Fe-Al-Cr heat resistant sinters

Abstract

Preparation, structure and properties of heat resistant Fe-Al-Cr sinters have been analyzed. Sinters were prepared from a mixture of Fe-Al, Fe and Cr powders, uniaxially pressed and sintered in a temperature 1448 K (1175 °C), a time ranging from 5-600 min, and in a vacuum of 10-4 Pa. The sinters produced were subjected to the following tests: metallographic, X-ray analysis, X-ray microanalysis and the high temperature oxidation resistance. Fe-Al-Cr sinters consists of diffusive aluminized and chromed iron particles and fine Al2O3 and/or Cr2O3 oxides. They have porosity below 6%. The relations between chemical contents of sinters as well as the parameters of the sintering process, structure and properties of sinters have been defined. The Fe-Al-Cr sinters have approximately as good oxidation resistance as non-porous Fe-Al-Cr alloys. A specific feature of oxidation Fe-Al-Cr sinters is filling of sinter pores by oxidation product in the initial period of the process. As a result of this process a Fe-Al-Cr sinters occurs similar behaviour to non-porous alloys during further stages of oxidation.