Research On The Preparation And Tribological Properties Of Mo₂FeB₂-based Cermets

Ternary boride based cermets have excellent properties of mechanical, abrasive resistance, corrosive resistance and high temperature resistance. So it is widely used inindustry and agriculture and plays a very important role. The institution of ternary boride based cermets is in minority countries in the world such as Japan and America. They focused in the sintering properties and knew very few about the high temperature performance and corrosion resistance.In this dissertation Mo2FeB2based cermets were obtained by vacuum liquid phase sintering. The composition and structure of cermets were investigated by means of X-ray diffraction(XRD) and scanning electron microscope(SEM). Then, the effects of graphite, chromium and nickle on the microstructure and the mechanical and wear properties of the cermets were investigated. Mo2FeB2based cermets are made up of Mo2FeB2hard phase and a-Fe bonding phase. The alloy elements Ni enter into the bonding phase, One part exists as simple substance, and the other part mixs with Fe and forms alloy Ni-Fe. Elements Cr gets into both bonding phase and hard phase. The results showed that when graphite was added singlely, the grain refinement, the hardness and transverse rupture stress(TRS) of the cermets was increased; when nickel was added singlely, the hardness was highest at nickel concent of3%and TRS was highest at nickel content of6%. When chromium was added singlely, the hardness of the cermets was increased with chrominum content increased but the TRS of the cermets increased at first and then decreased. When manganese was added singlely, the hardness and TRS was highest at manganese concent of2%. The alloying elements are effective in the modification of microstructure. The friction and wear properties of the cermets were also improved significantly. The alloying elements cermet has best tribological properties because of its less severe pull-out of grains. Temperature have huge influence on the friction and wear properties of the metal ceramic, metal ceramic has great wear resistance in high temperature situation.