Effective Thermal Conductivity of a Packed Bed of Hollow Zirconia Microspheres, under Vacuum and under 100 kPa of Argon

• Published in: Journal of the American Ceramic Society 1991-12, Vol.74 (12), p.3118-3125
• Main Authors: Londry, Frank A., Slavin, Alan J.
• Format: Article
• Language: English
• Subjects: 360204 - Ceramics, Cermets, & Refractories- Physical Properties; ALLOYS; Applied sciences; ARGON; Building materials. Ceramics. Glasses; Ceramic industries; CHALCOGENIDES; Chemical industry and chemicals; DESIGN; ELEMENTS; Exact sciences and technology; FLUIDS; GASES; insulation; MATERIALS SCIENCE; MICROSPHERES; Miscellaneous; NONMETALS; OXIDES; OXYGEN COMPOUNDS; PACKED BEDS; PHYSICAL PROPERTIES; porous materials; POWDERS; RARE GASES; Technical ceramics; TEMPERATURE RANGE; TEMPERATURE RANGE 0400-1000 K; THERMAL CONDUCTIVITY; THERMAL INSULATION; THERMODYNAMIC PROPERTIES; TRANSITION ELEMENT COMPOUNDS; YTTRIUM ADDITIONS; YTTRIUM ALLOYS; zirconia; ZIRCONIUM COMPOUNDS; ZIRCONIUM OXIDES
• ISSN: 0002-7820; 1551-2916
• DOI: 10.1111/j.1151-2916.1991.tb04309.x

Measurements have been made of the effective thermal conductivity of a packed bed of hollow, yttria‐stabilized zirconia microspheres, under vacuum and under 100 kPa of argon gas. Above 1400 K the spheres begin to sinter together. Before this occurs, the conductivity is given under vacuum by A1T3+A2 with A1= 2 × 10−11 W · m−1· K−4 and A2= 0.01 W · m−1· K−1. The thermal conductivity increases strongly with both the gas pressure and the degree of sintering of the spheres. The measured values can be fitted reasonably well by a model developed by Takegoshi et al. These results may have some applicability to the development of high‐temperature thermal insulation.