Tdk Corporation

Shigeki Yanagida

Yoshihiko Minachi

Takahiro Mori

Hiroyuki Morita

Nobuhiro Suto

Tatsuya Katoh

Naoki Mori

Yuuki Aburakawa

Noboru Ito

Junichi Nagaoka

Kunio Ohno

Syunsuke Kurasawa

A ferrite magnet and a ferrite sintered magnet including a ferrite magnetic material are provided. A main phase of the ferrite magnetic material includes a ferrite phase having a hexagonal crystal structure, and metal element composition expressed by Ca1-w-x-yR wSr xBayFezMm wherein 0.25&#x3c;w&#x3c;0.5, 0.01&#x3c;x&#x3c;0.35, 0.0001&#x3c;y&#x3c;0.013, y&#x3c;x, 8.7&#x3c;z&#x3c;9.9, 1.0&#x3c;w/m&#x3c;2.1, 0.017&#x3c;m/z&#x3c;0.055 and Si component is at least included as a sub-component, and wherein; when content y1 mass % of the Si component in the ferrite magnetic material, with respect to SiO2, is shown on Y-axis and a total content x1 of z and m is shown on X-axis, a relation between x1 and y1 is within a range surrounded by 4 points placed on X-Y coordinate having the X and Y axes.

Ferrite magnetic material, ferrite magnet, and ferrite sintered magnet

A sintered ferrite magnet having a ferrite phase with a hexagonal structure as the main phase, wherein the composition of the metal elements composing the main phase is represented by the following general formula (1):RCaA(FeM): &#x2003;&#x2003;(1),x, m, y and z in formula (1) satisfying all of the conditions represented by the following formulas (2)-(6):0.2&#x2266;&#x2266;0.5: &#x2003;&#x2003;(2)0.13&#x2266;&#x2266;0.41: &#x2003;&#x2003;(3)0.70.15: &#x2003;&#x2003;(4)0.18&#x2266;&#x2266;0.31: &#x2003;&#x2003;(5)9.6&#x2266;12&#x2266;11.8: &#x2003;&#x2003;(6),and wherein the density of the sintered ferrite magnet is at least 5.05 g/cm, and the crystal grains of the sintered ferrite magnet satisfy all of the conditions represented by the following formulas (7) and (8), where L &#x3bc;m is the average for the maximum value and S &#x3bc;m is the average for the minimum value among the diameters passing through the center of gravity of each grains in the crystal cross-section parallel to the c-axis direction of hexagonal structures.&#x2266;0.95: &#x2003;&#x2003;(7)1.8&#x2266;&#x2266;2.5: &#x2003;&#x2003;(8).

Ferrite sintered magnet

The present invention provides a ferrite magnet material comprising, as a main phase, a ferrite having a hexagonal structure, the main phase containing A, La, R, Fe and Co, wherein A is at least one element selected from Sr, Ba and Pb, R is Pr and/or Nd, and the proportions of the total metal elements A, La, R, Fe and Co in the main phase are respectively A: 1 to 13 atomic %, La: 0.003 to 10 atomic %, R: 0 to 10 atomic % (excluding 0) Fe: 80 to 95 atomic % and Co: 0.05 to 5 atomic % based on the total amounts of metal elements. The residual magnetic flux density Br and coercive force HcJ can be improved without increasing the content of Co by incorporating Pr and/or Nd along with La and Co in the ferrite magnet material.

Ferrite magnetic material and process for producing the same

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Tokyo, Japan

Shigeki Yanagida