本實驗利用固態反應法將金屬氧化物粉末進行煅燒合成出堇青石粉末，是現今最常運用在汽車觸媒轉換器載體的材料之一。關於引擎加熱所造成的二次熱處理對於堇青石陶瓷體的相變化以及熱膨脹行為之影響，尚未有深入之探討，本實驗的目的為觀察二次熱處理對於堇青石陶瓷體之相組成，以及熱膨脹係數之影響。
堇青石陶瓷體經過不同溫度的燒結後，再經過 700-1100℃ 之二次熱處理，淬冷並以不同持溫時間以觀察其影響。二次熱處理後之堇青石陶瓷體會利用 X 光繞射圖譜觀察陶瓷體的相鑑定、 Rietveld method擬合相組成以及熱膨脹分析儀量測熱膨脹行為。結果顯示堇青石陶瓷體在 1100℃ 以下不會受到多次熱處理而使得其熱膨脹行為有劇烈的改變，而在 1200℃/12 h 以上之二次熱處理才會使堇青石中的相組成比例關係趨於明顯，因此可推測二次熱處理與汽車觸媒轉換器需進行更換之原因並無明顯之關係。

Cordierite ceramic can be synthesized from metal oxide powders by solid state method and is one of the common carriers of catalytic converter in engines. The operation of engines produces secondary heat treatment whose effect on cordierite ceramic is not yet understood. The goal of this study is to investigate how the secondary heat treatment affects cordierite ceramic’s phase composition and thermal expansion coefficient.
Cordierite ceramics were sintered at different temperatures before underwent 700-1250℃ secondary heat treatments with different holding time and quenched to room temperature. The phase composition and thermal expansion coefficient before and after the secondary heat treatment were analyzed by X-ray diffraction, refined by Rietveld method for phase compositions and dilatometer for thermal expansion coefficient, respectively.
The results suggested that the secondary heat treatments under 1100℃ do not have a major effect on the phase composition and thermal expansion coefficient of cordierite ceramics. Therefore we concluded that the need of replacing the catalytic converter in engine (700-1100℃) has little to do with the change of the cordierite ceramics thermal expansion coefficient.

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