物理氣相與化學氣相沉積類鑽碳薄膜之微結構、機械性質與腐蝕研究

一般裝飾性保護薄膜可使在產品表面達到抗腐蝕，耐刮保持美觀使淘汰率降低。類鑽碳(DLC)薄膜因具備耐腐蝕與化學安定性，已用在五金零件及刀模具上作為保護鍍層。本實驗的裝飾性黑色系薄膜是用物理氣相沉積製備含鉻非晶碳(Cr-C)薄膜，另使用電漿強化化學氣相沉積(PECVD)製備類鑽碳(DLC)薄膜，以及用以上兩種技術沉積出Cr-C+DLC薄膜在矽晶片、不鏽鋼與高速鋼，藉以觀察所鍍製薄膜之微結構、機械性質與耐腐蝕性質。本研究分析儀器分別使用場發式電子顯微鏡(FESEM)、穿透式電子顯微鏡(TEM)與原子力電子顯微鏡(AFM)觀察薄膜的表面形貌、薄膜微結構與表面粗糙度；薄膜元素成分、化學組態及縱深分析則使用歐傑電子能譜與X光光電子能譜儀；薄膜硬度、楊氏係數與電阻分別使用奈米壓痕與四點探針分析，腐蝕特性測量使用恆定電位儀分析在3.5%氯化鈉(NaCl)水溶液中進行腐蝕電位測量。由穿透式電子顯微鏡分析結果，顯示Cr-C薄膜與DLC薄膜表面皆為非晶結構，Cr-C薄膜接近基材有Cr_7 C_3(051)簡單正交晶相結構。以場發射掃描式電子顯微鏡觀察薄膜表面形貌，顯示使用PECVD技術鍍出來的DLC薄膜較為緻密。XPS元素分析與奈米壓痕分析結果，可知Cr-C+DLC的DLC層有石墨化現象，使硬度降低。由色度分析結果DLC薄膜當加入Cr-C薄膜時L值會從43.08會下降到37.09，使薄膜顏色可達更接近所需要的黑色。在四點探針分析結果中知道Cr-C薄膜的電阻幾乎為零而具有導電性，DLC薄膜則是絕緣體電阻高達2百萬; 與DLC薄膜比較，Cr-C+DLC薄膜電阻降至5萬歐姆。由腐蝕實驗恆定電位測量結果顯示，Cr-C、DLC與Cr-C+DLC薄膜的腐蝕電位分別是-0.109 V、0.082 V以及0.455 V; Cr-C、DLC與Cr-C+DLC薄膜的極化阻抗分別是1.21×〖10〗^8 (Ω/cm^2)、9.14×〖10〗^8 (Ω/cm^2)以及1.04×〖10〗^9 (Ω/cm^2)，以上結果可知Cr-C+DLC複合薄膜有最高的腐蝕電位與極化阻抗，而具備最佳之抗腐蝕性能力。

關鍵字

類鑽碳；含鉻非晶碳；抗腐蝕； PVD ； PECVD

並列摘要

Diamond-like carbon (DLC) thin films, which are usually black, are used for decorative applications because of their good corrosion-resistance and chemical inertness. In this study, we used a physical vapor deposition (PVD) to prepare a Cr-C film, while we used a plasma enhanced chemical vapor deposition (PECVD) to prepare DLC films. At the same time, a composite film consisted of Cr-C and DLC (Cr-C+DLC) was depositedfor comparison. The microstructureand surface morphologies of the deposited coatings were analyzed using SEM, TEM and AFM. The chemical composition and bonding structure were analyzed using X ray photoelectron spectroscopy (XPS). A nanoindentation was used to measure the film hardness and Young's modulus of the deposited coatings. To identify the corrosion resistance of the deposited coatings, the samples were put in a 3.5% NaCL solution using a potentiostat. According to the TEM results, we found the deposited Cr-C and DLC films were amorphous. The interface near the substrate of the Cr-C film was orthogonal structure of Cr_7 C_3(051). It showed that the DLC film deposited by PECVD is the densest among the deposited coatings. According to the results of XPS and nanoindentation, The DLC layer of the Cr-C+DLC composite film showed graphitization, and the hardness of this coating is reduced. When DLC was add onto the Cr-C film, the L values reduced from 43.08 (Cr-C) to 37.09, and showed more black. From the Four Point Probe results, it showed that the resistances of the deposited Cr-C film, DLC and Cr-C+DLC’s value were near zero Ω, 2×〖10〗^6 Ω and 5×〖10〗^4Ω, respectively. The potentiostatic results showed that the corrosion potentials of the deposited Cr-C, DLC and Cr-C+DLC were -0.109 V, 0.082 V and 0.455 V, respectively. The corrosion resistance R_p of the Cr-C , DLC and Cr-C+DLC were, 1.21×〖10〗^8 (Ω/cm^2), 9.14×〖10〗^8 (Ω/cm^2), 1.04×〖10〗^9 (Ω/cm^2)respectively. It showed that the composite Cr-C + DLC film had the highest corrosion potential and polarization resistance.

並列關鍵字

DLC ； Cr-C ； Corrosion Resistance ； PVD ； PECVD

參考文獻

3.Ch. Donnet, A. Erdemir (Eds), 2010,Tribology of Diamond Like Carbon Films. Fundamentals and Applications, Springer, USA,

5.T. Haque, D. Ertas, A. Ozekcin, H.W. Jin and R. Srinivasan, 2013,Wear 302, pp.882.

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9.H. O. Pierson, 1993,“Handbook of carbon, graphite, diamond and fullerenes: processing, properties and applications”, Noyes publications, pp. 428-440.

12.J. Robertson, Diamond-like amorphous carbon. Materials Science and EngineeringR 37（2002）pp.129-281

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物理氣相與化學氣相沉積類鑽碳薄膜之微結構、機械性質與腐蝕研究

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