High energy product rare earth-iron magnet alloys

• US 4,851,058 A
• Filed: 09/03/1982
• Issued: 07/25/1989
• Est. Priority Date: 09/03/1982
• Status: Expired due to Term

• Current Assignee: General Motors Corporation (Motors Liquidation Co. GUC Trust)
• Original Assignee: General Motors Corporation (Motors Liquidation Co. GUC Trust)
• Inventors: Croat, John J.
• Primary Examiner(s): Sheehan, John P.
• Application Number:
  US06/414,936
• Time in Patent Office: 2,517 Days
• Field of Search: 148/31, 148/57, 148/403, 148/435, 148/302, 148/123 B, 420/455, 420/416, 420/442, 420/581, 420/583, 420/587, 420/83, 420/121, 75/123 E
• US Class Current: 148/302
• CPC Class Codes: C22C 45/02 with iron as the major constituent
• CPC Class Codes: H01F 1/057 and IIIa elements, e.g. Nd2Fe14B

Abstract

The hard magnetic properties, including intrinsic coercivity, remanence and energy product of rapidly quenched, rare earth-transition metal alloys has been substantially increased by the addition of suitable amounts of the element boron. The preferred rare earth constituent elements are neodymium and praseodymium, and the preferred transition metal element is iron.

Claims

1. A magnetically hard alloy composition comprised of at least about 10 to about 40 atomic percent neodymium, praseodymium or mixtures thereof;

at least about 50 to about 90 atomic percent iron and from about 0.5 to 10 atomic percent boron.

2. A magnetically hard alloy formed by melting and rapidly solidifying a mixture comprising from about 10 to about 40 atomic percent of one or more rare earth elements taken from the group consisting of praseodymium, neodymium, samarium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, and mischmetals thereof where the neodymium and/or praseodymium comprise at least about 10 atomic percent of the total composition;

up to about 90 atomic percent of one or more transition metals taken from the group consisting of iron, nickel and cobalt including at least about 50 atomic percent iron based on the total composition; and

from about 0.5 to 10 atomic percent boron.

3. A magntically hard alloy composition formed by melting a mixture consisting essentially of at least about 10 to about 40 atomic percent neodymium, praseodymium, or mixtures thereof;

at least about 50 to about 90 precent iron and greater than about 0.5 but less than about 10 atomic percent boron and quenching said mixture from its molten state at a rate such that the resultant alloy has a finely crystalline magnetic phase and intrinsic magnetic coercivity of at least about 1,000 Oersteds.

4. A magnetically hard alloy composition comprising one or more rare earth elements including at least about 10 to about 40 atomic percent of one or more rare earth elements taken from the group consisting of neodymium, praseodymium or mixtures thereof;

at least about 50 to about 90 atomic percent iron, and at least about 0.5 atomic percent boron, said atomic percents being based on the total alloy composition and said alloy having an intrinsic magnetic coercivity of at least about 5,000 Oersteds at room temperature.

5. A magnetically hard alloy composition having a coercivity of at least about 1,000 Oersteds at room temperature and consisting essentially of one or more earth elements including at least about 10 to about 40 atomic percent neodymium and/or praseodymium based on the total composition;

at least about 0.5 atomic percent boron;

up to about 90 atomic percent of one or more transition metal elements taken from the group consisting of iron, nickel, and cobalt where said iron comprises at least about 50 atomic percent of the total alloy composition;

the presence of the boron in the alloy increasing its Curie temperature with respect to a like alloy containing substantially no boron.

6. A magnetically hard, rapidly quenched alloy composition comprising at least about 10 to about 40 atomic percent of one or more rare earth elements taken from the group consisting of neodymium and praseodymium;

from about 0.5 to about 10 atomic percent boron; and

the balance one or more transition metal elements taken from the group consisting of iron, nickel and cobalt where said iron comprises at least about 50 atomic percent of the alloy composition.

7. A magnetically hard alloy having the constituent formula

8. A hard magnet consisting essentially of an alloy having the constituent formula

9. A magnetically hard alloy composition having a coercivity of at least about 1,000 Oersteds at room temperature and comprising from about 10 to about 40 atomic percent of one or more rare earth elements taken from the group consisting of praseodymium, neodymium, samarium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, and mischmetals thereof wherein the neodymium and/or praseodymium comprise at least about 10 atomic percent of the total composition;

one or more transition metal elements including at least about 50 to 90 atomic percent iron based on the total composition; and

at least about 0.5 atomic percent boron based on the total composition.

10. A magnetically hard alloy having a coercivity of at least about 1,000 Oersteds at room temperature formed by rapidly quenching a mixture comprised of about 10 to 40 atomic percent of one or more rare earth elements wherein at least about 10 atomic percent of said alloy is neodymium and/or praseodymium;

greater than about 0.5 but less than about 10 atomic percent boron based on the total composition and up to about 90 percent of mixtures of iron and cobalt including at least about 50 atomic percent iron based on the total composition, the Curie temperature and energy product of said magnetically hard quenched alloy being higher than that of a like alloy processed in like manner which contains substantially no boron.

11. A magnetically hard alloy composition comprised of one or more rare earth elements including at least about 10 to about 40 atomic percent based on the alloy composition of neodymium and/or praseodymium;

one or more transition metal elements including at least about 50 to 90 atomic percent iron based on the alloy composition, and greater than about 0.5 atomic percent of the alloy composition boron, said alloy having a magnetic coercivity of at least about 5,000 Oersteds and a remanence of at least about 4,000 Gauss at room temperature.