Trace Elements Can Influence On The Corrosion Of The Aluminum Brass

Four kinds of Al brass alloy with Ce addition have been developed with an aim to replace the As Al brass. The structures and properties of the aluminum brasses with Ce have been studied by means of the metallographic analysis, microhardness measurement, weight loss measurement, electrochemical testing and scanning electron microscopy.The results are as follows:1) The hot-working and cold-working characters of the Ce Al brass are good, and the suitable hot-working temperature of Ce Al brass is between 973 and 1023 K. The hot-working characters is better than that of the aluminum brasses with As. The annealed structure of the aluminum brasses with Ce is also more fine and homogeneous than that of the aluminum brasses with As.2)In the NaCl solution, the Ce Al brass is shown to have a slightly higher corrosion resistance than the As Al brass. Ce is an active element and likely to be oxygenated which leads to a little decrease of free corrosion potential of the brass, however the corrosion product layer is dense and has a much improved bonding with the matrix by it, which results in a significant increase of polarization resistance. It is likely that this dense film inhibited the diffusion of Zn atom from matrix into the solution and thus increased the corrosion resistance. In the NaCl + NH₄Cl solution, the corrosion average rates of the As Al brass and Ce Al brass are very similar and are much higher than those in the NaCl solution.3) The corrosion-resistant property of the CuAlNiCeBIn alloy are higher than those of CuAlNiCeB, CuAlNiCeBZr and CuAlNiCeBInZr alloy in the NaCl (3.5%) solution and NaCl(3.5%)+NH4Cl(0.5mol/L) solution respectively. In the NaCl + NH₄Cl solution, the corrosion average rates of the CuAlNiCeBIn alloy is much higher than those in the NaCl solution.