铜在碳钢中扩散及其对碳钢耐腐蚀性的影响

用水溶液电沉积法在碳钢表面电镀铜并进行高温扩散退火,用Den-Broeder法计算铜在碳钢中的扩散系数,研究了铜在碳钢中的扩散行为及其对碳钢耐腐蚀性的影响。结果表明,铜在碳钢中的扩散主要沿晶界进行,铜的扩散抑制了热处理过程中碳钢晶粒的长大。铜在碳钢中的扩散系数为1.11×10-16～3.03×10-11 cm2/s,扩散系数随着退火温度的提高而升高,随着铜浓度的提高而降低。铜在碳钢高温奥氏体区中扩散所需的激活能为126～167 kJ/mol,在高于低温铁素体+奥氏体混合区中激活能为90～108 kJ/mol。通过铜在碳钢中的扩散制备的Cu-Fe梯度材料,具有优良的耐腐蚀性。

Diffusion Behavior of Cu in Carbon Steel and Its Influence on Corrosion Resistance of Carbon Steel

The copper coating was deposited on the surface of carbon steel by electroplating method, and then annealed at high temperature. The diffusion coefficient of Cu in carbon steel were calculated by the Den-Broeder method, while the influence of Cu-metalizing on the corrosion resistance of carbon steel was investigated. Results show that the inward diffusion of Cu is mainly along grain boundaries of the carbon steel, while the diffusion of Cu will inhibit the growth of grains of the steel during heat treatment. The diffusion coefficient of Cu in carbon steel limits between 1.11×10^-16~3.03×10^-11 cm²/s, which increases with the increasing annealing temperature and decreases with the increasing Cu-concentration of copper. The diffusion activation energy of copper Cu in the ferrite + austenite region of carbon steel is between 90~108 kJ / mol at low temperatures, and in the ferrite region of carbon steel at high temperatures is between 126~167 kJ/mol. Furthermore, a Cu-Fe gradient material on the carbon steel gennerated via Cu-inward diffusion has better corrosion resistance rather than the bare carbon steel in NaCl solution.