Tdk Corporation

Ken-ichi Nishikawa

Chikara Ishizaka

Masashi Miwa

Tetsuya Hidaka

Jun Hagiwara

Haruna Nakajima

The present invention provides an R-T-B based sintered magnet including RTB crystal grains wherein; a grain boundary is formed by two or more adjacent RTB crystal grains, an R&#x2014;O&#x2014;C concentrated part, in which concentrations of R, O and C are higher than those in the RTB crystal grains respectively, is in the grain boundary, and a ratio (O/R) of O atom to R atom in the R&#x2014;O&#x2014;C concentrated part satisfies the following formula (1):0.4&#x3c;(O/R)&#x3c;0.7.

R-T-B based sintered magnet

The present invention provides an R-T-B based sintered magnet including RTB crystal grains wherein; a grain boundary is formed by two or more adjacent RTB crystal grains, an R&#x2014;O&#x2014;C concentrated part, in which concentrations of R, O and C are higher than those in the RTB crystal grains respectively, is in the grain boundary, and an area of the R&#x2014;O&#x2014;C concentrated part occupying in that of the grain boundary on a cut surface of the R-T-B based sintered magnet is within a range of 10% or more to 75% or less.

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Tokyo, Japan

Ken-ichi Nishikawa