基体偏压对非晶碳膜结构和耐蚀性的影响

Influence of substrate bias on the microstructure and the corrosion resistance of graphite-like carbon films

薄膜沉积过程中较高基体偏压能增强C膜对金属基体的保护,降低自腐蚀电流密度,提高自腐蚀电位。用磁控溅射法在4种偏压(0,-50,-100,-200 V)下制备Cr/CrN/C非晶碳多层薄膜,研究其结构和耐蚀性。观测了薄膜表面形貌和粗糙度,测量了C层中D峰和G峰的强度比值,使用三电极体系研究了薄膜耐蚀性能并分析了其机理。结果表明:各偏压下薄膜粗糙度在15~23 nm之间,在-100 V偏压下薄膜最光滑平整;各偏压下C层sp^(2)/sp^(3)比值无较大波动,但在-100 V偏压下有最高D峰和G峰的强度比值;随着偏压增大,薄膜自腐蚀电流密度降低,在-100V偏压下沉积的C层具有最高的腐蚀电位,表现出了最佳耐蚀性。

Increasing of substrate bias during the deposition can enhance the protection of carbon films on metal plates,leading to a reduction in self-corrosion current density and an increase in self-corrosion potential.The Cr/CrN/C multilayer films were fabricated by magnetron sputtering under 4 different substrate bias voltages then the microstructure and corrosion resistance were analyzed.The surface morphology of films and the roughness was observed,and intensity ratio of D and G peaks within the C layers was measured.The corrosion resistance of the coatings and the underlying mechanism was investigated.The results show that the surface roughness of the films varied between 15 and 23 nm under four bias voltages,and the films exhibited a smoothest surface by a bias of-100 V.Sp^(2)/sp^(3) ratios remained relatively stable in C layers at all the bias voltages,but the C layer prepared at-100 V bias exhibited the highest intensity ratio of D and G peaks.As the substrate bias increased,the self-corrosion current density of the films decreased gradually while the self-corrosion potential increased.The C layers deposited at-100 V substrate bias exhibited the highest corrosion potential.