Iron Plates Modified with ZrO2 Coatings by Surface Mechanical Attrition Alloy and Heat Treatment

In this study, a two-step treatment including surface mechanical attrition alloy treatment (SMAAT) and heat treatment process has been developed to coat ZrO2 powders mechanically on pure iron. A fine-grained ZrO2 alloy surface layer with a thickness of 100 mu m has been formed on a coarse-grained pure iron sheet. The thickness of the coatings was effectively increased and the formation of the alloy phase were promoted by repeated SMAAT combined with heat treatment. A significant alloy enhanced microstructure and a gradient increase in hardness from the coarse-grained core to the top coating surface have been shown by the microstructural and microhardness measurements. As a result, the average hardness of the coating increases up to 450 HV which is four folds that of the iron matrix sample. The roughness of the interface between target and coating was shown to ensure the strong bonding.