SURFACE TREATMENT OF FE-ND-B MAGNETIC POWDER

摘要

PURPOSE:To obtain a magnetic powder which is difficult to cause oxidation in and after manufacturing plastic magnets, by polymerizing and encapsulating in the presence of water an alloy powder of Fe-Nd-B or Fe-Nd-Pr-B with a monomer of mono- or bis-organic phosphite compound having unsaturated bonds or with a mixture of said monomer and a monomer capable of copolymerizing with said monomer. CONSTITUTION:An alloy powder of Fe-Nd-B or Fe-Nd-Pr-B is encapsulated in the presence of water with a 30-100 wt.% of monomer of mono- or bis- organic phosphite compound capable of radical polymerization and a 70-0 wt.% of monomer capable of copolymerizing with said monomer. The magnetic alloy to be used comprises 10-15 atomic % of Nd or in total of Nd+Pr, 4-10 atomic % of B, 0.4-3 atomic % of Si, 0.1-3 atomic % of Al and 0.5-3.5 atomic % in total of Si+Al, the remaining being Fe.