中温锌-钙系黑磷化膜的制备与性能研究

Preparation and Performance of Black Phosphating Coating of Zn-Ca System at Medium Temperature

为了改善锌-钙系黑色磷化膜的外观和性能,探讨了配方与工艺,采用扫描电镜(SEM)观察磷化膜表面微观形貌,X射线荧光光谱法(XRF)分析磷化膜成分,测试了膜层厚度、附着强度、耐磨性和耐蚀性能。结果表明:采用硝酸铜作发黑剂,Na2MoO4为氧化促进剂,经过硝酸铋预浸处理能够获得深黑色、防护性能良好的磷化膜。CaO的含量增加能改变膜表面晶体形貌,当氧化钙含量为30g/L时,晶体粒径明显减小,膜层中锌、钙元素含量增加,使耐磨性能和耐蚀性能提高。

Black phosphatizing formula and technological condition of Zn-Ca system at medium temperature were developed to obtain phosphatizing coating with good look and properties. SEM, X-ray fluorescence （XRF） were used to analyse the morphology and component of the film. The thickness, adhesive strength, friction times and corrosion resistance of the film were tested. The experimental results demonstrate the black phosphating coating with excellent protection can be obtained dipping in Bi（NO3）3 solution before phosphatizing, when Cu（NO3）2 and Na2MoO4 are used as the blackening component and accelerated oxidation component. With the content of CaO increasing the morphology of the crystals can be changed. When CaO is 30 g/L, the diameter of the crystal obviously descends and the content of Zn and Ca of the fihn increases. The wear-resistance and the corrosion resistance are improved.