Making EBSD on water ice routine

Abstract

Electron backscatter diffraction (EBSD) on ice is a decade old. We have built upon previous work to select and develop methods of sample preparation and analysis that give >90% success rate in obtaining high-quality EBSD maps, for the whole surface area (potentially) of low porosity (<15%) water ice samples, including very fine-grained (<10 μm) and very large (up to 70 mm by 30 mm) samples. We present and explain two new methods of removing frost and providing a damage-free surface for EBSD: pressure cycle sublimation and 'ironing'. In general, the pressure cycle sublimation method is preferred as it is easier, faster and does not generate significant artefacts. We measure the thermal effects of sample preparation, transfer and storage procedures and model the likelihood of these modifying sample microstructures. We show results from laboratory ice samples, with a wide range of microstructures, to illustrate effectiveness and limitations of EBSD on ice and its potential applications. The methods we present can be implemented, with a modest investment, on any scanning electron microscope system with EBSD, a cryostage and a variable pressure capability.

Monitoring the temperature-dependent elastic and anelastic properties in isotropic polycrystalline ice using resonant ultrasound spectroscopy

“…We were, however, able to characterize a statistically significant number of grains (> 4000) to make a robust prediction of anisotropy (using a Voigt-Reuss-Hill average), which we estimate at ≈ 0.1 % for V p . Additional electron backscatter diffraction (EBSD) analyses of samples made in this way (Prior et al, 2015;Vaughan et al, 2016;Qi et al, 2016) all show a close to random CPO, with an average maximum V p anisotropy of < 2 %. The orientation of the maximum anisotropy in different samples is different, suggesting that the small anisotropy we see in EBSD data relates to a small sample volumes (of a few thousand grains).…”

“…We acquired this map using a Zeiss Sigma VP FEGSEM fitted with an Oxford Instruments Nordlys camera and AZTEC software. Modifications required for cryo-EBSD are described in Prior et al (2015). ( preferred orientation (CPO), and nearly isotropic velocity characteristics were frozen in a cylindrical aluminium mould (70 mm internal diameter), and machined to 130 mm in length.…”

“…We estimate the resulting ice samples had < 2 % porosity in pores of < 100 µm size. The microstructure of a sample of standard ice manufactured using the same method was characterized using electron backscatter diffraction (Prior et al, 2015). This method maps fully resolved crystal orientations and allows us to model the anisotropy of samples as it relates to crystal orientation.…”

Rheology, microstructure and crystallographic preferred orientation of matrix containing a dispersed second phase: Insight from experimentally deformed ice

“…Noise reduction on the raw data was performed following the procedure tested by Prior et al (2002) and Bestmann and Prior (2003). In the sample with calcite, only ice can be indexed, therefore not indexed areas are occupied by calcite grains, or represent low quality ice surface.…”

A new HPF specimen carrier adapter for the use of high‐pressure freezing with cryoscanning electron microscope: two applications: stearic acid organization in a hydroxypropyl methylcellulose matrix and mice myocardium

“…At this temperature, amorphous ice does not present major modification due to recrystallization because artefactual modifications are not apparent at the magnification the samples are examined. According to DJ Prior data (Prior et al ., ), we can suppose that if ice grains are present, their size is smaller than 1 nm, and they are therefore not detectable. Anyway, these data concern water and dirty water freezing.…”