Thermal Spray Processes and Diagnostics
Graduate Students: Weidou Yu (Ph.D. ’99), Sergey Semenov (Ph.D. 2002) and Alper Ozturk (Ph.D. Candidate)
Collaborator: Prof. Theodore Bergman
Project Summary
This research concerns definition of processing conditions that are favorable to deposition of nano-structured thermal barrier coatings (TBCs). Nano-structured coatings are speculated to have superior thermal and mechanical properties in comparison to their conventional counterparts. We are currently making measurements of velocity and temperature of particles that are accelerated and heated in a thermal spray (a DC arc plasma or a high velocity oxy-fuel, HVOF delivery system). These measurements along with computational modeling and high speed imaging of the particle impact onto substrates enable to understand the dynamics of deposition and the most favorable deposition conditions for the formation of nano-structure. Currently, a custom-built two color pyrometer is used to measure particle temperatures along with a two component phase Doppler particle anemometer (PDPA) to determine particle velocities and size (if they are smooth and spherical). Additionally, a high speed framing camera (2x106frames/sec) is being used to image the particle impact phenomenon. Additionally, spatially resolved emission spectroscopy of Argon-Hydrogen plasmas is performed to measure plasma temperature fields.
Visualization of External Particle Injection into an Argon Plasma Stream
Publications
Semenov, S. Y. and Cetegen, B. M., “Spectrocopic temperature measurements in DC-arc plasma jets utilized in thermal spray processing of materials”, Journal of Thermal Spray Technology, Vol. 10 (1), March 2001
Cetegen, B. M. and W. Yu, “Simultaneous particle temperature, velocity and size measurements in HVOF Thermal Sprays”, Journal of Thermal Spray Technology, Vol. 8 (1), pp. 57 -67, March 1999
Yu, W., Strutt, P. and Cetegen, B. M., “Particle Temperature Measurements by Two-color Pyrometry in Thermal Sprays” Progress Report to Office of Naval Research, Contract #N0014-95-0829, March 1997.
Yu, W, Strutt, P. and Cetegen, B. M. “Particle Temperature Measurements in a HVOF Thermal Spray by Two color Radiant Emission Pyrometry” , 1997 Fall Meeting of the Materials Research Society, December 1- 5, 1997, Boston MA.