两步常压烧结工艺对氧化铝陶瓷制备及性能的影响

发布时间：2018-05-05 03:10

本文选题：氧化铝陶瓷 + 两步常压烧结　；参考：《铸造技术》2017年06期

【摘要】：采用高纯度氧化铝粉为原料,高纯MgO为烧结助剂,通过两步常压烧结工艺制备出了致密度较高的氧化铝陶瓷。探究了第一步烧结温度T1、第二步烧结温度T2的保温时间以及烧结助剂MgO的添加量的工艺条件对氧化铝陶瓷的致密度、微观形貌和力学性能的影响。结果表明,提高T1温度和延长T2温度下保温时间均能提高样品的相对密度。而随MgO添加量的增加,样品的相对密度先增加后降低。较高的T1温度和长的保温时间均会使样品的晶粒尺寸变大。由于MgO作为第二相添加剂的钉扎作用,MgO的加入有利于晶粒尺寸的降低。较长的保温时间会促进样品晶粒的生长并伴随晶粒的Ostwald熟化,小晶粒逐渐消失而大晶粒数量增加,粒径分布的不均匀性增加。样品的强度取决于致密化程度和晶粒尺寸。对于短时间保温的样品,当T1温度较高时力学性能较为出色,但随保温时间的增加呈现出相反的趋势。MgO添加量的增加虽然对晶粒有一定的细化作用,但会导致致密度下降,因此样品的强度随MgO添加量的增加先上升而后略有降低。
[Abstract]:Alumina ceramics with high density were prepared by using high purity alumina powder as raw material and high purity MgO as sintering assistant. The effects of the first sintering temperature T _ 1, the second step sintering temperature T _ 2 and the addition of MgO on the density, micromorphology and mechanical properties of alumina ceramics were investigated. The results show that the relative density of the samples can be increased by increasing T1 temperature and prolonging the holding time at T2 temperature. However, with the increase of MgO content, the relative density of the sample first increased and then decreased. Higher T 1 temperature and longer holding time increase the grain size of the sample. The addition of MgO as a second phase additive can reduce the grain size. The longer the holding time is, the more the grain growth is and the Ostwald ripening of the grain, the smaller grain gradually disappears, the larger grain quantity increases, and the inhomogeneity of particle size distribution increases. The strength of the sample depends on the degree of densification and grain size. When T1 temperature is high, the mechanical properties of the samples with short holding time are better, but with the increase of holding time, the increase of MgO content has a certain effect on refining the grain, but it will lead to the decrease of density. Therefore, the strength of the sample increases firstly with the increase of MgO content, and then decreases slightly.
【作者单位】：神华神东煤炭集团有限责任公司;西安交通大学金属材料强度国家实验室;
【基金】：国家自然科学基金资助项目(51672209) 神华集团科技创新资助项目(csie16036600) 中国教育部博士点基金资助项目(20130201120003) 陕西省自然科学基础研究计划资助项目(2016jq5046)
【分类号】：TQ174.758.11

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