2009-08-012024-05-18https://scholars.lib.ntu.edu.tw/handle/123456789/704208摘要：六價鉻在材料防護上常用在化成鈍化處理、腐蝕抑制劑和電鍍鉻。然而，六價鉻製程嚴重污染環境，因應歐盟RoHS危害物質限用指令的實施，發展替代六價鉻處理相關製程刻不容緩。本三年期研究計畫針對有前瞻性可以替代目前業界所用六價鉻硬鉻製程的相關電鍍製程進行研究，包括三價鉻電鍍、鎳鎢合金電鍍與鎳鈷磷/鎳鎢磷電鍍製程。除了著重鍍層的機械性質與抗蝕性外，特別著重厚鍍層的製備，即最大化三價鉻鍍層厚度，鎳基合金鍍層則挑戰1000m。所以，針對三價鉻製程，首重在解析導致鍍層生長停止的鈍化成組成與微結構。針對鎳基合金電鍍則需解決鍍層內應力過大與電流效率過低等問題。先藉由鍍液成分與電源形式控制，設計穩定電極表面pH值的脈衝電源形式，接著進行陰極極化曲線量測與旋轉電極實驗。並進行詳實的鍍層微結構分析與性質量測，釐清鍍液錯合劑效用、鍍層內應力成因與合金共鍍行為。最後，以較佳製程在4吋銅圓盤上電鍍1000m厚的合金鍍層，並評估整體鍍層厚度、成分與結構的均勻性。<br> Abstract: Hexavalent chromium has been used extensively in conversion coating treatment and chrome plating, and added as corrosion inhibitors in solutions. However, hexavalent chromium is a highly toxic substance. To comply with RoHS directive, developing alternative processes to those using hexavalent chromium is now all the more important. This three-year project aims at developing electroplating processes potentially alternative to hard chrome electroplating, and includes trivalent chromium electroplating, and electroplating of Ni-W, Ni-Co-P, and Ni-W-P alloys. In addition to the desired mechanical and corrosion protective properties, these electroplating focuses on fabricating thick deposits; that is, to maximize the thickness of trivalent chromium plating, and fabricate 1000 m thick Ni-based alloy electrodeposits. Consequently, efforts are made to characterize the microstructure of the passive film that effectively inhibits the growth of trivalent chromium deposit, and to understand the mechanisms associated with high internal stress and low cathodic current efficiency for Ni-W, Ni-Co-P and Ni-W-P electroplating. First, cathodic polarization measurement and rotating disc electroplating are performed in a proper electrolyte using a specific current waveform that is designed specifically to stabilize the pH at the interface between the growing deposit and the electrolyte. Together with the detailed microstructure, mechanical and corrosion protective properties of the various electrodeposits, a better understanding on the effects of different complexants, and the mechanisms associated with the internal stress and the codeposition of alloy elements in the deposits can be made. Finally, 1000 m-thick deposits are plated on 4” cupper disks in an optimal electroplating system, with emphasis on the uniformity in thickness, composition and microstructure of the deposit.六價鉻硬鉻三價鉻電鍍鎳鎢合金電鍍鎳鈷磷/鎳鎢磷電鍍RoHS指令hexavalent chromiumhard chrometrivalent chromium electroplatingNi-W alloy electroplatingNiCoP/NiWP alloy electroplatingRoHS directive