Effects of the Casting Temperature in the Leakage of Zamak 5

Recent studies evidenced that the Zamak 5 corrosion is associated to solidification defects arising from the injection process that occur mainly in areas where the solidification rate is faster. Given this factor, the aim of this research was to evaluate the influence of Zamak 5 casting temperature. For this study, Zamak 5 was casted at different temperatures (430 °C, 450 °C, 500 °C, 550 °C) with respective solidification curves. Zamak 5 was analyzed for chemical composition and microstructure. Moreover, complementary tests of microhardness and electrochemical analyses of open circuit potential and polarization were performed. From these analyses it was observed that the highest casting temperature of Zamak 5 originates larger grains and higher microhardness value, due to the lower solidification rate. In none of the leaking temperatures porosity defects were observed on the samples, which is coherent with previous researches, being originated from the injection process.