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Thursday, May 18, 2006 - 2:50 PM
APP19.5

TBC Characterization Using Capacitive and Inductive Sensors with Multivariate Inversion Methods

V. Zilberstein, Y. Sheiretov, N. Goldfine, JENTEK Sensors, Inc., Waltham, MA; D. Schlicker, JENTEK Sensors, Inc, Waltham, MA; R. Sikorski, Air Force Research Laboratory, Wright Patterson AFB, OH

Effective nondestructive characterization of thermal spray coatings on complex shape components can be provided by methods based on model based inductive and capacitive sensors using multivariate inversion algorithms (U.S. patents issued and pending).  The inductive sensors include flexible eddy current sensors such as the Meandering Winding Magnetometer (MWM®) and MWM-Arrays for characterization of conductive nonmagnetic, conductive magnetic and nonconductive magnetic materials.  The capacitive sensors include the flexible Interdigitated Electrode Dielectrometer (IDED®) for characterization of dielectric materials. Hybrid methods that use both sensor modalities can provide independent measurement of up to six unknown properties of the coating system, e.g., ceramic thermal barrier coating (TBC) thickness and property distribution, TBC surface roughness, bond coat thickness and another property of interest for bond coats, and substrate property distribution.  Both MWM and IDED sensors are described, together with multivariate inversion algorithms, used for property measurements with sensors and arrays. Example results of measurements with MWM and IDED sensors on coated specimens and component samples with TBC are provided.  This new nondestructive evaluation capability for plasma spray coatings can provide substantial cost savings by enhancing manufacturing quality, increasing coating life, and avoiding unforeseen failures and downtime.  This will be applicable to all life cycle stages of the turbine engine or land-based gas turbines.


Summary: This presentation will describe flexible model-based inductive MWM sensors and MWM-Arrays for characterization of conductive nonmagnetic, conductive magnetic and nonconductive magnetic materials, and capacitive sensors such as the flexible Interdigitated Electrode Dielectrometer for dielectric materials characterization. These sensors and multivariate inversion algorithms can provide effective nondestructive characterization of thermal spray coatings on complex shape components.