Application principle of high temperature resistant coating material

       Metal high-temperature structural materials should not only have sufficient mechanical properties and suitable processing and manufacturing properties, but also have excellent chemical stability. The most widely used superalloys at high temperatures suffer from severe oxidation and hot corrosion in corrosive gas environments, which are the main factors limiting their applications. The solutions are as follows: First, adjust the composition and structure of the alloy to improve its own resistance to high temperature oxidation and hot corrosion. Some progress has been made in this regard, but the amount of alloying elements added to improve the high temperature corrosion resistance of the alloy is limited. , when the addition amount is slightly larger, the mechanical properties of the alloy will be significantly reduced, and vice versa, this contradiction has not been resolved; another way is to apply a protective coating on the surface of the superalloy, which can not only improve the alloy's resistance to high temperature oxidation and hot corrosion, It can also keep the mechanical properties of the alloy within the allowable range. Satisfactory progress has been made in this regard, and it has been widely used in engineering.



High temperature resistant coating materials generally have the properties of high temperature oxidation resistance, high temperature corrosion resistance and high temperature wear resistance.



High temperature oxidation resistant coatings are generally used in oxidative corrosion environments higher than 550 °C, and currently commonly used materials are Fe-based, Co-based, and Ni-based alloys. Some oxide ceramics can also be used in high temperature oxidizing environments. This type of coating is mainly sprayed by atmospheric or low pressure plasma, and the density of the coating is very important. In addition to high temperature oxidation and corrosion resistance, alloy coating is mainly used for the intermediate bonding layer of functional ceramic coatings, and is also used for the repair of worn parts, such as guide vanes, valve seats, piston rods, sealing chambers, bearings, bushings of gas turbines Wait. When selecting high temperature resistant coating materials, the application conditions, substrate and coating should be considered as a whole, in order to obtain the results of good comprehensive performance.