金刚石砂轮用陶瓷结合剂的制备工艺与性能研究

发布时间：2018-03-26 09:09

  本文选题：陶瓷结合剂　切入点：金刚石砂轮　出处：《郑州大学》2017年硕士论文

【摘要】：陶瓷结合剂金刚石砂轮具有强度高、加工效率高、加工精度高、形状保持性好、使用寿命长等优点而被广泛地应用于金刚石复合片、硬质合金、结构陶瓷、宝石等高硬脆性材料的切削和磨削加工生产中。本文以降低金刚石砂轮结合剂的热膨胀系数、烧结温度、提高其机械强度为目的,设计了以SiO_2-Al_2O_3-B_2O_3-Na_2O系统玻璃为基础的陶瓷结合剂。采用高温熔融法制备出陶瓷结合剂。分别研究了Na_2O、Li_2O和ZnO对陶瓷结合剂以及金刚石砂轮块结构与性能的影响规律。采用高能球磨对陶瓷结合剂进一步破碎,研究了高能球磨时间对陶瓷结合剂粒度的影响及其对结合剂的结晶温度和抗弯强度的影响。通过XRD和FTIR研究分析了陶瓷结合剂的相组成和成分;采用热膨胀仪、维氏硬度仪、电子万能试验机分别测试结合剂及金刚石砂轮样品的热膨胀系数、硬度和强度;采用SEM观察陶瓷结合剂烧结体的微观结构和金刚石磨粒与结合剂界面结合特征;采用激光粒度分析仪测试高能球磨后陶瓷结合剂的粒度,采用DSC和XRD测试分析陶瓷结合剂的结晶温度和不同烧结温度的晶相组成。研究结果表明:(1)通过研究氧化钠含量对陶瓷结合剂性能的影响规律发现:随着Na_2O含量的升高,SiO_2-Al_2O_3-B_2O_3-Na_2O系陶瓷结合剂的烧结温度降低,当Na_2O含量达到12.31wt.%时,陶瓷结合剂具有最低的烧结温度。采用Na_2O含量为9.31wt.%的结合剂与230-270目金刚石混合制备出150浓度的金刚石砂轮试条,在680℃烧结的砂轮样品的抗弯强度最高,其值达到了53.5 MPa,此时该结合剂的热膨胀系数为10.3×10-6/℃。(2)通过调节Li_2O和ZnO的比例,可以有效地降低陶瓷结合剂的烧结温度,并提高结合剂的抗弯强度,当在Li_2O和ZnO的比例为4:1时,所合成的结合剂与230-270目金刚石混合制备出150浓度的金刚石砂轮试条,在580℃烧结所得的金刚石砂轮试块的抗弯强度达到了66.4 MPa,此时该结合剂的热膨胀系数约为9.5×10-6/℃。(3)通过高能球磨的方法可以有效地降低陶瓷结合剂粉体的粒度,高能球磨75 min后,得到的粉体粒径为358 nm,其结晶温度比原始粉体的结晶温度降低了约50℃,高温烧成所形成的晶体均为β-锂辉石晶体,并且球磨后得到的超细粉体在850℃温度烧结后,其抗弯强度达到61.67 MPa,比没有经过高能球磨的原始粉体烧结后样品的强度提升了近40%。通过进一步调节结合剂的配方,使其结晶温度降低至696℃,热膨胀系数降至4.6×10-6/℃,抗弯强度提高至105MPa,金刚石砂轮试样的抗弯强度达到了76.6 MPa。
[Abstract]:Ceramic bond diamond grinding wheel has been widely used in diamond composite, cemented carbide and structural ceramics because of its advantages such as high strength, high processing efficiency, high machining precision, good shape retention, long service life, etc. The purpose of this paper is to reduce the thermal expansion coefficient of diamond wheel bond, sintering temperature and improve its mechanical strength in cutting and grinding of hard brittle materials such as precious stones. Ceramic binders based on glass in SiO_2-Al_2O_3-B_2O_3-Na_2O system were designed. Ceramic binders were prepared by high temperature melting method. The effects of Na _ 2O _ 2 Li _ 2O and ZnO on the structure and properties of ceramic binders and diamond wheel blocks were studied respectively. High energy ball milling further crushing of ceramic binders, The effect of high energy ball milling time on the particle size of ceramic binder and its effect on the crystallization temperature and bending strength of the binder were studied. The phase composition and composition of the ceramic bond were analyzed by XRD and FTIR. The thermal expansion coefficient, hardness and strength of the binder and diamond wheel samples were measured by electronic universal testing machine, the microstructure of ceramic bond sintered body and the interfacial bonding characteristics of diamond abrasive particles and binder were observed by SEM. The particle size of ceramic bond after high energy ball milling was measured by laser particle size analyzer. The crystallization temperature of ceramic binder and the crystal phase composition of different sintering temperature were analyzed by DSC and XRD. The results showed that the effect of sodium oxide content on the properties of ceramic bond was studied. Increasing the sintering temperature of the SiO2-Al2O3-B2O3-Al2O3-Na2O-based ceramic binders, When the content of Na_2O is 12.31 wt.%, the sintering temperature of the ceramic bond is the lowest. The 150 concentration diamond grinding wheel test strip is prepared by mixing the binder with 230-270 mesh diamond with 9.31 wt.% Na_2O content. The bending strength of the grinding wheel sample sintered at 680 鈩，

本文编号：1667247