Abstract: A method for producing a raw material powder of a permanent magnet, includes: preparing a material powder of a permanent magnet, measuring magnetic characteristics of the material powder, and judging the quality of the material powder as the raw material powder based on a preliminarily determined relation between magnetic characteristics and the structure of the material powder. A method for producing a permanent magnet includes integrating material powders judged as good in the step of judging the quality as raw material powders by the method for producing a raw material powder of a permanent magnet. A method for inspecting a permanent magnet material powder includes transmitting a magnetic field to a material powder of a permanent magnet, receiving the magnetic field from the material powder, and measuring a magnetic field difference between the transmitted magnetic field and the received magnetic field as magnetic characteristics of the material powder.

Abstract: A method for producing a raw material powder of a permanent magnet, includes: preparing a material powder of a permanent magnet, measuring magnetic characteristics of the material powder, and judging the quality of the material powder as the raw material powder based on a preliminarily determined relation between magnetic characteristics and the structure of the material powder. A method for producing a permanent magnet includes integrating material powders judged as good in the step of judging the quality as raw material powders by the method for producing a raw material powder of a permanent magnet. A method for inspecting a permanent magnet material powder includes transmitting a magnetic field to a material powder of a permanent magnet, receiving the magnetic field from the material powder, and measuring a magnetic field difference between the transmitted magnetic field and the received magnetic field as magnetic characteristics of the material powder.

Abstract: Method of producing a rare earth magnetic alloy ribbon by rapid solidification using a rotary roll comprising: a step of preparing a rare earth magnetic alloy melt inside of a nozzle which faces said rotary roll, a step of applying a discharge pressure to said rare earth magnetic alloy melt in said nozzle, and a step of causing the discharge pressure to fall from a value at the time of start of discharge to a value which is required for sustained discharge at the instant that said rare earth magnetic alloy melt starts to be discharged from said nozzle. Preferably, the discharge pressure which is loaded on the melt surface inside the nozzle is made to increase from the sustained discharge pressure in accordance with the decrease in the amount of melt in the nozzle.

Abstract: A parting agent capable of being applied to a die with split die members closed, and preventing the production of defective castings and the occurrence of heat shock as well as the precipitation of a solid lubricant. The parting agent is composed of a mixture of a parting component, a dispersing component for dispersing the paritng component through water, a surface active agent as a foaming agent, and water, and is foamed into a foamy state. The foamy parting agent can be applied to the die with the split die members closed. This overcomes problems caused by the scattering of the parting agent due to spraying. In addition, since the parting component is retained with a film defining foam, the separation and precipitation thereof can be prevented.

Abstract: A method for coating a die surface with a foamed release agent is disclosed. The release agent is foamed outside a die and then is supplied to a die cavity. Alternatively, liquid release agent is supplied to the die cavity and then is foamed inside the die. Excess foamed release agent is removed from the die before molten metal is supplied to the cavity. Alternatively, the foamed release agent is left in the cavity, and molten metal is supplied to the cavity. The release agent is foamed through mechanical agitation, bubbling, or by gas released from the release agent when heated.

Abstract: A pressure casting method is disclosed, which permits sufficient pressurizing effect to be obtained for the entire molten metal by varying the speed of advancement of a pressurizing pin according to the state of solidification of the molten metal during pressurizing. In pressure casting using a pressure casting apparatus, while charged molten metal is solidified, it is pressurized by causing advancement of the pressurizing pin into a cavity of the die. During this time, the reaction force received by the pressurizing pin from the molten metal is measured by a pressure sensor, and the speed of advancement of the pressurizing pin is varied through control of the opening degree of a flow control valve according to the measured reaction force. While the reaction force during the progress of solidification of molten metal is high, the flow control valve is controlled to a high opening degree to provide for a high speed of advancement of the pressurizing pin so as to apply a high pressurizing force.

Abstract: The disclosed method of controlling a pressurizing pin, which serves to replenish for the necessary locality with molten metal during solidification of molten metal charged in the cavity, features that the operation of the molten metal replenishment by the pressurizing pin is caused when it is detected that the volume of non-solidified metal has become less than the volume effective for obtaining a molten metal replenishment effect. It is thus possible to obtain efficient replenishment for the necessary locality with molten metal by using a pressurizing pin which is limited in size and stroke.