Abstract: An Analytical Investigation of Thermal Contact Resistance in a Thermal Barrier Coating System (2011 SACNAS National Conference)

Saturday, October 29, 2011

Hall 1-2 (San Jose Convention Center)

Amelia Herrera , Mechanical Engineering, University of California, Santa Barbara, Santa Barbara, CA

Aimee Flores , Mechanical Engineering, University of California, Santa Barbara , Santa Barbara, CA

Raymond Valdes , Mechanical Engineering, University of California, Santa Barbara, Santa Barbara, CA

Ted Bennett, PhD , Mechanical Engineering, University of California, Santa Barbara, Santa Barbara, CA

We want to characterize and quantify the effective thermal contact resistance (TCR) induced by the degradation of Thermal Barrier Coating (TBC) systems. TBC systems are thin ceramic coatings that are applied in aircraft propulsion and power generation to improve the thermal efficiency and reliability by protecting components from high temperature gases. Aging and environmental factors may cause the coatings to delaminate, creating micro gaps at the coating-substrate interface which slows down the heat transfer rate at the interface and creates hotspots. These microgaps are precursors to total TBC failure. Our two-layer model system, nickel superalloy and borosilicate glass were chosen because they closely approximate the thermal and optical properties of a TBC system. The interface was characterized using a digital profilometer and hardness testing. These parameters were measured along with the material properties to analytically determine the TCR. We compared the results against a noncontact TCR measurement method which irradiates the front side of the sample using a CO2 laser and uses a thermal imaging camera to obtain a temperature field response on the back end. A successful comparison would allow us to determine the TCR using this noncontact test method and further our understanding of TCR in TBC systems.