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    Please use this identifier to cite or link to this item: http://ir.lib.ncu.edu.tw/handle/987654321/1788

    Title: 鋁鈧濺鍍薄膜中鈧含量對其微結構、光反射性與腐蝕性質之影響;The studies of the electrochemical behavior, optic property and surface morphology for Al-Sc thin film after annealing
    Authors: 沈建忠;Jian-Jhong Shen
    Contributors: 能源工程研究所
    Keywords: 車燈反射鍍膜;鋁鈧薄膜;腐蝕;突起物;壓應力釋放;hillock;stress relaxation;corrosion;Al-Sc films
    Date: 2009-07-10
    Issue Date: 2009-09-21 11:30:36 (UTC+8)
    Publisher: 國立中央大學圖書館
    Abstract: 本論文以DC磁控濺鍍法製作純鋁和鋁鈧薄膜。藉由電子微探儀(Electron probe microanalysis, EPMA)分析得知: 鋁鈧濺鍍膜中鈧含量分別為0.19、0.22、0.48、0.53wt.% Sc。經場發式電子顯微鏡觀察鋁鈧薄膜,顯示其晶粒之大小,隨著薄膜中鈧含量的增加而細化,當膜中鈧含量達0.53wt.% Sc時,晶粒最細(約達50 ±5 nm)。在薄膜加熱到450℃後自然降溫回復至室溫之過程,利用雷射光量測薄膜表面曲率變化,可求得薄膜之內應力,測量結果顯示: 升溫時薄膜產生壓應力,其值隨溫度先增至一極大值後下降,達特定溫度時壓應力消失;在薄膜降溫時,則產生拉應力,其值隨溫度下降而增加。比較薄膜內壓應力極大值之溫度,隨鈧含量減少而下降,依序排列如下: 290℃(0.53wt.% Sc) > 225℃ (0.48wt.% Sc) > 220℃(0.22wt.% Sc) > 190℃ (0.19wt.% Sc) > 110℃(Al)。採用原子力顯微鏡量測薄膜表面平均粗糙度(Ra)和最大表面粗糙度(Rmax.),結果顯示含0.53wt.% Sc之鋁鈧鍍膜,據有最小粗糙度(Ra= 4.729nm; Rmax= 6.481nm ),其表面最平滑,表面並未發現有突起物(hillock)生成,對光的反射率最佳。若以電化學儀器量測經不同溫度(85、185、450℃)熱處理一小時後之純鋁和鋁鈧薄膜,比較其在5wt.% NaCl環境下之抗腐蝕性。結果顯示: 薄膜之開路電位,會因鈧之添加由-1.10V(純鋁)偏移至-0.700V(±0.05V),薄膜的抗蝕性隨著薄膜中鈧含量增加而增加,當鈧含量達到0.53wt.% 時腐蝕電流密度最低(1.07nA/cm2),其抗蝕性能最佳。經腐蝕測試後之薄膜,比較其對光的反射率,也顯示含鈧量愈高,反射率的衰退較少。 Thin films of pure Al and Al-Sc alloys prepared by direct current (DC) magnetron sputtering technique were considered as the candidate of reflective films of the auto-lamp. Stable and good optical reflectivity is the major concern during the performance of auto-lamp for a number of thermal cycles under a corrosive environment. The optical reflectivity and corrosion behavior may depend upon the composition and structure of the films. Examination through electron probe microanalysis(EPMA), the Sc-contents of the Al-Sc films are at 0.19、0.22、0.48、0.53wt.%, respectively. Observation using field emission scanning electron microscope (FESEM), we found that the grains decrease their size with increasing the Sc-content in the films. Al-0.53wt.% Sc film exhibits the finest grains (roughly at 50 ±5 nm) among the five films. The stress exerted to a specific film in a thermal cycle (heating the film from room temperatue to 450℃and cooling down naturally to the ambient) was estimated by measuring the curvature change on the film in terms of a Laser beam. A compressive stress was induced in the heating stage but a tensile stress induced in the cooling stage. The compressive stress increases to a maximum and deceases to zero with increasing the temperature. However, the tensile stress increases with decreasing the temperature. The temperature in response to maximal compression is higher for the film containing greater Sc-content, i.e., 290℃(0.53wt.% Sc) > 225℃ (0.48wt.% Sc) > 220℃(0.22wt.% Sc) > 190℃ (0.19wt.% Sc) > 110℃(Al). The average and maximum surface roughness (Ra & Rmax.) of the films were determined by atomic force microscope (AFM). Among the five films, Al-0.53wt.% Sc film indicated the smallest Ra & Rmax (Ra= 4.729nm; Rmax= 6.481nm ) and revealed the smoothest surface where no any hillock could be found and result in the highest optical reflectivity. The corrosion behavior of the films annealed at 85, 185 and 450℃ for 1 h was electrochemically investigated in 5wt.% NaCl solution. The open circuit potential (OCP) of the Al-Sc films displays a noble value -0.700 (±0.05V) compared to the pure Al-film (at -1.10V). The corrosion-resistance increases with increasing the Sc-content in the films. The Al-0.53wt.% Sc is the most suitable candidate for the reflective material of auto-lamp due to its highest resistance to corrosion (lowest corrosion current at 1.07nA/cm2). The films containing higher Sc-content tend to have higher optical reflectivity and the reflectivity loss is much less when the film post corrosion test.
    Appears in Collections:[能源工程研究所 ] 博碩士論文

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