Nondestructive Evaluation of Sputtered-Deposited Tantalum Carbide Refractory Coatings.
Abstract
Desirable characteristics of refractory coatings for future projectile launchers include high wear resistance, high melting point, hardness, electrical conductivity, good adhesion, thermal stability, and high plasma resistance properties. Sputtered tantalum and tantalum compounds, such as tantalum nitride and tantalum carbide are being considered as future coatings to endure the high pressure, high temperature, and aggressive chemical environment of the bore. In this work, tantalum and tantalum carbide were reactively sputtered deposited from argon plasmas containing methane. Nondestructive x-ray diffraction analysis determined that body-centered-cubic (bcc) tantalum was deposited at methane concentrations below 20 percent, face-centered-cubic (fcc) tantalum carbide was deposited at methane concentrations above 25 percent, and a mixture of tantalum and tantalum carbide was deposited at the transitional 22 percent methane concentration. Coating composition, crystalline structure, particle size, preferred orientations, deposition rate, Knoop hardness, and temperature coefficient of resistivity are sensitive functions of percentage methane concentration in the sputtering-deposited process. jg p.3
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 01, 1995
- Accession Number
- ADA298084
Entities
People
- J. Walden
- S. L. Lee
- W. J. Heffernan
Organizations
- United States Army Armament Research, Development and Engineering Center