The Emittance of Refractory Metal Coatings.
Abstract
Current activity related to the emittance of coated refractory metals was reviewed to update a similar survey made under a previous contract. The review disclosed new hypersonic vehicles environments of significance to emittance measurements, new emittance data, and progress in emittance measurement techniques. Under the experimental part of the program new total spectral emittance data were gathered for the Cr-Ti-Si, W-3 and Si-20Cr-20Fe sytems at 2700F to 2800F, and at 5 and 100 Torr. Total and spectral normal emittance measurements were made of the Si-20Ti-10Mo coating on TA 222 at 2000F, to 2800F at pressures from 0.01 to 760 Torr. Total normal emittance values ranged from 0.59 to 0.94 for this latter system. Complex chemical rearrangements were found to occur in the coating during heating; Ti02 formed and silica and molybdenum oxide were notably not present in the analysis. An emittance variation study of two batches of Si -20Cr-20Fe showed no statistical difference based upon limited sampling. A statistical study of the effects of composition and thickness variation on the emittance of the Si-20Cr-20Fe system showed that composition may be permitted to vary from Si-17Cr-17Fe to Si-21Cr-21Fe without affecting emittance more than plus or minus 0.025 units. Thickness may also vary. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 1970
- Accession Number
- AD0883597
Entities
People
- Elden R. Geib
- J. W. Mccamont
- Karl O. Bartsch
- Thomas Place
- Walter P. Hudgins