添加劑對氧化鋁陶瓷材料機械性質及孔隙度影響之研究

本研究主要探討添加劑對氧化鋁陶瓷材料的機械性質及孔隙率之影響。α-氧化鋁是實驗的主要原料，並添加不同比例之矽灰石、鈉長石、鉀長石、氧化鎂、氧化錳、氧化鋅、莫萊石或滑石比較之。生胚的燒結溫度介於1300-1600℃，並在最高溫度之持溫時間為1或4小時，之後再對燒結完成之試體進行密度、孔隙率、抗壓強度、維克氏硬度測試及微觀結構觀察。實驗結果顯示，隨著燒結溫度的增加，氧化鋁陶瓷之密度隨之增加，而孔隙率也隨之下降。沒有添加物之氧化鋁陶瓷在燒結溫度1600℃、升溫速率10℃/min且持溫時間4小時的燒結條件下(相較於其他燒結條件)，可達到最佳的機械性質。而在相同之燒結條件下，添加5wt.%矽灰石、鈉長石或鉀長石之氧化鋁陶瓷，其抗壓強度皆高於未添加的情形(即使是升溫速率且持溫時間只有1小時的情形)。在燒結溫度1400℃的情況下，添加5wt.%矽灰石之氧化鋁陶瓷，其抗壓強度即可超過無添加之氧化鋁陶瓷在1600℃燒結之結果。另外，本研究利用海綿法及添加10-30wt.%的莫萊石及滑石兩種方法，製作多孔氧化鋁陶瓷。實驗顯示隨著莫萊石或滑石添加量的增加，可大幅降低氧化鋁陶瓷之密度並增加其孔隙度。而利用海綿法成型之氧化鋁陶瓷，其孔隙度可達64 %，但抗壓強度也會降至小於1MPa。

關鍵字

添加劑；機械性質；孔隙率；氧化鋁陶瓷；矽灰石；長石；海綿法；莫萊石

並列摘要

In this study, the influence of additives on the mechanical properties and porosity of alumina ceramics is investigated. The α-alumina is used as the starting raw material and the addition of wollastonite, sodium feldspar, potash feldspar, MgO, MnO2, ZnO, mullite, or talc is evaluated in various ratios. The samples are sintered at temperatures ranging from 1300-1600℃ with holding time for one or four hours. The sintered density, porosity, compressive strength, Vickers hardness, and microstructural features are then examined. The results show that as the sintering temperature increases the density of alumina ceramics increases as well, but the porosity decreases. The alumina ceramics without additive achieve the highest compressive strength with the sintering temperature of 1600℃; and the sintering condition with 10℃/min heating rate and soaking time for 4 hours can obtain the superior mechanical properties than others. With the same sintering conditions, the compressive strengths of alumina ceramics added with 5wt.% wollastonite, sodium feldspar, or potash feldspar are higher than the pure alumina ceramics without additives even with heating rate 2℃/min and soaking for one hour only. At the sintering temperature of 1400℃, the compressive strength of alumina ceramics with addition of 5wt.% wollastonite exceed the value of pure alumina ceramics at 1600℃ Besides, the polymeric-sponge method and the addition 10-30wt.% of mullite and talc are attempted to produce porous alumina ceramics. The increment of mullite or talc addition in alumina ceramics reduces the density but increases the porosity. With the sponge method, the porosity of pure alumina ceramics can reach 64 % and the compressive strength down to less than 1MPa

並列關鍵字

additives ； mechanical properties ； porosity ； alumina ceramics ； wollastonite ； feldspar ； sponge method ； mullite

參考文獻

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