Evaluation of Environmentally Friendly Zr Based Nano StructuredConversion Coating for HRS (Hot Rolled Steel) in Powder Coating

摘要

Metals, despite their deterioration in a corrosive atmosphere, continue to dominate theautomotive, agricultural, furniture, process and appliance industries and HRS (Hot Rolled Steel)plays a significant role in those areas. Powder coating on HRS is widely employed for protectiveand aesthetic purposes. Prior to powder coating, phosphating conversion coating is often used toincrease effectiveness of protection. However, due to tightening environmental legislations,phosphating process is now problems for industry. Therefore, newly developed environmentallyfriendly conversion coats are introduced to industry. In this study a new environmentally friendlyzirconium fluoro-based (H_2ZrF_6) generation of conversion coating has been introduced to replacethe conventional phosphating conversion coatings process. It is deposited on the surface with a thinnanometre range, therefore shortening the process, which also has advantages such as being free ofheavy metal and operating in low or ambient temperature. The present work closely examines Zrbased nano structured conversion coatings for HRS. Extensive corrosion and adhesion studies arecarried out on differently prepared HRS test panels, pre-treated with Zr based conversion coating invarious conditions, such as different composition ratio, temperature and contact time.