What are the causes of rust on metal surfaces How can you effectively prevent metal from rusting?

In contact with oxygen and water in the air.

Commonly used methods to prevent iron rusting are:

1) Forming alloys to change the internal structure of iron For example, adding chromium, nickel and other metals to ordinary steel to make stainless steel greatly increases the rust resistance of steel products

2) Covering the surface of iron products with a protective layer is a common and important way to prevent rust of iron products According to the different components of the protective layer, it can be divided into the following types:

a. Coating the surface of iron products with mineral oil, paint or firing enamel, spraying, etc. The machine is often coated with mineral oil, etc

b Plating a layer of metal that is not easy to rust by electroplating, hot plating and other methods on the surface of steel, such as zinc, tin, chromium, nickel, etc

c. Use chemical methods to generate a dense and stable oxide film on the surface of iron products to prevent rust of iron products

3) Keeping the surface of iron products clean and dry is also a good way to prevent iron products from rusting

If none of the above helps you, then you can try wrapping it in plastic film to see how it works.

We hope you find the following precautions helpful:

1.Oil rust prevention, this method is too greasy and polluting, not only not beautiful, but also the rust prevention effect is not ideal. The anti-rust method of unclean oil is less effective than desiccant and traditional paper packaging, and the cost is higher.

2.Anti-rust paper: Anti-rust paper is an economical and environmentally friendly anti-rust packaging material, which is used for the packaging, transportation and storage of iron or non-metallic parts with small volume; The anti-rust effect is relatively fast and simple to use.

It has the best moisture-proof, anti-rust and anti-corrosion functions. It also has the characteristics of long anti-rust time, safe use, beautiful packaging and low cost, and has been widely used at home and abroad, becoming an indispensable anti-rust material for industrial products and parts packaging, and is very suitable for anti-rust between processes and warehousing in the machining industry.

3.Anti-rust film anti-rust: (characteristics are the same as above).

Adopt paint protection or wax spraying to prevent rust: Wax spraying is to spray a layer of wax protective film on the metal surface to isolate the metal surface from moisture, so as to achieve the purpose of rust prevention. This method is simple to use, needs to be cleaned with hot water when removed, and is a safe and environmentally friendly disposable anti-rust material.

In addition to the above methods, the iron storage environment should be kept dry, and the humidity should not be higher than 50%.

In contact with oxygen and water in the air. The principle of effective rust prevention is to isolate air and water. The methods are oiled, painted, chromed, etc.

The main factors that cause metal rust: water and oxygen.

Causes of metal rusting: mainly electrochemical corrosion.

and air oxidation, pure or active metals are mainly due to the oxidation reaction between the metal surface and the oxygen in the air.

As a result, metal oxides are formed on the surface of the metal.

Rust appears. If the metal contains more impurities, the impurities will form a chemical galvanic cell with the metal, and electrochemical corrosion will occur, thereby oxidizing the metal to form metal oxides.

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Iron rusts because it reacts with oxygen and water in moist air, related to oxygen and water. If you have both at the same time, it is easy to rust. Rust is a chemical reaction.

It is essentially an oxidation reaction of a metal. The most common phenomenon of rust is the oxidation of iron products with oxygen after long-term exposure to air, or oxygen in water.

Erosion becomes oxide.

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(1) Relative humidity of the atmosphere

The percentage of the water vapor content of the atmosphere to its water vapor saturation content at the same temperature is called the relative humidity. The rate of metal corrosion is small below a certain relative humidity, and increases dramatically above this relative humidity. This relative humidity is called critical humidity.

The critical humidity of many metals is between 50% and 80%, and the critical humidity of steel is about 75%. Atmospheric relative humidity has the greatest effect on metal corrosion. When the atmospheric humidity is higher than the critical humidity, water film or water beads appear on the metal surface, if the harmful impurities contained in the atmosphere are dissolved in the water film and water droplets, it will become an electrolyte and aggravate corrosion.

(2) Temperature and humidity

The correlation between atmospheric temperature and humidity affects metal corrosion. This has the following main conditions: first, the water vapor content of the atmosphere increases with the increase in temperature; Second, high temperatures increase corrosion, especially in humid environments, where the higher the temperature, the faster the corrosion will be.

When the relative humidity is low, the effect of temperature on rust is not obvious, but when the relative humidity is higher than the critical humidity, the amount of rust increases sharply with the increase of temperature. In addition, if there is a temperature difference between the atmosphere and the metal, condensation will form on the surface of the metal at low temperature, which will also cause the metal to rust.

(3) Corrosive gases

Sulfur dioxide has the greatest impact on metal corrosion, especially for steel, copper and their alloys. Sulfur dioxide in the atmosphere is mainly used in the combustion of coal. At the same time, the combustion product carbon dioxide also has a corrosive effect.

Corrosive gases are mixed in the atmosphere around the plant. For example, hydrogen sulfide, ammonia, hydrochloric acid gas, etc. are all factors that promote metal corrosion.

Of course, it is self-evident that atmospheric oxygen is the most common for metal rust and that it can occur anytime and anywhere.

(4) Other factors

The atmosphere contains a large amount of dust, such as smoke, coal ash, chloride and other acids, alkalis, salt particles, etc., some of which are corrosive, or condensation nuclei of water droplets, which are also rust factors, such as chloride is considered to be the "sworn enemy" of corrosive metals.

The 3 main causes of metal rust.

Humidity: The critical humidity for many metals is between 50% and 80%, and about 75% for steel. If the ambient humidity is less than the critical humidity of the metal, the rate of oxidative corrosion of your gold will be much smaller, and conversely, it will accelerate the occurrence of metal rust.

Temperature: It is generally considered that a high-temperature corrosive environment is considered when the operating temperature of a metal reaches 30% to 40% of its melting point (absolute temperature). The higher the temperature, the higher the chance of metal corrosion.

Corrosion factors: Some metal processing processes will produce chlorides, sulfides and other corrosive gases, which are factors that directly accelerate the oxidation and rusting of metals.

The main cause of metal rust is chemical oxidation. For example, metallic iron, when exposed to oxygen in air or water, will be oxidized to ferric tetroxide, which will appear red. Over time, a layer of rusty rust forms on the surface of the iron, which is made up of ferric tetroxide.

There are many causes of metal rust, but the main factors are humidity, various elements such as acids and alkalis in the air, and corrosive liquids, which can cause metal rust and corrosion. To prevent metal rusting, painting can be done on the metal surface to effectively prevent metal rusting.

What are the main factors that cause metal rust? Dampness is the main cause of rust. Not commonly used.

1.Metal reactivity.

2.Environmental conductivity.

3.Exposure to oxygen.

Many metal parts in the home are prone to rust, try this method to remove rust stains.

Keep the surface of metal products (iron products) clean and dry; Surface coating protective film: such as oiling, painting, electroplating, blue baking, etc.; made into alloys (e.g. iron can be made into stainless steel).

Rational design. The design should pay attention to avoid the contact between the metal royal materials with a large potential difference. When two metals with large electrode potentials must be assembled together, they should be isolated with insulating materials, and if the contact between two materials with different electrode potentials cannot be avoided, the area of the cathode part should not be too large, and the area of the anode part should not be too small.

Reasonable rubber tremor material selection. That is, according to the requirements of the use environment, choose the appropriate materials, such as the selection of alloy steel and other materials containing nickel, chromium, aluminum, silicon, titanium and other elements.

1. Coat the metal surface with corrosion-resistant non-metallic materials such as engine oil and petroleum jelly.

2. With electroplating, a layer of metal that is not easy to be corroded is plated on the metal surface, such as zinc, tin, chromium, nickel, etc.

3) Keeping the surface of iron products clean and dry is also a good way to prevent iron products from rustingFrequently clean metal equipment, place desiccant in precision instruments, etc.

4. A more thorough way is to add some other metals to iron to make stainless alloys, such as stainless steel, which is an alloy made by adding a little nickel and chromium to the steel.