| Summary: | 碩士 === 國防大學中正理工學院 === 兵器系統工程研究所 === 96 === In the present and future study, for multiple purposes and applications in the industry technology, the smaller and thinner micro-electromechanical systems will be an important rule. However, if the thermal resistance and take-out ability of die patterns cannot progress to have long life cycle in the micro-model processing that for mass production of micro-electromechanical components. It would be failed to achieve the purposes of rapid mass-production and reduce costs. In this study, we attempt to produce ternary alloy that by adding an element such as molybdenum or phosphorous into nickel-tungsten based electrolyte in order to promote the thermal-resistance of the nickel based coatings for used in high temperature environments.
In this study, the Taguchi method was adopted for seeking the optimum coatings that with high tungsten contents, high-hardness and good thermal stability. The pulse electroforming technique was used through this research and compared with direct current plating technique. The analyzing of the coatings composition was detected with the FE-EPMA instrument. The Elastic modulous of the coating was measuring by Nano-Indenter, and the grain size was measured with XRD before and after heat-treated that for the thermal stability analysis.
Experimental results show that the tungsten contents in coatings were directly proportional influenced by sodium tungsten concentration, pulse current density and duty cycle. However, the pulse frequency is not a significant impact factor in the pulse electroforming experiments. In this research, the highest tungsten content of the alloy coatings is 35.7 wt.% that lead to it’s micro-hardness can be maintained about 920 HV around, and the grain size can be maintained around 16 nm after 700℃ heat-treated.
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