烤瓷用镍铬合金经不同预处理的表面氧化膜研究

目的：分析烤瓷用镍铬合金在上瓷前经过阳极钝化，除气预氧化处理后对其表面氧化膜的形貌、厚度的影响。方法：将15个试片随机分成3组，分别经不同的实验条件处理后，每组抽取2片进行扫描电镜观察，其余3片采用XPS和AES进行表面氧化膜分析。结果：1)阳极钝化处理的试片表面发生了轻度的选择性溶解，增加了金属的表面积，所形成的氧化膜厚度是空白对照组的1．72倍。2)除气加预氧化组则形成较厚的氧化膜，为空白对照组的23．32倍，而且氧化膜内氧原子的相对含量远远高于其他实验组。厚的氧化膜的热膨胀系数与金、瓷不同，产生较高的残余应力，不利于烤瓷时金属离子向陶瓷内的扩散，且易形成一些碳化物，影响金瓷界面的化学结合。结论：采用阳极钝化法处理镍铬合金表面，方法简便，形成的氧化膜容易控制，操作可重复性强，是烤瓷前金属表面处理的新方法。

The Research of the Surface Oxide Film on Different Pretreated Ni-Cr Porcelain Alloy

Objective: To study the shape and thickness of oxide film on Ni-Cr porcelain alloy after different surface pretreatment including anodizing and degassing-preoxidation. Methods: 15 samples were made and divided into 3 groups at random. Then after different surface pretreatment,the oxide film of two samples of each group were analyzed using electronic scanning microscope. The rest 3 samples were measured by x- ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES). Results: 1)Lightly selective solution appeared on the surface of anodizing samples. The sample's metal surface expanded and the thickness of oxide film is 1.72 times of the control samples. 2) The samples of degassing-preoxidation group formed very thick oxide film on surface and it was 23.32 times of the control samples, the relative content of O element in thick oxide film was higher than the other 2 groups. The thick oxide film's thermal expansion coefficient was different from Ni-Cr alloy & ceramic which led to higher residual stresses. It hindered the metallic ions from migrating into the porcelain and formed some carbonate resulting in the poor chemical bonding of porcelain-to-metal. Conclusion: The method of anodizing Ni-Cr porcelain alloy is technically feasible and repeated.It can easily control the forming of oxide film and is a good method of surface pretreatment before firing cycle.