Development of Electro-discharge Coating for Coloring Treatment with Titanium powder green compact electrode

表面工程的功能與目的便是利用不同的表面改質技術以增進基材的特殊性質。本研究便是藉由利用放電披覆與氧化反應，將自行壓製的純鈦生胚電極，於去離子水中對SUS304不鏽鋼工件進行放電披覆發色。實驗中主要針對放電電流、放電脈衝時間及工作因子對披覆層中不同表面特性進行探討，包括披覆層厚度、表面粗糙度、表面硬度、表面狀態及顏色顯現，並將不同放電參數對披覆層形成機制作歸納。 研究結果顯示，提高放電電流會因放電能量變大而使厚度變厚，但也會因熔融組織的單位體積變大而使表面粗糙度變差，並會在表面形成凸起凝固體點及凸緣。放電脈衝時間在31μs以下，所披覆之厚度會隨放電持續時間增加而變大，但表面粗糙度則會隨著放電脈衝時間的拉長而變差。當Duty factor由0.33變為0.5時，其厚度會隨之增加，但當再改變為0.8時，披覆層厚度便會因有效放電次數減少而又下降，而Duty factor越大，表面粗糙度則會越差。披覆層硬度則會隨著披覆層厚度的變厚而變大。綜合而言，我們歸納出放電電流主要影響粉末熔漿量及單位粉末熔漿的尺寸，放電脈衝時間則會決定影響電極熔融的極間溫度，Duty factor則會影響粉末熔漿的冷卻模式。The function and purpose of surface engineering utilizing various kinds of surface modification techniques are to improve the particular properties of the workpiece. In this research, we propose a new surface coloring treatment, utilizing Electro-Discharge Coating (EDC) and oxidation, to make the oxide layers piled up on the SUS304 stainless steel substrate in the distilled water by using Ti powder green compact electrode. The following characteristics of the surface layers were investigated in this study: thickness, roughness, hardness, surface condition, and color tone. During this process, the effects of peak current, pulse duration, and duty factor were discussed respectively. The results revealed that the higher peak current can make the thickness of oxide layers thicker due to the larger discharging energy, and it would make the surface roughness worse, owing to the larger unit volume of melting metal and the formation of the dendritic precipitates. As the pulse duration time was under 31μs, the thickness of oxide layers would grow with the increasing pulse duration time. The surface roughness would get worse with the elongation of pulse duration time. The value of duty factor turned from 0.33 to 0.5, the thickness of the layers would get thicker thereupon, but when the duty factor became to 0.8, the reducing number of effective discharge would make the layers thinner. When the thickness of the surface layers became thicker, an increasing of the surface layers hardness was observed. As a conclusion, peak current affected the amount and the dimension of the melting powder mainly, pulse duration time would influence the temperature of the gap, and the cooling time were decided by duty factor.總 目 錄 中文摘要................................................Ⅰ 英文摘要................................................Ⅱ 致謝 ...................................................Ⅲ 總目錄..................................................Ⅳ 圖目錄..................................................Ⅷ 表目錄..................................................XI 第一章 緒論..............................................1 1.1 研究背景.............................................1 1.2 文獻回顧.............................................9 1.3 研究動機與目的 ......................................13 1.4 論文大綱 ............................................16 第二章 本研究相關基礎理論介紹............................17 2.1 放電加工相關技術.....................................17 2.1.1放電加工過程........................................17 2.1.2放電加工參數........................................18 2.1.3基本放電迴路........................................21 2.2 放電披覆.............................................24 2.2.1放電披覆機制...............................24 2.2.2放電披覆參數...............................24 2.3 陽極處理技術介紹.....................................26 2.3.1製程.......................................26 2.3.2電化學參數.................................26 2.3.3陽極氧化膜成長步驟.........................27 2.4 田口方法及其系統體系.................................28 2.5 發色機制 ............................................34 2.5.1光與色彩的關係.............................34 2.5.2色彩的屬性.................................34 2.5.3光譜的範圍與分佈情形.......................34 2.5.4成色機制...................................35 2.5.5光彩的表示方法.............................40 第三章 實驗方法與步驟....................................42 3.1實驗目的..............................................42 3.2實驗設備..............................................42 3.2.1放電加工機台........................................42 3.2.1.1機台可調整參數....................................45 3.2.2 粉末生胚成型設備...................................46 3.2.3 其它實驗設備.......................................48 3.3 實驗材料.............................................50 3.4 實驗設計.............................................52 3.5 實驗方法.............................................54 3.5.1 實驗流程..................................54 3.5.2 生胚電極製作..............................55 3.5.3 鈦電極放電披覆............................57 3.6 實驗量測.............................................60 第四章 實驗結果與討論....................................63 4.1 利用田口式L18表進行預備實驗..........................63 4.1.1 選擇控制因子.......................................64 4.1.2數據分析...................................65 4.2 實驗參數選擇.......................................68 4.2.1調變參數的選擇.............................68 4.2.2固定參數的選擇.............................68 4.3 加工參數對披覆層特性之影響...........................71 4.3.1 放電電流對披覆層特性的影響................71 4.3.1.1放電電流對表面粗糙度的影響.............73 4.3.1.2表面狀態觀察...........................74 4.3.1.3放電電流對披覆層厚度的影響.............76 4.3.2 放電脈衝時間對披覆層特性的影響.....................77 4.3.2.1放電脈衝時間對表面粗糙度的影響.........78 4.3.2.2表面狀態觀察...........................79 4.3.2.3放電脈衝時間對披覆層厚度的影響.........81 4.3.3 Duty factor對披覆層特性的影響......................82 4.3.3.1 Duty factor對表面粗糙度的影響.........84 4.3.3.2表面狀態觀察...........................85 4.3.3.3 Duty factor對披覆層厚度的影響.........86 4.3.4各放電參數對披覆層厚度的影響...............87 4.3.4.1放電披覆時間對披覆層厚度的影響.........87 4.3.4.2其他放電參數對披覆層厚度的影響.........89 4.3.5 各放電參數對表面粗糙度的影響..............90 4.3.6 各放電參數對披覆層表面狀態的影響..........90 4.3.7 各放電參數對披覆層表面硬度的影響..........91 4.3.8 披覆層之成分分析...................................93 4.3.9 披覆層之微觀組織..................................104 4.4 披覆層之發色觀察....................................108 4.4.1 披覆層之表面發色觀察.....................108 4.4.2 披覆層之側面發色觀察.....................110 4.4.3 實驗檢討.................................113 第五章 結論與未來展望...................................115 5.1 結論..............................................115 5.2未來工作...........................................119 參考文獻................................................12