Microstructure control and grain refinement mechanism of ceramic corundum abrasives prepared by sol-gel combined with two step sintering process
ZHAO Jiong1, LI Zhuan1, ZOU Lingfeng2, TANG Huixian1, XU Yang1, LI Yuxing1, ZOU Huijing3
1. State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China; 2. College of Materials Science and Engineering, Changsha University of Science and Technology, Changsha 410114, China; 3. College of Arts and Science, New York University, New York 10012, United States
Abstract：Ceramic corundum abrasive precursor containing La2O3-TiO2-SiO2 composite additive was prepared by sol-gel method using pseudo boehmite with grain diameter of 6 μm as raw material. The ceramic corundum abrasives were prepared by conventional sintering method and two-step sintering method, respectively. The microstructure and element distribution of abrasives were analyzed by SEM and TEM, and the grain sizes were analyzed by imagePro software. The results show that the temperature of the first sintering stage significantly affects the final grain size of the abrasive when the two-step sintering method is adopted. Due to the low temperature in the second sintering stage, the later sintering mechanism changes from grain boundary migration to grain boundary diffusion, thus the grains are significantly refined and the abnormal grain grow this avoided. Appropriately reducing the sintering temperature in the second stage is conducive to obtaining fine equiaxed grains with uniform distribution, but it will lead to a decrease in abrasive density. Compared with the corundum abrasives prepared by the traditional sintering method, the abrasives prepared by the two-step sintering method have a smaller grain size, uniform size and high hardness, although the density is reduced. Fine and uniform equiaxed grains are obtained by two-step sintering at 1 300 ℃ and 1 200 ℃ for 10 h, respectively. The average grain size is (334±97) nm, and the density and hardness (HV) are 3.87 g/cm3 and (18.3±0.29) GPa, respectively.
赵炯, 李专, 邹凌峰, 唐惠娴, 许阳, 李郁兴, 邹慧璟. 溶胶-凝胶法结合二步烧结制备陶瓷刚玉磨料的微结构控制及晶粒细化机理[J]. 粉末冶金材料科学与工程, 2022, 27(3): 319-326.
ZHAO Jiong, LI Zhuan, ZOU Lingfeng, TANG Huixian, XU Yang, LI Yuxing, ZOU Huijing. Microstructure control and grain refinement mechanism of ceramic corundum abrasives prepared by sol-gel combined with two step sintering process. Materials Science and Engineering of Powder Metallurgy, 2022, 27(3): 319-326.
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2022, Vol. 27 
