Thermal expansion

About: Thermal expansion is a research topic. Over the lifetime, 21040 publications have been published within this topic receiving 349407 citations. The topic is also known as: heat expansion.

High-temperature thermal expansion and conductivity of cobaltites: potentials for adaptation of the thermal expansion to the demands for solid oxide fuel cells

Abstract: Thermal expansion and conductivity measurements of LaCoO3−δ, EuCoO3−δ, Y1−xCoO3−δ and Y1−xCo1−yMnyO3−δ perovskites are presented and compared with magnetization and magnetic susceptibility data. An analysis by means of a phenomenological model reveals the importance of the spin state transition and its dependence on changes of the lattice structure in cobaltites. The influence of the insulator-to-metal transition at high temperature on the thermal expansion is also discussed. The potential of these compounds as cathodes for solid oxide fuel cells (SOFCs) is evaluated.

Thermal expansion of the hexagonal (6H) polytype of silicon carbide

Abstract: X-ray diffraction is presently used to determine the thermal expansion of the hexagonal (6H) polytype of alpha-SiC over the 20-1000 C range. The principal (alpha-11 and alpha-33) axial coefficients of thermal expansion can be expressed by second-order polynomials; the former is noted to be larger than the latter over the entire temperature range, while the thermal expansion anisotropy increases continuously with increasing temperature. The thermal expansion and thermal expansion anisotropy obtained are compared with previously published results for the (6H) polytype, and discussed with respect to the structure.

Thermal Expansion of Al2O3, BeO, MgO, B4C, SiC, and TiC Above 1000°C.

Abstract: Thermal-expansion data on Al2O3, BeO, MgO, B4C, SiC, and TiC were obtained to the temperatures where permanent deformation begins, due to sintering or other causes. The thermal expansion for these materials was found to be approximately linear over the measured temperature range. But as a linear extrapolation to room temperature was not possible, the coefficient of thermal expansion is not a constant over this temperature range. The results are compared with the latest published data for each material. The average coefficients of linear thermal expansion are given as follows: All BeO specimens which were heated to above 2050°C. had a very large expansion. Visual examination of the cooled specimens revealed that they had bent and cracked, the physical dimensions had enlarged, and the color had changed to a bright milky white. A brief discussion of the probable reasons for these changes is given. In the attempt to extend the expansion measurements, the melting point of BeO was obtained. A specimen of hot-pressed BeO melted at 2450°± 30°C., whereas a slip-cast BeO specimen melted at 2470°± 20° C.