Research Of Hollow Spherical Fe Powder And Its Porous Materials

This study discusses the reduction process parameters (reduction temperature, reduction time), Fe2O3aggregates hollow ball be restored to hollow ball Fe powder, to impact the particle size, morphology and surface area of the hollow ball Fe powder, and get the best technological parameter to have had good dispersion and mechanical properties of hollow ball Fe powder. The preparation of oily self-lubricating materials is the traditional method of powder metallurgy. The impacting of the pressure and the sintering temperature to the porosity and mechanical properties of sample was researched. The best thrust pressure and sintering temperature was made sure, which satisfied the performance requirements of oily self-lubricating materials. At the same time, the influence of the add alloy elements and their content on the mechanical properties and friction performance of the samples was researched. The main conclusions of available as follows:(1) The Fe2O3aggregates are hollow ball which is made by Spray granulation, the ratio of the hollow aperture radius and the radius of the ball is0.4-0.5. After reduction, sintering, The Fe2O3aggregates become Fe particle, whose structure is hollow ball with porous shell. The ratio of the hollow aperture radius and the radius of the Fe hollow ball is also0.4-0.5. Along with the increase of the sintering temperature or the extension of time, grain of Fe hollow balls grow up obviously, the microporous of Shell also gradually reduce tend to be dense, and then, the hardness and elastic modulus of the shell of Fe particle increased. Fe particles have good dispersion and mechanical properties of the shell of hollow ball Fe powder at720℃restore2.5h.(2) The porosity of the sample made by hollow ball Fe particles decreases with the pressure increasing. At100,200,300MPa, the compaction have three kinds of pore:They are hollow holes, clearance between particles and micro hole of the shell of hollow ball. After sintering, the yield strength increasing as pressing pressure and sintering temperature increased, and the change of the porosity is the opposite of the trend. After200MPa repression and900℃sintering, the porosity and mechanical properties of sample satisfied the basic performance requirements of oily self-lubricating materials.(3) Fe-based porous material, whose yield strength less than pure Fe porous material, prepared by hollow ball Fe powder and Sn powder, Sn and Fe reacts to form in the intermediate compound FeSn, which result in stress-strain curve appear stress platform. Fe-based porous material, whose yield strength increases with the increase of the content of Cu, and more than pure Fe porous material, prepared by hollow ball Fe powder and Cu powder, add graphite, the yield strength of porous materials instead of lower. Fe-based porous material, whose yield strength more than pure Fe porous material, prepared by hollow ball Fe powder and Cu-lOSn powder, the yield strength increases with the increase of the content of Cu-10Sn, add graphite, the yield strength of porous materials instead of higher. Fe、Cu、Sn Sintering diffusion among all of them, the radial crushing strength of sample better than a pure Fe material’s.(4) Friction experiments of pure Fe and add Cu-10Sn powder and graphite sample show that, As the same seed of Friction dual, the friction factor and the volume of wear of sample with oil is lower than the friction factor and the volume of wear of sample without oil. Increase the rate of movement of the friction dual increase the friction factor and the volume of wear of samples. The sample, whose chemical composition is Fe-20%Cu-10Sn with the worst of the friction performance.