Chemistry: electrical and wave energy – Processes and products – Processes of treating materials by wave energy
Patent
1992-05-12
1994-06-28
Tung, T.
Chemistry: electrical and wave energy
Processes and products
Processes of treating materials by wave energy
204412, 204434, 204DIG8, 4274431, 427435, G01N 2726
Patent
active
053243994
ABSTRACT:
A method and system for monitoring the quality of a phosphate coating on a metal surface having a large surface area. The method comprises applying a current or potential between the metal surface and one or more counter electrodes while they are in the phosphating solution and superimposing a constant ac signal thereon. An ac impedance spectra is obtained by measuring the ac potential between the metal substrate and one or more reference electrodes located between the counter electrode and the substrate. The ac impedance spectra provide an indication of defects in the phosphate coating even when the defects are located within a relatively small region of the total surface area of the metal surface.
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Eliash Bruce M.
Ludwig Frank A.
Denson-Low W. K.
Hughes Aircraft Company
Lachman M. E.
Sales M. W.
Tung T.
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