The present study demonstrates an improved and facile method for the exfoliation and chemical oxidation of bulk hexagonal boron nitride (h-BN) powder. Further, chemical functionalization of oxidized h-BN with (3-aminopropyl) trimethoxysilane (APTMS) as a bifunctional chemical linker has been undertaken to prepare APTMS-grafted h-BN (h-BNAS). Amino-terminated functional groups on the basal plane defect and edge sites of h-BNAS were targeted for further chemical grafting with graphene oxide (GO) through covalent interaction to achieve an h-BN/GO nanocomposite (h-BNAS@GO). The chemical structure and morphology of h-BN, oxidized h-BN, h-BNAS, and h-BNAS@GO were investigated through standard spectroscopic and microscopic analyses. The macro- and microtribological results depicted that the h-BNAS@GO hybrid composite (0.5 wt %) as an oil-dispersible additive significantly reduced the coefficient of friction (COF) and wear of the steel-steel tribopair, revealing superior tribological properties. The COF of h-BNAS@GO nanocomposite exhibited a reduction of 50.7% (at P_m ≈ 1.95 GPa) than that of base paraffin oil and showed a lower specific wear rate (1 × 10^–8 mm³/N-m) at macrotribological trials, revealing the best wear-resistance performance. At microtribological reciprocating sliding, the composite nanolubricant was observed to diminish the COF by ∼41.18% (at P_m ≈ 2.15 GPa) compared to base oil. The post-tribological analysis of the worn tribotracks demonstrates that the h-BNAS@GO nanocomposite has a superior ability to adhere and form a thicker, continuous, synergetic lubricating tribofilm at the interfaces, thereby effectively reducing COF and protecting the tribopairs from wear. Therefore, the h-BNAS@GO nanocomposite has a great prospect as a load-bearing lubricating advanced material in convenient industrial application.

中文翻译：

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共价连接的六方氮化硼-氧化石墨烯纳米复合材料作为高性能油分散性润滑油添加剂

本研究证明了一种改进的，简便的剥落和化学氧化六方氮化硼（h-BN）粉末的方法。此外，已经进行了以（3-氨基丙基）三甲氧基硅烷（APTMS）为双官能化学连接基的氧化h​​-BN的化学官能化，以制备APTMS接枝的h-BN（h-BNAS）。h-BNAS的基面缺陷和边缘位点上的氨基末端官能团可通过共价相互作用与氧化石墨烯（GO）进一步化学接枝，从而获得h-BN / GO纳米复合材料（h-BNAS @ GO）。通过标准的光谱和显微镜分析研究了h-BN，氧化的h-BN，h-BNAS和h-BNAS @ GO的化学结构和形态。宏观和微观摩擦学结果表明h-BNAS @ GO杂化复合材料（0。5重量％）作为油分散性添加剂显着降低了钢摩擦副的摩擦系数（COF）和磨损，显示出优异的摩擦学性能。h-BNAS @ GO纳米复合材料的COF降低了50.7％（在P_米≈1.95 GPa）的比基石蜡油和显示较低的特定磨损率（1×10 ^-8毫米³在macrotribological试验/牛顿米），揭示了最好的耐磨性性能。在微生物摩擦往复滑动下，观察到复合纳米润滑剂使COF降低了约41.18％（在P _m下≈2.15 GPa）。磨损的摩擦痕迹的摩擦后分析表明，h-BNAS @ GO纳米复合材料具有出色的粘附能力，并在界面处形成较厚的，连续的，协同润滑的摩擦膜，从而有效地降低了COF并保护了摩擦副。因此，h-BNAS @ GO纳米复合材料作为一种方便工业应用的承重润滑高级材料具有广阔的前景。