Equipex PLANEX Orléans

Experimental Planet: In-situ analyses and simulations under extreme conditions
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Equipment

The instruments acquired or improved are the following:

1 Griggs press : With respect to the standard Griggs-type apparatus, the new press in Orléans has been improved in several ways: 1) both the confining and deformation rams are fully hydraulic and controlled by high-accuracy syringe pumps provided by Sanchez Technologies; 2) it is equipped with an end-loaded piston, which preserves the vessel and increases its capacities toward higher pressures; 3) the sample size has been enlarged from 6 to 8 mm diameter, allowing to better develop microstructures; and 4) it is equipped with an acoustic receiver located within the deformation piston and dedicated to explore the ductile-to-brittle transition. It allows to go up to 5 GPa and over 1400°C (Figure below).

2 Paterson press : The Paterson press is the « low-pressure » counterpart of the Griggs press presented above, allowing to explore and define rheological laws of solid, partly molten, and fully molten material up to 300 MPa and 1400°C. The Orléans Paterson is unique worldwide in that it allows to deform low viscosity material (down to 103-4 Pa s) under pressure (ie with volatiles are dissolved in the silicate melt). The controlling temperature system and monitoring devices have been entirely renewed via PLANEX. The press also allows to perform experiments on fluid flow through porous material, over the same P-T range, enabling the direct measurement of permeability and its evolution with reaction progress (Figure below).

3 Reactive transfer : The 2 reactive transfer benchmark devices developed by PLANEX are dedicated to explore typically hydrothermal conditions (up to 500°C and 50 MPa) using large volume samples (several cm3). Two externally heated vessels (1 L each) have been equiped with 2 metering pump each (inlet and outlet pressures), in addition to a hydraulic pump for imposing total pressure (H2O). The system allows to impose differential pressure of up to 20 MPa, and to monitor fluid/gas flow with high precision (up to 30±0.001 cm3/min), in runs of durations exceeding several weeks or months if needed. The system allows a continuous sampling of the fluid to monitor its evolution in composition, via a GC (Figure below).

4 Electrochemical devices : The devices installed at IRCP allows improved measurement on the thermochemisty and conductivity properties of carbonate melts used in molten carbonate fuel cells (MCFC). It allows thermal analyses with TGA/DSC coupled to GC, mass spectrometer and IR analyses.

5 IHPV for gas sampling and analyses : This is a standard IHPV coupled to a device allowing sampling of the gas phase at HT-HP in the vessel (either at equilibrium or during decompression down to atmospheric pressure), with a specific tool that mix the sampled gas with Ar (or N2, in which case, this species will not be measured) at high temperature so as to prevent as much as possible from condensation effects during sampling and decompression. Once mixed, the sampled gas is inserted in parallel into (1) a FTIR spectrometer to make a first-order analysis of the main species present (H2O, CO2 etc..), and (2) a highly sensitive laser-based spectrometer (laser optical-feedback cavity enhanced spectrometry) allowing the measurement of minor species down to the ppb-100xppb level (CO2, CO, CH4, OCS, NH3, NO2, N2O, HCl, HF, H2S, SO2). Foreseen developments include the analysis of C isotopes (Figure below).

6 Transparent IHPVs for in-situ measurements with IR, Raman and X-Ray : 6 transparents IHPV have been acquired, 3 of which will be installed at ISTO:

 

A general sketch of the new IHPV is shown below:

 

The X-ray based device consists of an X-ray source (either Cu or Mo) which is focused through lenses and passes through the Be-windows (of various thickness depending on pressure, up to 4 mm for 2 kb) of the IHPV hitting an unreactive glassy carbon hollow tube which contains the material (molten silicate+gas+solids) to be investigated. The transmitted beam is collected by a photon counting detector (silicon CMOS of 300 um thickness), located at various distances of the second Be window from which the X-ray beam emerges, depending on the required spatial resolution (down to a few microns). Exposure time for image acquisition is about 0.1 sec. Owing to the existence of three windows on each IHPV, 2 coaxial and 1 perpendicular, it will be possible to use the latter for X-ray fluorescence. The system will be equiped of two detectors, one for X-ray imaging and one for X-ray diffraction, which can be used sequentially (see below).

Sketch of the X-Ray+IHPV instrument being mounted at ISTO. Two different lines of data acquisition will be possible. On the left an X-Ray transmission line will be operational, on the right a DRX and X-Ray fluorescence data will be obtained. The IHPV is mounted on a device allowing alternative use of each method.

The transparent IHPV coupled to a dedicated IR spectrometer, reproduces the set-up developed and routinely operated at 1 bar at the nearby CEMHTI laboratory to measure, inter alia, silicate melt emissivities in the IR range, which is here deployed at HP. The system consists of an IHPV transparent vessel (with ie sapphire, diamond, CaF2 BaF2 windows depending on T), a black body reference (lanthanum chromite body) also encapsulated in a similar IHPV vessel operated at the same P-T, to correct from instrumental radiative noise. The twin vessels are fixed on a rotary stage, which allows to alternate flux measurements of the target and black body under the same experimental and geometrical conditions. Both are placed into a purged enclosure, to eliminate atmospheric water vapor and CO2 along the optical path between the vessel and the IR spectrometer (Figure below).

 

A third IHPV is coupled to a Raman spectrometer, in a setup similar to that developed by the I. Néel. Owing to the existence of three windows, the geometrical configuration will allow to perform both Raman and IR measurements on the same sample.

7 Brillouin and Raman spectrometers on a heating stage : this set up consists of coupled Brillouin and Raman spectrometers associated to a heating stage allowing 2D mapping at high spatial resolution.

8 Analytical tools of run products (SIMS, FEG-SEM) : PLANEX funding has been used to upgrade the SIMS national facilities in CRPG Nancy. The facility hosts two large radius multi-collection ion microprobes, an ims 1270 installed in 1996 and an ims 1280HR2 installed in 2009. PLANEX funds were used to upgrade the ims 1270 into an ims 1270 E7, consisting basically in (i) a replacement of all the electronic controlling the instrument, (ii) an improvement of the transfer optic of the instrument allowing automatic re-centering of the secondary beam and (iii) replacement and upgrade of softwares and controls of the instrument. All together, this upgrade transformed the ims 1270 into an instrument able to reach routinely very high precision for isotopic ratio measurements (typically better than ±0.1‰ level for many isotopic systems). This new ims 1270E7 is devoted to this type of measurements while the ims 12780HR2 is devoted to specific analyses requiring very high mass resolution (M/DM= 25 000) such as for instance for the development of K-Ca dating. PLANEX funding has allowed to build a national facility which is unique at the international level. The Field Emission Gun MEB has been purchased at the Zeiss company. The magnification ranges from 12 to 2,000,000, corresponding to a spatial image resolution of 0.8-1.6 nanometer in the range of 1-30 kv accelerating voltage. The SEM has been also fit with a X-microfluorescence device equiped of a X-ray focused optics (IFG-iMOXS/sem), the first one installed in France, allowing enhanced sensitivity for trace elements (down to 100 ppm or less) at high spatial resolution (10 microns).

In addition to the above instruments, the consortium has also purchased a specific intensifier system allowing to pressurize the IHPVs using directly Ar-H2 mixtures as a gas medium. The motivation is a reduction of risks associated to the handling of H2-loaded bottles and a better control on the composition of the mixture, ensuring a greater reproductibility in redox control at high pressures via H2 permeability. The system is fully automated and allows performing experiments with a fine tuning of decompression rates.

Lastly, in order to maintain the capacity of the workshop at the highest level of production and quality, a numeric controlling lathe for milling/turning work having a plurality of tool posts, the position of which can be independently controlled, has been also acquired. This allows the production of high precision pieces (all consumables used in HP/HT experiments) in large quantities (Figure below).

Other facilities

The new or upgraded equipments listed above constitute the core of the platform hosted in Orléans by ISTO and CEMHTI, to which existing facilities (and allied expertises) of both laboratories need to be added. The correct working and access of these existing facilities are mandatory for a good functionning of the entire system. In particular, at ISTO, which hosts the bulk of equipement, the platform is equiped with 5 conventional IHPVs of large volume, allowing pre-annealing or synthesis of material in large quantities under controlled redox state, which will be used for in-situ measurements. ISTO has also 3 piston-cylinder, 10 standard cold seal pressure vessels (CSPV), 1 CSPV equiped for decompression-assisted runs, 2 large volume rocking autoclaves equiped with flexible Ti-capsules for fluid sampling. Analytical tools include a SX-Five electron microprobe, a micro-FTIR and Raman spectrometers, an elemental analyser, a coupled Raman-SEM, and various other small devices needed for preparing experiments (ie 3 HT furnaces with controlled atmospheres). The ISTO-lab has also a workshop with 5 permanent engineers or assistant engineers, who are fully dedicated to the maintenance and fixing of HP/HT equipments and operation of related spectroscopic devices. Similarly, CEMHTI is equiped with a 1 bar and HT IR emissivity measurement device, which gives the room-pressure reference value for HP measurements, and several Raman spectrometers. Within the framework of labex VOLTAIRE, a nanofluidic platform has been built, in which fluid transfer at the micro to nano scale in porous media can be simulated and monitored : this allied platform is considered as part of PLANEX ensemble, being clearly dedicated to the understanding of the fundamental physics and chemistry of fluids (and of the feedback with their host) in inclusions or micro channel networks, offering access to smaller scale processes at work in more macroscopic approaches such as those performed in the reactive transfer vessels. In the field of IR spectroscopy, additional expertises come from LPC2E scientific/technical staff.