The Preparation And Characterization Research Of Al₂O₃Ceramic And Ti₃SiC₂-Ni Composites

Alumina（Al₂O₃） is a very important ceramic material. But the characteristics ofceramics is brittle, this will hinder the development of alumina application. At thesame time, through the fine-grain strengthening can effectively improve the strength ofmaterial. It make the toughness of material improved. Ti₃SiC₂is a new type ofmaterials in Mn+1AXn. It has metal and ceramic of performance, but Mn+1AXnphasematerials has brittle at room temperature, Its hardness is low.This paper main reported that Al₂O₃ceramics, Ti₃SiC₂-Ni composite material wasprepared by new Spark Plasma Sintering. At the same time, We examines mechanicalperformance of the Al₂O₃ceramics under different sintering system. Meanwhile, westudies friction and wear performance for the sintering Al₂O₃ceramics under differentsintering system. And we will explore the sintering process of Ti₃SiC₂-Ni compoundmaterials. The main results were as follows:（1）By using two kinds of commercial powder, we sintering Al₂O₃ceramics but Wedoes not add any additives, with the condition of Spark Plasma Sintering, we preparedAl₂O₃ceramics with grain size for micron grade and the high density. We explore theinfluence of Al₂O₃ceramics of the grain size and high density factors, for example: thesintering temperature, heating rate and holding time etc. Al₂O₃ceramics is preparedfor the average grain size of0.59μm. We have found the best sintering process ofAl₂O₃ceramics by Spark Plasma Sintering, and the best sintering process was sinteringtemperature of1150℃, pressure30MPa, heating rate90℃/min, holding time5min.（2）We have tested mechanical performance of Al₂O₃ceramics with different grainsizes. The results show that hardness reached25.81±1.58GPa, three point bendingstrength reached601.25MPa. And we have tested friction and wear with the aluminaof the different sintering system. We have discovered friction coefficient close atdifferent sintering system of the alumina. The results are all in0.7, and the wear rate isin10^-7mm³N^-1m^-1of the order of magnitude, this is belong to the mild wear.（3）The Ti₃SiC₂-5vol%Ni composite material was prepared by Spark PlasmaSintering （SPS） and intermediate frequency hot pressing sintering. In the sinteringtemperature（1150℃-1450℃）, the decomposition of the Ti₃SiC₂is TiC, Si products. Itscan reaction with metal Ni, the generation product is Ti₄Ni₄Si₇. Because the heatingrate of SPS is fast and sintering time is short. Thus, it can effectively reduce thesintering temperature. We observed the fracture morphology of the samples, and foundthe Ti₃SiC₂-5vol%Ni composite material had relatively uniform structure by Spark Plasma Sintering.