Permanent magnet and process for producing the same
AssigneeFujitsu Limited
InventorsMasato Sagawa, Takeaki Sakai, Tatsuji Sasaki, Zenzo Henmi
Life of this patent
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Abstract
The brittle nature and magnetic properties of the rare earth cobalt magnet are improved by the simultaneous addition of Cu and V. Cu and V are included in amounts of from 0.5 to 6% by weight and from 7 to 19% by weight, respectively. The simultaneous addition enables the rear earth cobalt magnet to be cast in the form of an article. In addition, the simultaneous addition not only improves the mechanical properties of the sintered article, in which form the conventional magnet was available, but also the magnetic properties, such that, for example, the coercive force is increased when the molar ratio of cobalt with respect to rear earth elements is great.
Claims29
In a permanent magnet of an RCo type, wherein the R component Co is cobalt or both cobalt and iron, and the molar ratio of said R component to said Co component is from 1:5 to 1:8.5,
- an improvement comprising replacing a part of said Co component with both vanadium and copper, in a manner such that said vanadium and said copper are included from 0.5 to 6% by weight, respectively, based on said components R and Co.
In a process for producing a permanent magnet of an RCo type, wherein the component R is one or more rare earth elements and the component Co is cobalt or both cobalt and iron, and the molar ratio of said R component to said Co component is from 1:5 to 1:8.5,
- an improvement comprising adding vanadium and copper to said components R and Co and
- melting the resultant mixture, wherein a part of said Co component is replaced with both vanadium and copper in a manner such that said vanadium and said copper are included from 0.5 to 3% by weight and from 9 to 15% by weight, respectively.
In a process for producing a permanent magnet of an RCo type, wherein the component R is one or more rare earth elements and the component Co is cobalt or both cobalt and iron, and the molar ratio of said R component to said Co component is from 1:5 to 1:8.5,
- an improvement comprising adding vanadium and copper to said components R and Co,
- melting the resultant mixture, wherein a part of said Co component is replaced with both vanadium and copper, in a manner such that said vanadium and said copper are included from 0.5 to 6% by weight and from 7 to 19% by weight, respectively, based on said components R and Co,
- solidifying the obtained melt in a vessel, through which the heat is withdrawn in a predetermined direction and
- solution-treating and ageing the solidified melt.
In a process for producing a permanent magnet of a RCo type, wherein the R component is one or more rare earth elements and the Co component is cobalt or both cobalt and iron, and the molar ratio of said R component to said Co component is from 1:5 to 1:8.5, said process comprising the steps of pressing a powder consisting of said components, and sintering said pressed powder, an improvement comprising replacing a part of said Co component with both vanadium and copper, in a manner such that said vanadium and said copper are included from 0.5 to 6% by weight and from 7 to 19% by weight, respectively, based on said components R and Co.
Dependencies are inferred from the claim text.