Claims
- 1. A method of producing an iron-based powder composition for powder metallurgy excellent in flowability and compactibility, the method comprising:
- coating at least one of an iron-based powder and an alloying powder with a surface treatment agent;
- adding at room temperature to the iron-based and alloying powders subjected to a surface treatment and mixing, for a primary mixing, a fatty acid amide and at least one lubricant, the lubricant has a melting point higher than a melting point of the fatty acid amide and is selected from the group consisting of a thermoplastic resin, a thermoplastic elastomer, inorganic compounds having a layered crystal structure and organic compounds having a layered structure;
- heating and stirring the mixture after the primary mixing at a temperature above the melting point of the fatty acid amide to melt the fatty acid amide;
- mixing and cooling the mixture subjected to the heating and stirring so that the alloying powder and the lubricant having a melting point higher than the melting point of the fatty acid amide adhere to a surface of the iron-based powder subjected to the surface treatment by an adhesive force of the melt; and
- adding during the cooling, for a secondary mixing, a metal soap and at least one member selected from the group consisting of thermoplastic resin powders thermoplastic elastomer powders, inorganic compounds having a layered crystal structure and organic compounds having a layered structure.
- 2. A method of producing an iron-based powder composition for powder metallurgy excellent in flowability and compactibility, the method comprising:
- adding at room temperature to iron-based and alloying powders and mixing, for a primary mixing, a surface treatment agent, and in addition, for a secondary mixing, a fatty acid amide and at least one lubricant, the lubricant has a melting point higher than a melting point of the fatty acid amide and is selected from the group consisting of a thermoplastic resin, a thermoplastic elastomer, inorganic compounds having a layered crystal structure and organic compounds having a layered structure;
- heating and stirring the mixture after the secondary mixing at a temperature above the melting point of the fatty acid amide to melt the fatty acid amide, and causing the surface treatment agent to combine with the iron-based and alloying powders;
- cooling, while mixing, the mixture subjected to the heating and stirring so that the alloying powder and the lubricant having a melting point higher than the fatty acid amide adhere to a surface of the iron-based powder subjected to the surface treatment by an adhesive force of the melt; and
- adding during the cooling, for a tertiary mixing, a metallic soap and at least one member selected from the group consisting of thermoplastic resin powders, thermoplastic elastomer powders, inorganic compounds having a layered crystal structure and organic compounds having a layered structure.
- 3. A method of producing an iron-based powder composition for powder metallurgy excellent in flowability and compactibility, the method comprising:
- adding to iron-based and alloying powders and mixing, for a primary mixing, a fatty acid amide and at least one lubricant, the lubricant has a melting point higher than a melting point of the fatty acid amide and is selected from the group consisting of a thermoplastic resin, a thermoplastic elastomer, inorganic compounds having a layered crystal structure and organic compounds having a layered structure;
- heating and stirring the mixture after the primary mixing at a temperature above a melting point of the fatty acid amide to melt the fatty acid amide;
- cooling the mixture subjected to the heating and stirring so that the alloying powder and the lubricant having a melting point higher than the melting point of the fatty acid amide adhere to a surface of the iron-based powder subjected to the surface treatment by an adhesive force of the melt, and adding and mixing a surface treatment agent in a temperature range not less than 373K and not more than the melting point of the fatty acid amide; and
- adding during the cooling, for a secondary mixing, a metallic soap and at least one member selected from the group consisting of thermoplastic resin powders, thermoplastic elastomer powders, inorganic compounds having a layered crystal structure and organic compounds having a layered structure.
Parent Case Info
This is a Division of application Ser. No. 08/973,142 filed Nov. 28, 1997 U.S. Pat. No. 5,989,304, which in turn is the U.S. National Stage of International Application No. PCT/JP97/00029 filed Jan. 9, 1997. The entire disclosure of the prior application(s) is hereby incorporated by reference herein in its entirety.
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Divisions (1)
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Number |
Date |
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Parent |
973142 |
Nov 1997 |
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