氧化鋯添加微量氧化鋁或鎳之機械性質

陶瓷的機械性質可以經由添加金屬或陶瓷顆粒達到改善的效果，而強度的增加量與第二相的添加量息息相關。以往研究，第二相的添加量往往在5vol%以上，本研究在ZrO2中加入Al2O3或Ni，而添加量少於5vol%。本研究以無壓燒結的方式製備複合材。ZrO2/Al2O3複合材分別在15000C (一階段式)及16000C (二階段式) 下燒結，ZrO2/Ni複合材則在16000C下燒結，採用二階段式燒結可避免試樣大量的變形。ZrO2/Al2O3複合材的相對密度皆在99%以上。但是ZrO2/Ni複合材的相對密度則隨著鎳添加量的不同而有所變動，本研究所使用的燒結氣氛有空氣或一氧化碳混合，燒結氣氛對ZrO2基複合材緻密化行為扮演重要的角色。本研究以四點彎曲的方式量測撓曲強度。ZrO2/Al2O3複合材的強度並未隨著第二相添加量之增加而提升。而ZrO2/Ni複合材其強度隨著第二相添加量的增加而上升，但是在更高的鎳添加量下，強度呈現下降，強度變化的趨勢與密度有密切的關聯。本研究以單邊切槽法(SENB)的方式量測破壞韌性，得到的結果顯示與強度測試有相同的趨勢。ZrO2/Al2O3複合材之機械性質在16000C燒結溫度下較ZrO2/Ni複合材良好，但是ZrO2的機械性質在Ni微量添加下有所提升。依照微結構的觀察去計算晶粒的大小。氧化鋯基材的晶粒受微量氧化鋁及鎳的添加影響不大，機械性質亦沒有受到晶粒大小的影響。這可能是由於孔隙之作用太大的原因。

關鍵字

機械性質；氧化鋯；氧化鋁；鎳；複合材；撓曲強度；破壞韌性；燒結氣氛

並列摘要

The mechanical properties of ceramics can be enhanced by adding either metallic inclusions or ceramic particles. The extent of enhancement is closely related to the second phase content. In the present study, the amount of second phase added is lower than 5vol%. Two systems, ZrO2/Al2O3 and ZrO2/Ni composites are investigated. Pressureless sintering technique was used to prepare the composites. The sintering temperature was 15000C (one-stage) and 16000C (two-stage) for ZrO2/Al2O3 system and 16000C for ZrO2/Ni system. The two-stage sintering technique provides better dimension control. The relative density of the ZrO2/Al2O3 composites after sintering is higher than 99%. But the relative density of ZrO2/Ni composites varies with the Ni content. The sintering atmosphere used in the present study, air vs. CO, may play an important role on the densification behavior of the composites. The flexural strength was determined by using the 4-point bending technique. The strength of ZrO2/Al2O3 composites does not increase when a small amount of Al2O3 is added. The strength of ZrO2/Ni system depends strongly on the Ni content. The strength variation of ZrO2/Ni composites corresponds closely to their density variation. The fracture toughness was determined by using the single-edge-notched beam method. The similar results were obtained as that for strength. The mechanical properties of ZrO2/Al2O3 composites sintered at 16000C are superior to those of the ZrO2/Ni composites sintered at 16000C. But there is an increase of strength in ZrO2/Ni system as a small amount of 0.17vol%, is added. From the microstructural observation, the grain size was determined. The addition of Al2O3 affects little on the size of ZrO2 matrix grains. However, the addition of Ni particles also affect little on the grain size of ZrO2. Nevertheless, the mechanical properties are not affected by the grain size. It may be due to that the mechanical properties are over-shadowed by the influence of porosity.

並列關鍵字

mechanical property ； ZrO2 ； Al2O3 ； Ni ； composite ； flexural strength ； fracture toughness ； sintering atmosphere

參考文獻

[35] P.A. Evans, R. Stevens, J.G.P. Binner, “Quantitative X-ray Diffraction Analysis of Polymorphic Mixes of Pure Zirconia,” Br. Ceram. Trans. J., 83, 39-43, 1984.

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國際替代計量

氧化鋯添加微量氧化鋁或鎳之機械性質

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