| 摘要 |
PURPOSE: To improve reaction resistance and durability and to reduce the production cost of a tool material for firing of a soft ferrite compsn. having a spinel structure by using a material containing MgO.Al2 O3 as the main component and ZrO2 as the subcomponent. CONSTITUTION: This tool material contains 85-99.5wt.% MgO.Al2 O3 as the main component and 0.5-15wt.% ZrO2 as the sub component. Compared to a tool material comprising alumina or alumina-mullite, the obtd. material causes no irregular shrinkage in the ferrite nor such a problem that SiO2 reacts with the ferrite to damage the crystal of the ferrite and to deteriorate the characteristics of the ferrite. Since the obtd. material contains ZrO2 , it is excellent in durability and inexpensive compared with a material comprising zirconia or magnesia. Since the obtd. material contains one or more elements of the metal elements which are present in the soft ferrite having a spinel structure, and since the material contains <=5wt.% compsn. of the same spinel structure as the ferrite, no influence of movement of the component from the ferrite to the tool material is caused, which means any pretreatment is not necessary. |
