PROPERTIES OF THE COMBINED COATING FOR THE RESTORATION OF WORN CYLINDER LINERS

Abstract

The service life of the cylinder liner of an internal combustion engine after repair caused by wear of the internal working surface has a shorter service life than a new one. This circumstance necessitates the search for a method of applying a more wear-resistant coating. The possibility of using a combined coating to restore worn cylinder liners by applying a layer of aluminum alloy by cold gas-dynamic spraying followed by micro-arc oxidation of the working surface was investigated. (Research purpose) The research purpose is increasing the life of cylinder liners by applying a combined coating using cold gas-dynamic spraying and micro-arc oxidation of the inner working surface of the cylinders. (Materials and methods) Conducted studies on the adhesive and cohesive strength of the coating and comparative tribological tests to determine the suitability of the coating under study for the repair of cylinder liners. We performed studies according to the standards of OST 90148-74 and GOST 23.224-86, respectively. (Results and discussion) The values of adhesive and cohesive strength were determined for various modes of coating with cold gas-dynamic spraying on a cast-iron base. The optimal loading parameters for accelerated wear resistance tests were identified and the run-in rate, the factor and the wear intensity for the studied and reference coatings were calculated. It was established that the adhesive and cohesive strength is sufficient for the application of this method in practice, the wear resistance of the coated sample exceeds the wear resistance of the reference sample. (Conclusions) The combined coating has sufficient strength indicators and high wear resistance indicators compared to the standard, which makes their use in cylinder liners possible and appropriate, however, further investigation of the coating properties is necessary.