Preparation And Friction And Wear Properties Of WS₂-Cu Composite

As a material with good ductility,excellent thermal conductivity and electrical conductivity,copper is commonly used in electronics,aerospace and other fields.However,due to the shortcomings of low hardness and poor wear resistance of copper,the application in the fields of machinery,automobiles and high strength is restricted to a certain extent.With the advancement of modern technology and the rapid development of science,pure copper metal materials are difficult to meet the needs of practical applications,and copper-based self-lubricating wear-resistant composite materials have received increasing attention.The sheet-like structure of WS₂ is an outstanding self-lubricating material with high hardness.It is usually used as a particle reinforcement phase on Cu-based composite materials to enhance its hardness and friction and wear performance.Therefore,WS₂-Cu composite material has the potential to become a self-lubricating composite material with superior performance.At present,due to the serious agglomeration phenomenon of WS₂ itself,and the weak binding force between WS₂ and Cu matrix,WS₂ is easy to fall off during the friction and wear process.Therefore,it is particularly important to improve the interface wettability and bondability of WS₂ and Cu matrix.This article first uses chemical coating to plate WS₂ powder with Cu,and then mechanically mixed with copper powder to obtain WS₂-Cu composite powder.Then WS₂-Cu bulk material was prepared by SPS.The effects of the concentration of plating solution,SPS process and different WS₂ content on the structure and friction and wear properties of WS₂-Cu composites were discussed.The experiment showed that,1.Copper-coated WS₂ powder has a significant effect on the structure and properties of WS₂-Cu composites.The surface-plated copper-plated WS₂ particles are evenly dispersed in the copper-based composite material,which has good interface with copper and can fully exert its lubricity.Moreover,the WS₂-Cu composite material after copper plating on the surface of WS₂ has a density of up to 98%and a hardness of85.5Hv.And,compared with pure copper,its friction coefficient is 88%lower and its wear rate is 93%lower.Copper-clad WS₂-Cu composite material shows the best comprehensive performance.2.Under different SPS processes,the structure and friction and wear properties of WS₂-Cu composites show that when the sintering temperature is higher than 750?,W is found in the prepared WS₂-Cu composites.With the increase of sintering temperature,the density and hardness of the prepared WS₂-Cu bulk materials tended to increase.700?750?,the friction coefficient is the lowest(0.1?0.15)and the wear rate is the smallest((1.6?1.8)�10^-5mm³/Nm).When the sintering pressure is higher than 30MPa,the compactness and hardness of the prepared WS₂-Cu composite material do not change much.The best SPS process is,700?-30Mpa-6min.When the sintering temperature is lower than 750?,the wear mechanism of the prepared WS₂-Cu composite material is mainly oxidative wear,which is accompanied by adhesive wear.When the sintering temperature is higher than 800?,abrasive wear occurs.3.The influence of different WS₂content on the structure and friction and wear properties of WS₂-Cu composites.With the increase of WS₂ content,a small amount of WS₂ has agglomeration.At the same time,the density of WS₂-Cu composite decreases,but its hardness increases.When the WS₂ is 10?20Vol%,the friction coefficient is low(0.1?0.2),and the wear rate is in the range of(2.6?5.1)�10^-5mm³/Nm.15Vol%WS₂-Cu composite material shows excellent friction and wear performance.The wear mechanism of pure copper is mainly oxidative wear.The wear mechanisms of5Vol%WS₂-Cu composite materials include oxidative wear,abrasive wear and adhesive wear.As the WS₂ content increases(10?15Vol%),the wear mechanism of WS₂-Cu composites is mainly oxidative wear,and there is adhesive wear.20Vol%WS₂-Cu composite material appeared plastic deformation.4.The friction and wear properties of WS₂-Cu composites at 25?500?indicate,as the temperature increases,their friction and wear properties decrease.25?500?,the friction coefficient of WS₂-Cu composite material is more than 20%lower than that of pure copper.25?100?,WS₂-Cu composite material is mainly oxidative wear,adhesive wear.200?400?,stratified oxidation wear occurred.500?,WS₂-Cu composite material fatigue wear.Load change,25?,the load increases,which reduces the wear resistance of WS₂-Cu composite.400?,its friction and wear performance increases with the increase of load.When the load is in the range of 2.5?5N,the wear mechanism of WS₂-Cu composite material is mainly oxidative wear,and there is adhesive wear.As the load increases(7.5?10N),the adhesive wear and oxidative wear of WS₂-Cu composite materials increase.Speed change,25?and 400?,the speed increases,which improves the wear resistance of WS₂-Cu composite material.150r/min,the WS₂-Cu composite material suffered oxidative wear and adhesive wear.300r/min,oxidative wear increases and adhesive wear decreases.Abrasive wear was also found at high speed(600r/min).