碳奈米膠囊顆粒與碳-鐵奈米膠囊顆粒作為潤滑油添加劑之磨潤特性研究

Tribological Properties of Carbon Nanocapsule Particles and Carbon-Fe Nanocapsule Particles as a Lubricant Additive

黃耀輝(Yao-Huei Huang)

指導教授 ： 鄭友仁

國立中正大學/工學院/機械工程學系/博士(2015年)

摘要

摩擦行為是導致機械系統磨耗和元件壽命降低的根源，潤滑技術是降低摩擦行為的重要手段。隨著全球化、客製化、綠色環保的發展趨勢，開發低污染、高效率之潤滑系統已是不可避免的趨勢。近來奈米材料與奈米科技的發展，開啟以操控各種奈米機制達成嶄新的表面界面潤滑機能與接觸行為之可能性。
本研究使用的碳奈米膠囊(Carbon Nanocapsules (CNCs))與碳-鐵奈米膠囊(Carbon-Fe Nanocapsules (CFNCs))具有可壓縮變形、低表面能、球軸承潤滑機制、化學修飾特徵。CNC與CFNC奈米顆粒是使用脈衝電弧放電製備，透過化學-硬脂酸改質方式，添加0 ~ 0.1 wt.%不同濃度在礦物潤滑油，進行塊對環潤滑油測試，並且使用HRTEM、SEM、MAP分析探討CNC與CFNC奈米顆粒添加潤滑油之磨潤特性。CNC奈米顆粒研究結果指出，在650N負荷與添加0.05 wt.%濃度可以降低摩擦係數。HRTEM、SEM與MAP觀察顯示，添加0.05 wt.%濃度與1.65 m/s滑動速度為最佳CNC顆粒滲透與填補行為，因此低負荷(650N)時，CNC顆粒呈現滾動潤滑機制(球軸承潤滑機制)，因此可以有效降低表面接觸界面摩擦係數與磨耗。在高負荷(1000N)時，則導致滾動機制轉變為滑動潤滑機制(層狀石墨潤滑機制)。分子動力學(MD)模擬是進行證明CNC奈米顆粒的轉變，模擬結果證實，奈米顆粒在磨耗過程中，會進行球狀到片狀相變。相變會促使潤滑模式改變，從滾動模式到滑動模式(球軸承潤滑形態轉變石墨潤滑形態)。CFNC顆粒研究結果顯示，在650N負荷與添加0.07wt.%濃度與1.65 m/s滑動速度，有效減少摩擦係數。HRTEM、SEM與MAP觀察顯示，低負荷(650N)時，CFNC顆粒提高表面滲透與填補特性及球軸承潤滑機制，並且在表面接觸界面減少摩擦與磨耗，在高負荷(1000N)時，CFNC顆粒球狀層結構，容易發生塑性變形、結構壓裂和Fe晶體損失，而CFNC顆粒會從原本球狀多層結構轉變成為石墨層狀結構。
本研究也進行CNC與CFNC奈米顆粒特性比較，在摩擦係數結果顯示發現，添加CNC顆粒(0.05 wt.%)摩擦係數有明顯下降，而添加CFNC顆粒(0.07 wt.%)摩擦係數則有下降趨勢，主要原因可能是顆粒結構塑性變形與結構破裂，產生較高摩擦係數。表面磨耗量結果顯示，添加CFNC顆粒(0.07 wt.%)，將有助於降低高負荷(1000N)表面磨耗量，主要原因可能是顆粒結構斷裂跟層結構剥離及Fe晶體損失，形成類-石墨潤滑層並且滲透與填補到磨耗表面，提升表面抗磨耗特性。

關鍵字

固體潤滑添加劑 ； 碳-鐵奈米膠囊 ； 碳奈米膠囊 ； 磨耗

並列摘要

Friction behavior is lead to the mechanical systems and components life reduced reason. The lubrication technology it is reduced of the friction behavior to important means. Along with, globalization, customized, green trends, The development of low pollution, the high efficiency lubrication system is inevitable. Recently, the development of nano materials and nano technology, to manipulate a variety of nano mechanisms to achieve the possibility of a new surface boundary lubrication function and behavior of contact.
In this study, used the carbon nanocapsule (CNC) and carbon-Fe nanocapsule (CNC) characterized by fully-reversible deformation, low surface energy and ball bearing lubrication mechanism and the potential for chemical modification. CNC and CFNC particles use the pulsed arc discharge synthesis preparation. Through the chemical stearic acid modified. Using mineral oil lubricants containing CFNC particles with concentrations ranging from 0.01 to 0.1 wt% and performed the Block-on-ring wear tests, and used the HRTEM and SEM and MAP analysis investigates the tribological properties of CNC and CFNC Nano particles. CNC particles results showed, that for a contact load of 650 N, and a CNC concentration of 0.05 wt.% can reduce the friction coefficient. The HRTEM and SEM observations suggest, that a CNC addition of 0.05 wt.% and a sliding velocity of 1.65 m/s optimize the penetration and filling behavior of the CNC particles. The the low load (650N), that the CNC particles shows rolling lubrication mechanism (ball bearing lubrication mechanisms), yields an effective reduction in the friction coefficient and wear at the surface contact interface. In the high load (1000N), that the CNC particles show to change from a rolling lubrication mechanism to a sliding lubrication mechanism (graphite-like lubrication mechanism).Molecular dynamics (MD) simulations are performed to clarify the structural transformation of the CNC nanoparticles during the wear process. The results confirm that a sphere-to-sheet phase transformation of the CNC nanoparticles occurs as the wear process proceeds. The phase transformation prompts a change in the lubrication mode from a pure rolling mode to a sliding mode (Ball bearing to graphite). CFNC particles results showed, that for a contact load of 650 N, a CFNC concentration of 0.07 wt.% and a sliding velocity of 1.65 m/s, effective reduction in the friction coefficient. The HR-TEM, SEM and MAP analysis results shows, in the a low load (650N), enhance the surface permeability, fill-up properties, and ball bearing lubrication mechanism, and effective reduction in the wear at the surface contact interface.
In this study, will conducted the CNC and CFNC particles properties compared. the friction coefficient results showed, add the CNC particle friction coefficient significantly reduced, the CFNC particles friction coefficient increased. The main reason may this the CFNC particles would experience plastic deformation, multilayer graphitic fracturing, with higher friction coefficient. The surface wear volume results show, add the CFNC particles (0.07 wt.%), Will help to reduced the under high load (1000N) the volume of wear surface, The main reason may was the CFNC particles structure fracture, structure exfoliation and a loss of Fe crystals, form the like-graphite lubricant layer, penetration and fill to that the wear surface, Increase surface anti-wear properties.

並列關鍵字

Solid lubricant additive ； Carbon-Fe nanocapsules ； Carbon nanocapsules ； Wear

參考文獻

[1] C. Mabery, Lubrication and lubricats, Franklin institute, 169 (1910) 4317-328.

[2] G. Salomon, A. W. J. De gee, J. H. Zaat, Methanol-chemical factors in MoS2-film lubrication, Wear, 7 (1964) 87-101.

[3] N. Lambropoulos, T. J. Cardwell, D. Caridi, P. J. Marriott, Separation of zinc dialkyldithiophosphates in lubicaing oil additives by normal phase high performance liquid

[4] M. Hubacek, M. Ueki, T. Sato, V. Brozek, High-temperature behavior of hexagonal boron nitride, Thermochimica Act, 282/283 (1996) 359 -367.

[5] Q. Xue, W. Liu, Z. Zhang, Friction and wear properties of a surface modified TiO2 nanoparticle as an additive in liquid paraffin, Wear, 213 (1997) 29-32.