Accession Number : ADA291345

Title :   Electrochemical Impedance Pattern Recognition for Detection of Hidden Chemical Corrosion on Aircraft Components. Phase 1.

Descriptive Note : Final rept. 15 Jun-15 Dec 94,

Corporate Author : ELTRON RESEARCH INC BOULDER CO

Personal Author(s) : Sammells, A. F. ; Bowers, J. S.

PDF Url : ADA291345

Report Date : 08 FEB 1995

Pagination or Media Count : 87

Abstract : This investigation addressed the need for diagnostic instrumentation compatible with performing the Nondestructive Evaluation (NDE) of hidden chemical corrosion with a high degree of accuracy, sensitivity and versatility on both titanium and aluminum alloys currently used in Air Force and commercial aircraft. The overall approach was directed towards development of pattern recognition schemes based upon the on-line data acquisition of Fast Fourier Transform Electrochemical Impedance Spectroscopy (FFTEIS) instrumentation from the suspect hidden chemical corrosion site. Resulting impedance patterns were then analyzed by application of a Neural Network pattern recognition scheme. The Neural Network Analysis (NNA) was then trained to both detect and grade the severity of hidden corrosion present on the aircraft metal substrate interface of interest. Nueral Net Analysis of FFTEIS data was verified as a powerful diagnostic strategy for in situ hidden corrosion process identification, quantitative analysis and severity grading. Correlations between impedance measurements and corrosion depth were verified by subsequent SEM and EDX examination of the metal interfacial regions. The approach will also be powerful for gaining fundamental information into the nature of corrosion processes and conditions leading to their inception at hidden sites. jg

Descriptors :   *DETECTION, *CORROSION, *ELECTROCHEMISTRY, *PATTERN RECOGNITION, *AIRCRAFT EQUIPMENT, *IMPEDANCE, METALS, MEASUREMENT, AIR FORCE, SCANNING ELECTRON MICROSCOPES, QUANTITATIVE ANALYSIS, NEURAL NETS, DISPERSING, HIGH RATE, COMMERCIAL AIRCRAFT, NONDESTRUCTIVE TESTING, ALUMINUM ALLOYS, CHEMICALS, INTERFACES, ENERGY, ACCURACY, SUBSTRATES, X RAYS, DEPTH, IDENTIFICATION, DATA ACQUISITION, DIAGNOSIS(GENERAL), DIAGNOSTIC EQUIPMENT, FAST FOURIER TRANSFORMS, TITANIUM, NETWORK ANALYSIS(MANAGEMENT), ONLINE SYSTEMS, FOURIER SPECTROSCOPY.

Subject Categories : Physical Chemistry
      Aircraft
      Inorganic Chemistry
      Properties of Metals and Alloys

Distribution Statement : APPROVED FOR PUBLIC RELEASE