表面修飾法合成了油酸表面改性奈米 SiO2粉體，利用Ball on Ring式磨耗試驗機，評估了油酸修飾奈米 SiO2粉體作為潤滑油添加劑的摩擦行為，並用電子顯微鏡 (SEM) 對鋼球磨損表面進行分析。研究結果表明：所合成的油酸修飾奈米SiO2粉體在液體石蠟基礎油中有良好的分散性，油酸修飾奈米 SiO2粉體做為潤滑油添加劑，能夠明顯提高石蠟基礎油的減摩、抗磨能力，當添加質量分數為 0.5 wt.%時，與基礎油相比可使磨疤直徑降低 28%。SEM分析結果表明，在摩擦過程中，奈米 SiO2粉體存在於兩接觸表面間，形成微滾珠效應，以滾動摩擦方式取代原先之滑動摩擦方式，故其磨疤表面較為光滑平整，使得油酸修飾奈米 SiO2粉體作為潤滑油添加劑表現出良好的磨潤性質。

The tribological behavior of liquid paraffin added by SiO2 nanoparticles are studied. In this work, the SiO2 nanoparticles were prepared by sol-gel method, the agglomeration of SiO2 nanometer particles was solved by putting surface modification agents during sol-gel process. The structure of the modified SiO2 nanoparticles which are prepared by oleic acid (OA) is observed by scanning electron microscopy (SEM) and infrared spectroscopy (IR). Also, the dispersivity of these nanoparticles in liquid paraffin is measured by nanoparticle analyzer. The measurement results reveal that the dispersion capability of OA modified SiO2 nanoparticles and indicate that the dispersing stability in liquid paraffin of the OA which is bonded to the surface of SiO2 nanoparticles. The influence of adding SiO2 nanoparticles in liquid paraffin is evaluated by using a ball-on-ring wear tester. It is found from testing results that the SiO2 nanoparticle as additive in liquid paraffin at proper concentration show better tribological properties for antiwear and antifriction than the pure liquid paraffin. Also, the grooves plowed nanoscale grooves worn surfaces due to SiO2 nanoparticles are observed by SEM.