Na_2O含量对金刚石砂轮用Na_2O-SiO_2-Al_2O_3-B_2O_3系陶瓷结合剂性能的影响

Effect of Na_2O Content on Properties of Na_2O-SiO_2-Al_2O_3-B_2O_3 System Vitrified Bond for Diamond Grinding Wheel

采用球磨法制备Na_2O质量分数分别为12.31%,9.31%,7.31%的Na_2O-SiO_2-Al_2O_3-B_2O_3系陶瓷结合剂,研究了Na_2O含量对烧结前后陶瓷结合剂的物相组成、力学性能、热膨胀系数,以及对陶瓷结合金刚石砂轮抗弯强度的影响。结果表明:较高的Na_2O含量有利于抑制石英相的析出;随着Na_2O含量的增加,烧结后陶瓷结合剂的硬度和抗弯强度降低,热膨胀系数在较低温度(620~640℃)烧结后增大,在较高温度(660~680℃)烧结后先增后降;当Na_2O的质量分数为9.31%、烧结温度为680℃时,所得陶瓷结合金刚石砂轮的抗弯强度最大,为53.5 MPa;3种陶瓷结合剂制备得到的金刚石砂轮具有相似的微观结构。

Na2O-SiO2-Al2O3-B2O3 system vitrified bonds with Na2O mass fractions of 12.31%,9.31% and7.31%,respectively,were prepared by ball milling,and then the effects of Na2O content on the phase composition,mechanical properties,coefficient of thermal expansion of the vitrified bonds before and after sintering,and on the bending strength of the vitrified bond combined diamond grinding wheel were investigated.The results show that relatively high content of Na2O helped inhibit the precipitation of quartz phases.With the increase of Na2O content,the hardness and bending strength of the vitrified bond decreased,and the coefficient of thermal expansion increased at relatively low temperatures（620-640℃）while first increased and then decreased at relatively high temperatures（660-680 ℃）.When the mass fraction of Na2O was 9.31% and the sintering temperature was 680℃,the obtained vitrified bond combined diamond grinding wheel had the highest bending strength of 53.3 MPa.The diamond grinding wheel prepared with the three vitrified bonds had a similiar microstructure.