氧化鋁含量對氧化鈣/氧化鋯/氧化鋁複合材料與鈦金屬介面反應之影響

Abstract

本研究將不同體積之氧化鋁粉末，摻雜於等體積比的氧化鋯/氧化鈣粉末中，並以1300°C/30MPa/30分鐘的條件熱壓成複合材料後，將複合材料與Cp-Ti在1600°C下進行介面反應，並以x光繞射儀(XRD)和Rietveld-method對複合材料進行相鑑定和定量分析，以及掃描式電子顯微鏡(SEM/EDS)觀察複合材料及介面微觀結構。從研究結果發現隨著氧化鋁添加量增加，依序出現了鋯酸鈣(CaZrO3)、立方晶體氧化鋯(c-ZrO2)、鋁酸鈣 (CaAl2O4)及二鋁酸鈣(CaAl4O7)等相；在複合材料樣品中，鋯酸鈣的比例隨著氧化鋁含量的增加而降低，立方晶體氧化鋯比例反而增加。其原因為氧化鋁較容易與氧化鈣反應形成鋁酸鈣，使得生成鋯酸鈣所需之氧化鈣含量不足，遺留了大量氧化鋯。此外，由XRD和SEM/EDS結果指出，隨著鋯酸鈣比例降低，在複合材料與Cp-Ti的介面反應越發劇烈。氧化鋁在複合材料及高溫擴散介面中扮演重要的角色，當氧化鋁添加量低於10 vol%.時，鋯酸鈣成為複合材料的主要相並且能抑制介面反應。

The samples with various contents of Al2O3 were hot pressed with the same volume ratio CaO/ZrO2 at 1300°C/30 MPa for 30 min and then reacted with Cp-Ti at 1600°C/30 min. The as-hot pressed specimens were characterized by x-ray diffraction (XRD) and the interfacial microstructures were observed by analytical scanning electron microscopy (SEM/EDS). The XRD spectra indicated that there existed CaZrO3, c-ZrO2, CaAl2O4 and CaAl4O7 phases. In addition, the amount of CaZrO3 phase was decreased with increasing Al2O3, but that of c-ZrO2 was in the opposite manner. According to SEM observations, there were less reaction layers in the sample with high CaZrO3 content than in others. The XRD and SEM/EDS results showed that Al2O3 played an important role in the processing of composites and the reactions between composites and titanium. When the amount of Al2O3 in the composites was below 10 vol.%, CaZrO3 became the major phase and it could suppress the diffusion of oxygen to titanium.