Experimental and numerical investigations on plasma sprayed ceramic coatings with varying coating thickness

Abstract

Coatings are extensively used in many tribological applications in order to reduce the wear rate. Despite its advantages, life of the coatings has been limited by the stresses arising at the interfacial region. The purpose of this work is to study three different types of ceramic coatings grown by plasma spraying method on titanium substrate by ball indentation and finite element method (FEM). Micrometer-sized powders of the following compositions were plasma sprayed on to the Ti6Al4V (TAV) substrate (flat plate): 1) Al2O3 (AO); 2) 8 mol% yttrium stabilised zirconia (8YSZ); 3) Al2O3-40 wt% 8YSZ (A4Z). The effect of type of material and coating thickness on stress distribution and contact pressure has been investigated. The dimensionless parameters which aid in the comparison of the behaviour of the elastically coated sphere and coating thickness with different material properties were identified and used for further investigation. The investigation has revealed that Al2O3-40 wt% 8YSZ coating on titanium substrate is the most desirable one for protecting the substrate against yielding and hence it could be used as a protective layer.