Thermodynamic and diffusivity measurements in potential ultra high temperature composite materials. Final report, October 1987-January 1990

Technical Report · Wed Aug 01 04:00:00 EDT 1990

OSTI ID:7187431

Cawley, J D; St Pierre, G R; Kalen, J D; Amante, J C; Gourishankar, K

The study of the vaporization kinetics of CaZrO[sub 3] and BaZrO[sub 3] have been carried out in the temperature range 1600-2000 C using a vacuum microbalance technique. Oxygen tracer diffusion coefficients in CaZrO[sub 3], BaZrO[sub 3] and SrZrO[sub 3] have also been measured using the gas exchange technique. Tracer concentration profiles were determined using nuclear reaction analysis. Both CaZrO[sub 3] and BaZrO[sub 3] have a relatively high rate of evaporation at high temperatures. However, dry-pressed CaZrO[sub 3] shows a smaller rate of evaporation than hot-pressed but impure BaZrO[sub 3]. Results of the diffusion experiments indicate that CaZrO[sub 3] exhibits the largest penetration with BaZrO[sub 3] showing the smallest. Apparent oxygen tracer diffusion coefficients were measured for CaZrO[sub 3] and SrZrO[sub 3] at 1000C. Over the temperature range of 900-1100C, the apparent oxygen tracer diffusion coefficient in BaZrO[sub 3] is described by D=5.0 x 10-3 sq.cm/sec exp (-247 KJ/mole/RT). Calcium Zirconate, Barium Zirconate, Strontium Zirconate.

• Research Organization: Ohio State Univ. Research Foundation, Columbus, OH (United States)
• OSTI ID: 7187431
• Report Number(s): AD-A-256151/2/XAB; ON: TI93745625
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360602* -- Other Materials-- Structure & Phase Studies
ALKALINE EARTH METALS
BALANCES
BARIUM
BENCH-SCALE EXPERIMENTS
CALCIUM
CHEMICAL ANALYSIS
COMPOSITE MATERIALS
DIFFUSION
ELEMENTS
ENTHALPY
EVAPORATION
FABRICATION
HOT PRESSING
KINETICS
MATERIALS
MATERIALS WORKING
MEASURING INSTRUMENTS
METALS
MICROBALANCES
NONMETALS
NUCLEAR REACTION ANALYSIS
NUCLEAR REACTIONS
OXYGEN
OXYGEN COMPOUNDS
PHASE TRANSFORMATIONS
PHYSICAL PROPERTIES
POWDERS
PRESSING
STRONTIUM
TEMPERATURE RANGE
THERMAL ANALYSIS
THERMAL DIFFUSIVITY
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENT COMPOUNDS
TRANSITION HEAT
VAPORIZATION HEAT
WEIGHT INDICATORS
ZIRCONATES
ZIRCONIUM COMPOUNDS