Structural changes in the surface layer of plasma coatings with ultrasonic treatment by steel balls

Conclusions Ultrasonic treatment with metal balls provides a reduction in the surface roughness of plasma coatings with a mcirohardness of 5630–7890 MPa by a factor of one and a half, and with a thickness of deposited layer less than 4·10^–4 m the time required in order to achieve the minimum roughness depends considerably on the magnitude of residual compressive stresses and the properties of the base.The shock effect of balls changes the size of mosaic blocks, dislocation density, and the magnitude of microstresses in the surface layer of a coating, and the treatment time required in order to achieve the maximum changes is reduced with a smaller deposited layer thickness.Ultrasonic treatment of plasma coatings provides formation at their surface layer of structures which improve the wear resistance of deposited coatings under fretting conditions by a factor of two to four.Translated from Poroshkovaya Metallurgiya, No. 2(350), pp. 23–28, February, 1992.