Fabrication of Iron Hollow Spheres by Reduction Sintering Process

Iron hollow spheres were fabricated by reduction sintering process. The reduction of iron oxide completed in a range from 573 to 973 K, and the shrinkage (sintering) advanced rapidly in a range from 673 to 1073 K. In spite of the large shrinkage, the shape of sintered body showed only an at all small distortion from a sphere. The compression curve of the block which joined iron spheres showed the plateau load region where a load change is small, and the average plateau load strongly depends on the compression strength of unit spheres. By means of chemical reaction controlled un-reacted core model, activation energy of reduction process has been estimated to be 22 kJ/mol.