| 摘要 |
PURPOSE:To improve the mechanical strength and magnetic characteristics of a resin-bonded type rare earth-iron group permanent magnet by thermally treating alloy powder, a fundamental composition thereof consists of rare earth R, iron Fe, and boron B, in a high vacuum. CONSTITUTION:The titled permanent magnet mainly comprises alloy powder consisting of a 10-30% rare earth metal (including a case of rare earth metals of two kinds or more), 3-10% boron B, and 60-87% iron Fe (including Fe in which at least one kind or more of transition metals, such as Co, Cu, etc. are substituted for one part of Fe) in an atomic percentage, and includes inevitable impurities in manufacture. An alloy having this composition is thermally treated in a high vacuum of 10<-5>Torr or more in the state of powder having particle size of 10-80mum, and a thermosetting organic resin having a weight ratio of 0.5-10% is added. When the particle size of alloy powder is too small, alloy powder is easy to be oxidized, and causes trouble during heat treatment and crushing; when the particle size exceeds 80mum, there are a plurality of magnetic domains in a particle, and magnetic characteristics are deteriorated. An elevation to a high temperature in a vacuum of 10<-5>Torr or less is undesirable because oxidation progresses and magnetic performance lowers. |
