【作者】 张云浩；

【导师】 李志宏；

【作者基本信息】 天津大学 ， 材料学， 2007， 硕士

【摘要】 本实验利用溶胶-凝胶法制备了陶瓷刚玉磨料前驱体,并采用无压烧结技术最终制备出了新型陶瓷刚玉磨料。利用扫描电镜、金刚石单颗粒抗压强度测定仪和显微硬度测试仪等测试设备,系统的研究了不同种类添加剂、添加剂配比及加入量、造粒方式、烧结工艺对磨料的显微结构、单颗粒抗压强度和显微硬度的影响。实验结果表明,不同添加剂种类、添加剂配比及加入量、造粒方式、升温速率、烧结温度、保温时间对磨料的性能均有很大的影响。选取合适的添加剂成分能有效地控制晶粒的大小和晶型;适当的添加剂配比不但可以有效地促进氧化铝烧结,抑止晶粒的长大,同时可以提高磨料的单颗粒抗压强度;加入适量的添加剂能够细化晶粒,提高磨料的强度及显微硬度;使用干凝胶直接造粒的方法得到的坯体密度较高,能显著地提高烧结体的致密度及抗压强度;烧结过程中低温阶段较高的升温速率会导致磨料颗粒出现宏观裂纹,高温阶段升温过慢会促进晶粒生长,使磨料性能恶化;烧结温度对磨料的性能影响较为明显,烧结温度过高会直接导致晶粒的长大及强度的降低;在所研究的保温时间范围内保温时间对磨料的显微结构影响不明显,但适当的保温时间却有利于提高磨料的单颗粒抗压强度。更多还原

【Abstract】 New ceramic corundum abrasives were prepared through pressureless sintering of the precursor made by sol-gel method. The effects of different additives, additives combination and amounts, granulation methods and sintering process on the microstructure, single particle compressive strength and microhardness of the abrasives were analyzed systematically by using SEM, diamond single particle compressive strength tester and microhardness tester.The results showed that the properties of the abrasives were influenced intensely by additives combination and amounts, granulation methods, heating rates, sintering temperature, holding time in the sintering temperature. The grain size and shape could be well controlled by choosing suitable additives. Proper additives combination would promote sintering of alumina, restrain the growth of grains, improve the single particle compressive strength. With appropriate additives amounts, the grain size was reduced, the strength and microhardness of the abrasives were improved. Direct granulation method from dry gel was good to increase the density of green bodies and the strength of sintered bodies. Higher heating rate in low temperature period would lead to macrocracks, while much lower heating rate in high temperature period would result in the overgrowth of abrasive grains, which would deteriorate the properties of abrasives. Sintering temperature had obvious effect on the properties of the abrasive, higher sintering temperature would induce the growth of the grain and decrease the strength of abrasives. Holding time in the researched range had little influence on the microstructure of abrasives, but proper holding time would improve the single particle strength of abrasives.更多还原