LIU Jie 1, JIANG Qiangguo 2
(1. School of Electromechanical Engineering, Guangzhou Panyu Polytechnic, Guangzhou 511483, Guangdong, China;
2. School of Electromechanical Engineering, Guangdong University of Technology, Guangzhou 510006, Guangdong, China)
Abstract: Si3N4 ceramic powder was sintered to make cutting tools by using ternary sintering additives such as MgO-Lu2O3-Re2O3(Re represents La, Gd, Er, Yb), and then heat treatment was carried out on some SN-LuYb samples, so as to change Si3N4 intergranular phase into a crystalline phase. All the samples were tested for fracture toughness, Vickers hardness, and XRD, and then cut the cast iron HT250 under the same conditions. After that, SEM and EDS were used to analyze the wear surface morphology and elemental composition of the tool after cutting. Results show that the Si3N4 sample sintered by using such ternary sintering additives as MgO-Lu2O3-Re2O3 fully meets the requirements of the use of cutting tools. In the HT250 cutting experiment, abrasion and adhesion are the main forms of tool wear. The cutting life of all the samples have surpassed that of imported Si3N4. In addition, the life of the heat treated SN-LuYb substantially increases by 137%, which shows that the second intergranular phase has a decisive influence on the wear resistance of Si3N4 ceramics.
Key words: silicon nitride ceramic tool; ternary sintering additives; wear; intergranular phase; heat treatmen