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One of the ongoing needs in the materials industry is to facilitate significant production cost saving due to energy usage. One way to do this is to use the thermal energy generally emitted during heat treatment to facilitate additive reactions with the material surface. This has been successfully done by formulating specific lubricity additives into on a oil or aqueous quenching media. When the material is heated and subsequently quenched, the lubricity additive will then react with the surface providing substantial improvements in lubricity. This process is called: “coat forming”. The objective of this paper is to provide an overview of coat forming reactions, additives, and subsequent application performance.

Surface engineering encompasses numerous vital and diverse technologies in the design and wear of automotive and off-highway components. These technologies include CVD, PVD, ion implantation and conventional heat treatments such as carburizing, nitriding and carbonitriding. Although these technologies are well known, it is considerably more difficult to understand the relative importance of the various technology niches for these processes, and it is very difficult to find effective summaries of the impact of these technologies on comparative lubrication formulation and practice. The objectives of this paper are two-fold. One is to review the impact of surface engineered coatings on the surface chemistry of steel. The second objective is to review the impact of the surface chemistry obtained by different surface treatments on boundary film formation to reduce frictional losses during fluid lubrication.

Atmosphere carburizing remains one of the most important surface treatment technologies throughout the world. In this paper, various important metallurgical design variables are identified by examining the results of the carburisation of 15HN steel. These results showed the importance of the formation of martensite-retained austenite-carbide microstructure after hardening. Increasing austenization temperature causes a decrease in the carbide fraction and an increase in the fraction of retained austenite. By optimisation of the composition of these microstructures through variation of carburisation process, hardening, and tempering variables, it is possible to optimise compressive stresses, abrasive wear resistance, and contact fatigue resistance.