David Weiss

Caterpillar, Inc.

The goal of this technical program Is to develop wear-resistant coatings for application to metallic components of low heat-loss dlesel engines, specifically, piston rings and cylinder liners. The effects of the combustion environment upon coating characteristics such as mlcrostructure, wear, strength, adherence, and other properties shall be minimal.

Obtaining adequate coating adherence will be the first problem to be addressed in developing wear resistant coatings. An experimental plan will be developed for each coating system to optimize the adherence of the chosen coatings. After optimization for adherence, the coatings will be screened for wear and friction. Further adjustments to the coating systems will be made to optimize for wear and friction. Statistical experimental design will be used in developing the experimental plan. While performance will not be sacrificed, simplicity of design and ease of coating application will be important considerations throughout the program.

Caterpillar's concepts for achieving improved adherent wear resistant coatings will focus on the interdependence of each of the major components of the coatings systems. These include:

* substrate surface pretreatments

* coating compositions

* coating deposition parameters

* post deposition treatments

* coating surface finish

* sliding pairs

* lubricant compatibility

The major variables which affect coating adherence are listed in Table 1. In general, the components of a coating system that control coating adherence are:

* Coating composition

* substrate composition

* surface pretreatments (grit blasting and bond coating)

* post-deposition treatments (laser glazing)

Coating properties which influence adherence and : the methods to be considered in tailoring the properties for better adherence.

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