原料处理工艺及气孔演化对AZO靶材烧结致密化的影响

发布时间：2018-02-23 07:00

  本文关键词： 热压 靶材 孔径 氧化锌铝 煅烧　出处：《粉末冶金技术》2017年06期 　论文类型：期刊论文

【摘要】：以ZnO和Al_2O_3粉体为原料,按照98∶2(质量比)球磨混合制备氧化锌铝(aluminum zinc oxide,AZO)粉体,通过扫描电镜和透射电镜观察粉体形貌及均匀性,确立最佳混合工艺;将混合均匀的粉体进行煅烧预处理后进行热压烧结致密化试验,通过差热法分析原料性能,阿基米德法分析靶材密度以及压汞实验分析气孔演化对AZO靶材烧结致密化的影响。结果表明:微纳米粉体在球磨4 hr时Al元素分布均匀性最好,煅烧前的混合粉体在差热分析过程中失重0.43%并伴随放热效应;煅烧处理后粉体形貌类球形,在差热分析实验0℃-1000℃无失重,表明挥发组分排除干净且无异常放热效应,烧结性能得到优化。采用预处理的AZO粉体在不同热压温度和保温时间下制备AZO靶材,分析热压致密过程中平均孔径和闭孔率的变化规律。由此发现:在热压致密化初级阶段(温度900℃~1100℃时),连通气孔发生合并与生长,平均孔径先稍有收缩随后迅速增大为158 nm,同时闭孔率维持在0.5%以下,靶材密度不断上升;当温度升高至1150℃时,连通孔径逐渐缩小至108 nm,大量连通气孔转为闭合状态导致闭孔率迅速上升至7.2%以上,表明体系已经进入到热压深度致密化阶段。在1150℃、18 MPa下,保温时间延长到70 min时,连通气孔合并生长同时闭孔率异常增加至7%,孔径分布范围变宽导致出现反致密化现象;当保温保压时间延长至90 min时,气孔尺寸减小到136 nm,闭孔率下降至3.7%,靶材相对密度上升到96.2%,在较低压力和较短保温时间下实现了AZO靶材的深度致密化。
[Abstract]:Zinc oxide aluminum zinc oxideAZO powder was prepared from ZnO and Al_2O_3 powder by ball milling with mass ratio of 98: 2. The morphology and homogeneity of the powder were observed by scanning electron microscope and transmission electron microscope, and the optimum mixing process was established. After calcining and pretreating the mixed powder, the densification test of hot pressing sintering was carried out, and the properties of raw materials were analyzed by differential calorimetry (DTA). The effects of pore evolution on the sintering densification of AZO targets were analyzed by Archimedean method and mercury injection experiments. The results showed that the distribution of Al elements was the best when the powder was milled for 4 hr. The weight loss of the mixed powder before calcination was 0.43% with exothermic effect during DTA, and the powder morphology was spherical after calcination, and there was no weight loss at 0 鈩，

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