Structure, thermal stability, and microhardness of ZrO2 coatings produced by different techniques

Abstract

Using ion-beam and rf magnetron sputtering of oxide targets, we have grown thin ZrO₂ coatings on 12Kh18N10T high-temperature steel substrates. Depending on the deposition technique, amorphous or crystalline (t + c) coatings have been obtained. The amorphous zirconia retains a disordered structure and high microhardness values up to 600°C. Its crystallization leads to a sharp drop in its microhardness and peeling from the substrate. The initially crystalline coating retains continuity and high microhardness values despite the t → с phase transition at 600 and 700°C. Only annealing at 800°C or higher temperatures reduces its microhardness. This is tentatively attributed to the influence of the substrate.