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The search for novel lubricants to improve the energy efficiency of engines and help mitigate the environmental effects of carbon dioxide emissions has gained increasingly importance in recent years. Commercial lubricants contain a wide range of compounds including those that undergo tribochemical reactions and form friction- or wear-reducing films. A microscopic understanding of tribochemical reactions is of paramount importance for designing new, environmental-friendly lubricants. However, many aspects of tribochemistry remain elusive due to the difficulties in experimentally probing the sliding buried interface. Simulations can play a decisive role in this context, in particular ab initio molecular dynamics (AIMD), where both the ionic and electronics degrees of freedom are fully taken in into account. This is essential for an accurate description of reactions in situations of enhanced reactivity imposed by the tribological conditions. This chapter offers an example of application of ab initio methods in tribochemistry. A twofold analysis of the reaction mechanisms and effects of tribochemical reactions involving organophosphorus additives at iron interfaces allowed to understand the mechanisms of function of phosphorus-based additives in boundary lubrication. |
