The viability of microwave sintering process to produce a ceramic tool insert

Abstract

Microwave processing of ceramics is fast emerging as a new field of ceramic processing and material synthesis. The past year has witnessed significant progress in the aspects of commercialization and application of the technology in new areas. Due to that reason, several experiments were conducted on microwave heating of ceramics. The aim of the study is to investigate i) whether microwave is a viable alternative to produce sintering parts, ii) the effect of soaking time on the properties of the sample, and iii) the influence of several binders including nickel, ferum, chromium and cobalt to tungsten carbide cermets. The study involved studying the density, hardness and microstructure of the sintered samples. The samples were compacted using an Instron machine at 200 MPa in a cylindrical shape using pallet press with a height of 10 mm and a diameter of 20 mm and sintered in microwave hybrid sintering at 1450°C for two different soaking time (10 min and 20 min). The soaking time of 10 min showed better density, hardness and microstructural results compared to those of 20 min. In comparing between the binders, Ni and Fe (Ni-Fe) showed better results compared to Ni and Cr. While cobalt, nickel and ferum (Co-Ni-Fe) had enhanced results compared to Co and Cr (Co-Cr). Although there are a lot of research studies on several other binders, there is still no finding on the use of microwave hybrid sintering to sinter different mixing binders of tungsten carbide cermets. Therefore, in this research, it is believed that the use of microwave hybrid sintering is viable to sinter tungsten carbide cermets with different binders. The density result showed that each composition of the sintered density was higher compared to green density, which increased by 30% than the green density on average. On the other hand, the hardness results from the commercial cutting tool for tungsten carbide cermet was in the range of 80 to 92 HRA and the highest result for hardness in this research was 84.3 HRA, which means that the insert can be used for commercial use depending on the application.