嵌入物與殘留應力對類鑽碳薄膜機械與磨耗性質的影響

THE EFFECTS OF INCLUSIONS AND RESIDUAL STRESS ON THE MECHANICAL AND TRIBOLOGICAL PROPERTIES OF DIAMOND LIKE CARBON FILMS

楊叡峰(Jui-Feng Yang)

指導教授 ： 魏哲弘

大同大學/工程學院/機械工程學系所/碩士(2010年)

摘要

類鑽碳膜許多的性質來自於高能量鍍膜離子的轟擊效應，導致產生極大的殘留應力及低韌性的特性。
為了瞭解影響類鑽碳膜的機械性質因素，本研究以有限元素法模擬在薄膜中添加微結構如奈米碳管、奈米粒子，並利用奈米壓痕與奈米刮痕試驗模擬，瞭解微結構如何影響類鑽碳膜機械性質。並由微結構濃度、尺寸對薄膜的硬度與應力的影響，期望能改善類鑽碳膜的整體薄膜性質。此外沉積時產生的殘留應力也影響薄膜的機械性質，因此本研究利用有限元素法模擬沉積因溫度變化所產生的殘留應力，探討在不平滑基材上鍍類鑽碳膜，瞭解殘留熱應力與粗糙度的關聯。由粗糙度、薄膜厚度、中間層、中間層硬化效應、熱膨脹係數等條件做一系列的模擬，探討如何降低殘留熱應力，改善類鑽碳膜的附著力。並進一步的探討當類鑽碳膜有殘留熱應力時，利用奈米壓痕模擬殘留熱應力對薄膜機械性質的影響。
壓痕模擬結果顯示，添加水平奈米碳管/奈米粒子能幫助類鑽碳膜硬度的提升，添加的嵌入物含量與大小亦是影響整體機械性質的因素。在刮痕模擬結果顯示，適當的奈米碳管可降低類鑽碳膜的內應力，增加薄膜附著度。因此，加入奈米碳管/奈米粒子會改善類鑽碳膜之機械與磨潤性質。
就基材而言，粗糙表面的基材會增加薄膜殘留熱應力，添加中間層、增加薄膜厚度可降低類鑽碳膜所產生的殘留熱應力。由結果得知基材與薄膜的熱膨脹係數不匹配是產生高殘留熱應力的主要原因。

關鍵字

類鑽碳膜

並列摘要

The properties of diamond like carbon (DLC) films like high internal stress and low toughness are direct results from high energy bombardment during deposition.
Many methods can reduce internal stress and increase toughness like element doping, interlayer adding and substrate pretreatment. In this thesis, finite element method was employed to analyze the microstructure doping effect in mechanical properties of DLC. The microstructures include different orientation of carbon nanotubes (CNTs) as well as nanoparticles. In the meantime, the roughness in substrate and the pre-stress are important factors that affect the mechanical properties of DLC.
The results indicate that horizontally aligned CNTs doping DLC have the largest hardness increase compared to 45 degree aligned or vertically aligned CNTs doping DLC. The higher concentrations and smaller size will lead to hardness increase for CNTs and nanoparticles.
As for substrate roughness, the rougher substrate induces higher internal stress which is adverse for adhesion and affects the mechanical properties. The reduction of internal stress caused by substrate roughness can be eliminated by interlayer deposition or more film thickness. The proper choice of interlayer is more efficient than film thickness increase. This is due to the mismatch of coefficient of thermal expansion between film and substrate is the primary source for thermal stress.

並列關鍵字

DLC

參考文獻

1. S. Aisenberg, S. Ronald, (1971) Ion-beam deposition of thin films of diamond-like carbon. Applied Physics. 42(7):2953-2958.

2. F. Piazza, D. Gramboleb, D. Schneiderc, C. Casiraghia, C. Ferraria, J. Robertson, (2005) Protective diamond-like carbon coatings for future optical storage disks. Diamond Relate Mater, 14:994– 999.

3. A.C. Ferrari, (2004) Diamond-like carbon for magnetic storage disks. Surface and Coatings Technology. 180/181:190-206.

4. J. Robertson, (2001) Ultrathin carbon coatings for magnetic storage technology. Thin Solid Films. 383:81-88.

5. P.R. Goglia, J. Berkowitz, J. Hoehn, A. Xidis, L. Stover, (2001) Diamond-like carbon applications in high density hard disc recording heads. Diamond Relate Mater. 10:271-277.