Investigation on glow-discharge ionized nickel-chromizing with arc source of Ti alloy and its properties

A new technique of glow-discharge ionized surface alloying with arc source was used to treat Ti₅Al₂. 5Sn alloy. The microstructure and constituent distribution in diffusion layer were studied. The wear resistance and the galvanic corrosion susceptibility of the alloyed surface layer contacted with titanium alloy Ti₅Al₂. 5Sn were evaluated. It is found that a composite modified surface of NiCr coating over nickel-chromium diffusion layer can be quickly formed with the new technology. The alloyed surface consists of Ni₃Ti, Ni₃Al, Cr ₂Ti and other phases. The hardness and the wear resistance of the alloyed surface are higher than that of nitrided surface. The modified titanium alloy has high corrosion resistance in Cl^-1 environment and low galvanic corrosion susceptibility contacted with Ti base metal.