Quantitative Evaluation of Pinehole Defects in Corrosion-Resistant Thin Films Prepared by Dry Coating Process

关键被动当前密度（CPCD）方法已应用于TiN涂层SUS 304不锈钢上的缺陷评估。薄TiN薄膜0.5- 4.0毫米厚，由几种干燥涂层工艺组成，包括空心阴极释放离子片、等离子体增强化学气相沉积、动力混合、阴极释放离子片和激活反应蒸发。为了在针孔变形的区域部分和TiN薄膜的厚度之间建立定量关系，CPCD对TiN涂层的SUS 304不锈钢进行了优化的测量条件。最佳极化条件确定为汇总;解决方案：老化0. 5 M-H_2SO_4 + 0. 05 M-KSCN在298 K，潜在范围： -0.45至0.40 V（vs. Ag/AgCl，3. 33 M-KCl），扫描速率：从0.3到0.4 m V·s^&lt;-1&gt;.发现了区域片段，R_i，在TiN薄膜中的针孔变形，增加了薄膜的厚度，d_<TiN>，并且几乎恒定，当d_超过<TiN>2.5毫米的值时。针孔缺陷的数量也取决于TiN薄膜的制备方法。TiN电影4.0 mm厚，是由激活反应式蒸发形成的，显示了R_i的最低值。

Critical passivation current density (CPCD) method has been applied to the defect evaluation on TiN-coated SUS304 stainless steels. Thin TiN films 0.5-4.0mum thick were prepared by several kinds of dry coating processes including hollow cathode discharge ion plating, plasma enhanced chemical vapor deposition, dynamic mixing, cathode are discharge ion plating, and activated reactive evaporation. To obtain quantitative relationships between the area fraction of pinhole defects and the thickness of TiN films, the measurement conditions of CPCD were optimized for TiN-coated SUS304 stainless steels. The optimum polarization conditions thus determined are summerized as follows ;Solution : deaerated 0.5M-H_2SO_4+0.05M-KSCN at 298K,Potential range : -0.45 to 0.40 V (vs. Ag/AgCl, 3.33M-KCl),Scan rate : 0.3 to 0.4 m V・s^<-1>.It was found that the area fraction, R_i, of pinhole defects in the TiN films decreased with increasing the thickness of the films, d_<TiN>, and became almost constant when the value of d_<TiN> exceeded 2.5mum. The amount of pinehole defects depends also on the preparation method of TiN films. The TiN film 4.0mum thick, which was formed by activated reactive evaporation, showed the lowest value of R_i.