CeO2添加及碳含量对超细WC-9Ni-0.4Cr3C2硬质合金热性能与表面形态的影响

Effect of Carbon Content and CeO2 Addition on Thermal Properties, Surface Morphology of Ultra-fine WC-9Ni-0.4Cr3C2 Cemented C

摘要:

摘要：本文以超细WC-9Ni-0.4Cr3C2硬质合金为研究基体，采用传统粉末冶金方法制备了不同CeO2添加量与碳含量的四组合金试样，利用HotDisk热常数分析仪，采用瞬变平面热源法（TPS）技术测量了材料的热性能；并采用XRD、SEM和EDX等方法对四组合金烧结后基体与表面进行了分析与观察。实验结果表明：合金的热导率和热扩散系数随着CeO2的添加量增加而降低，而合金的比热容则出现小幅下降。另外，当WC-9Ni-0.4Cr3C2-CeO2合金中碳含量较低时，Ce会在合金表面以硫化物或氧化物的形式聚集。随着碳含量的升高，Ce的表面聚集现象逐渐消失，同时合金的热导率和热扩散系数明显上升，比热容变化并不明显。同时，合金出现了渗碳的趋势。

Abstract:

Abstract: Four groups of different carbon and CeO2 content of ultrafine WC-9Ni-0.4Cr3C2 cemented carbide samples were prepared by powder metallurgy method. The thermal properties of the alloys were measured and analyzed using thermal constant Hot Disk analyzer through transient plane heat source method (TPS) technology; meanwhile, the phase composition and different surface morphology of the alloys after sintering were also studied by XRD, SEM and EDX analysis. The results show that, with the CeO2 content increase, the thermal conductivity and thermal diffusion coefficient of the alloy decrease, while the heat capacity increases in smaller extent. When carbon content in the WC-9Ni-0.4Cr3C2-CeO2 is low, Ce tends to gather in the alloys’ surface in the form of sulfide and oxide. With the increasing of carbon content, the gathered phenomenon of Ce in the alloy’s surface is gradually disappearing, and the thermal conductivity and thermal diffusion coefficient rise obviously. However, the specific heat capacity changes a little.