摘要
溶胶-凝胶法是一种新颖的原位凝固成型工艺。将硝酸盐溶液、Si O_2溶胶和表面改性金刚石颗粒混合,引入高效分散剂等途径制备出了低黏度高固含量的金刚石微粉浆料,原位凝固后坯体各部位密度具有很好的均匀性,制备的胚体在850℃/1.5h条件下烧结后得到金刚石砂轮,研究混合料浆中固含量对砂轮的微观结构以及表面粗糙度、抗弯强度和气孔率等性能的影响。结果表明:采用溶胶-凝胶法制备的砂轮烧结体可达到理论密度的97%,基本实现致密化。Si O_2-Al_2O_3-Zn O-Na_2O-Li_2O-P_2O_5复合氧化物陶瓷结合剂晶化程度高,晶型完整;随混合料浆中固含量增加,砂轮的气孔率先降低后升高,而抗弯强度则先升高后降低,当固含量(体积分数)为60%时,砂轮的孔隙率和抗弯强度分别达到最小值(26.5%)和最大值(68MPa)。与传统粉末压制法相比,采用溶胶-凝胶原位法制备的砂轮,微观结构均匀,磨削后的硬质合金工件表面无较深划痕,工件的表面粗糙度为0.049μm,砂轮的抗弯强度和气孔率分别提高约33.8%和41.1%。
Sol-gel method is a novel in-situ solidification process.By mixing nitrate solution,SiO_2sol and surface modified diamond particles,adding highly efficient dispersant,the low viscosity and high solid content of diamond powder slurry is prepared.After in situ solidification,the density of each part of the body has good uniformity.The diamond grinding wheel was obtained sintering the body at 850℃/1.5h.It has studied the effects of solid content on microstructure,surface roughness,bending strength and porosity of the grinding wheel.The results show that the sintered body of the grinding wheel prepared by sol-gel method can reach 97%of the theoretical density and basically realize the densification.SiO_2-Al_2O_3-Zn O-Na_2O-Li_2O-P_2O_5composite oxide ceramic binder exhibits high crystallization degree and the integrity crystal structure.With the increase of solid content,the porosity of sintered body decrease first and then increase,while the bending strength changes in the opposite trend simultaneously.When the solid content is 60vol%,the porosity and the bending strength of sintered body reach the minimum of 26.2%and the maximum of 69MPa respectively.Compared to the traditional pressing method,the microstructure of grinding wheels prepared by in-situ sol-gel method is uniform and no deep scratches are observed on the workpiece surface with roughness of 0.049μm,and the bending strength and porosity were increased by 33.8%and 41.1%respectively.
出处
《超硬材料工程》
CAS
2018年第1期7-12,共6页
Superhard Material Engineering
