The invention has the advantages of lower cost, good treatment effect to water obstruction scales with high hardness and high silicon content and no secondary pollution to a film system.
本发明有益效果为：成本较低、对高硬度、高硅含量的水阻垢处理效果好、对膜系统不会造成二次污染。
2
Applications of black Cr plating, different types of baths and the secondary additives used, and relationship between blackness and hardness of the coating have been summarised.