Investigation of microstructure and thermophysical properties of Morasko iron meteorites

Abstract

AbstractChemical etching and electron microscopy were used to reveal and characterize minerals and microstructure of four samples of Morasko iron meteorites. All important iron meteorite minerals such as: kamacite, taenite, schreibersite, rhabdite, troilite, and graphite, as well as typical of iron meteoritc structures: Widmanstätten patterns and Neumann bands have been revealed. This implies that all the samples represent the extraterrestrial materials. Apart from similarities, differences in microstructure of various samples have also been noted, and this nonuniformity is expected for this type of material. To characterize the physical properties of Morasko meteorites, density and thermophysical properties have been chosen to compare with the properties of terrestrial materials of similar composition. Thermal diffusivity and specific heat capacity were measured by the laser flash method. Thermal conductivity was calculated on the basis of measured parameters. For the Morasko meteorites, the thermal diffusivity of various samples is in the range (7–19)·10–6m2/s, and the thermal conductivity (25–67) W/m·K at room temperature. Specific heat capacity in the temperature range between 163 and 303 K increases from 50 to 590 J/kg·K, and is equal to 478 J/kg·K at 293 K, but various samples have their heat capacity in the range (440–596) J/kg·K at room temperature. Thermal diffusivity, thermal conductivity and specific heat capacity of Morasko meteorites are within the range of values attained in terrestrial metals: iron, nickel, steels and iron alloys. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)