SiO_(2f)/SiO_2复合材料表面碳活化辅助钎料润湿机理

Mechanism of activated carbon layer on SiO_(2f)/SiO_2 composite to assist brazing alloy wetting

针对SiO_(2f)/SiO_2复合材料钎焊中存在表面钎料润湿性差、难以获得有效接头的难题,提出一种表面碳活化辅助钎料润湿的方法.利用PECVD方法低温原位在复合材料表面制备极薄的碳活化层,以辅助活性钎料在其表面铺展润湿.研究表明采用该方法在400℃/15 min条件下即可在SiO_(2f)/SiO_2表面制备出碳活化层,且复合材料表面形貌无变化.润湿结果表明碳活化层的引入显著改善了Ag-Cu-Ti钎料在复合材料表面的润湿性,860℃/10 min下润湿角从131°降至27°.碳活化层主要借助碳与活性元素良好的亲和力活化了复合材料表面状态,进而促进活性钎料在其表面铺展润湿.

A new method was proposed to preparation of activated carbon layer on SiO_(2f)/SiO_2 composite to assist brazing alloy wetting,in order to solve the problems that poor wettability of brazing alloy on SiO_(2f)/SiO_2 and poor performance of joints.PECVD was occupied to preparation of extremely thin activated carbon layer on the surface of SiO_(2f)/SiO_2 composite to assist active brazing alloy spreading and wetting. Analysis showed that the method can prepare activated carbon layer on the surface of SiO_(2f)/SiO_2 composite at the temperature of 400 ℃ and holding time for 15 min,and the surface morphology of composite showed no obvious changes. Wetting results showed that introducing activate carbon layer can significantly improve the wettability of AgCu-Ti brazing alloy on the surface of SiO_(2f)/SiO_2 composite when the wetting angle dropped from 131° to 27° at the temperature of 860 ℃ and holding time for 10 min. Activate carbon layer can promote the wettability of active brazing alloy,because carbon showed good affinity with active elements to activate the surface state of SiO_(2f)/SiO_2 composite.