Carbothermal Reduction Of Titanium Concentrate And Reaction Sintering Of TiC-based Cermets By Spark Plasma Sintering

Traditional TiC cermets usually use Co and Ni as binder phase,and the price isexpensive.The Fe is cheap,but the conventional powder metallurgical process is so long and entail disadvantages,including high energy consumption,high raw material and equipment cost,complex operation,and easy oxidation of Fe,resulting in difficult control of products components.In this paper,the TiC cermets were fabricated by in situ synthesis via spark plasma sintering(SPS)treatment.The two elements of Ti and Fe were made full use of in the titanium concentrate,which had solved the problem of easy oxidation of Fe.In this paper,we chose the unique titanium concentrate resources of Wenchang City in Hainan Province for the study,mainly for the titanium concentrate on the carbothermal reduction reaction thermodynamics and SPS carbothermal reaction process of phase transition and reaction kinetics were analyzed.Researches show that,the phases of hainan titanium concentrate mainly for false rutile(Fe2Ti3O9)and rutile(TiO2).The order of SPS carbothermal reactant facies evolution sequence of the fake rutile is:Fe2Ti3O9?Fe2TiO5??Fe2TiO5+Fe?TiC + Fe.The order of the carbothermal reduction of the rutile is:TiO2?Ti3O5?Ti2O3?TiC.The thermal reaction process of SPS in Hainan titanium concentrate can be divided into three stages,the first stage reaction rate is the slowest,and the reaction rate is the fastest in the third reaction stages.TiC-Fe mixed powders were prepared by using the method of spark plasma carbothermal reduction.The effect of ball milling on the thermal reaction of SPS in titanium concentrate and SPS process factors on the influence of the carbon thermal reduction product were studied.Researches show that,mechanical ball milling resulted in the decrease of the size of the titanium concentrate,and the mechanical activation of increase the ball material ratio by carbothermal reduction reaction of titanium concentrate more fully;The feed rate of the mixture is more uniform and the powders particle size is smaller,so that the carbothermal reduction reaction of the titanium concentrate can be more fully.Increasing the SPS temperature and prolonging the SPS holding time are beneficial to the carbothermal reduction of Hainan titanium concentrate,and the reaction will be more thorough.The new TiC-Fe cermets were prepared by two steps reaction of spark plasma sintering.The effect of SPS sintering temperature and sintering pressure on the mechanical properties of the cermets during the subsequent two reactions of Hainan titanium concentrate were explored.Researches show that,the suitable temperature range of the new TiC cermets products which made by the twice reactions of SPS of Hainan titanium concentrate is 1200?1300?,40MPa is the optimal pressure value,at this time,the density of TiC cermets is 4.975g/cm3,rockwell hardness is 86.6HRA.