New Corrosion Resistant High-zinc Brass

Brass used for sanitary ware and plumbing fittings is an important basis material in construction industry. It is a great subject in both industry and research area to develop an As-free and good corrosion property brass alloy for sanitary ware and plumbing fittings. A new As-free and high-zinc complex-brass with Sn,Ce,Al and B was investigated in present paper. The corrosion property, mechanical properties and microstructure of the previous alloy have been studied by means of electrochemical experiments, XRD, SEM, EDAX, static corrosion experiments and tensile test. The main results are as follows:The comprehensive mechanical properties and corrosion resistance of the alloy can be improved with a reasonable amount of Sn,Ce,Al and B additions, but it is only fit for casting and hot-forming because of its main phase isβ′-phase.The electrochemical experiments show that when the alloy with 1.5%Sn,0.05%Ce,1.5%Al,0.05%B,60.5%Cu,36.4%Zn may exhibit the lowest passivating current density and corrosion rate. The alloy occur passivating reaction and to form a homogeneous film, which is tight and well bonded to the matrix, inhibiting dezincification effectively and increasing corrosion resistance.Stress-relief annealing with 450℃and one hour is the better heat treatment process for the corrosion resistance and mechanical properties. After annealing, the experiment alloy's microstructure is (β′+α+γ)phase, among which,β′phase is the matrix phase,α-phase needle-like distribution in the matrix andγ-phase showed granular distribution in the matrix.Effects of Rare-earth elements La, Y and Ce on the corrosion resistance of the experiment alloys are different. The corrosion resistance of Ce addition is better than La and Y addition of the experiment alloys.With the above results, it can be concluded that two-phase brass with As addition can be replaced by high-zinc brass alloy with Sn,Ce,Al and B additions, and the harmful effects caused by As addition can be solved.