MATERIALS FOR HIGH TEMPERATURE NUCLEAR ENGINEERING APPLICATIONS. Progress Report No. 2, August 15, 1959 to August 15, 1960 (Part 1)

Technical Report · Tue Oct 31 04:00:00 EST 1961

OSTI ID:4058421

Fleming, J D; Johnson, J W

Investigations of the properties of slip cast fused silica were continued. The slip had a panticle size distribution of 94% less than 44 microns and 13% less than 1 micron. A statistical study was carnied out to evaluate the relative importance of the different slip casting variables. Surface contamination of the silica was minimized by removal of the Keltex prior to firing or by using the graphite mold release. Vioration of the silica slip during casting was found to increase the reproducibility of fired strength by a factor of about two but to result in a substantial decrease in the level of strength. Methods of heat treating the silica were explored in an attempt to increase the strength of fired silica bodies but none proved successful. Tensile strengths of the silica determined at elevated temperatures varied from - 3,000 psi at room temperature to - 8,000 psi at 2000 deg F. Mathematical analysis of the tracer gas permeation measurement system was completed. Studies were begun to decrease the permeability of the porous silica by various sealing techniques. Design studies were begun for the construction of an electron microscope hot stage for the investigation of the bonding method of slip cast fused silica, and the mechanics of devitrification of fused silica. Development of a temperature monitor for the hot stage was begun. Devitrification studies were continued using a high temperature x ray diffractometer. Difficulties with platinum evaporation from the heating elements prompted development of a new furnace. Preferred orientation of the devitrification products in fused silica was investigated. Fused silica was irradiated to a total fast dose of 1.5 x 10/sup 20/ nvt; the cristobalite in the fired samples was reconverted almost completely to amorphous silica under the irradiation. An experiment was designed to allow irradiation of fused silica at high temperatures produced by gamma heating. A comparative study of the slip casting behavior of several different refractory materials was begun. An alumina slip was developed which yielded bars with a fired modulus of rupture in excess of 20,000 psi. A system was constructed for motion photomicrography of slip casting. Investigations were begun of the formation of refractory fuel mixtures by self-sintering exothermic reactions. (auth)

• Research Organization: Georgia Inst. of Tech., Atlanta. Engineering Experiment Station
• NSA Number: NSA-15-014642
• OSTI ID: 4058421
• Report Number(s): ORO-325
• Country of Publication: United States
• Language: English

Related Subjects

ALUMINUM OXIDES
BONDING
CASTING
CONTAMINATION
DIFFRACTION
ELECTRON MICROSCOPY
EVAPORATION
FURNACES
FUSED SALTS
GASES
GRAPHITE
HEAT TREATMENTS
HIGH TEMPERATURE
IRRADIATION
MATHEMATICS
METALS, CERAMICS, AND OTHER MATERIALS
MICROSCOPY
PHOTOGRAPHY
PLATINUM
POROSITY
REFRACTORIES
SEALS
SILICON OXIDES
SINTERING
SLIP CASTING
STATISTICS
SURFACES
TENSILE PROPERTIES
TRACER TECHNIQUES
VIBRATIONS
X RADIATION