Al_2O_3陶瓷涂层电镀和刷镀封孔机理及效果评价

本文提出了用电镀、刷镀方法对A1_2O_3陶瓷涂层封孔的规范选择原则,并研究了封孔机理,评价了封孔效果。研究表明,在足够时间的条件下,电镀封孔应选择较小的电流密度,刷镀封孔应选择较低的电压;电镀、刷镀封孔过程中当阴极反应在涂层孔洞内充分进行时,大部分贯穿性孔洞将被封闭;当阴极反应移至表面进行时,涂层表面将沉积大量金属,而涂层内孔洞却未被封闭。用铜、镍刷镀封孔的Al_2O_3涂层在NaOH20％,NaC120％溶液中的耐蚀性提高,用镍封孔的涂层的抗热冲击性能得到改善。

Mechanism of Porosity Filling with Alumina Ceramic Coatings Using Electroplating and Brush-plating Methods and Evaluation on Their Effects

This paper presents a rule for select of porosity filling specifications using the alumina coatings,i nvestigates into the mechanism of porosity filling, and evaluates the effects of filling. The investigation shows: when the filling time is long enough, a smaller current density should be selected for electroplating and a lower voltage for brush-plating. If the cathode reactions develop fully within the porosities, the majority of penetrating porosities are filled up. If the cathode reactions remove to the surface of the coating and develop, a lot of metals are deposited on the surface with the penetrating porosities being not filled up. Filling the alumina coating with copper or nickel improves it's corrosion resistance in the NaCl 20% and NaOH 20% aqueous solutions. The heat impact resistance of that filling coating is improved, however, only for nickel filling.