DEVELOPMENT OF THICK THERMAL BARRIER COATINGS FOR DIESEL APPLICATIONS

ABSTRACT An integrated process for the design, plasma spray processing, laboratory evaluation, rig test verification and hardware evaluation of thermal barrier coatings for diesel engine applications is described. This method relies heavily on a thorough understanding of the process at each step. The properties and residual stress condition of the coating were modified to meet design criteria through control of the various plasma spray processing parameters. Coating uniformity and repeatability issues were also addressed by adjusting the process conditions to properly account for the specific geometric features of the substrate. These steps are described in detail with particular emphasis on the effect of the process on the coating characteristics. It is shown that a thick thermal barrier can be produced which is durable under accelerated engine test conditions through proper choice of material and processing parameters.