Magnetic material containing rare earth element, iron, nitrogen, hydrogen and oxygen and bonded magnet containing the same

A magnetic material represented by the formula:

• R.sub..alpha. Fe.sub.(100-.alpha.-.beta.-.gamma.-.delta.) N.sub..beta. H.sub..gamma. O.sub..delta. (I) 637
• wherein
• R is at least one rare earth element inclusive of Y;
• .alpha. is from 5 to 20 atomic percent,
• .beta. is from 5 to 25 atomic percent,
• .gamma. is from 0.01 to 5 atomic percent,
• .delta. is from 3 to 15 atomic percent,
• and the Fe atoms are substituted by Co atoms in a substitution ratio of from 0.01 to 49 atomic percent of the Fe atoms,
• said magnetic material being in the form of particles, at least 50 percent by volume of which are single magnetic domain grains having a particle size of from 1 .mu.m to 5 .mu.m,
• at least 80 atomic percent of the oxygen, based on the total amount of the oxygen, being present in a surface portion of the particles,
• and said magnetic material exhibiting a higher (BH).sub.max when fabricated into a magnet than said magnetic material without oxygen.

A bonded magnet comprising:

• particles of at least one magnetic material represented by the formula:
• R.sub..alpha. Re .sub.(100-.alpha.-.beta.-.gamma.-.delta.) N.sub..beta. H.sub.65 O.sub.67 (I)
• wherein
• R is at least one rare earth element inclusive of Y;
• .alpha. is from 5 to 20 atomic percent,
• .beta. is from 5 to 25 atomic percent,
• .gamma. is from 0.01 to 5 atomic percent and
• .delta. is from 3 to 15 atomic percent,
• at least 50 percent by volume of the particles being single magnetic domain grains having a particle size of from 1 .mu.m to 5 .mu.m, at least 80 atomic percent of the oxygen, based on the total amount of the oxygen, being present in a surface portion of the particles, and
• a binder interspersed between the particles to bond the particles together,
• and said bonded magnet exhibiting a higher (BH).sub.max than a bonded magnet as defined above, but where oxygen is absent from said magnetic material.

A bonded magnet comprising:

• particles of at least one magnetic material represented by the formula:
• R.sub..alpha. Fe.sub.(100-.alpha.-.beta.-.gamma.-.delta.) N.sub..beta. H.sub..gamma. O.sub..delta. (I)
• wherein
• R is at least one rare earth element inclusive of Y;
• .alpha. is from 5 to 20 atomic percent,
• .beta. is from 5 to 25 atomic percent,
• .gamma. is from 0.01 to 5 atomic percent,
• .delta. is from 3 to 15 atomic percent,
• and the Fe atoms are substituted by Co atoms in a substitution ratio of from 0.01 to 49 atomic percent of the Fe atoms,
• at least 50 percent by volume of the particles being single magnetic domain grains having a particle size of from 1 .mu.m to 5 .mu.m, at least 80 atomic percent of the oxygen, based on the total amount of the oxygen, being present in a surface portion of the particles, and
• a binder interspersed between the particles to bond the particles together,
• and said bonded magnet exhibiting a higher (BH).sub.max than a bonded magnet as defined above, but where oxygen is absent from said magnetic material.