Research on optimizing spray parameters for Cr3C2 – NiCr coating created on alloy steel by plasma spraying technique

In this work, Cr3C2-NiCr ceramic coating with NiCr content of 30% was created on E355 (St 52-3)/1.0060 alloy steel substrate by air plasma thermal spraying (APS) method. The adhesion, tensile strength of the coating were studied in relation to spray parameters including current intensity, powder feed rate, and stand-off distance according to experimental planning. Experiments were designed based on Central Composite Design method. The adhesion and tensile strength of the coatings were measured by a tensile-compression machine. Analysis of variance (ANOVA) were used to build regression functions expressing the relationship between each property and spray parameters. The experimental results showed that those spray parameters significantly influence the properties of the coating. ANOVA results indicated that the spray parameters have different influences for each coating properties. In addition, regression model of the properties gives prediction results very close to experimental results. The optimization problem was solved in order to achieve the maximum value of adhesion and tensile strength of the coating. Values of the spray parameters for Cr3C2 – NiCr coating to achieve the above criteria have been determined and proposed in this study.