A METHOD OF PRODUCING A DIFFUSION ALLOYED IRON OR IRON-BASED POWDER, A DIFFUSION ALLOYED POWDER, A COMPOSITION INCLUDING THE DIFFUSION ALLOYED POWDER, AND A COMPACTED AND SINTERED PART PRODUCED FROM THE COMPOSITION.

摘要

The present invention relates to a method of producing a diffusion alloyed powder consisting of an iron or iron-based core powder having particles of an alloying powder containing Cu and Ni bonded to the surface of the core particles, comprising providing a unitary alloying powder capable of forming particles of a Cu and Ni containing alloy, mixing the unitary alloying powder with the core powder, and heating the mixed powders in a non-oxidizing or reducing atmosphere to a temperature of 500–1000 ˚C during a period of 10–120 minutes to convert the alloying powder into a Cu and Ni containing alloy, so as to diffusion bond particles of the Cu and Ni alloy to the surface of the iron or iron-based core powder. The alloying powder may be a Cu and Ni alloy, oxide, carbonate or other suitable compound that on heating will form a Cu and Ni alloy. Preferably, the total content of Cu and Ni is at most 20wt%, the particle size distribution of the Cu and Ni alloying powder is such that D50 is less than 15 μm, and the ratio Cu/Ni in wt% is between 9/1 and 3/1. The compacted and sintered parts produced from the diffusion alloyed iron-based powder of the invention present a minimum of variation of dimensional change from component to component.