What is abradable sealing coating and what are the commonly used materials

       

The so-called "wearable seal" refers to the coating applied between the rotating blades and the casing of the high-speed rotating machinery (such as compressors, gas turbines, etc.) that compress gas or liquid to obtain ideal clearance control, which can obtain the maximum Therefore, the efficiency of the whole machine is improved, the energy consumption is reduced, the design of the air seal structure is simplified, and the service life is prolonged. The abradable sealing coating is generally a high temperature resistant, anti-oxidative, soft and porous coating prepared on the inner surface of the compressor volute and the hard coating on the tip of the compressor forms a pair of abradable sealing wear pairs. During the process, an ideal radial airflow gap can be formed, and the maximum pressure difference can be obtained, thereby increasing the engine power

In order to achieve the characteristics of high temperature resistance, oxidation resistance, good bonding, soft quality (general surface hardness is 50~80HR15y), porous (porosity 25%~30%), and high temperature airflow erosion resistance, nickel-coated graphite is generally used. , copper-aluminum-nickel graphite, nickel-chromium-aluminum-nickel-graphite, aluminum-silicon-polyphenylene grease, copper-nickel steel alloy, silver-copper alloy, nickel-diatomite, nickel-chromium-aluminum-BN and other composite materials.