Powder metallurgy as a metal-processing technology containing metal powder preparation and sinter it as close meshed component.
Powder metallurgy as a metal-processing technology containingmetal powder preparation and sinter it as close meshed component. Traditional powder metallurgy including metal powder mixed powder pressing and pressed body sintering under different climate. However, the void ratio of vast majority of powder sintering parts are more than 5l%, so there have been all kinds of sintering technology used for getting higher density and improving sintered components performance. Compressed iron powder sintering is usually by adding some alloying elements to iron powder to improve the sintering performance. Some alloy iron atoms by providing easy diffusion path in terms of enhancing sinter iron powder compression capability. The balance system of boron and iron does not allow the three allotropes of iron dissolved in it. Due to the presence of boron, when sintering temperature is above 1165-1175 will appear liquid. Due to the limited solubility of boron in iron, so that the sintered will be conducted in the presence of liquid phase, which will change the morphology and the porosity of the material, so as to improve the density of materials, improving the mechanical and wear properties of materials.
Material loss is performance as the area, volume and quality, expressed as the abrasion value and abrasion rate, its loads way and loads time is closely related. Use the countdown of wear extent express wear-resistant ability, and the economic life of most structural parts are qualified by the wear extent. Therefore, abrasion resistance value is as important as material yield strength and materials fracture toughness. When some materials are wearing because of contacts with other hard surfaces, their wear materials are ductility materials, and the presents sub-surface deformation and hard phase will affect material's wear performance.
Many studies of iron-based powder metallurgy alloys indicated that sintering of boron as sintering additives can improve the material density. For complete dense can select different boron additives, this is due to its excellent wetting properties and the very low solubility in the solid. A large number of studies have shown that boron as FeB, Fe2B, NiB, CrB2 form added to iron or stainless steel can get higher density. By joining 0.4-0.6% boron in iron alloy can get completely compact and materials mechanical properties significantly improved. Studies suggest that boron's accession will significantly affect the melting point, density, deformation of powder metallurgy stainless steel.
The metallographic microstructure analysis showed that, after adding boron powder to the material, the porosity of the material has changed, and the development of eutectic liquid phase in Golden world place make grain thick, at the same time, with the boron content of materials rising, eutectic phase network will cover almost all of the grain boundary, in addition, the shape of the hole close to circular, and the size is relatively small.
Sintering not added boron additives sample in 1150 for 30 minutes, the holes of inside material contact area including circular and irregular shape. When the material adding 0.5wT% or 1WT% boron additive, from the metallographic microstructure analysis, organizations were formed in an adequate amount of liquid phase make the eutectic materials were almost closed to fully compact. Observe from added 1WT% boron additives alloy microstructure found that all grains are surrounded by eutectic phase. It is well known that during the sintering process, because of the capillary forces to wetting liquids, materials liquid-phase will rearrange. This rearrangement has two stages, primary rearrange mainly consist of individual particles, that is the random filled of mixing powder and the non-uniform capillary forces produced by liquid not evenly distributed in all contact particles, thus giving rise to sintering densification. Relatively small particles have a greater degree of capillary stresses, which pulls together particles lead to material rapidly shrink, therefore total phase improve the material density and hardness.
Source:http://www.mhcmp.com
The application of tungsten in various industries
Steel Industry Most of tungsten applied in the production of special steels. The widely used high-speed steel was containing 9-24% of tungsten, 3.8-4.6% of chromium, 1-5% of vanadium, 4-7% of cobalt, 0.7-1.5% of carbon.
Magic effects of coconut oil
According to records, coconut oil can be regarded as the nobility of skin care plant extracts. It was rich in exotic tension of tropical plants, which can enhance the contractile force of the pores, perfectly beautify and nourish the skin.
Exploring the Potentials of Nano-Aluminum Powder
Nano-aluminum powder, a material with remarkable properties due to its minuscule particle size, is revolutionizing various industries with its high reactivity and large specific surface area. Unlike its bulk counterpart, nano-aluminum powder begins to oxidize at a lower temperature of 550°C, compared to the 950°C oxidation point of ordinary aluminum. This lower ignition energy and full combustion without apparent cohesion make it a superior choice for applications requiring high energy and efficiency. The unique characteristics of nano-aluminum powder, such as faster burning rates and greater heat release, are largely influenced by its synthesis method, which determines its particle size, surface area, and shape.
