GOALI: Understanding Tribological Properties of Thermally-Synthesized Carbon

这项学术与工业联络资助机会（GOALI）奖将支持基础摩擦化学研究，以阐明碳材料的摩擦和磨损行为。碳块和涂层广泛用于控制制造过程或制成品滑动界面的摩擦和磨损。本项目的重点是了解和改善热合成碳（TSC）材料的摩擦化学性能，以应用于低摩擦有益的领域。多晶石墨粉末和其他TSC材料表现出相对较高的摩擦，尽管在石墨基面上和通过等离子体增强沉积工艺生产的氢化类金刚石碳上很容易观察到超润滑。这就提出了一个重要的问题——是什么控制了不同类型的碳材料的超润滑行为？解决这个问题可以导致更好的碳材料设计，可以用作电机或发电机的碳刷和/或不能使用油或油脂润滑的机械密封。减少这些部件的摩擦和磨损将大大提高制造过程中的能源效率。这些问题对新能源的应用和美国的竞争力都很重要。摩根先进材料公司作为GOALI合作伙伴参与，并将为该研究提供商业和定制设计的碳材料。该项目将为宾夕法尼亚州立大学联邦系统的本科生提供研究机会。本项目的表面分析结果将与研究生水平教育相结合。本文将研究两种假设：(i)碳材料的摩擦取决于sp2和sp3杂化的分布以及它们如何连接形成非晶网络，这随合成方法的不同而不同。（ii）暴露在滑动界面上的反应位点的化学活性也因碳材料的合成方式而异。研究这些假设需要分析剪切引起的结构转变和发生在摩擦界面的化学反应；但是这个界面不容易进行现场表征。或者，可以通过对不同碳材料形成的反表面转移膜的非原位分析推断出相关信息。这是因为摩擦是一个非平衡过程，转移膜的最终状态将是初始状态和摩擦过程条件的函数。各种光谱技术将被用于分析转移膜，以确定控制热合成碳材料摩擦和磨损行为的摩擦化学参数。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

This Grant Opportunity for Academic Liaison with Industry (GOALI) award will support fundamental tribochemistry research that will elucidate the friction and wear behaviors of carbon materials. Carbon blocks and coatings are widely used to control friction and wear of sliding interfaces in manufacturing processes or manufactured goods. This project focuses on understanding and improving tribochemical properties of thermally-synthesized carbon (TSC) materials for the application where low friction is beneficial. Polycrystalline graphite powders and other TSC materials show relatively high friction, although superlubricity is readily observed on the basal plane of graphite and for hydrogenated diamond-like carbon produced via plasma enhanced deposition process. This raises an important question – what controls superlubricous behaviors of different types of carbon materials? Addressing this question can lead to a better design of carbon materials that can be used as carbon brushes for electrical motors or generators and/or mechanical seals in which oil or grease lubrication cannot be employed. Reduction of friction and wear of these components will greatly improve energy efficiency in manufacturing processes. These issues are important in new energy applications and hence US competitiveness. Morgan Advanced Materials is participating as the GOALI partner and will provide commercial and custom-designed carbon materials for the study. The project will provide research opportunities to undergraduate students in the Penn State Commonwealth system. The surface analysis results of this project will be integrated with graduate-level education. Two hypotheses will be studied: (i) Friction of carbon materials depends on the distribution of sp2 and sp3 hybridizations and how they are connected to form the amorphous network, which varies with synthesis method. (ii) The chemical activity of reactive sites exposed at the sliding interface also varies depending on how carbon materials are synthesized. Studying these hypotheses requires the analysis of shear-induced structural transforms and chemical reactions occurring at the frictional interface; but that interface is not readily accessible for in-situ characterization. Alternately, relevant information can be deduced from the ex-situ analysis of the transfer film on the counter-surface formed from different carbon materials. This is because friction is a non-equilibrium process, and the final state of the transfer film will be a function of the initial state and the condition during friction. Various spectroscopic techniques will be employed to analyze the transfer film to identify tribochemical parameters governing friction and wear behaviors of thermally-synthesized carbon materials.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.