Effects of Reducing Agents and Pre-sintering Annealing on Phase Changes during the Sintering of W-type Ferrites

W-type ferrites are easily decomposed into M-type ferrite and spinel ferrite during the sintering process, so it is difficult to obtain a W-type single-phase sintered bodies. Therefore, carbon as a reducing agent is added and heat treatment before sintering is performed. However, the effect of these treatments on the change in the crystal phase during sintering has not been clarified in detail. In this study, the effect of carbon addition and heat treatment before sintering on the change in the crystal phase during sintering was investigated in detail by removing the samples from the electrical furnace during sintering. Furthermore, similar experiments were carried out with the addition of CaCO3 and SiO2 as sintering aids.