Mechanical integrity in PVD coatings due to the presence of residual stresses

The functionality and reliability of coated devices are strongly related to residual stresses of thin films and coatings. A methodology for thermo-mec hanical design in layered coatings is needed that complements experimental procedures for evaluation of coatings. This paper discusses the role of res idual stresses on the mechanical integrity of physical vapour deposition (P VD) functional coatings. A numerical model of the residual stress distribut ion within a layered metal-ceramic composite coating is presented. The stre ss-induced failure modes are analysed. The topics discussed should provide some insights regarding the development of a methodology for designing fail -safe layered coating systems used in optical devices, (C) 2001 Elsevier Sc ience B.V. All rights reserved.