Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/10058
標題: Characterization and Mechanical Properties of Cu-DLC on 7075 Aluminum Alloys
合成含銅&;#63952;鑽碳膜於輕&;#63754;屬合&;#63754;表面之機械性質與膜層特性之研究
作者: Liu, Yu-Ching
劉又菁
關鍵字: 含銅類鑽碳膜;Cu-DLC;鋁合金;陰極電弧電漿沈積系統;7075 aluminum alloys;residual stress
出版社: 材料科學與工程學系所
摘要: 
目前能源短缺問題越來越嚴重,環保意識抬頭的情形下,自行車的使用率也越來越高,而汽車工業的發展也趨向於輕量化製程,以減少車體重量造成行車時汽油量的耗損。高強度鋁合金因為其高比強度及重量輕的特性,目前已經廣泛使用於汔機車工業及航太科技上面。但由於其表面耐蝕性及耐磨耗性相較於一般不鏽鋼來講性質還是較差,所以使得在某些機件上不鏽鋼無法完全用鋁合金取代。
類鑽碳膜(diamond-like carbon film, DLC)性質優良,硬度高(約幾十GPa),化學穩定性高,耐腐蝕,抗磨耗等等,不論是在機械、電機、生物及化學等領域上應用廣泛,且製程環境可在室溫下操作,生長方式多樣且製備容易。但由於其硬度高所以容易產生高殘留應力,與基材附著性差,所以目前大多使用不鏽鋼作為基板,以減少硬度梯度所造成的薄膜與基材間的應力破壞。
藉由金屬的摻雜,使薄膜內部能量釋放,藉此降低薄膜內應力,使薄膜與基材間附著性提昇,不受高硬度梯度及高殘留內應力破壞而導致薄膜剝落,增加輕金屬合金與高硬度類鑽碳膜之間的附著性。
本實驗為利用陰極電弧電漿沈積系統,藉由改變乙炔氣體流量找出最佳沈積速率,再藉由改變基材負偏壓,分析對銅含量及薄膜特性及硬度的影響。利用場發射掃描式電子顯微鏡觀察類鑽碳膜表面形貌及痕截面量測薄膜厚度;X 光電子能譜儀分析薄膜成份及各成份鍵結型態;拉曼分析碳的鍵結型態;X 光繞射分析薄膜內銅元素之結晶型態;利用HRTEM 觀察銅原子的顆粒團聚現象,以及由繞射圖形比對銅化合物類型;使用維式硬度測試薄膜硬度,洛式壓痕測試機測試類鑽碳膜對7075 鋁合金之附著性;以水接觸角量測薄膜表面其親水疏水性質,鑑定其表面能大小。
量測結果得到,在乙炔流量50 sccm 時有最高沈積速率,故選擇50 sccm 作為固定流量之參數。利用控制基材負偏壓,發現在 -150 V 時有最佳硬度值,並且與sp3/sp2 比及ID/IG 比結果相互吻合。XPS 及Raman 光譜分析膜層中鍵結型態含有sp3及sp2 鍵結,以及純銅、氮化銅及氧化銅存在,並藉由TEM 及XRD 繞射圖形加以印證比對。並利用洛式壓痕測試附著性,發現摻雜銅的類鑽碳膜均有良好的附著性,壓痕周圍裂痕少,為HF1 等級,顯示銅的添加有助於降低殘留應力並增加附著性。最後以水接觸角測試不同參數下的表面能,發現接觸角介於98 度到112 度之間,與硬度呈正相關,疏水性質良好,表面能低而化學穩定性佳。

Aluminum alloys are widely using in automobile, aerospace and bicycle industry because of its high strength and low density. While its resistance of wear and hardness is not excellent to protect the matrix.
Diamond-like carbon (DLC) thin films contain superior properties, example for high hardness (several tens of GPa), well wear resistance, low friction coefficient, well chemical inertia and high biological compatibility and so on. DLC are widely used in mechanical, biological, electrical. But its adhesion is bad with soft substrate because of the gradient of hardness that induced higher residual stress. We could reduce the residual stress and increasing the adhesion between DLC and substrate by doping metal particles.
Cathodic arc plasma evaporation system (CAPE) is deposited containing copper diamond-like carbon thin films on 7075 aluminum alloys. By controlling ethyne gas flow rate, we could find the best deposition rate. The feature of thin films and hardness is influenced with copper content by changing substrate negative bias. FESEM observed the Cu-DLC morphology and cross section. XPS analyzed the thin film contents and bonding type. Raman spectroscopy detected carbon bonding species and intensity. XRD could tell us the structure in carbon films. HRTEM observed the phenomenon of copper clustering and compare copper oxide with diffraction pattern. Hardness is tested by Vicker''s hardness testing. The Rocker''s testing could determine the adhesion between Cu-DLC and 7075 aluminum alloys. Water contact angle measured the surface energy of Cu-DLC.
The results that we had the highest deposition rate when the ethyne flow rate was 50 sccm。At constant flow rate, changing the substrate negative bias, we found that it was highest hardness value at bias -150 V. The result was coincident with sp3/sp2ratio and ID/IG ratio. XPS and Raman spectrum analysis observed the bonding type including sp3 and sp2, accompany with pure copper and copper oxide, and proved it by TEM and XRD. Rocker''s testing discovered that cracks on DLC/7075 alloys were seldom traces and it was good adhesion with aluminum alloys. Finally, the water contact angle measured that the Cu-DLC was excellent in hydrophobicity and its had the lowest surface energy in negative bias -150 V. It was relative with hardness.
URI: http://hdl.handle.net/11455/10058
Appears in Collections:材料科學與工程學系

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