Coating Processes for Columbium Alloys
Abstract
The purpose of the program was to develop improved processing techniques for depositing the NS-4 coating on columbium alloys. The NS-4 coating consists of depositing a vacuum sintered modifier layer (nominal composition 20Mo-50W-15Ti-15V) and then siliciding the modifier layer. The objectives of this program were to develop an electrophoretic process for depositing the modifier layer and a chemical vapor deposition process for siliciding the modifier layer. Electrophoretic deposition from both waterbase and isoproponol suspensions was investigated for deposition of the modifier layer. Satisfactory deposits could not be obtained from waterbase suspensions. Gases resulting from electrolysis of the water produced defects in these deposits. Satisfactory deposits were obtained from isoproponol-nitromethane suspensions. Parameters were developed for depositing nominal modifier layer thicknesses of 2.0, 3.5 and 5.0 mils from suspensions containing total Ti+V contents of 10 w/o, 20 w/o and 30 w/o. Deposition parameters were developed for depositing silicon on the modifier layer by hydrogen reduction of SiCl4.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 1976
- Accession Number
- ADA031030
Entities
People
- M. T. Groves