- 學位論文
Effects of Electrochemical Coating on Phosphating Carbon Steels
Effects of Electrochemical Coating on Phosphating Carbon Steels
摘要
Protecting metals from corrosion plays a vital role in manufacturing industry. The economic loss caused by corrosion is a big issue. The amount of metals directly lost by corrosion makes up about 10% of the world’s annual metal products. Nowadays, researchers have found a number of methods of anti-corrosion such as: passive barrier, sacrificial and active corrosion protection. Among those methods, phosphate coating is widely used due to its simple and high effectiveness. As well known, there are various ways to accelerate the phosphate coating process such as physical, chemical and electrochemical acceleration. Realizing its numerous benefits, electrochemical phosphating method is employed in this study. In this study, the phosphate coatings are formed by four commercial solutions A, B, C and D in order to protect the surfaces of low carbon steel from corrosion. With methods of immersion, anodic electrochemical and cathodic electrochemical applied in the phosphating processes; the four solutions could create protection films on the surfaces. In order to exam the quality of the coatings, this study employ several criteria such as examination of physical appearance, determination of coating weight, estimation of porosity, evaluation of surface morphology, adhesion measurement, determination of acid/alkaline resistance, anti-corrosion performance and chemical analysis. The results showed that method of cathodic electrochemical demonstrate lots of outstanding advantages such as heavy coating, high chemical stability, low porosity and better anti-corrosion performance. Therefore, this thesis aims to emphasize learning about the effects of cathodic electrochemical method on phosphating low carbon steel substrate. After comparing the results of fours solutions, the solution D emerges to have better characteristics in forming high-quality coatings. Hence, this solution is chosen to further study on its life time. This life time is evaluated through these criteria: surface composition analysis, salt spray test, determination of coating weight and chemical composition analysis. It was found that 500 ml of solution D is effective only when used for 300 cm2 area of low carbon steel with the method of cathodic electrochemical phosphating. With the obtained results, this study is expected to contribute to the development of protection methods in surface engineering.
並列摘要
Protecting metals from corrosion plays a vital role in manufacturing industry. The economic loss caused by corrosion is a big issue. The amount of metals directly lost by corrosion makes up about 10% of the world’s annual metal products. Nowadays, researchers have found a number of methods of anti-corrosion such as: passive barrier, sacrificial and active corrosion protection. Among those methods, phosphate coating is widely used due to its simple and high effectiveness. As well known, there are various ways to accelerate the phosphate coating process such as physical, chemical and electrochemical acceleration. Realizing its numerous benefits, electrochemical phosphating method is employed in this study. In this study, the phosphate coatings are formed by four commercial solutions A, B, C and D in order to protect the surfaces of low carbon steel from corrosion. With methods of immersion, anodic electrochemical and cathodic electrochemical applied in the phosphating processes; the four solutions could create protection films on the surfaces. In order to exam the quality of the coatings, this study employ several criteria such as examination of physical appearance, determination of coating weight, estimation of porosity, evaluation of surface morphology, adhesion measurement, determination of acid/alkaline resistance, anti-corrosion performance and chemical analysis. The results showed that method of cathodic electrochemical demonstrate lots of outstanding advantages such as heavy coating, high chemical stability, low porosity and better anti-corrosion performance. Therefore, this thesis aims to emphasize learning about the effects of cathodic electrochemical method on phosphating low carbon steel substrate. After comparing the results of fours solutions, the solution D emerges to have better characteristics in forming high-quality coatings. Hence, this solution is chosen to further study on its life time. This life time is evaluated through these criteria: surface composition analysis, salt spray test, determination of coating weight and chemical composition analysis. It was found that 500 ml of solution D is effective only when used for 300 cm2 area of low carbon steel with the method of cathodic electrochemical phosphating. With the obtained results, this study is expected to contribute to the development of protection methods in surface engineering.