0Cr18Ni9Ti不锈钢表面渗锆合金层的硬度及耐蚀性

Microhardness and corrosion resistance of Zr-alloyed layer formed on 0Cr18Ni9Ti stainless steel surface

利用双层辉光等离子渗金属技术,在0Cr18Ni9Ti不锈钢表面形成厚约65μm、均匀致密连续的渗锆合金层,并对不锈钢基材与渗锆合金层分别进行硬度检测与电化学腐蚀性能测试。结果表明:渗锆后,试样表面的硬度约为1530 HV0.05,明显大于不锈钢基材的表面硬度(约为350 HV0.05);渗Zr合金层的硬度由表及里逐渐降低,呈梯度分布;在0.5 mol·L-1H2SO4溶液、0.5 mol·L-1HNO3溶液、3.5%NaCl溶液中,不锈钢基材的相对腐蚀速度分别是渗Zr合金层的2.18倍、9.73倍、2.44倍;未处理的不锈钢表面腐蚀较为严重,而渗Zr合金层表面只出现轻微的局部腐蚀,可见经渗锆处理后,不锈钢的耐蚀性能有所改善。

A continuous and compact zirconium alloying layer was prepared on 0Crl8Ni9Ti stainless steel by double-glow plasma surface alloying technology. The microhardness and the electrochemical corrosion experiments were carried out for the stainless steel and Zr- alloyed layer, respectively. The results show that the microhardness of Zr-alloyed layer is about 1530 HV0. 05, which is obviously higher than that of the microhardness of stainless steel （ about 350 HV0. 05） , and the microhardness of Zr-alloyed layer decreases gradually from the surface to the inside. The relative corrosion rates of the stainless steel are 2.18, 9.73 and 2.44 times as those of Zr-alloyed layers in 0. 5 mol-L-1 H2SO4 solution, 0. 5 mol. L-1 HNO3 solution and 3.5% NaCl solution, respectively. The surface of unprocessed stainless steels are corroded seriously, but the surface of Zr-alloyed layers only exist slight localized corrosion, which indicates that corrosion resistance of 0Cr18Ni9Ti stainless steel with Zr-alloyed layer can be improved.