Microstructure and Properties of Carbonyl Iron Powder

As characterized by scanning and transmission electron microscopy, the microstructure of carbonyl iron powder is that of an expanded a-iron lattice containing carbon, oxygen and nitrogen, having a high internal stress, but no martensite phase. This fine, spherical powder is made by the thermal decomposition of iron pentacarbonyl. In the laboratory, particle size distribution has been characterized by image analysis and laser light scattering techniques. Data on narrow particle size distributions has been obtained, including electrical (P and Q) values, and compared to standard grades. As a result, the relationship of the decomposition process to the resulting metallurgical properties can be explored.