Engineering Commons^™

The Elastic And Anelastic Constants Of A Synthetic Fluor-Mica Formed By Glass-Ceramic Fabrication Techniques, John H. Ainsworth

Masters Theses

"A tetrasilicic fluor mica, K₂Mg₅Si₈O₂₀F₄, was synthesized using glass forming techniques. Density changes, weight losses, and shrinkage, as well as elastic and anelastic properties, were measured on bars heat-treated at selected temperatures between 500°C and 1150°C to determine the characteristics of this material. Phase changes were followed by determining thermal expansion, logarithmic decrement, and modulus of elasticity from room temperature to 800°C.

It was found that the elastic and anelastic constants decreased gradually with heat treatments from 600°C to 1000°C. This indicated progressively increased structural ordering. Heat treatments above 1000°C …

Internal Friction Of Mixed-Alkali Silicate Glasses, James E. Shelby

Doctoral Dissertations

"The mixed alkali effect in silicate glasses was examined from internal friction measurements made over the temperature range from -190 to 500⁰C and at a frequency of 0.4 Hz. Supplemental measurements of the activation energy for the different internal friction peaks, dynamic shear modulus, density, and index of refraction were also made. All measurements were confined to silicate glasses containing mixtures of Li-Na, Li-K, Li-Rb, Li-Cs, Na-K, Na-Rb, Na-Cs, and K-Rb. Rötger's interpretation of the internal friction of mixed-alkali silicate glasses is shown to be incorrect. A previously unreported internal friction peak was observed whenever two different alkali oxides were …

The Dielectric Properties Of A Synthetic Fluor-Mica Formed By Glass-Ceramic Fabrication Techniques, Ray Fred Schumacher

Masters Theses

"A tetrasilicic fluor-mica, K₂Mg₅Si₈O₂₀F₄, was synthesized, utilizing glass forming techniques and subsequent heat treating of the mica glass. Discs, approximately two inches in diameter, were formed and heat-treated at selected temperatures between 700⁰C. and 1150⁰C. for various time periods. Density change, weight loss, shrinkage, and dielectric properties were measured to determine the characteristics of this material"--Abstract, page ii.