powder metallurgy, by powder metallurgy refers to the product manufacturing process, comprising a porous, semi-dense or fully dense materials and products.
1. Powder Metallurgy advantages
PM materials with unique physical and chemical composition, mechanical properties of the traditional casting process can not be obtained, such as controlled porosity materials, homogeneous material structure , no macrosegregation (chemical composition after solidification which different parts of the cross section does not flow due to the liquid alloy caused by macroscopic unevenness), may be a molding.
2. Classification of powder metallurgy
Powder Metallurgy use can be divided into the following types:
(1) Powder Metallurgy high temperature material. Powder metallurgy including superalloys, refractory metals and alloys, cermets, dispersion strengthening and fiber-reinforced materials. For manufacturing a turbine disk for use at a high temperature, nozzle, vane, and other high-temperature components.
(2) Powder metallurgy tool and die materials. Comprising a cemented carbide, high-speed steel powder metallurgy. The latter tissue uniform, fine grain size, there is no segregation, the high-speed casting of steel is better than the toughness and wear resistance, heat distortion, and long service life. The blank may be used to manufacture cutting tools, molds and parts.
(3) The structure of the powder material. Also known as sintered structure material. Can withstand tensile, compression, distortion and other loads, and able to work under conditions of friction and wear. Due to the presence of internal residual porosity materials, low ductility and impact values than the same chemical composition of castings and forgings, so its application range is limited.
(4) Powder Metallurgy antifriction material. Also known as sintered antifriction material. By the lubricating oil impregnated in the pores of friction material or subtraction agent or in the material component of the solid lubricant obtained. Friction coefficient between the surface of the material under limited conditions lubricating, long life, high reliability; under dry conditions, relying on its own or skin containing a lubricant, i.e., self-lubricating effect. Widely used in manufacturing a bearing, the bearing bush or the like as a face seal.
(5) a porous material powder metallurgy. Also known as a porous sintered material. By molding and sintering an alloy powder made of a metal or a spherical or irregular shape. Tunnel interior material criss-cross through each other, generally 30% to 60% by volume porosity, pore diameter of 1 to 100 microns. Permeability and thermal conductivity, good electrical conductivity, high temperature, low temperature, thermal shock, anti-corrosion medium. For the manufacture of filters, the porous electrode, fire extinguishing equipment, freezing devices.
(6) The friction material powder metallurgy. Also known as sintered friction material. A base metal (copper, iron or other alloys), lubricating element (lead, graphite, molybdenum disulfide, etc.), a friction component (silica, asbestos, etc.) 3 parts. Its high coefficient of friction, can quickly absorbKinetic energy, braking, transmission speed, low wear; high strength, high temperature resistance, good thermal conductivity; seizure resistance, corrosion resistance, by oil, little moisture influence. Mainly used in clutches and brakes.
(7) an electromagnetic powder metallurgy material. Including electrical materials and magnetic materials. Electrical material, the first material is used as electrical energy gold, silver, platinum, a noble metal material and powder metallurgy of silver, copper was added to the matrix material powder metallurgy tungsten, nickel, iron, tungsten carbide, graphite or the like; as electrodes are tungsten copper, tungsten, nickel and copper powder metallurgy materials; as a metal brush – graphite powder metallurgy materials; as an electric thermocouple and a molybdenum alloy, tantalum, tungsten powder metallurgy material.
soft magnetic material and a magnetic material into a hard magnetic material. Soft magnetic material powder, powder cores, soft ferrite, the magnetic moment of ferrite, ferrite pressure, microwave ferrite, and the ferrite powders such as silicon steel n; hard magnetic material with a hard ferrite, rare earth cobalt hard magnetic, magnetic recording materials, hard magnetic powder, a magnetic plastic. Conversion used in the manufacture, transfer, and storage of magnetic energy device information.