Wear resistant and thermal barrier coatings in diesel engines. Methods for optimisation of strength and service life

Based on experiments undertaken both within and outside Rounds I and II of the European COST 501 Action a strategy is presented for optimisation of the performance of thermally sprayed coatings against thermal and wear attack, mainly when used in Diesel engines. A model for the understanding of the phenomenon of adhesion has been derived and the influence of residual strains, detrimental for lifetime, is assessed. Methods for dimensioning randomly loaded fatigue tests were found to be capable of modelling this phenomenon completely, if some basic principles of the physics of materials and stress mechanics were also incorporated. Examples and a guide for further improvement are given.