Abstract
The production method of composite material having a large amount of porosity, relatively high-strength and small dimensional change during sintering has been proposed by the authors. The composite material can be obtained by sintering a mixture of metal powder and ceramic powder containing vanishing binder in the oxidizing atmosphere. And it is already employed as molds for vacuum forming of plastic sheets and molding of ceramics utilizing its permeability of air and water.
In this report, the sintering behavior and the mechanical properties of this composite material was examined with the use of iron powder as metal powder and mullite powder as ceramic powder. It was clarified that iron changes into a-Fe2O3 during sintering process, and the interaction of expansion and shrinkage of iron particles caused by oxidation and sintering produces relatively high strength and small dimensional change. The sintered body consists of twe layers, outer sintered hard layer has high strength and smooth surface, and inner non-sintered layer has large porosity and superior permeability. It is an advantageous feature for the mold of several forming and molding process.
