Frequency-based electric fingerprint and thermal properties of the NWA 869 chondrite

Abstract

The NWA 869 chondrite is among many common stony regolith breccia meteorites that have been collected from northwest Africa (NWA). It is composed of Fe sulphide and Fe-Ni metallic phase inclusions embedded in a silicate stony matrix (primarily pyroxene). Although the physical properties of meteorites are the implementation of their mineral and chemical compositions, their electric and dielectric properties (electric conductivity σ, dielectric constant ε′, and dielectric loss ε") are rarely studied, while no literature has been published on their thermal properties (thermal conductivity K, thermal diffusivity α, specific heat capacitance Cp, and thermal effusivity e). Consequently, the present study deals with studying the electric and dielectric properties of the NWA 869 chondrite at a frequency range (4.0 Hz-8.0 MHz), and their behavior against the applied frequency (fingerprint) was matched. Also, the thermal properties were measured at the ambient conditions. The porosity and density of the chondrite were also measured using helium injection technique. To explain the electric and thermal properties of the meteorite sample, its internal structure as well as its mineral and chemical compositions were revealed using the environmental Scanning electron microscopy (ESEM) supported by the EDAX technique. It is indicated that the chondrite is composed of iron sulphide and Fe-Ni inclusions scattered in a stony silicate matrix; it is characterized by moderate density (3.5069 g/cc) with a considerable porosity value (2.12 %). It is also characterized by moderate electric conductivity (σ), dielectric constant (ε′), and dielectric loss (ε") values (0.50 < σ < 2037.3 ohmm, 67.0 < ε' < 1713.7, and 0.22 < ε" < 12,432 at frequency range 4 Hz-8MHz, respectively). Also, it is characterized by thermal conductivity (K), thermal diffusivity (α), thermal capacitance (Cp), and thermal effusivity (e) values of average 1.5185 W/(K.m), 1.5425 mm2/s, 286 J/(K.kg), and 2628 W(s)0.5/m2K, respectively.