Preparation of Zn-Ca Phosphate Coating in Presence of PTFE on 45 Steel and its Corrosion Properties in Simulated Seawater

Abstract

Zn-Ca phosphate coating in presence of PTFE was prepared on the surface of 45 steel by dipping method using a phosphate solution containing PTFE particles. By investigating the influence of the amount of PTFE particles added, stirring rate, phosphate solution temperature and phosphate time on the thickness and PTFE particles content of Zn-Ca phosphate coating in presence of PTFE , the optimal process parameters for preparing Zn-Ca phosphate coating in presence of PTFE were determined as follows: amount of PTFE particles added 16 g/L, stirring rate 200 r/min, phosphate solution temperature 65°C and phosphate time 18 min. The comparative experimental results show that the thickness of the optimized Zn-Ca phosphate coating in presence of PTFE reaches 9.5 μm with the highest PTFE particle content (approximately 11%) which can slow down the phosphate coating corrosion process. After immersion in simulated seawater for different time, the corrosion current density of the optimized Zn-Ca phosphate coating in presence of PTFE gradually increases and then remains stable. The optimized Zn-Ca phosphate coating in presence of PTFE can inhibit the electrochemical reaction and provide ideal corrosion protection for 45 steel.

Effect of Temperature on the Morphology and Corrosion Resistance of Modified Boron Nitride Nanosheets Incorporated into Steel Phosphate Coating

“…Similarly, the effects of different phosphate solution temperatures and phosphate time immersions on the Zn-Ca phosphate coating with PTFE on the surface of 45 steel were studied by Zhang et al through the dipping method. It was concluded that the optimum conditions for coating thickness and PTFE particle content were achieved at a phosphate solution temperature of 65 • C. The elevated temperature accelerates hydrolysis and crystallization reactions, increasing the coating formation rate and improving coating thickness [13].…”