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氧化钨/碳SPS原位合成WC硬质合金的XPS研究
XPS Study on WC Bulk in-Situ Synthesized through Directly Carbonized Tungsten Oxide by SPS
【摘要】 以WO3+14.5%C(质量分数,下同)的混合粉作为原始粉末,采用放电等离子烧结(SPS)在不同温度下烧结保温3min,直接一步合成致密WC硬质合金。借助于X射线光电子能谱(XPS)分析了合成样品的元素价态变化,探讨了SPS原位合成的过程和机理。结果表明:随着烧结温度的升高,样品中的W元素的价态逐步由氧化态的W+6,W+5,W+4过渡到单质W0+和碳化物态的W+2;而样品中的碳元素价态却逐步由单质碳转变为化合碳,氧化物态的晶格氧强度逐渐降低,以碳氧键存在吸附的氧强度逐渐增强。XPS分析结果表明,在SPS原位合成中,WO3首先被碳还原,并经历了一系列中间钨氧化物状态后得到金属钨,然后金属钨进一步发生碳化反应最终形成WC。
【Abstract】 The WC bulk was in-situ synthesized with mixed WO3 +14.5%C powders by spark plasma sintering at different temperatures. The chemical valence state of W, C, O in the samples were investigated by XPS. The results indicates that the element W changes from W+6, W+5, W+4 in oxidative state to metallic W0 and W+2 in carbide state with the rising of synthesizing temperature. It reveals that WO3 is firstly reduced by carbon to form intermediate tungsten oxides such as WO2.72, WO2, and metallic W in the reduction process, then the carbonization reaction occurs, and the WC is formed finally.
【Key words】 XPS; in-situ synthesis; SPS; cemented carbide; tungsten carbide; tungsten oxide;
- 【文献出处】 稀有金属材料与工程 ,Rare Metal Materials and Engineering , 编辑部邮箱 ,2006年06期
- 【分类号】TG135.5;TF125
- 【被引频次】15
- 【下载频次】706