無電鍍製備鈀系列多元合金薄膜於氧化鋁基材應用於氫氣分離

Abstract

本研究主要是利用無電鍍法沉積鈀合金薄膜於多孔氧化鋁管上，並在高溫環境下作氫氣和二氧化碳分離。陶瓷封裝部分，由熱重分析儀分析在600°C去除有機黏合物，並由SEM觀察在1150°C熱處理後，表面有燒結之現象，最後GC測試下沒有發現二氧化碳漏氣，證實本封裝材料及參數可有效作用。 鈀合金薄膜部份選用鈀銀銅鎳多元合金薄膜作透氫材料，在無電鍍於管形基材前，先無電鍍於緻密氧化鋁片上，求得各金屬之最佳鍍膜參數，並分析各成份之金屬合金膜。各成分金屬膜厚度都可控制在2 μm左右。600°C退火過後除了鈀銀銅鎳合金膜出現雜相外，推測鎳銅有二相分離之結果，其而鈀銀、鈀銀銅之金屬膜為均一。退火後膜表面形貌沒有出現破損，但是鈀銀銅、鈀銀銅鎳合金膜表面粗糙度上升，推測主要是銅無電鍍時均勻性成核之結果。各合金膜之成份分析都能約略控制在預期之組成，且可以使用秤重減量法來粗估膜沉積之量。 管形基材部分採用先封裝後鍍膜方式操作，目前以成功製備鈀銀銅鎳多元合金膜於多孔氧化鋁管上，接著將利用氣相層析儀作氣體分離測試。

In this work, we attempt to fabricate a Pd-based alloy membrane on an alumina support via a sequential electroless deposition technique. The membrane enables the separation of hydrogen from a mixture of hydrogen and carbon dioxide at elevated temperature. We use commercial ceramic paste as a sealing material in which the debindering and sintering temperatures are identified as 600 and 1150 degree Celsius, respectively. From GC results, after proper sealing we attain desirable air tightness at 600 degree Celsius. The electroless deposition is conducted on a flat alumina disk initially in order to determine suitable processing parameters for targeted alloy composition. Materials characterization such as phase, composition, and morphology are carried out. The PdAg and PdAgCu membranes show homogenous single phase, and the surface maintains nicely after annealing at 600 degree Celsius. However, the PdAgCuNi membrane behaves differently because of phase separation between Cu and Ni. The roughness is found to increase in PdAgCu and PdAgCuNi as the deposition progresses, a fact that is attributed to the homogenous nucleation of Cu during electroless plating. The expected ratio for Pd-based alloy membrane can be controlled and estimated after careful weight determination. In addition, we successfully prepare PdAgCuNi alloy membrane on a porous alumina tube after proper sealing and the hydrogen permeation test will be performed shortly.