| 摘要 |
PURPOSE:To prevent the magnet from being easily oxidized and easily absorbing moisture by a method wherein the surface of R-Fe-B (R represents one or more of rare earth elements including Y) rare earth alloy powder for permanent is coated with ester phosphoric acids. CONSTITUTION:The rare earth group permanent magnet alloy powder may be composed of R-Fe-B magnet alloy but preferably R-Fe(Co)-B-M base comprising 25-35weight% of R exceeding one more of rare earth group elements including Y, 0.5-2.0weight% of B, 0-10weigt% of M exceedng one or two kinds out of Al, Ng, Mo, Ga, Ti, V, Cr, Ni, Si, Mn and the remaining element comprising Fe of Fe and Co. The ester phosphoric acid group as a stabilizer having the moisture absorption resistance is the general term of the compound comprising hydrocarbon radical substituted for hydrogen of orthophosphoric acid, in the concrete, such as triethyl phosphate, trioley phosphate, etc. The coating procedures are as follows, i.e., in the sealed wet type process, an inert solvent comprising previously melted specific amount of ester phosphoric acid group as well as a magnet powder are prepared and after they are finely crushed, the solvent is removed by vacuum drying process. |
