成分参数对原位反应合成TiC/Cr18Ni8钢结硬质合金的影响

Influence of Composition Parameters on In situ Reactive Synthesis of TiC/ Cr18Ni8 Steel Bonded Carbides

以钛铁粉、铬铁粉、铁粉、胶体石墨等为原料,原位反应合成了TiC/不锈钢钢结硬质合金,并用扫描电镜(SEM)、X射线衍射等测试方法对所制备的试样进行了组织结构分析.主要研究了成分参数硬质相TiC含量和C/Ti原子比对原位反应合成TiC/Cr18Ni8钢结硬质合金的影响.研究结果表明:钢结硬质合金主要相组成为TiC+Fe-Cr-Ni固熔体,TiC颗粒较细小,形状较规则,最大约2～3μm,大部分在1μm以下,随理论硬质相TiC含量的增加,钢结硬质合金的孔隙度增加,密度降低,TiC颗粒长大.C/Ti原子比为0.9的钢结硬质合金比C/Ti原子比为1.0的钢结硬质合金的密度更高,所原位反应合成的TiC颗粒的尺寸更小、数量更多,而且分布更均匀.

TiC/stainless steel-bonded-carbides was in situ synthesized by vacuum sintering the compacts of mixed ferrotitanium, ferrochromium, iron and carbon powders, etc. The microstructure of the steel bonded carbides was analyzed by scanning electron microscope (SEM), X-ray diffraction (XRD) and EDS. The results show that TiC particles are fine and the particle sizes are mostly less than 1 μm. With the increasing of drafted amount of the hard phase TiC, the porosity of steel bonded carbides and the size of TiC particles increased, but the density and hardness of steel bonded carbides decreased. The steel-bonded-carbides which drafted C/Ti atomic ratio is 0.9 has higher density and hardness, better refinement and much uniform of TiC particles than those that drafted C/Ti atomic ratio 1.0.