Adherence of zirconia composite coatings produced by gas tunnel-type plasma spraying

The sprayed coating is formed by the mechanical bonding to the substrate. Zirconia coating produced by gas tunnel-type plasma spraying at a short spraying distance has a high hardness layer at the surface side of the coating, which shows the graded functionality of hardness. However, the adhesive strength between the coating and the substrate has not been investigated for these coatings. In this study, the adhesive strength of such high hardness zirconia composite coatings in the case of different mixtures of alumina was investigated as well as its mechanical properties. The alumina mixture of spraying powder weakened the adherence of such high hardness coatings to the substrate. The hardness of the coating was also much influenced by the alumina mixing rate. (C) 2004 Elsevier Ltd. All rights reserved.