钨酸盐对无铬锌铝涂层性能的影响

为实现锌铝涂层的无铬化,利用具有缓蚀作用的钨酸盐替代部分钼酸盐在Q235A碳钢板上制备无铬锌铝涂层。通过超景深三维体式显微镜、划格法、铅笔硬度法、中性盐雾试验及电化学工作站研究了钨酸盐用量对自制无铬锌铝涂层的形貌、硬度、附着力及耐蚀性的影响。结果表明:当钨酸盐含量过低时,由于钝化膜不完整,形成"活化-钝化"电池使涂层的腐蚀速率加快,耐蚀性下降;当钨酸盐含量超过2.0%时,涂层硬度降低;当钨酸盐含量为2.0%时,涂层的综合性能最佳。

Influences of Tungstate on Properties of Non-Chromium Zn-Al Coatings

The present work focused on the preparation of non-chromium Zn-Al coating using tungstate instead of partial molybdate,and the influences of tungstate addition on the surface,pencil hardness,adhesion and corrosion resistance of the coatings were investigated by means of super depth 3D stereo microscope,pencil hardness test,cross cut test,neutral salt spray test and electrochemical workstation.Results showed that when the addition amount of tungstate was low,the corrosion rate of the coating increased due to activation-passivation battery resulting from the incomplete passivation film.When the addition amount was beyond 2.0％,the pencil hardness of the coating decreased.When the addition amount was 2.0％,the coating revealed good comprehensive properties.