(北京科技大學 材料科學與工程學院，北京 100083)
摘 要: 基于試驗研究和理論計算從宏觀和微觀尺度揭示了分子結(jié)構(gòu)對鋁材軋制基礎(chǔ)油摩擦學性能和鋁表面吸附行為的影響。研究分別以異構(gòu)烷烴煤制油(CTL)和正構(gòu)烷烴白油(D100)為基礎(chǔ)油，制備含不同濃度亞磷酸二丁酯(DP)的鋁材軋制油，并采用四球摩擦磨損試驗表征其摩擦學性能；基于量子化學計算和分子動力學模擬研究CTL、D100和DP的分子結(jié)構(gòu)特征、吸附反應(yīng)活性及在鋁表面的吸附行為。結(jié)果表明：對于理化性能相近的CTL與D100，CTL的油膜強度(88 N)低于D100的(98 N)，但CTL對DP極壓劑的敏感性更好。在同等DP濃度下，以CTL為基礎(chǔ)油時，鋁材軋制油具有更高的油膜強度，最大值為1050 N；而以D100為基礎(chǔ)油時，油膜強度僅為981 N。理論研究表明：CTL和D100分子的最高占據(jù)軌道(HOMO)分布相同，均分布于整個分子碳鏈，但二者的最低空軌道(LUMO)分布不同，前者位于分子支鏈側(cè)末端，而后者位于分子中心。CTL和D100分子均具有穩(wěn)定的化學結(jié)構(gòu)，且二者化學穩(wěn)定性的差異較小；CTL和DP分子具有協(xié)同吸附作用，二者復配能顯著促進軋制油體系在鋁表面的吸附，并提高吸附膜穩(wěn)定性。
關(guān)鍵字: 鋁材軋制油；煤制油；摩擦；量子化學；分子動力學
（School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China）
Abstract:In the present work, the effects of molecular structure on tribological properties and adsorption behaviors of aluminum rolling oil were revealed from macroscopic and microscopic scales by combining experimental research and theoretical calculations. Aluminum rolling-oil containing different concentrations of dibutyl phosphite (DP) were prepared by using coal-to-liquid (CTL) and traditional mineral oil (D100) as base oils, respectively. The tribological properties were characterized by four-ball tester. The molecular structure, adsorption activity and adsorption behavior of CTL, D100 and DP on aluminum surface were investigated based on quantum chemical calculation and molecular dynamics simulation. The results show that CTL with similar physical and chemical properties as D100, has a lower maximum non-seizure load of 88 N, but CTL is more sensitive to DP. When CTL is used as the base oil, aluminum rolling oil has a higher non-seizure load at the same DP concentration, the maximum value is 1050 N. Investigation results show that the highest occupied orbital (HOMO) distributions of CTL and D100 molecules are the same, distributing in the whole molecular carbon chain, but the lowest unoccupied orbital (LUMO) distribution is different, the former locates at the side end of the molecular branch chain, while the latter locates at the center of the molecule. Both CTL and D100 have stable chemical structures, and the difference of their chemical stability is also similar. In addition, CTL and DP molecules have synergistic adsorption effect, and the combination of CTL and DP molecules can significantly promote the adsorption activity of rolling-oil system on aluminum surface and improve the stability of adsorption film.
Key words: aluminum rolling oil; coal-to-liquid; tribology; quantum chemistry; molecular dynamics
