Accession Number:

ADA167864

Title:

Mold and Crucible Coatings

Descriptive Note:

Final rept. Apr 1984-Dec 1985

Corporate Author:

NUCLEAR METALS INC CONCORD MA

Personal Author(s):

Report Date:

1986-04-28

Pagination or Media Count:

83.0

Abstract:

This report details the investigation of coating materials and their application to the graphite crucible and molds used in melting and casting DU-0. 75 Ti Alloy. Different types of washes were investigated zirconium oxide, zirconium silicate, yttrium oxide, titanium carbide used as an undercoat, and boron nitride. The parameters investigated in the application of these coatings were number of burnouts of the crucible, method of cleaning, surface condition of the crucible, temperature of the crucible during painting, number and time between coats, and method of drying the crucible. The method of applying the wash affects its adherence to the graphite. The more thorough the drying of the first coat, the more effectively the coating protects the crucible. Drying in still air was detrimental to the success of most washes. Both oven or vacuum drying of the coated crucibles improved the adherence of most washes. Performance of yttrium oxide washes was dependent on the physical properties of the CMC binders. Yttria coating of the molds improved ingot surface quality, compared with zirconia coated or uncoated molds. Generally zirconium oxide washes outperformed titanium carbide under coated systems and yttrium oxide washes in the elevated temperature tests and in chemistry and ultrasonic results. Keywords Depleted Uranium DU Ceramic Coatings Graphite Coatings MMT - Process improvement Large caliber penetrators.

Subject Categories:

  • Coatings, Colorants and Finishes
  • Metallurgy and Metallography
  • Machinery and Tools

Distribution Statement:

APPROVED FOR PUBLIC RELEASE