Effects of microstructural factors and alloying elements on dezincification of brass.

From the viewpoint of ecomaterals, development of dezincification resistant Pb-less brass is required. In order to reveal the effects of microstructural factors and alloying elements on dezincification of (α+β) brass, the brasses with different β phase area ratio and mean grain size of α phase were prepared by melting pure Cu, Zn and alloying elements and then pouring into a metal mold with three different solidification rates. Dezincification corrosion of the casting brass was examined by means of galvanostatic anodic polarization test. The results show that the mean and maximum dezincification depths of Cu-Zn system decrease with the decrease of the mean grain size of α phase. However, reduction of the dezincification depth by only controlling the microstructural factors has a limitation. The dezincification can be retarded significantly by the addition of a small amount of P and the refinement of the mean grain size of α phase with controlling the solidification rate.