US4135953A — Permanent magnet and method of making it

Claim 1

Independent Claim 199 words

A rare earth permanent magent comprising an alloy consisting of: RE.sub.2 (Co.sub.1-x-y Fe.sub.x TM.sub.y).sub.17+z wherein: Re is at least one rare earth element; Tm is at least one transition element selected from the group consisting of chromium, manganese, titanium, tungsten and molybdenum; -2 ≦ z ≦ 1; 0.5 < (1-x-y) < 1 0.05 ≦ x ≦ 0.4 0.01 ≦ y ≦ 0.2 wherein said rare earth permanent magnet is further characterized by possessing high values of coercive field strength, an ideal demagnetization curve and a remanence of more than 9KG and wherein said rare earth permanent magnet is prepared by the process which comprises mixing together a starting alloy of the composition RE 2 (Co 1-x-y Fe x TM y ) 17+z and 8 to 14 wt.% of a samarium-rich sinter additive compound composed of 50-60 wt.% samarium and 40-50 wt.% of an alloy Co 1-x-y Fe x TM y wherein both said starting alloy and said sinter additive are each in powder form of average grain size 2.0 to 10 μm; magnetically aligning the mix; compressing it to a greenling; sintering it to form a magnet; and subjecting said magnet to a heat treatment to 400° C.-600° C.

Claim 2

Dependent Claim 199 words

A rare earth permanent magent comprising an alloy consisting of: RE.sub.2 (Co.sub.1-x-y Fe.sub.x TM.sub.y).sub.17+z wherein: Re is at least one rare earth element; Tm is at least one transition element selected from the group consisting of chromium, manganese, titanium, tungsten and molybdenum; -2 ≦ z ≦ 1; 0.5 < (1-x-y) < 1 0.05 ≦ x ≦ 0.4 0.01 ≦ y ≦ 0.2 wherein said rare earth permanent magnet is further characterized by possessing high values of coercive field strength, an ideal demagnetization curve and a remanence of more than 9KG and wherein said rare earth permanent magnet is prepared by the process which comprises mixing together a starting alloy of the composition RE 2 (Co 1-x-y Fe x TM y ) 17+z and 8 to 14 wt.% of a samarium-rich sinter additive compound composed of 50-60 wt.% samarium and 40-50 wt.% of an alloy Co 1-x-y Fe x TM y wherein both said starting alloy and said sinter additive are each in powder form of average grain size 2.0 to 10 μm; magnetically aligning the mix; compressing it to a greenling; sintering it to form a magnet; and subjecting said magnet to a heat treatment to 400° C.-600° C.

Claim 3

Dependent Claim 34 words

The permanent magnet of claim 1, wherein the rare earth (RE) element is samarium, or a mixture of samarium and a light rare earth element of atomic number 57-62, misch metal or mixtures thereof.

Claim 4

Dependent Claim 24 words

The permanent magnet of claim 1, wherein the average grain size of the material used to prepare the magnet is smaller than 3.0 μm.

Claim 5

Dependent Claim 12 words

The permanent magnet to claim 1, which has a predominantly single-phase structure.

Claim 6

Dependent Claim 192 words

A process for preparing a rare earth permanent magnet comprising an alloy consisting of: RE.sub.2 (Co.sub.1-x-y Fe.sub.x TM.sub.y).sub.17+z wherein: Re is at least one rare earth element; Tm is at least one transition element selected from the group consisting of chromium, manganese, titanium, tungsten and molybdenum; -2 ≦ z ≦ 1 0.05 ≦ x ≦ 0.4 0.01 ≦ y ≦ 0.2 wherein said rare earth permanent magnet is further characterized by possessing high values of coercive field strength, an ideal demagnetization curve and a remanence of more than 9KG; which comprises mixing together a starting alloy of the composition RE 2 (Co 1-x-y Fe x Tm y ) 17+z and 8 to 14 wt.% of a samarium-rich sinter additive compound composed of 50-60 wt.% samarium and 40-50 wt.% of an alloy Co 1-x-y Fe x TM y wherein both said starting alloy and said sinter additive are each in powder form of average grain size 2.0 to 10 μm; magnetically aligning the mix; compressing it to a greenling; sintering it to form a magnet; homogenizing and annealing said magnet; and then subjecting said magnet to a heat treatment of 400° C.-600° C.

Claim 7

Dependent Claim 192 words

A process for preparing a rare earth permanent magnet comprising an alloy consisting of: RE.sub.2 (Co.sub.1-x-y Fe.sub.x TM.sub.y).sub.17+z wherein: Re is at least one rare earth element; Tm is at least one transition element selected from the group consisting of chromium, manganese, titanium, tungsten and molybdenum; -2 ≦ z ≦ 1 0.05 ≦ x ≦ 0.4 0.01 ≦ y ≦ 0.2 wherein said rare earth permanent magnet is further characterized by possessing high values of coercive field strength, an ideal demagnetization curve and a remanence of more than 9KG; which comprises mixing together a starting alloy of the composition RE 2 (Co 1-x-y Fe x Tm y ) 17+z and 8 to 14 wt.% of a samarium-rich sinter additive compound composed of 50-60 wt.% samarium and 40-50 wt.% of an alloy Co 1-x-y Fe x TM y wherein both said starting alloy and said sinter additive are each in powder form of average grain size 2.0 to 10 μm; magnetically aligning the mix; compressing it to a greenling; sintering it to form a magnet; homogenizing and annealing said magnet; and then subjecting said magnet to a heat treatment of 400° C.-600° C.

Claim 8

Dependent Claim 28 words

The method of claim 5, wherein the starting alloy is produced by melt-metallurgy, is then subjected to a stabilization annealing below the liquidus temperature and is then crushed.

Claim 9

Dependent Claim 26 words

The method of claim 5, wherein the starting alloy and the sintering additive are ground to an average grain size of from 2.0 to 5 μm.

Claim 10

Dependent Claim 24 words

The method of claim 5, wherein the greenling is sintered in the temperature range of 1110° C. to 1180° C. to form a magnet.

Claim 11

Dependent Claim 25 words

The method of claim 5, wherein the magnet, after the sintering treatment, is homogenization-annealed in the temperature range of from 1000° C. to 1100° C.

Claim 12

Dependent Claim 14 words

A method of claim 5, wherein the magnet is magnetized after being heat treated.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1982-01-22	1982-07-24	1983-01-23	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1986-01-22	1986-07-24	1987-01-23	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1990-01-22	1990-07-24	1991-01-23	$7700.00	Window Closed / Lapsed

Permanent magnet and method of making it

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