Basic Experiment of Etching of the Ceramic Surface by Electrolytic/Electro-Discharge Composit Machining Method

采用电解液放电加工方法对陶瓷材料表面进行了刻蚀实验研究。氧化铝或碳化硅陶瓷样品分别浸泡在0.01 - 1 mol/lNaOH、HCl、H_3PO_4、NaH_2PO_4、Na_2HPO_4和Na_3PO_4溶液中。0.8结果表明，阴极和对电极之间的电压、电解液的种类和浓度以及电极的极性对熔坑的最大穿透深度和形状有影响，阴极的熔坑深度大于阳极的熔坑深度，阴极的熔坑深度大于阳极的熔坑深度。观察到两种类型的陨石坑。最深的部分对应于火山口的中心（类型I）的情况下，深火山口和对应于火山口的边缘（类型II）的情况下，浅火山口。结果表明：（1）氧化铝陶瓷中存在于晶界处的微量成分在早期受到侵蚀，随后氧化铝颗粒脱落;（2）氧化铝在Na_2HPO_4或Na_3PO_4溶液中的溶解效果较好。（1）SiC在0.01或0.1mol/lNaOH溶液中的分解效果较好;（2）SiC颗粒本身在这些溶液中受到侵蚀。

An experimental investigation of the etching of the surface of ceramic materials was carried out by means of electro-discharge machining method in electrolyte solutions. Specimens of alumina or SiC ceramics were immersed in 0.01 - 1 mol/l NaOH, HCl, H_3PO_4, NaH_2PO_4, Na_2HPO_4 and Na_3PO_4 solutions. 0.8 mm tungsten wire was used as a tool electrode and it was pressed to the specimen.The maximum penetration depth and shape of crater depend on (1) kinds of electrolyte and its concentration, (2) applied voltage between tool electrode and counter electrode and (3) polarity of it. Craters in case of negative tool electrode were deeper than those in case of positive tool electrode. Two types of craters were observed. The deepest portion corresponded to the center of crater (TYpe I) in case of the deep crater and corresponded to the edge of crater (TYpe II) in case of the shallow crater. It was observed that (1) minor composition of alumina ceramic, which existed at the grain boundary of alumina grain, was attacked at the early stage and then alumina grain broke away, and that (2) alumina in Na_2HPO_4 or Na_3PO_4 solutions gave the good results. It was also observed that (1) SiC in 0.01 or 0.1 mol/l NaOH soultion gave the good results and that (2) SiC grain itself was attacked in these solutions.