Mold and Crucible Coatings
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.
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 28, 1986
- Accession Number
- ADA167864
Entities
People
- Arthur L. Geary
- Sylvia J. Canino