Accession Number : AD0839936

Title :   PASSIVATION OF METAL AIRCRAFT SURFACES.

Descriptive Note : Final rept. 1 Jun 67-30 Jun 68,

Corporate Author : AMERICAN CYANAMID CO STAMFORD CT CENTRAL RESEARCH DIV LABS

Personal Author(s) : Rauch, F. C. ; Luciw, F. W. ; Murray, M. A.

Report Date : JUL 1968

Pagination or Media Count : 40

Abstract : The approach to the problem was based on the concept that suitably chosen chelating agents would be capable of forming chemical bonds with the metal surface to give a corrosion capable of forming chemical bonds with the metal surface to give a corrosion resistant barrier layer and, further, could provide bonding sites of superior strength on which to anchor the paint coating, if appropriate functional groups are incorporated in the molecule. Qualitative screening studies of some twenty-four potential chelating agents using a multiple specular reflectance technique provided indications of the desired surface reaction in eleven cases. Based partly on the results of the screening studies, adsorption measurements of three chelating agents, diphenylphosphinic acid, acetylacetone and 8-hydroxyquinoline, were undertaken. Analysis of the adsorption isotherms for the first two compounds indicates that a strongly bound monolayer is formed, while multilayer adsorption is found for the 8-hydroxyquinoline. Electrochemical measurements and salt spray tests were employed to determine the degree of corrosion protection provided by treatment of aluminum with the promising passivating systems. The polarization curves for high purity aluminum electrodes treated with several of the chelating systems indicated a considerably more noble critical corrosion potential than that observed for untreated electrodes. Salt spray tests of similarly treated aluminum panels confirmed the enhanced corrosion resistance of appropriately treated metal surfaces. Of particular importance was the low degree of pitting with several of these treatments. (Author)

Descriptors :   *CORROSION INHIBITION), (*AIRCRAFT FINISHES, (*CHELATE COMPOUNDS, CORROSION INHIBITION), BARRIER COATINGS, CHEMICAL BONDS, COATINGS, ADHESION, ALUMINUM ALLOYS, ADSORPTION, ELECTROCHEMISTRY, SALT SPRAY TESTS, ACETONES, QUINOLINES, ORGANIC PHOSPHORUS COMPOUNDS.

Subject Categories : Coatings, Colorants and Finishes

Distribution Statement : APPROVED FOR PUBLIC RELEASE