VC and Cr3C2 doped WC-based nano-cermets prepared by MA and SPS
VC and Cr3C2 doped WC-based nano-cermets prepared by MA and SPS
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DOI：
10.1016/j.ceramint.2014.04.004
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发表时间：
2014-09-01
影响因子：
5.2
通讯作者：
Saheb, N.
中科院分区：
文献类型：
--
作者：
Al-Aqeeli, N.;Mohammad, K.;Saheb, N.
采用行星式球磨法对微米级WC粉末进行球磨，获得了平均晶粒尺寸为10 nm的WC粉末。然后将纳米尺寸的WC粉末与9和12重量%的Co以及0.2-0.8重量%的晶粒生长抑制剂VC和Cr 3C 2机械研磨。然后使用放电等离子烧结（SPS）在两个不同的温度（即1200和1300摄氏度）下固结粉末混合物。分析了晶粒生长抑制剂的种类和量、Co含量和烧结温度对烧结纳米金属陶瓷的显微结构、致密化和力学性能的影响。在一般情况下，添加VC和Cr 3C 2被发现降低致密化。然而，发现在具有较高Co含量的含Cr 3C 2的组合物中该效果较低。通过FESEM显微照片上的传统线相交方法和使用晶粒分析仪软件发现晶粒尺寸变化。发现VC在烧结过程中限制不期望的晶粒生长方面相对更有效。此外，使用微压痕测量显微硬度（H-V30）和断裂韧性，并对每种组合物的结果进行比较，以比较评估抑制剂的单独效果。增加抑制剂的浓度被发现限制晶粒生长，甚至更多，获得更高的硬度值，但仅达到一个临界抑制剂浓度，超过该浓度的硬度降低。(C)2014 Elsevier Ltd和Techna Group S.r.l. All rights reserved.
WC powders with average crystallite size of 10 nm were obtained through planetary ball milling of micron sized WC powder. Nanosized-WC powders were then mechanically milled with both 9 and 12 wt% Co, and the grain growth inhibitors VC and Cr3C2 in the range 0.2-0.8 wt%. Powder mixtures were then consolidated using spark plasma sintering (SPS) at two different temperatures, i.e. 1200 and 1300 degrees C. The microstructure, densification and mechanical properties of the resulting sintered nano-cermets were analyzed as a function of the type and amount of grain growth inhibitors, Co content, and sintering temperature. In general, the addition of VC and Cr3C2 was found to reduce densification. Nevertheless, the effect was found to be lower in Cr3C2 containing compositions with higher Co contents. The grain size variation was found by both a conventional line intersection method on FESEM micrographs, and by using grain analyzer software. VC was found to be comparatively more effective in restricting undesirable grain growth during the sintering processes. Moreover, the micro-hardness (H-V30) and fracture toughness were measured using micro-indentation and the results were compared for each composition to comparatively assess the individual effect of the inhibitors. Increasing the concentration of inhibitors was found to restrict grain growth even more and higher hardness values were obtained but only up to a critical inhibitor concentration, beyond which the hardness degrades. (C) 2014 Elsevier Ltd and Techna Group S.r.l. All rights reserved.