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Title: NDI using mm-wave resonant techniques

Millimeter wave resonant measurements are commonly used for surface and near-surface materials characterization including the detection of cracks and defects, analysis of semiconducting and dielectric materials, and analysis of metallic electrical properties beneath coatings. Recent work has also shown the approach to be useful in evaluating corrosion products and the detection of incipient corrosion and corrosion cracking. In the analysis area, complex permittivity data of the corrosion products can be extracted, usually with accuracy of a few percent or better, to aid in identification of the product and possibly of mechanisms. In the detection area, corrosion-related cracks of order 100{mu}m or less near the surface have been detected and corrosion products have been detected beneath a variety of paints. Surface preparation requirements are minimal, particularly compared to some optical techniques, giving increased hope of field applicability. A number of examples of NDI on aircraft related materials and structures will be presented along with an assessment of detection and accuracy limits.
Authors:
;  [1] ;  [2]
  1. Conductus, Inc. (United States)
  2. Sandia National Labs., Albuquerque, NM (United States)
Publication Date:
OSTI Identifier:
100225
Report Number(s):
SAND--95-1651C; CONF-951135--16
ON: DE95016100; CNN: F49620-94-C-0049
DOE Contract Number:
AC04-94AL85000
Resource Type:
Conference
Resource Relation:
Conference: 1995 International mechanical engineering congress and exhibition, San Francisco, CA (United States), 12-17 Nov 1995; Other Information: PBD: [1995]
Research Org:
Sandia National Labs., Albuquerque, NM (United States)
Sponsoring Org:
USDOE, Washington, DC (United States);Department of Defense, Washington, DC (United States)
Country of Publication:
United States
Language:
English
Subject:
42 ENGINEERING NOT INCLUDED IN OTHER CATEGORIES; 36 MATERIALS SCIENCE; AIRCRAFT; INSPECTION; NONDESTRUCTIVE TESTING; AIRCRAFT COMPONENTS; ALUMINIUM ALLOYS; MICROWAVE RADIATION; CORROSION; SALTS; FOG; SEAWATER