Research On The Preparation And Properties Of Al₂O₃-TiC/Fe Metal Ceramic Composite

With the efforts of national energy conservation policy implementation continuing increasing, the pressure of the high energy-consuming enterpriseson thermal power generation, cement building materials, metallurgyn mining is increasing on the energy saving and reducing emission aspects. Therefore the demand for the better energy-saving effect, lower abrasion products is increasing.In this context, powder metallurgy method is used to prepare /Fe metal-matrix ceramic composites and TiC, C, Mn, Ni, Mo, 3, reduced Fe powder are as the main raw materials, zinc stearate, calcined kaolin, wollastonite as sintering aids, paraffin as forming agent, and alcohol as milling liquid medium.Through the experiments, the basic formula is comprised of 2% TiC,1% C,12% Mn,1% Ni,1% Mo,17% ?-Al2O3,61% Fe,2.5%zinc stearate, 1%calcined kaolin,1.5%wollastonite,1.5%paraffin(mass fraction,wt%). The water absorption, bulk density and wear rate of the basic formula are respectively 0.21%,5.20g/cm3 and 4.20%.Based on this basic formula, the density and wear resistance have been further improved through optimizing ball milling process, changing molding pressure and adding rear-earth additives. The samples'microstructure have been observed and analyzed by scanning electron microscopy (SEM), the phases are analyzed by X-ray diffractometer, the particle size distribution of powder of samples are measured by Malvern laser particle size analyzer, and finally the grinding experiment on the ground and wear tests instrument has been carried out to analyze the wear-resistence of the specimen, as well as hardness and flexural strength are also measured.Through these research work, the results are as follows:(1)Through a series of experiments, the final basic formula is:2%TiC? 1%C?12%Mn?1%Ni?1%Mo?17% ?-Al2O3,61%Fe,2.5%zinc stearate, 1%calcined kaolin,1.5%wollastonite,1.5%paraffin(mass fraction,wt%).(2) Through experiments of changing ball milling process parameters, the result is that wet grinding in high-energyplanetary ballmilling machine is better than dry grinding, and the influence of ball milling time is more prominent, and the optimum wet milling time is 12 hours.(3)The molding pressure on the density and mechanical properties of sampleshave been studied. The experimental results show that the optimum molding pressure is 140 MPa, which lead to 94.7%of the relative density,467 HB of hardness,882 MPa of flexural strength, and 2.92%of the wear rate.(4)Vacuum drying of formulas'powder have been done and sintering has been carried out by using tube-type vacuum sintering furnace (?150 mm) with 4 Pa of high vacuum,1 520? of sintering temperature and 60 min of holding time. The different rare earth additives on the influence of water absorption, bulk density, wear-resistance and micro structure are investigated.The test results show that:under above conditions, thebulk density and water absorption reach the best state when 0.3% Y2O3added, that is 0.03% and6.78 g/cm3 respectively, and the wear-resistance of the material wasincreased.