Characterization method for micron-scale sealing coating wear of long-life infrared detector cryocooler assembly

Infrared detector cooler assemblies with extended operational longevity derive benefits from the utilization of linear compressors. This article is dedicated to the examination of the coating applied to linear compressor piston seals, as even coatings measuring only a few micrometers in thickness can precipitate cryocooler failure. Our investigation delves into the wear resistance characteristics of these coatings. Traditional methods reliant on wear rate for assessing wear may prove inadequate in quantifying micrometer-level wear loss; hence, we introduce a novel indentation method for accurately determining wear depth. This method furnishes a precise means of characterizing micrometer-level wear in the piston coatings of linear compressors. To validate our approach, experiments were conducted using three samples composed of specialized engineering materials. Initially, sample wear resistance was indirectly characterized through scratch width measurements and subsequently assessed directly using the indentation method. Notably, results obtained from both methods were consistent, demonstrating the validity and practicality of employing the indentation method for characterizing micro-level wear in highly resistant materials.