JPS6173861A - Hard magnetic material and its production - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a permanent magnet, that is, a hard magnet 5 formed from a transition metal, a rare metal, and boron, and also relates to a method for manufacturing such a material for a permanent magnet. It depends.

BACKGROUND OF THE INVENTION Hard magnets, or permanent magnets, are characterized by high coercivity and large remanence. These are formed from transition metals and rare earth metals such as samarium-cobalt, have a good temperature and 11. It may also be formed from transition metals, rare earth metals and boron, such as iron-iron-boron. Transition metals
A hard magnet made of rare earth metal-boron is characterized by low cost and a crystal grain size of about 1 to about 10 magnetic domains. A transition metal-rare earth gold and 1-boron hard magnet and its manufacturing method are disclosed in U.S. Pat.
No. 70 "Hard magnetic alloys of transition metals and lanthanides", U.S. Patent No. 4,409,043 "Amorphous transition metal lanthanide alloys" of NC Turn (N.:, Koon), and Noe No.・Float (J, J,
Japanese Patent Application Publication No. 59-64,739 "High Energy Laminated Rare Earth-Iron Magnet Alloy" corresponding to U.S. Patent Application No. 414,936 by No. ), U.S. Patent Application No. 508,766, "High Energy Rare Earth-Iron Magnet Alloys."

In order to produce a transition metal-rare earth metal-boron based magnetic alloy, it is necessary to rapidly cool the material from a molten state. However, in order to obtain the highest performance, i.e., high coercive force, large remanence, and high energy product,
The composition and quenching conditions must be extremely precisely controlled.

That is, it is necessary to control the stoichiometric ratio and quenching conditions within extremely narrow ranges. Moreover, even if the optimum composition and/or quenching conditions β) are extremely deviated, a weak and hard magnet is formed or a soft magnetic material is formed.

Materials with an apparent chemical composition have a minimum melting point, a composition close to that of eutectoid alloys, for example. However, the properties of the solidifying melt are not constant, but are considered to be largely influenced by local deviations in the liquid composition relative to the eutectoid composition. Therefore, if the quenching rate is too slow, the material becomes soft magnetic and requires remelting and recasting. See, for example, U.S. Patent No. 4,402,770 to Turn et al. and U.S. Patent Application No. 5 to Float.
According to the description in No. 08,266, if the quenching rate is too fast, the magnet becomes weak, and subsequent annealing is required to obtain a hard magnetic one-stroke structure.

Both Goon and Float utilize a 52-step process with sequential super-quenching and back-annealing.

The two-step process of quenching and pack annealing avoids the effects of magnetic/ξ-mirameter sensitivities on the process nozzle, but it is economically burdensome because it increases the manufacturing stage.

SUMMARY OF THE INVENTION The present invention provides microcrystalline hard magnets that are manufactured without requiring strict process parameters, remain quenched, and do not require annealing. The present invention further provides a method for making quenched non-annealed microcrystalline hard magnets that are manufactured without requiring strict process parameters and do not require subsequent annealing.

According to a preferred embodiment, the magnetic material is (1 iron,
(2) rare earth metals or lanthanides such as cerium, neodymium, praseodymium and mixtures thereof; (3) boron; and (4) e.g. aluminum, aluminum-vanadium, zirconium. and an amount of a glass-forming additive selected from the group consisting of zirconium-niobium and t-quench rate range.

According to a particularly preferred embodiment, the magnetic material for forming the as-quenched microcrystalline hard magnet is produced by high-speed quenching of a molten composition consisting of iron and neodymium or praseodymium and boron and aluminum. . Using this magnetic material, a microcrystalline hard magnet that remains quenched and is not annealed is manufactured.

The invention will be better understood from the following description based on the drawings.

Characteristics of the hard magnetic alloy as quenched according to the present invention are that it has a morphological structure that combines large residual magnetism, high energy product, high coercive force, and high temperature; , no annealing is required to obtain the above properties.

A preferred composition is represented by the formula TMwRExByGz.

TM represents one or more transition metals selected from the group of iron, cobalt, nickel, manganese and mixtures thereof. Preferably iron is used as the main or only transition metal. When iron is not the only transition metal, iron constitutes the majority of the total transition metal content of the alloy, generally comprising about 70 atoms or more of the total transition metals present in the magnetic material. Cobalt, nickel and/or manganese may optionally be present in an amount of up to 30 atomic parts of the total transition metal content of the composition, i.e. it is preferred that the transition metal in the alloy, except for minor impurities, consists essentially entirely of iron. However, they have no harmful effects and sometimes have additional effects.

RE represents one or more rare earth metals. The rare earth gold KF4 is a light rare earth metal selected from the group consisting of cerium, neodymium, praseodymium and mixtures thereof.

B represents boron.

G represents a glass-forming additive selected from the group consisting of aluminum, aluminum-vanadium, zirconium, zirconium-niobium to extend the range of quenching rates in Class 11 or combinations. It is believed that the types of combined glass forming agents interact synergistically. For example, aluminum
Vanadium and zirconium-niobium are examples of this;
This combination is preferred. Opposite types of combined glass-forming materials act inversely to each other. Examples are aluminum-zirconium, aluminum-niobium, vanadium-zirconium and vanadium-niobium.

Wl, the transition metal atomic number, is about 60 to about 92. X, that is, the atoms of the entire rare earth metal are about 8 to about 40
It is. yl, that is, the number of boron atoms is from very small to about 20. 2, ie, the atoms of the substance that extend the range of quenching rates, is the amount of glass-forming material that extends the range of quenching rates. The content of glass-forming materials is generally greater than about 1 atom, preferably greater than about 2 atom, but generally less than about 10 atom.

Hard magnetism results from the interaction of boron, transition metals, and rare earth metals. The advantageous processing method of the present invention can be used because any or all of the boron, transition metals, rare earth metals, or other alloy constituents are partially replaced by glass-forming agents.

Despite the presence of glass formers, the amount of boron must be sufficient to interact with the transition metals and rare earth metals, but not to form non-magnetic phases or to form soft or non-magnetic alloys. The amount should not be so large as to cause Furthermore, the amount of boron should not be so small that it cannot produce an effective hard magnet. While the boron composition is maintained within these ranges, glass-forming agents are added to extend the range of quenching rates at which magnetic alloys with high coercivity, large remanence, and high energy products are formed.

The invention further provides a method of forming an alloy. Alloy 1i,
It is formed by a rapid solidification method, ie, a rapid cooling method, to form a hard magnet. In the melt spinning method that rapidly cools molten metal, the quenching speed e
1 (rotational speed of the chill wheel) x (radius of the cooling wheel) When the hydrostatic head and melt temperature are constant, the quenching rate is monotonous and approximately proportional to the linear velocity of the cooling surface.0.5
~0.2 caliber with a head of ~104 inches/square inch~
When using a melt spinning machine with a copper-clad cooling wheel of 20 inches in diameter spaced 1 to 30 mm apart from the 20 sequential openings and using a cooling wheel speed of 1000 pm f5, the linear velocity is 1.
．． 32×103α/sec.

The quenching rate is greater than 0.5 x 105 C/sec, preferably greater than about I x 105 C/sec. In particularly preferred embodiments, it is greater than about 10.times.10.sup.5 C/sec.

The transition metal-rare earth metal-boron molten composition, for example, has a relatively steep local i & large value of coercivity as a function of cooling wheel speed. Cooling wheel speed [is 10 inches of cooling wheel speed corresponding to peak coercivity or 10
% reduction, the coercive force drops to 30% of its peak value. In contrast, for the transition metal-rare earth metal-boron-aluminum molten composition, for example, when coercive force is plotted as a function of cooling wheel speed, the coercive force has a gradual local maximum and peaks at the cooling wheel speed. Even if the cooling wheel speed corresponding to the coercive force is increased or decreased by 10%, the peak value of coercive force of 85 to 90 inches is maintained. The peak coercive force of 60 inches is maintained even if the magnetic field is increased by 20% or decreased by 20%. According to the present invention, a molten composition of a-transfer metals, rare earth metals, boron, and glass formers is quenched within a range of quenching rates that form a vitreous hard material with an optimum particle size. The method may optionally include an anneal after quenching when a larger particle size is required than that achieved by quenching.

It is preferred that the component materials of the magnetic alloy have a purity of 99.9%, preferably 99.99%.

The precursors, ie, the A-transfer metal, the rare earth UA@Ii, the boron, and a glass-forming material for extending the range of quenching rates are melted together in an inert atmosphere, such as an argon-helium atmosphere. The melt-remelt process may be repeated several times to obtain a substantially homogeneous alloy.

The substantially homogeneous alloy is delivered to the surface to be quenched for rapid quenching of the material. Quenching surface a is a fast moving inert surface, i.e. melt III! 11 alloy effluent at a quench rate of at least about 300 ports/minute. Preferably the fast moving surface has a surface area of about 300α/
preferably a high speed rotating inert surface such as a smooth steel wheel rotating at an angular velocity such as to provide a four-line velocity of greater than or equal to about 10,000 α/min and less than about 5,000 α/min.

The method of the invention is illustrated by the following examples.

Example (2) Preparation of Alloy Appropriate constituent components were weighed to prepare alloys of Examples. Praseodymium is Morton'l'hiokola alpha with a declared purity of 99.99%.
lfa) Praseodymium. Neodymium is manufactured by Research Chemicals, Inc.
h Chemicals Inc.) display purity 999
It is neodymium of chi. The boron is Morton Thiokol alpha boron with a declared purity of 99.9%.

The aluminum is from Atlantic Equipment with an indicated purity of 99.99%.
ENT) aluminum. The purity of iron is indicated as 99.9.
99 inch Atlantic 2 type electrolytic iron.

The above components were placed in a quartz crucible with an outer diameter of 19 m and an inner diameter of 17 sn, and heated in an electric induction furnace in a pure argon atmosphere to form an ingot. The ingot was homogenized by repeated remelting.

■Quick cooling Rapid cooling was performed in an Alvin pressurized quartz crucible with an orifice at the bottom. The orifice was vertically spaced from a moving cooling surface, a rotating steel wheel having a diameter of 45 tx (20 inches). Molten metal was injected through an orifice into a copper-clad cooling wheel.

The crucible was purged with argon. Then, a portion of the homogeneous ingot was placed in a crucible, and the crucible was heated in an induction furnace. Once the ingot was melted, the molten composition was injected into a rapidly rotating copper-clad cooling wheel.

A thin ribbon was collected.

■Magnetization Sample Shake The magnetization was measured using a J-type magnetometer. Standard N,
B, S, The magnetometer was calibrated with a nickel bulb sample.

Example l FeB286 Pr12 sample and Fe79 B6
Samples of Pr11, SA et al., and 5 were prepared, quenched, and tested as described above with the following results.

Composition FeB2 B6 Pr12
Fe7p 86 prll, 5) Jt56 Example 2 Fe7986Nd15 sample and Fe77 B6N
Samples of d15AN.2 were prepared, quenched, and tested as described above. The following results, shown graphically in FIG. 2, were obtained.

Composition Fe7? B6Nd15 Fe77 B6
Although the present invention has been described above with respect to preferred embodiments and examples, it is to be understood that the invention is not limited by these descriptions.
Graph showing the energy product of boron-aluminum alloy as it is quenched, Figure 2! It is a graph showing the energy product of fIh ozim-iron-boron alloy and neodymium-iron-boron-aluminum alloy as they are quenched.

Claims (13)

[Claims] (1) (a) a transition metal selected from the group consisting of iron, cobalt, nickel, manganese and mixtures thereof; (b) a lanthanide selected from the group consisting of praseodymium, neodymium and mixtures thereof; and (c) boron. and a hard magnetic material containing an amount of a glass-forming additive to extend the range of quenching rates, the glass-forming additive comprising aluminum, aluminum-vanadium, zirconium, and A hard magnetic material selected from the group consisting of zirconium-niobium. (2) The hard magnetic material according to claim 1, wherein the transition metal is iron. (3) The hard magnetic material according to claim 1, wherein the glass-forming additive is aluminum. (4) The hard magnetic material according to claim 3, wherein the aluminum content is about 2 to about 10 atomic percent. (5) Claim 4 wherein said alloy contains from about 8 to about 40 atomic percent lanthanides, from about 2 to 10 atomic percent aluminum, and up to about 20 atomic percent boron, with the balance being iron. Hard magnetic alloys described in Section. (6) [1] (a) a transition metal selected from the group consisting of iron, cobalt, nickel, manganese and mixtures thereof; (b) a lanthanide selected from the group consisting of praseodymium, neodymium and mixtures thereof; c) forming a molten composition comprising boron; and (d) an amount of a glass-forming additive selected from the group consisting of aluminum, aluminum-vanadium, zirconium, and zirconium-niobium to extend the range of quenching rates; [2] The method for forming a glassy hard magnetic material according to claim 1, wherein the molten composition is quenched within a quenching rate range that forms a glassy hard magnetic material. (7) The method according to claim 6, wherein the transition metal is iron. (8) The method according to claim 6, wherein the glass-forming additive is aluminum. (9) The method of claim 8, wherein the aluminum content is from about 2 to about 10 atomic percent. (10) The hard magnetic alloy comprises about 8 to about 40 atomic percent of lanthanide, up to about 20 atomic percent of boron, and about 2 to 10 atomic percent of boron.
10. The method according to claim 9, wherein the method comprises aluminum and the remainder is iron. 7. The method of claim 6, comprising the step of: (11) quenching the molten composition on a cooling surface. 12. The method of claim 11, comprising the step of: (12) discharging the molten composition onto a cooling surface. (13) The method of claim 12, wherein the cooling surface moves relative to the molten composition.