球磨介质对玻璃渗透氧化铝复合材料微观结构的影响

Effects of milling media on microstructure of glass infiltration alumina composite

目的 :探讨球磨介质对玻璃渗透氧化铝复合材料微观结构的影响 .方法 :在粉体球磨时选用了两种不同的球磨介质 玛瑙和Al2 O3 制备玻璃渗透氧化铝复合材料 .采用扫描电镜观察微观形貌 ,采用EDAX进行分析局部成分 .结果 :在粉体球磨过程中 ,玛瑙球磨介质会形成碎屑进入到Al2 O3 粉体中 ,在后续的烧结过程中 ,玛瑙碎屑和Al2 O3 粉体发生低共熔反应形成先驱玻璃相 ,阻碍了后续玻璃渗透过程的进行 ,从而在最终的复合材料中保留了玛瑙碎屑所形成的缺陷孔 .而使用Al2 O3 球磨介质的复合材料中无此缺陷 .结论 :使用Al2 O3球磨介质 ,可以显著减少氧化铝渗透玻璃复合材料中的缺陷气孔 .

AIM: To investigate the effects of milling media on the microstructure of glass infiltration alumina ceramic. METHODS: Different milling medias were employed in powder milling processes. The microstructure of the samples was investigated by scanning electron microscopy (SEM) and the local composition was studied by EDAX. RESULTS: In the powder milling process, agate granules were doped into Al 2O 3 powder. When Al 2O 3 blanks were partially sintered, eutectic reaction between the agate granules and Al 2O 3 particles led to the formation of colorless glass. The colorless glass was infiltrated into the adjacent Al 2O 3 networks and voids formed. During the colorful glass infiltration, the colorless glass kept solid and hampered the infiltration of the colorful glass into the voids. As a result, the voids became some permanent defects in the glass/Al 2O 3 composites. CONCLUSION: With the change of the milling media, this permanent defect decreases dramatically.