Accession Number:

ADA285869

Title:

Demonstration of Multifunctional DNBM Corrosion Inhibitors in Protective Coatings for Naval Air/Weapon Systems

Descriptive Note:

Final rept. Sep 1989-Jul 1992

Corporate Author:

LOCKHEED MISSILES AND SPACE CO INC PALO ALTO CA RESEARCH AND DEVELOPMENT DIV

Personal Author(s):

Report Date:

1993-12-01

Pagination or Media Count:

50.0

Abstract:

The corrosion protective properties of multifunctional DNBM salts quaternary ammonium dichromate, nitrate, borate, and molybdate have been demonstrated on high-strength steel and aluminum alloys found in prototype aerospace weapon systems. The 100 DNBM mixture added to MIL-P-23377 epoxy-polyamide, minus strontium chromate inhibitor, on bare 7075-T6 aluminum alloy resisted 1000 h ASTM B-117 salt spray. However, the coatings were not resistant to hydraulic fluid immersion at the higher concentrations required for the corrosion inhibition. Microencapsulation of the reactive DNBM mixture was adopted as a means to prevent this susceptibility, as well as the destructive oxidation of the hydroxyl groups in the epoxy resin during cure. In the scale-up operation, approximately 20 gallons of DNBM weighing 64 kg 141 lb was prepared from the four starting quarternary salts synthesized in a chemical process pilot plant. The salts were mixed by dissolving in toluene. Following removal of solvent, the resultant dark-brown liquid, approximating molasses in viscosity, was microencapsulated by the following method The DNBM was dispersed to form an oil-in-water emulsion in an aqueous colloidal solution of low-viscosity, high-purity methyl cellulose using a Gifford-Wood homogenizer, followed by spray drying in an Anhydro spray dryer. The maximum practicable payload was 75 DNBM. After spray drying, the capsules Corrosion inhibitors, DNBM, Microencapsulation, Epoxy primers, Protective coatings.

Subject Categories:

  • Coatings, Colorants and Finishes
  • Properties of Metals and Alloys

Distribution Statement:

APPROVED FOR PUBLIC RELEASE