Overview
The use of thermal spraying technology can not only improve the wear resistance, corrosion resistance, erosion resistance, thermal stability and chemical stability of machinery and equipment, but also give ordinary materials special functions, such as high-temperature superconducting coatings and biological coatings. , Diamond coatings, solid oxygen fuel cell (SOFCs) electrode catalytic coatings, etc. Therefore, thermal spraying technology will inevitably attract more and more people's attention, and it will be more and more widely used in various industrial fields. However, actual parts differ greatly due to their material, shape, size, application environment, service conditions, etc. To successfully use thermal spray coating to solve the technical problems faced, a specific process must be followed. Among them, the most The important ones are the following five key processes.
1. Accurately analyze the problem and clarify the coating performance requirements;
2. Reasonably carry out coating design, including correct selection of spraying materials, equipment, technology, and compliance with strict coating quality performance evaluation system, etc.;
3. Optimize the coating preparation process;
4. Strictly control the coating quality;
Coating design plays a role in linking up and down, is the basis for the successful solution of practical problems with thermal spraying technology, and is one of the most important links in all links. When designing the coating, it is necessary to consider all links involved in the coating. Obvious system characteristics. Therefore, in order to obtain a coating that meets the performance requirements, careful and reasonable coating design must be carried out before spraying.
The main content of the thermal spray coating design includes: First, determine the technical requirements of the surface coating of the part or the surface coating system according to the working condition of the surface of the part or the analysis result of the part that has already suffered surface failure. Including bonding strength, hardness, thickness, number and size of pores, wear resistance, corrosion resistance, heat resistance or other properties, etc.; second, use the basic knowledge of thermal spraying technology (including spraying materials, spraying process, coating Layer performance, etc.), carry out economic and technical feasibility analysis to meet the performance requirements as the basis, consider the economics of the coating, and then select the appropriate spraying materials, equipment and process methods; third, prepare a reasonable coating preparation process specification; and finally , Propose strict coating quality inspection and control standards, parts packaging and transportation conditions, etc. Now, more stringent requirements even include comprehensive quality management requirements for spraying raw material manufacturers. All the above content constitutes a complete thermal spray coating design process.
It needs to be pointed out that although the performance of thermal spray coating mainly depends on the performance of spraying materials, it is also obviously affected by the selected spraying equipment and spraying process. When spraying the same spraying material with different spraying equipment and different spraying process parameters, the performance of the resulting coating will be very different. In addition, all other links involved in the preparation of the coating will determine the final coating performance, such as surface pretreatment, cooling measures, coating processing, etc. Therefore, it is only possible to obtain a comprehensive quality control for each process of preparing the coating. Coatings with satisfactory performance and stable quality.
*This article is excerpted from the WeChat public account: thermal spraying and remanufacturing. If there is any infringement, please contact the staff to delete
