Abstract:

A new impact scraping test machine has been developed successfully. The machine is simpler and closer to application condition that the blades scrape the seal coating in the aircraft turbine enginge than other methods used in abradability evaluation. The impact scraping load displacement curve and scraping work can be measured by the machine. The specific scraping work has been proposed to evaluate the abradability. The specific scraping work increases with the increase of hardness and exhibits a threshold. The upper limit of the range of the coating hardness used in the quality control in production can be determined according to the threshold in the specific work hardness curve. The abradability of 313 type of coating is the best, 601 is fairly good, and 307 is the worst. The specific work at 300℃ decreases slightly, but the decrease extent is different in different kinds of coatings.

Key words: seal coat ing, impact-scrap ing test mach ine, abradability