A spray coating and its mechanical properties of Al-Si-Zn alloy produced by the spray forming process

A 55mass%Al-L5mass%Si-Zn system alloy with good corrosion resistance was sprayed on a plaster substrate. Then, the formation process and some properties of the sprayed coating were investigated. Using the interrupted quenching method, it was found that the sprayed coating structure was not only the layer structure but also a casting structure. Due to large solidification range, the solidification pattern was a mushy type with characteristic of Al-Si-Zn alloys. The maximum temperature and the shrinkage ratio of the sprayed coating decreased as the spray distance increased, due to the decreasing melt particle temperature. Tensile strength and the elongation of the sprayed coating decreased as the spray distance increased, due to an increase in the porosity ratio. In particular, a large amount of oxide was formed in the sprayed coating when air was used as the carrier gas. This oxide formation causes an increase in the shrinkage ratio.