Combining XRD and XRF analysis in one Rietveld-like fitting

Abstract

X-ray diffraction (XRD) and X-ray fluorescence (XRF) are widely used analytical techniques for materials characterization; the information they provide can be considered complementary, as the former is mostly used to obtain crystallographic information and analyze phase content, whereas the latter is sensitive to elemental composition. Many researchers and technologists working in a variety of application fields already use them together in some sort of a “combined” approach, by separately performing XRD and XRF data collection and analysis on the same sample and then comparing the analytical results obtained to integrate and complement the respective analytical information. In this work, we propose a true combined approach to merge both XRD and XRF data acquisition and analysis. Custom analytical X-ray instrumentation has been developed to perform the simultaneous data acquisition, by using a single X-ray source and dedicated detectors to collect the diffracted and fluorescent X-ray photons from the same sample volume. Additionally, a combined XRD/XRF data analysis methodology has been implemented by extending Rietveld based code to incorporate the full pattern fitting of XRF spectra starting from the phases instead of a simple matrix elemental composition. We report two analytical examples from different application fields to better illustrate the capabilities of the proposed approach.

Influence of Milling Time on Structural and Microstructural Parameters of Ni50Ti50 Prepared by Mechanical Alloying Using Rietveld Analysis

“…The phase analysis was performed by using ICDD (PDF-2, 2012) files. Both structural and microstructural parameters were determined from the refinements of XRD patterns using MAUD program (version 2.55) based on the Rietveld method [31].…”

“…Using the Rietveld refinement and Warren-Averbach method [24,25] in the frame of MAUD software [31], a detailed analysis of XRD profiles can be performed leading to the determination of phase composition in addition to structural and microstructural parameters for each phase, such as lattice parameters ( , , ), the average crystallite size ⟨ ⟩, microstrain ⟨ 2 ⟩ 1/2 , and stacking fault probabilities (SFP).…”

“…where is the area of the peak, 1 is the peak intensity in the diffraction angle ( 0 + 2 ), and 0 is the completely symmetrical profile center [31].…”

“…The amount of the amorphous phase is obtained as the complement to one of the total amounts of crystalline phases [31]. The weight percentage of the amorphous phase in a sample can be given by the following relationship [35]:…”

Mineralogical investigations using XRD, XRF, and Raman spectroscopy in a combined approach

“…It has already been demonstrated that the combined application of XRD and XRF from both an experimental and analytical point of view is a powerful tool for material characterization. The extension of the combined approach also to RS for the phase identification and quantification in drill core samples is part of the objectives of the SOLSA project (G.A.…”