本實驗分為兩部分來進行，分別是固態Mg與固態Ni進行界面反應與在介金屬Mg2Ni中主要擴散元素的探討，然後進一步計算Mg-Ni界面反應動力學資料。 此實驗主要是利用Mg片與Ni片組成擴散偶，再將此擴散偶分別在400、430、450和480℃下進行10到75小時的熱處理，熱處理完的試片經金相處理後，在以掃描式電子顯微鏡觀察界面處的介金屬生長情形，接著透過電子微探儀去做組成的鑑定。為了更精確判斷介金屬生成種類，將反應過的擴散偶沿界面拆開，以Ni片端去做X光繞射分析。由實驗結果顯示在界面處只可以觀察到Mg2Ni相的存在，且此介金屬生長厚度對反應時間的二分之ㄧ次方呈線性關係，故Mg2Ni生長行為擴散控制。 另一部份為探討在Mg-Ni擴散偶中，於400-480℃下界面反應生成Mg2Ni相的主要擴散元素，根據電子顯微鏡觀察反應後的試片結果顯示，Mg為介金屬相中的主要擴散元素，此實驗結果與文獻中Mg-Ni在225℃之界面反應的主要擴散元素不同，我們推測因溫度上的差異造成介金屬中的主要擴散元素改變的現象，但我們實驗結果並無法支持此推論，仍需更多的實驗數據來證實。 Two sets of experiments were carried out in this work. The first was the reaction between solid Mg and solid Ni, and the second was the investigation of dominant diffusion species in the formation of Mg2Ni. The data of kinetics for Mg-Ni interfacial reaction would be established. In this work, the Mg and Ni sheets were combined and then taken to perform solid/solid reaction at 400℃, 430℃, 450℃ and 480℃ for 10~75 hours, respectively. The morphology of the heat-treated specimens was observed by scanning electron microscope(SEM). The chemical composition was measured by electron probe microanalysis(EPMA). The diffusion couple specimen was taken apart to analysis which kind of intermetallic compound was formed at the interface of Mg/Ni by X-ray diffractometer(XRD). The result showed that just single Mg2Ni phase was formed at the interface of Mg/Ni and the thickness of Mg2Ni is linear to the square root of reaction time. Thus, it is believed that the reaction of the formation of Mg2Ni at the Mg/Ni interface is diffusion controlled. In addition, it was also investigated that which element in Mg/Ni diffusion couple diffused faster at reaction temperature between 400 and 480℃. The result presented that Mg possesses higher diffusivity than Ni in accordance with SEM pictures. However, this result is different from that of other researchers made by simulation of Rutherford backscattering spectrometer(RBS) research of Mg/Ni coating membrane at relatively low temperature(225℃). We consider that the dominant diffusion species in the formation of Mg2Ni could change at different reaction temperature. But this assumption need more experimental result to support.
