Inspection of plasma-sprayed coatings using fast infrared scanning technique

Abstract

Evaluation of fracture behavior in a plasma-sprayed ceramics coating by acoustic emission using laser interferometer AIP Conf.Fast infrared scanning technique (FIRST), in which a laser beam focused to a line is used for heating and the temperature rise is detected with an IR scanner, is applied to the nondestructive inspection of plasma-sprayed coatings. The surface temperature profiles are computed numerically for faultless and defective coatings, and the functionality of the technique is demonstrated using a sample with artificial defects.

Observations on Image Formation in the Line Scanning Thermal Imaging Method

“…3) described earlier by Hartikainen [3]. The line heat source was generated with an argon laser beam, which was focused in a line on the sample surface.…”

“…A third method that uses the lateral heat flow for detecting flaws in a sample is a line scanning technique [3], where a moving line source is scanned over the sample surface. This method has not traditionally been considered a crack detection technique because the spatial resolution of the method is not comparable to that of the mirage or flying spot methods.…”

<title>Use of imbedded fiber optic thermal sensors to monitor the health of composite structures</title>

“…In contrast to heating techniques, the sensing side of thermography is customarily performed with IR cameras [3,4,5,9,10,11]. Typically, an IR camera is scanned across the sample surface to measure the temperature profile, or it is used to image the entire specimen.…”

Fast Photothermal Inspection of Plasma-Sprayed Coatings of Primary Circulation Seal Rings of a Nuclear Reactor

“…The kind of a situation can be modeled with a computational technique similar to the method previously used to simulate laser heating for crack inspection [3] and delamination detection [4]. Thus, a few computer simulations were performed in order to optimize measurement parameters.…”

“…The sampIe under inspection is heated by a scanning laser beam focussed on a line and the increased thermal radiation from the sampIe surface is monitored with an infrared line scanner. Possible delamination defects affect the surface temperature and can thus be detected.The kind of a situation can be modeled with a computational technique similar to the method previously used to simulate laser heating for crack inspection [3] and delamination detection [4]. Thus, a few computer simulations were performed in order to optimize measurement parameters.…”