Of Mosi <sub> 2 </ Sub> Electric Materials Research

MoSi₂ is a kind of intermetallic compound with the conductivity like metal and the high antioxidation property like ceramics. Because of its excellent property in heat rates and antioxidation, for many years it has been used in glass industry, electronic industry, metallurgy industry and ceramic industry as one of the mainstream of resistance heat element used in high temperature industry furnace. The Kanthal in Sweden is the best company which produces the M0Si₂ heat element all over the world. It almost forestall the international market, but its process is still in secret. There are a long distance between China and overseas in the performance of MoSi₂ heating element.On the basis of MoSi₂ heating element produced by one company, we used Copper Block Quenching (CBQ) to analyze the microcosmic process of SHS used in powder preparation. We used different sintering process to prepare the heating element. The reaction products were analyzed using a scanning electron microscope (SEM), optical microscope and X-ray diffractometer (XRD). The bending strength was measured by universal material tester and the antioxidation performance was measured by using the box high temperature calcar.Many valued results have been obtained in the study. Finally pure MoSi₂ can be obtained by SHS although there are intermediate products Mo3Si and Mo₅Si₃, and their free enthalpy reduce no matter what intermediate product has been generated. The inter-products were also generated in combustion synthesis, but the generation of MoSi₂ must on the basis of the melting of Si. The relative densities of heat elements can be improved by increasing the sintering temperature and extending sintering time rationally, but it can result in secondary recrystallization if the sintering temperature is too high and the sintering time is too long. It can be seen from the oxidation kinetics curve that as the sintering temperature higher, the oxidation resistance becomes excellent, and it shows the steady trend in the mass. The element that did not take safeguard cementing badly, and it distributes in the pore in majority which cause the stress concentration. There is an evidence phenomena of secondary recrystallization and can not be bent because of its brittleness in high temperature. The element that took safeguard did not cementing, and there is no phenomena of secondary recrystallization, and so it can be bent into needed shape at high temperature. Furthermore, the bent surface is as clean as a whistle and the SiO₂ film is in a good condition, and the bending strength is high.