Laboratory of X-ray Diffractometry and Spectrometry

XRD and XRF data collection

Ambient temperature X-ray diffraction analysis

X-ray powder diffraction data were collected at room temperature with a Bruker AXS D8 θ-θ powder diffractometer with parafocusing Bragg-Brentano geometry using CoK_α radiation (λ = 1.79028 Å, U = 34 kV, I = 20 or 30 mA). Data were scanned with an ultrafast detector LynxEye over the angular range 5-60° (2θ) with a step size of 0.0196° (2θ) and a counting time of 19.2 s step^-1. Data evaluationwere performed in the software package HighScore Plus 4.0.

X-ray powder diffraction data were collected at room temperature with an X'Pert PRO θ-θ powder diffractometer with parafocusing Bragg-Brentano geometry using CoK_α radiation (λ = 1.79028 Å, U = 35 kV, I = 40 mA). Data were scanned with an ultrafast detector X'Celerator (or with a scintilator detector equipped with a secondary curved monochromator) over the angular range 5-60° (2θ) with a step size of 0.017° (2θ) and a counting time of 20.32 s step^-1. Data evaluation was performed in the software package HighScore Plus 4.0.

X-ray powder diffraction data were collected at room temperature with an X'Pert³ Powder θ-θ powder diffractometer with parafocusing Bragg-Brentano geometry using CuK_α radiation (λ = 1.5418 Å, U = 40 kV, I = 30 mA). Data were scanned with an ultrafast detector 1D detector PIXCEL over the angular range 5-60° (2θ) with a step size of 0.013° (2θ) and a counting time of 56.86 s step^-1. Data evaluation was performed in the software package HighScore Plus 4.0.

High temperature X-ray diffraction analysis

Temperature dependent X-ray powder diffraction (TDXD) was carried out with a Bruker AXS D8 θ-θ powder diffractometer with parafocusing Bragg-Brentano geometry using CoK_α radiation (λ = 1.79028 Å, U = 34 kV, I = 30 mA). The sample was placed on a Pt/Rh ribbon in a MRI high-temperature oven-camera and VPSlits were used to fix the constant irradiated length (20 mm). Data were scanned with an ultrafast detector LynxEye over the angular range 3-38° (2θ) with a step size of 0.0196° (2θ) and a counting time of 58.6 s step^-1. The heating and cooling process was controlled by Eurotherm 2404. The sample was heated and cooled with rate 10 °C/min.

MicroXRD – microdiffraction system D8 Discover with 2D Vantech detector

Sample is placed on XYZ programmable stage with X,Y,Z translations in range 0-25mm. The maximum weight of the sample is 2 kg, height 50mm. X-ray powder diffraction data from microspot were collected at room temperature with an D8 Discover microdiffraction system with parallel geometry using CoK_α radiation (λ = 1.7903 Å, U = 35 kV, I = 40 mA). Two images (Debye-Scherrer frames) were collected in θ-θ geometry for 2θ = 26°, 56° with 2D detector Vantech and counting time of 30min per image. Debye-Scherrer frames were converted into a standard 1D powder pattern in the software package Bruker EVA 4.0.

WD-XRF analysis

An ARL 9400 XP sequential WD-XRF spectrometer was used to perform XRF analysis. It is equipped with a Rh anode end-window X-ray tube type 4GN fitted with 50 μm Be window. All peak intensity data were collected by software WinXRF in vacuum. The generator settings-collimator-crystal-detector combinations were optimised for all 82 measured elements with analysis time of 6s per element. The obtained data were evaluated by standardless software Uniquant 4. The analyzed powders were pressed into pellets about 5mm thick and diameter of 40 mm without any binding agent (or with Dentakryl as binding agent if F,O,N,C,B elements must be measured or sample does not stick together by pressing) and covered with 4 μm supporting polypropylene (PP) film. The time of measurement was about 15 min.

An Axios sequential WD-XRF spectrometer was used to perform XRF analysis. It is equipped with a Rh anode end-window X-ray tube type 4GN fitted with 75 μm Be window. All peak intensity data were collected by software SuperQ 5.0 in vacuum. The generator settings-collimator-crystal-detector combinations were optimized for collecting 11 scans for all 83 measured elements, for a lot of elements are more than one X-ray line available. The obtained data were evaluated by standardless software Omnian. The analysed powders were pressed into pellets about 5mm thick and diameter of 40 mm without any binding agent (or with Dentakryl as binding agent if F,O,N,C,B elements must be measured or sample does not stick together by pressing) and covered with 4 μm supporting polypropylene (PP) film. The time of measurement was about 20 min. Axios can be used to measure SMALL samples, but having one dimension at least 6mm.

MicroXRF analysis – spot analysis and mapping of elemental distribution

The ARL PERFORM’X is sequential WD-XRF spectrometer capable to perform standard XRF analysis (like ARL 9400XP) and furthermore spot and mapping analysis from 1.5mm spot. It is equipped with a Rh anode end-window X-ray tube type 4GN fitted with 50 μm Be window. All peak intensity data were collected by software Oxsas in vacuum. The generator settings-collimator-crystal-detector combinations were optimized for all 82 measured elements with analysis time of 6s per element. The obtained data were evaluated by standardless software Uniquant 5 integrated in Oxsas. The analyzed powders were pressed into pellets about 5mm thick and diameter of 40 mm without any binding agent (or with Dentakryl as binding agent if Fluorine is important) and covered with 4 μm supporting polypropylene (PP) film. The time of measurement was about 15 min.

Spot analysis can be performed from the narrow spot of 1.5mm selectable with on-board camera. The time of measurement can be adjusted respect to required detection limits and number of measured elements, 60 min/sample is necessary for Na-U elements to detect concentration above 0.05%.

X-ray mapping capability provides complete elemental visualization of complex non-homogenous surfaces, characterization of elemental impurities and inclusions.

LOI method - sample preparation for XRF

Method LOI (Loss On Ignition) can be used for accurate elemental concentration in the case when sample contains unmeasurable elements - C,H,N,O). About 1g of sample was weighted ,heated at proper temperature (temperature depends on sample chemistry – to get rid of H₂O - oven drying at 100-140°C, to burn organic components – heating at 200-250°C, to remove CO₂ and change carbonates in oxides –heating at 800°C for about 10min and to weight again. Than the product after heating is analysed and the weight difference (LOI) is used as known value in program Uniquant. Suitable temperature and time of heating can be found by TGA and DTA.