本研究利用有機金屬化學氣相沈積法（MOCVD）配合流體床（Fluidized Bed）技術，製備Cr2O3/Al2O3奈米複合粉體，並經由甲烷－氫氣氣氛下碳化熱處理將Cr2O3碳化為Cr3C2，研究其碳化熱處理過程之相轉換機制，期望能夠找出最佳的碳化溫度和時間，製備出Cr3C2//Al2O3複合粉末在真空環境中以1400℃進行熱壓燒結，製備出緻密性之碳化鉻/氧化鋁奈米複合陶瓷。
本實驗將先導物Cr(CO)6 經由流體床熱烈解後，將裂解的奈米粉末經由XRD、TEM、XPS和Raman等做為分析。實驗結果發現隨著碳化熱處理的溫度時間改變，碳化過成中碳首先沉積在奈米粉末的表面進行氧化還原的反應，之後碳會包覆在奈米粉末外層經由擴散的方式進行反應，由XRD相分析可得知裂解的奈米粉末Cr(CO)6由非晶質的C-C、CrC、C-O的化合物依序轉變Cr2O3→Cr3C2-x→Cr3C2。利用TEM觀察得知奈米粉末的表面形貌和碳擴散層，由STEM line scan mode 發現其組成物的表面梯度：分別為非晶質的碳、Cr3C2-x 以及 Cr3C2。EELS證明Cr3C2-x 以及 Cr3C2 計量比和鍵結價數上的差別最後由XPS、Raman證明碳的增加以及結構上的改變。
於真空熱壓燒結合成之Cr3C2/Al2O3奈米複合陶瓷的強度、硬度、韌性均較單質氧化鋁提升許多，顯示大部分第二相的奈米碳化鉻產生了強、韌化的效果。

Nanochromium carbide were prepared by metal-organic chemical vapor deposition (MOCVD) method in a fluidized bed and carburized in the mixtures of CH4/H2 atmosphere in temperature ranged from 700-850 oC. Under these conditions, the carburization process involved carbon deposition on the outer surface of the powder, diffusion of carbon into nanopowder as well as carbide formation, Cr2O3, metastable Cr3C2-x and stable Cr3C2.
The relation among the products, reduction temperature and time was summarized from the XRD. TEM is employed to investigate the detailed structure of the carbon diffusion layer. Use the STEM line scan mode to find out the compositional gradient within the interlayer: Cr3C2-x 、 Cr3C2 and pure C amorphous. The experimental results indicated that, carbonthermal reduction process of Cr2O3 consists of two steps, the rate-controlling step is CO /CO2 gas diffusion through the layer of reduction products. With the longer duration time, the stoichiometry of the mixture Cr3C2-x is the first carbide form, then to form stable Cr3C2.。
The hot-pressed Cr3C2/Al2O3 nanocomposites have better mechanical performances such as bending strength, and hardness than the monolithic Al2O3. The nano-sized Cr3C2 particles were mainly located within the Al2O3 grains as well as on the Al2O3 grain boundaries.

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