Cu43Zr43Al7Ag7非晶合金在375~500℃之空氣氧化行爲

Air-Oxidation Behavior of Cu43Zr43Al7Ag7 Bulk Metallic Glass at 375~500℃

高佩琴(P. C. Kao) ； 林品辰(P. C. Lin) ； 開物(W. Kai) ； 廖楷輝(P. K. Liaw)

《防蝕工程》 24卷2期 (2010/06) Pp. 129-139

https://doi.org/10.6376/JCCE.201006.0129

摘要

本研究探討Cu43Zr43Al7Ag7非晶合金在375~500℃空氣下的氧化行爲。研究結果顯示，銅鋯基非晶合金的氧化反應速率常數(k(下標 p))與溫度呈現不規則之變化；當氧化溫度低於425℃時，k(下標 p)值隨溫度上升而加快，但在450℃以上時，卻有相反的趨勢。氧化後的氧化生成物以正方晶體的ZrO2(t-ZrO2)和CuO爲主，另外，有少量的單斜及斜方的ZrO2（m-和o-ZrO2）以及α-Al2O3（只有在500℃生成）。此外，少量Ag的添加可增加非晶在375~425℃的抗氧化能力，但高溫時（溫度大於450℃）並無此種的效果產生。當溫度低於玻璃轉換溫度(T(下標 g))下時，基材仍保有非晶狀態；但當溫度升高時，非晶合金會先氧化後結晶的相變化發生，基材轉變爲Cu10Zr7和ZrAl兩種結晶相。

關鍵字

銅鋯基非晶合金 ； 正方晶體ZrO2 ； CuO ； α-Al2O3

並列摘要

Air-oxidation behavior of the Cu43Zr43Al7Ag7 bulk metallic glass was studied over the temperature range of 375~500℃. The oxidation rate constants (k(subscript p) values) of the glassy alloy fluctuated with temperature. The k(subscript p) values increased with increasing temperature when the oxidation temperature (T(subscript oxid)) was below 425℃, but these values instead decreased with increasing temperature at T(subscript oxid)＞ 450℃. The scales formed on the Cu43Zr43Al7Ag7 consisted mostly of tetragonal-ZrO2 (t-ZrO2), CuO, minor amounts of monoclinic- and orthorhombic-ZrO2, (m- and o-ZrO2), and α-Al2O3 (only detected at 500℃). In the meantime, small amounts of Ag addition provided a better oxidation resistance at the temperature range of 375~425℃, but no improvement was obtained at higher temperatures. In addition, the glassy substrate remained unchanged at temperatures below the glass-transition temperature (T(subscript g)), yet it underwent a preoxidation process and a phase transformation after the oxidation at T(subscript oxid)＞ 425℃, causing the substrate to transform from an amorphous state to crystallized Cu10Zr7 and ZrAl.

並列關鍵字

Cu43Zr43Al7Ag7 BMG ； t-ZrO2 ； CuO ； α-Al2O3