Determination of creep behaviour of monolayer thick plasma sprayed coatings, by means of the impact test and an analytical FEM supported evaluation procedure

The material surface enhancement that is being used in tribosystems, with the aid of the plasma spray method, is nowadays a well-known practice. This flexible and relatively economically efficient method enables improved properties for machine elements that are designed for demanding purposes. Hereby the plasma transferred are (PTA) method is widely used for new parts as well as for repair and aims to produce mono or multilayer coatings with a wide variety of mechanical properties. The deposition strategy and the applied conditions are responsible for the occurring properties of such coating types, as for instance for their porosity. This property might induce creep phenomena during the operation of the coated machine elements according to the acting loads. In the present paper investigations of the creep mechanism at low temperatures and under various loads of two plasma spray deposited coatings, by means of the impact test and an FEM supported method, are described. These established analytical and experimental tools offer the ensemble of the coatings bulk mechanical, creep properties and may be used to characterise quantitatively the quality of such coatings and their loading limitations. Hereby, a plasma sprayed relatively hard film, i.e. the two-lateral AI 1031 (W-based) coating and the softer Ni-5%Al one, are examined with respect to their mechanical and creep behaviour. (C) 2000 Elsevier Science B.V. All rights reserved.