The concept of ‘process maps’ has been utilized to study the fundamentals of process–structure–property relationships in high velocity oxygen fuel (HVOF) sprayed coatings. Ni- 20%Cr was chosen as a representing material of metallic alloys. In this paper, concurrent experiments including diagnostic studies, splat collection, and deposition of coatings were carried out to investigate the effects of fuel gas chemistry (fuel gas/oxygen ratio), total gas flow, and energy input on particle temperature (T) and velocity (V), and coating microstructure formation and properties. Coatings were deposited on an ‘in situ’ curvature monitoring sensor to study residual stress evolution. A strong influence of particle velocity on induced compressive stresses through peening effect is discussed. The complete tracking of the coating buildup history including residual stress evolution and temperature deposition, in addition to single splat analysis allows the interpretation of resultant coating microstructures and properties, and enables coating design with desired properties.

Aside from its importance as a design parameter for thermal barrier coatings, measuring thermal conductivity of thermal sprayed coatings itself provides a unique method to critically characterize the nature, quantity and anisotropy of the defect morphologies in these splat-based coatings. In this paper, we present a systematic assessment of thermal conductivity of wide range of thermal sprayed coatings using the flash diffusivity technique. For the case of plasma sprayed yttria-stabilized zirconia (YSZ), coatings obtained from wide ranging initial powder morphologies as well as those fabricated under different particle states were characterized. Both in-plane and through-thickness properties were obtained. Other material systems that were considered include: metallic alloys, semiconductors and other oxides of interests. Issues such as reproducibility and reliability in measurements were also considered and assessed. Finally, working in collaboration with the Oak Ridge National Laboratory (ORNL) for alternate approaches to characterization of thermal conductivity as well as high temperature measurements was performed.