MgO与Li_2O摩尔比及烧结温度对结合剂及cBN磨具性能的影响  

Effect of MgO:Li_2O molar ratio and sintering temperature on properties of vitrified bond and cBN grinding wheel

作　　者：翟浩冲[1,2] 万隆[1] 王俊沙[1] 王志起[1] 胡伟达[1] 宋冬冬[1] 

机构地区：[1]湖南大学材料科学与工程学院,长沙410082 [2]国家电网许继集团有限公司,许昌461000

出　　处：《复合材料学报》2013年第1期119-124,共6页Acta Materiae Compositae Sinica

基　　金：湖南省科技厅(2011GK2066)

摘　　要：以ZnO-Na2O-SiO2-Al2O3-B2O3陶瓷体系为基础,制备了添加不同摩尔比Li2O和MgO的陶瓷结合剂及立方氮化硼(cBN)磨具。利用X衍射测试仪、线性热膨胀测试仪、扫描电镜等研究了MgO∶Li2O摩尔比(M值)和烧结温度对陶瓷结合剂及磨具性能的影响。结果表明:随着M值增加,结合剂的软化点温度增加,耐火度及化学稳定性均增强,线性热膨胀系数先增加后降低。当M值为0.67时,随着烧结温度的升高,石英晶相的析出被抑制,诱导析出Mg(Zn)Al2O4晶相,且含量逐渐增加,尺寸先减小后增加;当温度为870℃时,Mg(Zn)-Al2O4晶粒尺寸最小,约为2μm,结合剂结构最为致密,抗折强度达到最大值136.28MPa。随着烧结温度的提高,cBN磨具气孔率和吸水率先降低后增加,体积密度、硬度、抗折强度、磨耗比以及磨削效率先增加后降低;当烧结温度为890℃,磨耗比及磨削效率最高,分别为98.72%和1.3675g.min-1。The vitrified bonds with different molar ratios about MgO = Li20（M ） and cBN wheels were prepared at the base of ZnO - Naz O - SiO2 - A12 Oa - B2 Oa ceramic system. X- diffraction analysis, SEM and thermal expansion coefficient tests were used to study the influence of M and sintering temperature on the properties of vitrified bonds and eBN wheels. The results show that with the M value increasing, the soften temperature, refractoriness and chemical stability of the bond increase, while the thermal expansion coefficient increases and then decreases. When the M value is 0. 67, the increasing of the temperature restrains the quartz crystal separating. Meanwhile, the content of Mg（Zn）A12 04 crystalline phase increases, and the size decreases at first and then increases. Moreover, when the temperature reaches 870 ℃, the grain size is the minimum about 2 Um, and the most compact microstructure is obtained. At the same time, the bending strength of the bond reaches the maximum value of 136. 28 MPa. As the sintering temperature increasing, the porosity and water absorption of cBN wheel decrease at the beginning and then increase. However, its bulk density, hardness, bending strength, abrasion and grinding efficiency exhibit contrary trend. When the temperature is 890 ~C, the abrasion and grinding efficiency reaehe the maximum values of 98.72~ and 1. 3675 g ~ min 1respectively.

关 键 词：磨具 陶瓷结合剂 立方氮化硼 抗折强度 磨耗比 

分 类 号：TG74[金属学及工艺—刀具与模具]