Matsushita Electric Industrial Co., Ltd.

Kiyoshi Kojima

Shigeru Kojima

Takeshi Takahashi

Yoichi Sakamoto

Isago Konno

Nobuyuki Kato

Takao Kubo

Masaharu Tsukahara

Tadao Ohtani

Shizuo Furuyama

Hiroshi Ueda

Yoshihiro Hara

Satoru Mitani

Masayuki Wakamiya

Kazuyoshi Amami

Tadashi Kawamata

Susumu Sanai

Tadoa Ohtani

Kyoichi Hasegawa

Kazuhiro Ohyama

A rare earth-iron-nitrogen based magnetic material has superior magnetic properties. A method of manufacturing the rare earth-iron-nitrogen based magnetic material controls the decline in the magnetic properties of the material during pulverizing processes, and pulverizes the material to a critical particle dimension for single-domain behavior. The fragility of the material is increased since the material includes at least one element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo and W at 0.05-5% atomic percentage. The material is pulverized by a gas current type jet mill. Sample powder injected from a hopper is introduced from a supply mouth to a pulverizing chamber by nitrogen gas spouting from a pressure nozzle, and the powder is then accelerated to acoustic velocity by high pressure nitrogen gas spouting from gliding nozzles. As a result, the powder particles collide with each other. Pulverization is mainly carried out by collisions between powder particles, but can be accomplished by the collision of powder particles against the inner wall of a pulverizing chamber. The powder is then exhausted from a classifying zone.

Rare-earth-iron-nitrogen based magnetic material and method of

Homogenizing heat-treatment is conducted for changing an ingot containing R (R: Sm or a substance obtained by replacing a part of Sm with one or more kinds of rare earth elements) and T (T: Fe or a substance obtained by replacing a part of Fe with one or more kinds of transition elements) as main component into an alloy ingot mainly containing a R.sub.2 T.sub.17 phase. Next, the above-described alloy ingot is allowed to absorb hydrogen in hydrogen gas in the temperature range of 70.degree. C. to 300.degree. C. and at pressures of 5kgf/cm.sup.2 or more, thus conducting coarse crushing treatment.

Method for producing alloy powder of the R2T17 system, a method for

A magnetic circuit unit for a loud-speaker is provided, in which an adhesion step can be reduced or omitted, magnetic properties can be improved through enhancement of magnetic efficiency, and a durable anti-corrosive treatment can be performed at low price, so that higher performance and lower cost of the loud-speaker can be attained. A method of manufacturing the same is also provided. A top plate has a conical, columnar, truncated conical, or partially spherical hollow part formed on one side whose inner surface is integrated with an anisotropic Nd--Fe--B system magnet under a forming pressure of 100 to 200 kgf/cm.sup.2 through Joule heating by passing a current under compression. The forming die is cooled to a temperature below 100.degree. C. while maintaining the pressure, and the compact is then taken out from the forming die. This integrated compact is adhered to an outer yoke, and a looped yoke and a loop anisotropic Nd--Fe--B system magnet are also adhered thereon to fabricate a magnetic circuit unit. Subsequently, this magnet circuit unit is dipped in acrylic resin emulsion, and a coating of 7 to 15 .mu.m thick is formed by using a rotary coating device.

Magnetic circuit unit for loud-speaker and method of manufacturing the

Rare earth-iron-nitrogen based magnetic material and method of

Homogenizing heat-treatment is conducted for changing an ingot containing R (R: Sm or a substance obtained by replacing a part of Sm with one or more kinds of rare earth elements) and T (T: Fe or a substance obtained by replacing a part of Fe with one or more kinds of transition elements) as main component into an alloy ingot mainly containing a R.sub.2 T.sub.17 phase. Next, the above-described alloy ingot is allowed to absorb hydrogen in hydrogen gas in the temperature range of 70.degree. C. to 300.degree. C., and at pressures of 5 kgf/cm.sup.2 or more, thus conducting coarse crushing treatment.

Method for producing alloy powder of the R.sub.2 T.sub.17 system, a

A magnetic circuit component molding device for integrally molding a compound a center yoke with a ring-shaped magnet includes top and bottom press vertically arranged at opposed positions. A ring-shaped magnet is place on a bottom die between top and bottom press. The top and bottom press compress the compound against the ring-shaped magnet ring with a vertical pressure. A holder unit, separated in plural segments, having tapered outer circumferences is provided around the ring-shaped. A holder presser having a tapered inner circumference is mounted on the holder unit as tapered portions thereof are engaged together. A portion of the vertical pressure, when the top press compresses the compound, is transferred by springs 10 to the holder presser, and is amplified by the tapered portions and applied to the outer circumference surface of the ring-shaped magnet by the holder unit.

Magnetic circuit component molding device

This invention relates to an anisotropic neodymium-iron-boron system plastic bonded magnet containing from 10 to 20% by weight an anisotropic neodymium-iron boron system magnetic powder having a grain-size distribution from 10 to 49 microns and a resin binder. By employing this constitution, a substantially improved (BH).sub.max of the compressed mold body, due to improved magnetic field orientation, is realized.

Anisotropic neodymium-iron-boron system plastic bonded magnet

A permanent magnetic alloy characterized in that phosphorus of 0.6% or less by weight is added with respect to an Mn--Al--C alloy of 100% by weight comprising manganese of 68.0% to 73.0% by weight, carbon of (1/10)Mn--6.6)% to (1/3Mn--22.2)% by weight, and the remainder aluminum.

Mn--Al--C Alloys for anisotropic permanent magnets

A permanent magnetic alloy which is obtained by adding copper in amount of 0.5 to 6.2 wt% to the conventional Mn-Al-C alloy comprising 68.0 to 73.0 wt% of manganese, (1/10 Mn -- 6.6) to (1/3 Mn -- 22.2) wt% of carbon and the remainder aluminum and subjecting thus prepared alloy to warm plastic deformation in order to improve plasticity of the alloy.

Permanent magnetic Mn-Al-C alloy

Magnetic alloys consisting of 68.0.about.73.0 weight % manganese, (1/10 Mn - 6.6).about.(1/3 Mn - 22.2) weight % carbon, the balance aluminum, which show wasp-waisted magnetic hysteresis loops with the ratio of the residual magnetization 4.pi.I.sub.r to the intensity of magnetization 4.pi.I.sub.10000 in a magnetic field of 10000 Oe, I.sub.r /I.sub.10000, falling 0.0.about.0.2.

Magnetic alloys having wasp-waisted magnetic hysteresis loop

An anisotropic permanent magnet of an Mn-Al-C alloy containing 68.0% to 73.0% by weight of manganese, (1/10Mn-6.6)% to (1/3Mn-22.2)% by weight of carbon, and the remainder aluminum, which alloy is rendered anisotropic by deforming it plastically at a temperature of 530.degree. to 830.degree. C. The permanent magnet has excellent mechanical characteristics and magnetic properties such that the (BH) max is above 4.8 .times. 10.sup.6 G.Oe up to about 9.2 .times. 10.sup.6 G.Oe in its bulk state.

Anisotropic permanent magnet of Mn-Al-C alloy

An anisotropic permanent magnet of an Mn-Al-C alloy containing 68.0% to 73.0% by weight of manganese, (1/10 Mn-6.6)% to (1/3 Mn-22.2)% by weight of carbon, and the remainder aluminum, which alloy is rendered anisotropic by deforming it plastically at a temperature of 530.degree.C to 830.degree.C. The permanent magnet has excellent mechanical characteristics and magnetic properties such that the (BH)max is above 4.8 .times. 10.sup.6 G.Oe up to about 9.2 .times. 10.sup.6 G.Oe in its bulk state.

Machinable anisotropic permanent magnets of Mn-Al-C alloys

A method of making isotropic Mn-Al-C alloy magnets which comprises the step of subjecting an alloy comprising 71.0% to 73.0% by weight of manganese, (1/10 Mn -- 6.6)% to (1/3 Mn -- 22.2)% by weight of carbon and the remainder aluminum to plastic deformation at a temperature of 550.degree.C to 780.degree.C. By utilizing this method, it is possible to obtain isotropic Mn-Al-C alloy magnets having excellent magnetic characteristics, i.e. (BH)max = 2.0 .times. 10.sup.6 G. Oe or more.

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Nara, Japan

Kiyoshi Kojima