The characteristics of chemical reaction between metal materials and other substances are called the chemical properties of metals. It mainly refers to the ability to resist the corrosion of various media at normal temperature or high temperature, such as acid resistance, alkali resistance, oxidation resistance, etc.

In practical applications, the corrosion resistance and oxidation resistance of metals (also called oxidation resistance, which refers to the resistance or stability of metals to oxidation at high temperatures), and the effect of compounds formed between different metals and between metals and non-metals on mechanical properties are mainly considered. In the chemical properties of metals, especially the corrosion resistance, is of great significance to the corrosion fatigue damage of metals.

Oxidation resistance of metal materials

The ability of metal materials to resist the corrosive action of oxidizing atmosphere at high temperature. High-temperature components of thermal equipment in thermal power plants, such as boiler superheater, water-cooled wall tubes, steam turbine cylinders, blades, etc., are prone to oxidative corrosion when working at high temperature for a long time. Many metals can combine with oxygen in the air to form oxides and form an oxide film on the metal surface. If the oxide layer formed on the metal surface is relatively loose, The external oxygen can continue to interact with the metal and destroy the metal material. This phenomenon is called metal oxidation. If the oxide layer formed on the metal surface is relatively dense and firmly covered on the metal surface, a protective layer is formed to prevent the oxygen from contacting with the metal, preventing the continuous oxidation of the metal, and the metal is protected, Such metals have high oxidation resistance, such as aluminum in the air. The ability of x0d metal materials to resist the corrosion of various media (atmosphere, acid, alkali, salt) is called corrosion resistance

Corrosion resistance of metal materials

Some thermal components in thermal power plants have been exposed to high-temperature flue gas, steam and water or some corrosive media for a long time, resulting in various kinds of corrosion on the metal surface and sometimes invading the metal interior, which will bring adverse effects on safe operation, and even cause rupture and damage accidents in serious cases. The corrosion of boiler tubes in thermal power plants is mainly sulfur corrosion and hydrogen corrosion, and oil-fired boilers are also subject to vanadium corrosion. The main corrosion of turbine turbines in hydropower stations is water vapor corrosion