The character of fracture of iron based thermal coating during fretting

The character of destruction of thermal coatings during fretting has been investigated. An iron based plasma coating has been tested with oscillation amplitude from 30 to 200 microns. The tests were conducted in air. It has been determined that the main factor influencing the rate of the wear of the coating during fretting corrosion is the size of the coating area involved into the wear process. The coating exhibits high wear resistance when the amplitude of the oscillation is commensurate with the size of the sprayed particles. During destruction of the coating the leading role belongs to fatigue-oxidation processes. The wear of the coating acquires a catastrophic character when coating macro defects - pores and interlayer boundaries - are involved into the wear process

Investigation of surface adhesion produced by high-speed flame spraying

Peculiarities of surface adhesion based on nickel, produced by high-velocity spraying on steel base with different surface morphology have been analysed. It is shown that ultrasound final polishing builds up wavy submicrorelief providing the reliable adhesive connection between covering and base. Ultrasound finite polishing is suggested as a method of preparing surface for high-speed flame