In situ experimental formation and growth of Fe nanoparticles and vesicles in lunar soil

Abstract

We report the results of the first dynamic, in situ heating of lunar soils to simulate micrometeorite impacts on the lunar surface. We performed slow‐ and rapid‐heating experiments inside the transmission electron microscope to understand the chemical and microstructural changes in surface soils resulting from space‐weathering processes. Our slow‐heating experiments show that the formation of Fe nanoparticles begins at ~575 °C. These nanoparticles also form as a result of rapid‐heating experiments, and electron energy‐loss spectroscopy measurements indicate the Fe nanoparticles are composed entirely of Fe0, suggesting this simulation accurately mimics micrometeorite space‐weathering processes occurring on airless body surfaces. In addition to Fe nanoparticles, rapid‐heating experiments also formed vesiculated textures in the samples. Several grains were subjected to repeated thermal shocks, and the measured size distribution and number of Fe nanoparticles evolved with each subsequent heating event. These results provide insight into the formation and growth mechanisms for Fe nanoparticles in space‐weathered soils and could provide a new methodology for relative age dating of individual soil grains from within a sample population.

Formation of Interstellar C60 from Silicon Carbide Circumstellar Grains

“…Two types of samples were used: (1) pure "dry" SiC particles and (2) a slurry of SiC particles and methanol. These samples were deposited onto supporting SiN films (Norcada) for in situ heating and analysis, e.g., Thompson et al (2017). The films consist of a microelectromechanical systems (MEMS) platform to provide uniform heating.…”

Deconvolution of distinct lithology chemistry through oversampling with the Mars Science Laboratory Alpha Particle X‐Ray Spectrometer

“…Figure displays Morrison , a brushed, raised, and resistant nodular feature at the Pahrump waypoint interpreted as diagenetic . APXS data obtained via a 2 × 2 + 1 raster showed elevated MgO, SO 3 , and Ni concentrations in the diagenetic feature relative to the immediately adjacent bedrock.…”

In situ Thermal Shock of Lunar and Planetary Materials Using A Newly Developed MEMS Heating Holder in A STEM/SEM

“…At the center of the isothermal region, there are 19 sample wells in 5 arrays. These sample wells have a 30 nm-thick SiN support film, providing electron transparency and exceptional chemical, thermal and mechanical stability.In this paper, we report the in situ heating study of lunar and planetary materials using the Blaze heating holder [2]. The lunar soil samples were acquired from the Apollo 14 and 17 missions.…”

“…In this paper, we report the in situ heating study of lunar and planetary materials using the Blaze heating holder [2]. The lunar soil samples were acquired from the Apollo 14 and 17 missions.…”

“…The new sample stage enables a wider, jewel-less sample holder design, providing a larger platform which is advantageous for laying out electric contacts and transportation of stimuli. As shown in In this paper, we report the in situ heating study of lunar and planetary materials using the Blaze heating holder [2]. The lunar soil samples were acquired from the Apollo 14 and 17 missions.…”