Study On Preparation And Powder Alloy Characteristic Of Nano Metal Alloy Powders--Research On Preparation Of Fe-Ni And W-Ni-Fe Nano Alloy

The technique that sol-gel method was used to prepare Fe-Ni and W-Ni-Fe nano alloy powder by using iron nitrate (Fe(NO3)3·9H2O) , nickel nitrate (Ni(NO3)2·6H2O) and ammonium metatungstate (AMT) et al as main raw materials was studied. The results are as follows: Sol-gel with H2 reducing method can be used to prepare nano Fe-Ni and W-Ni-Fe alloy powder, the powders are about 30nm in the grain size and distribute as polygon state, which was approved by XRD,TEM and SEM.When nano powders were used in powder alloy process, it can decrease melting of the materials and the sintering temperature of which is below far-off that of normal. In order to attain nano grain size sintering materials, we must control strictly not only sintering temperature but also sintering time. Hot pressed sintering can shorten sintering time and be beneficial to attain nano grain size sintering materials. However, it is difficult to attain nano grain size sintering material by using sintering methods as usual.When the grain size of Fe-10at%Ni alloy sintering material reached nano magnitude, martensite was found during the course of succeeding quick cooling(quenching treatment) after sintering.The W95Ni3.5Fe1.5 heavy gravity alloy powder was prepared by addition nano alloy powder and the structure of which is successive W base alloy solid solution and disperse distributive ((Ni,Fe),W) phase. The structure creates condition to obtain high compact and high hardness W-Ni-Fe alloy. And it radically changes the specific structure attained by normal powders, which is composed of sphericity W base alloy phase and Ni-Fe alloy phase.