Remote quantitative temperature and thickness measurements of plasma-deposited titanium nitride thin coatings on steel using a laser interferometric thermoreflectance optical thermometer.
Published: 2005
Language: eng
Number of pages: 151
Description: A novel optical thermometer based on the principle of laser thermoreflectance has been introduced to monitor the surface temperature of thin coatings on steel parts undergoing an industrial titanium nitride (TiN) alloy deposition process. To study the feasibility of the optical thermometer, various thermo-optical parameters of TiN affected by the deposition process have been investigated; namely, the reflectance-temperature relation, the thermoreflectance coefficient, and the coating thickness dependence of thermoreflectance and of total reflectance. A theory of interferometric thermoreflectance has been introduced to model the total reflectance variations during the coating process. An inverse reflectance-temperature relation for the TiN-D2 steel substrate system has been found and a first-order Taylor series expansion used to model thermoreflectance has been shown to yield a thermoreflectance coefficient which is independent of temperature. Both results are in quantitative agreement with the Drude-Zener theory of conductors and semi-conductors. An empirical formula has been derived to effectively model the experimental thermoreflectance coefficient dependence of the TiN-D2 steel system on TiN coating thickness, in qualitative agreement with scattering mechanisms of the Boltzmann transport theory in conductors and semi-conductors. The good agreement of theoretical interferometric thermoreflectance simulations with in-situ measurements during a specific industrial TiN sputter-coating growth process and the independence of the thermoreflectance and thin-coating-thickness reflectance coefficients from temperature show the potential of using this non-intrusive non-contacting technique as an optical thermometer to determine surface temperatures of physically inaccessible samples undergoing industrial coating deposition processes. Preliminary results obtained from rotating sample using a fast data acquisition technique have proved the feasibility of the optical thermometer temperature measurement on rotating sample measurements.
Notes: Source: Dissertation Abstracts International, Volume: 66-10, Section: B, page: 5645.

Thesis (Ph.D.)--University of Toronto, 2005.

Electronic version licensed for access by U. of T. users.