以電鍍法製作含奈米粒子之金屬微結構的熱膨脹係數及疲勞特性研究

Abstract

在先前本實驗室的研究中，已成功地將奈米鑽石粒子加入鎳電鍍液中 製作鎳-鑽奈米複材，並應用在電熱式微致動器，我們發現鎳-鑽石奈米複 合材料相較於純鎳金屬，在相同的位移輸出下可減少73％的輸入功率，熱 膨脹係數並會隨著鑽石奈米粒子濃度而增加，但無法用一般複材常用的混 合定律解釋。另外，在我們的研究中也發現加入二氧化矽奈米粒子，則可 使鎳-奈米複材之熱膨脹係數降低。本計畫將進一步探討電鍍鎳-奈米複材 熱膨脹變化原因及其疲勞特性，即為：(I) 鎳-奈米複合材料熱膨脹行為測 試與模型建立。(II) 鎳-奈米複材疲勞測試元件製作、方法建立及疲勞特性 測試。在熱膨脹行為方面，將利用添加不同種類奈米粒子、不同粒徑且變 化奈米粒子濃度對各項製程參數做詳細的熱膨脹行為量測，再透過內應力 及晶格尺寸等多項量測數據，以期了解熱膨脹係數變化原因。在疲勞特性 方面，將發展三種疲勞測試方法—包括微拉力試驗、振動平台試驗和共振 微致動器試驗，並製作相關測試試片，以不同的施加負載頻率及大小，探 討所製作奈米複材之疲勞特性，進而希望建立鎳-奈米複材疲勞特性之資料 庫。

In previous investigation, our group has successfully fabricated Ni-diamond nanocomposite by adding nano-diamond particles in Ni electroplating process, and demonstrated its application in electro-thermal microactuators. Comparing to the device made of pure Ni, we found that the required input power could be reduced 73% to achieve the same output displacement, and the coefficient of thermal expansion would increase with the concentration of diamond particles, but it is also found that the enhancement on coefficient of thermal expansion can not be modeled by the typical rule of mixture. Furthermore, the coefficient of thermal expansion was found to be decrease due to the nano-SiO2 particles adding into Ni electroplating process. Here the thermal expansion and fatigue behavior of Ni-based nanocomposites adding different nano particles with different sizes under various concentrations will be designed, fabricated, and tested. In the investigations of thermal expansion behavior, the micro-strain, crystal parameters and so on will be discussed in detail. About the fatigue behavior, three methods, including micro tensile test, resonant test, and comb-drive test, will be developed for the establishment of S-N curve of Ni-based nanocomposites.