Catalytic phenomena in protection against corrosion and wear of internal combustion engines

Abstract

From the chemical point of view, the engines and mechanisms in which lubricating oils with additives are used are actually reactors, in which high temperatures and pressures are developed in certain zones of friction (components). Under such conditions, hydrocarbon or synthetic oils undergo chemical and electrochemical reactions reflecting the presence of oxygen, water, and hydrogen in the reactor - engine, as well as considerable quantities of surfactants - both natural surfactants and those introduced as oil additives. Chemical and physicochemical processes in the engine, including electrochemical processes, are intensified by strong electric, magnetic, electromagnetic, and acoustic fields, by electron emission, by the catalytic and tribocatalytic action of solid surfaces, and by other tribochemical factors. The reactions that take place in the oil medium, primarily oxidation, together with the accumulation of sulfur-containing fuel combustion products and electrolytes, result in a substantial increase of corrosivity of the oil and greater frictional losses, corrosion, and corrosive-mechanical forms of wear. The importance of processes and phenomena taking place in {open_quotes}resting{close_quotes} engines and mechanisms (during storage and transportation) is greatly underestimated; these processes and phenomena show up subsequently in their effects during startup and operation, in terms of corrosive-mechanical wear that results from fatigue andmore » electrochemical pitting, corrosion in friction, corrosion-cyclic fatigue, hydrogen-induced wear, and fretting corrosion. In all of these processes and phenomena, catalysis plays an important role. In this article we will examine the principles of homogeneous, micellar, and heterogeneous catalysis from the standpoint of their possible use to protect against corrosion and wear of internal combustion engines and other metal parts that come into contact with the lubricant.« less