Effect of raw materials on microstructure and bending strength of porous in situ MgO/Fe–Cr–Ni composites

Abstract

Abstract Porous in situ MgO (17.0–34.9 wt.%)/Fe–Cr–Ni composites were prepared from the mixtures of Mg and the powder compositions, such as nano-Fe 2 O 3 + Cr + Ni, micro-Fe 2 O 3 + Cr + Ni, micro-Cr 2 O 3 + Fe + Ni or micro-Ni 2 O 3 + Fe + Cr, via pressureless reactive sintering at 600–800 °C for 2 h. The influence of raw materials on microstructure and bending strength of the resultant porous composites were studied. The results showed that the porous composites, fabricated at 700 °C for 2 h, consisted of MgO, Cr 0.7 Fe 0.36 Ni 2.9 and CrFe phases generally. The porous composite fabricated from the mixture of nano-Fe 2 O 3 , Mg, Cr and Ni, whose fracture mode was a mainly ductile manner, had uniform pore size and possessed higher bending strength than other resultant porous composites.