Abstract: The present invention intends to provide an iron-based powder composition for powder metallurgy having excellent flowability at room temperature and a warm compaction temperature, having improved compactibility enabling lowering ejection force in compaction, to provide a process for producing the iron-based powder composition, and to provide a process for producing a compact of a high density from the iron-based powder composition. The iron-based powder composition comprises an iron-based powder, a lubricant, and an alloying powder, and at least one of the iron-based powder, the lubricant, and the alloying powder is coated with at least one surface treatment agent selected from the group of surface treatment agents of organoalkoxysilanes, organosilazanes, titanate coupling agents, fluorine-containing silicon silane coupling agents.

Abstract: The present invention intends to provide an iron-based powder composition for powder metallurgy having excellent flowability at room temperature and a warm compaction temperature, having improved compactibility enabling lowering ejection force in compaction, to provide a process for producing the iron-based powder composition, and to provide a process for producing a compact of a high density from the iron-based powder composition. The iron-based powder composition comprises an iron-based powder, a lubricant, and an alloying powder, and at least one of the iron-based powder, the lubricant, and the alloying powder is coated with at least one surface treatment agent selected from the group of surface treatment agents of organoalkoxysilanes, organosilazanes, titanate coupling agents, fluorine-containing silicon silane coupling agents.

Abstract: An iron-based powder composition is produces in accordance with a method comprising the steps of: adding to iron-based and alloying powders, for a primary mixing, a surface treatment agent, and in addition, for a secondary mixing, a fatty acid amide and at least one lubricant, wherein the lubricant has a melting point higher than that of the fatty acid amide and can be, a thermoplastic resin, a thermoplastic elastomer, and inorganic or organic compounds having a layered crystal structure; heating and stirring up a mixture after the secondary mixing at a temperature above a melting point of the fatty acid amide to melt the fatty acid amide; cooling, while mixing, the mixture subjected to the heating and stirring process so that the alloying powder and a lubricant having a melting point higher than the fatty acid amide adhere to a surface of the iron base powder subjected to the surface treatment by an adhesive force of the melt; and adding at the time of the cooling, for a tertiary mixing, a metallic soap and

Abstract: An iron-based powder composition for powder metallurgy excellent in flowability and compactibility is produced in accordance with a method comprising the steps of: adding to iron-based and alloying powders, for a primary mixing, a surface treatment agent, and in addition, for a secondary mixing, a fatty acid amide and at least one lubricant, wherein the lubricant has a melting point higher than that of the fatty acid amide and can be a thermoplastic resin, a thermoplastic elastomer, and inorganic or organic compounds having a layered crystal structure; heating and stirring up a mixture after the secondary mixing at a temperature above a melting point of the fatty acid amide to melt the fatty acid amide; cooling, while mixing, the mixture subjected to the heating and stirring process so that the alloying powder and a lubricant having a melting point higher than the fatty acid amide adhere to a surface of the iron base powder subjected to the surface treatment by an adhesive force of the melt; and adding at the

Abstract: An iron-based powder mixture for powder metallurgy, comprising: an iron-based powder, and from 0.05 to 0.50% by weight of a thermoplastic resin powder which comprises 50% or more by weight of units of at least one monomer selected from the group consisting of acrylic esters, methacrylic esters, and aromatic vinyl compounds, and whose average primary particle size is from 0.03 to 5 .mu.m, whose average agglomeration particle size is from 5 to 50 .mu.m, and whose average molecular weight measured by the specific viscosity of a solution is from 30000 to 5000000.

Abstract: This invention provides permanent magnets that are excellent not only in magnetic properties but also corrosion resistance by using two magnetically useful phases, i.e., RE.sub.2 TM.sub.14 B phase having a high residual magnetic flux density and a low melting point RE-TM' phase or RE-TM'-B phase which enhances the sinterability and possesses a cleaning action against grain boundaries of the RE.sub.2 TM.sub.14 B main phase. Further the invention provides a method for forming an electrochemically noble composition as a starting material to prepare a two phase magnet.

Abstract: A corrosion-resistant rare earth metal-transition metal-boron permanent magnet having improved corrosion resistance and excellent magnetic properties, including RE: 10-25 at % (where RE is at least one of Y, Sc and lanthanides), B: 2-20 at % and the remainder being substantially Fe, Co and Ni. In this case, the magnet has an average crystal grain size of 0.1-50 .mu.m and includes a crystal grain boundary phase of RE(Ni.sub.1-x-y Co.sub.x Fe.sub.y) compound having a thickness of not more than 10 .mu.m.