oxidation resistance of copper and tin, and why is the copper tin plated?

Copper oxidizes easily.

General copper connectors, terminals.

Copper bars and other strips are tin plated on the surface to resist oxidation.

Tin is oxidized to produce a layer of tin dioxide, which prevents further oxidation, while copper cannot, it will continue to oxidize. That's right. Electrical conductivity of tin.

It is also good, and the solderability of the workpiece is also increased after tinning. So tin plating.

Generally, the brightness of tin plating is related to the brightener added to it, the bright tin plating solution is more acidic, and the matte tin can be made neutral. There is not much difference between the two types of tin plating.

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Chuangjing tinning machine".

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First of all, copper and tin are different, one is a secondary group element, the other is a main group element, and its oxidation and reduction cannot be compared by position!

Secondly, copper has good conductivity, while tin only forms an oxide film and adheres to the copper surface, which has no effect on conductivity.

Matte tin plating and ordinary tin plating, the former is expensive and resistant to high temperatures.

The surface of copper is tin plated, mainly for solderability and conductivity, but it is not oxidation resistant, and if it is alloy tin, it is a different matter. Bright tin plating has a smooth, shiny effect in appearance. Matte tin tin ion deposition is coarser and unsightly, but the effect is the same.

Copper is susceptible to oxidation in the air.

It produces patina and is oxidized all the time.

The activity of tin in the air is relatively stable.

Let's see what others have to say.

Copper is easily oxidized in the air, and will form patina and will continue to be oxidized, while tin should not be oxidized in the air, and the activity is relatively stable.

Hello, there are several reasons why tinned copper wire is easy to yellow There are usually several reasons for yellowing: 1. The temperature of the tin pot is too high, and the fluidity is large, resulting in too large pinholes in the plating layer, and the copper-tin penetration is fast 2. The tin layer is too thin, and the copper-tin penetration is fast 3. There are too many flux halogen residues, and the pickling of the copper surface is not thorough enough 4. The packaging time is too fast, the heat is not dissipated, and there are too many impurities in the tin pot 5The quality of copper is not up to par, and there are too many miscellaneous seeds because the temperature affects the speed of atomic activity, so the yellow color is faster in hot days than in cold days.

First of all, from my understanding of nickel, nickel forms a dense oxide film on the surface in humid air, which can not only prevent continued oxidation, but also resist the corrosion of alkali and salt solutions, and does not react to the oxidant solution, including nitric acid, and is also more convenient when soldering with solder, and generally the machine should be nickel-plated or chrome-plated under harsh conditions.

The tin dioxide protective film is formed on the surface of tin in the air and stabilized, and the oxidation reaction is accelerated under heating. Tin can also react with sulfur; Tin is stable to water, can be slowly dissolved in dilute acid, and quickly dissolved in concentrated acid; Tin can be soluble in strong alkaline solutions; It will corrode in acidic solutions of salts such as ferric chloride and zinc chloride. It is not easily oxidized by oxygen at room temperature, so it often retains its silver shine. Tin is non-toxic, and people often plate it on the inner wall of copper pots to prevent the copper warm water from producing toxic patina.

Therefore, tinned copper is more suitable for use in places that come into contact with food.

The conductivity should be discussed, if it is used as a low-voltage contact, it is good to plated tin, if it is used as a high-voltage and high-current contact, do not plating anything, or it will be silver-plated. If it is only used as a conductor, it makes no difference, because the conductivity of copper is not said.

Tin plating is mainly to prevent copper from being oxidized, and nickel plating should be more conductive.

1. Of course, the conductivity is good for tin, and its molecular weight is relatively active. 2. The oxidation resistance is still stronger than nickel, if it is tin alloy, tin-nickel, tin-cerium, tin-bismuth, tin-cobalt and other alloys, the oxidation resistance is relatively strong. 3. If you want both good conductivity and oxidation resistance, you can only use tin-plated alloys.

Nickel is better! Nickel is less lively!

Aluminum will be corroded by acid when heated in acid, hydrogen will be released when heated in hydrochloric acid, dilute sulfuric acid and other acids, sulfur dioxide will be released when heated in concentrated sulfuric acid, nitric oxide will be released when heated in dilute nitric acid, and nitrogen dioxide will be released in concentrated nitric acid.

Copper does not react when heated in acids such as hydrochloric acid and dilute sulfuric acid, and reacts with aluminum to release sulfur dioxide in concentrated sulfuric acid, and nitric oxide and nitrogen dioxide are released in dilute nitric acid and concentrated nitric acid like aluminum.

Aluminum is also corroded when heated in alkali, releasing hydrogen.

Copper does not react with bases.

Aluminum is an amphoteric metal, so it can react with both acids and bases. Copper is a basic metal, so it can only react with acids.

In addition, as mentioned earlier, nitric oxide is quickly oxidized into nitrogen dioxide by oxygen as soon as it hits the air.

That's it, all the above chemical equations are omitted, which one won't ask me again. ：）

Pure copper is purple-red, so it is also known as copper, has excellent thermal and electrical conductivity, and its conductivity is second only to silver and ranks second in metal. Copper has excellent chemical stability and corrosion resistance, and is an excellent metal material for electrical engineering.

Copper alloys widely used in classified industries are brass, bronze, and cupronickel. The alloy between Cu and Zn is called brass, of which Cu accounts for 60% 90% and Zn accounts for 40% and 10%.

It has excellent thermal conductivity and corrosion resistance, and can be used as a variety of products.

Instrument parts. Another example is to add a small amount of SN to brass, which is called navy brass, which has a good ability to resist seawater corrosion. A small amount of lubricating PB is added to the brass and can be used as a plain bearing material.

Bronze is the metal material that has been used by human beings for the longest time, and it is an alloy of Cu and Sn. The addition of tin significantly increases the strength of copper, and its plasticity is improved, and the corrosion resistance is enhanced, therefore.

Tin bronze is often used in the manufacture of wear-resistant parts such as gears and corrosion-resistant accessories. Sn is more expensive, and a large number of Al, Si, and Mn have been used to replace Sn to obtain a series of bronze alloys.

The corrosion resistance of aluminum bronze is better than that of tin bronze. Beryllium bronze is the strongest copper alloy, which is non-magnetic and has excellent corrosion resistance, and is a spring material that can compete with steel.