Microstructure and properties of sintered Cu-MoS2 composite materials

Samomazalni kompozitni materiali iz sistemov grafit/baker in molibdenov disulfid/baker so poznani po dobrih mehanskih lastnostih, električni in toplotni prevodnosti in nizkem koeficientu trenja. Ustrezna kombinacija lastnosti je zagotovljena samo v primeru enakomerno porazdeljenih drobnih delcev grafita (C) ali molibdenovega disulfida (MoS2) v matrici bakra (Cu). Boljša izbira je MoS2, ker ima nižji koeficient trenja in boljše mehanske, električne ter toplotne lastnosti. Kompozit Cu-MoS2 ima tudi znatno boljšo odpornost proti obrabi tako zaradi MoS2 kot zaradi drobno dispergirane faze, ki je nastala z reakcijo med Cu in MoS2 med sintranjem. V diplomskem delu smo analizirali vpliv temperature in časa sintranja na mikrostrukturo in lastnosti samomazalnega kompozita Cu-MoS2. Izbrali smo štiri temperature (med 750 °C in 900 °C) in tri različne čase sintranja (ena ura, dve uri in štiri ure). Kompozit smo izdelali po postopkih metalurgije prahov. Za analizo vpliva temperature in časa sintranja na mikrostrukturo, kemijsko sestavo in lastnosti smo uporabili številne analizne metode. Največ pozornosti smo posvetili naslednjim raziskovalnim metodam: analizi mikrostrukture z elektronsko vrstično mikroskopijo, meritvam trdote, meritvam električne prevodnosti ter meritvam obrabe in koeficienta trenja.Self- lubricated composite materials from the graphite/copper and molybdenum disulfide/copper systems are known for their good mechanical properties, electrical and thermal conductivity, and low coefficient of friction. Appropriate combination of properties could be achieved only in the case of uniformly distributed fine particles of graphite (C) or molybdenum disulfide (MoS2) in the copper (Cu) matrix. A better choice is MoS2 because it has a lower friction coefficient and better mechanical, electrical, and thermal properties. The Cu-MoS2 composite also has a significantly better wear resistance both due to MoS2 and the finely dispersed phase formed by the reaction between Cu and MoS2 during sintering. In this diploma thesis the effect of sintering temperature and time on microstructure and properties of self lubricated composite material Cu-MoS2 have been analysed. Four different sintering temperatures between 750°C and 900°C and three different sintering times (one hour, two hours and four hours) were selected. Several analytical methods were used to analyse the influence of temperature and sintering time on the microstructure, chemical composition, and other properties. Most attention was focused on the following research methods: microstructure analysis by electron microscopy, coefficient of friction and wear resistance measurements, hardness and microhardness measurements and electrical conductivity measurements