Research On The Preparation And Tribological Properties Of Ti(C,N)-based Cermets

Ti?C,N?-based cermet has high hardness,high wear resistance,high melting point,high oxidation resistance and high corrosion resistance.It is a material with excellent performance and a wide range of uses.In terms of wear resistance and cutting efficiency,Ti?C,N?-based cermets are superior to traditional WC-based cemented carbides,and have successfully replaced WC-based cemented carbides in many occasions in production and processing.However,with the continuous progress of society,the requirements for Ti?C,N?-based cermets in industrial production are becoming higher and higher.In order to improve the comprehensive mechanical properties and tribological properties of the material,the following research ideas are designed in this paper.:In this project,Ti?C,N?powder was prepared by high temperature self-propagating reaction method,and samples were prepared by plasma sintering process.This paper studies the microstructure,mechanical properties and tribological properties of Ti?C,N?cermets with different compositions.In this paper,the effects of Co element in the binder phase,added phase?Ti,Nb?N,WC and VC on the cermet are studied.Explore the reasons for the refinement of grains and increase the density,and study the mechanism of friction and wear.The friction and wear test parameters of this subject are:load 20N,speed 400rpm,test time 60 minutes.?1?In this paper,the high-temperature self-propagating reaction method was used to prepare:Ti(C_0.3,N_0.7),Ti(C_0.5,N_0.5),Ti(C₀₇,N_0.3)and?Ti,Nb?N four kinds of powder.The advantage of this method is that it is easy to control the C/N ratio of the powder,the powder has high purity,high crystallinity,high production efficiency,low production cost,and is suitable for mass production.The method used for sintering the samples in this experiment is the spark plasma sintering method,which has a fast temperature rise and a low sintering temperature.In this paper,through experimental research,the sintering parameters formulated are:temperature 1350?,time 10minutes.?2?Comparing different Ti?C,N?/Co composite materials,the sample with the composition Ti(C_0.3,N_0.7)/Co has better performance,its hardness is 1731HV,and its toughness is 11.14MPa.m^1/2,Friction coefficient is 0.25,wear rate is 2.045×10^-10 mm³·N^-1m^-1.Co can improve the wettability of the hard phase and the binder phase,the sample grains are fine and dense.It is easy to form a stable lubricating film during the friction process,and part of the CoxTi metal compound is pushed out of the surface from the matrix on its surface layer,improving the surface lubricity.?3?In order to further improve the friction and wear performance of Ti?C,N?cermets,different Ti?C,N?/?Nb,Ti?N/Co composite materials were prepared in this subject.The sample with the composition of Ti(C_0.3,N_0.7)/?Nb,Ti?N/Co has better performance.Its hardness is1640HV,fracture toughness is 9.62MPa.m^1/2,friction coefficient is 0.22,wear rate is 1.69×10^-10mm³·N^-1m^-1.Adding phase?Nb,Ti?N can improve the sintering performance and density of cermet.During the friction test,the running time of the sample is short,the friction coefficient enters smoothly and quickly,and a high hardness lubricating film is formed on the surface to improve the tribological performance of the material.Through microscopic analysis of the wear scars of the sample,we can see that the wear mechanism of the sample is mainly fatigue wear and oxidative wear.?4?In order to further increase the hardness of Ti?C,N?cermets without losing toughness,this subject prepared different Ti?C,N?/WC/VC/Co composite materials.The sample with WC content of 10wt.%Has better performance,its hardness is 1997HV,fracture toughness is9.11MPa.m^1/2,friction coefficient It is 0.25,and the wear rate is 2.39×10^-10 mm³·N^-1m^-1.Adding WC can improve the sinterability and density of the material,but when the WC content is too large,free WC will appear in the microstructure and reduce the mechanical properties of the sample.In this paper,VC is added as an additional phase.VC has the effect of refining grains,and can form a stable?Ti,W,V?C solid solution with WC and TiC at high temperature,which plays a role of solid solution strengthening and makes The hardness of ceramics has been greatly improved,while the fracture toughness loss is very small,and the mechanical properties and tribological properties are optimized.The surface load capacity of the sample matrix is high,and the sample surface is not easy to break at the initial stage of friction,and the friction coefficient rises steadily.It can be seen from the microscopic analysis of the wear scar of the sample that the wear mechanism is mainly fatigue wear and abrasive wear.