Open AccessComparison of Calibration Methods Used for Rietveld Quantitative Phase Analysis of Cement and Fly Ash
Author(s) -
Yongqi Wei,
Wu Yao,
C. Y. Wang
Publication year - 2019
Publication title -
iop conference series. materials science and engineering
Language(s) - English
Resource type - Journals
eISSN - 1757-899X
pISSN - 1757-8981
DOI - 10.1088/1757-899x/542/1/012069
Subject(s) - amorphous solid , fly ash , cement , materials science , calibration , rietveld refinement , phase (matter) , crystallite , clinker (cement) , powder diffraction , mineralogy , analytical chemistry (journal) , diffraction , chemistry , metallurgy , chromatography , composite material , crystallography , mathematics , optics , portland cement , statistics , physics , organic chemistry
The overestimated contents of crystalline phases in polycrystalline powder samples containing amorphous phases must be calibrated when they are done by using Rietveld phase analysis (RPA) for quantitative X-ray diffraction patterns of samples. It has been indicated that there are two methods for this calibration are verified with nice accuracy involving internal standard method (ISM) and G-factor method (GFM) that have been applied to the RPA of both cement and fly ash that contain amorphous mine phases. However, the consistency between these two methods in quantitative determination of phase contents in silicate materials has not yet been discussed. Therefore, the accuracy and consistency between them in quantifying standard mixtures, cement and fly ash were evaluated experimentally. Results indicate that (1) both ISM and GFM gained the very nice accuracy and consistency for the ternary standard mixture, and also the good consistency for cement clinker and fly ash; (2) relatively, GFM is suitable for systems with any content of amorphous phases while ISM is preferably suitable for the system with much more amorphous phase contents, e.g. more than 50% in weight (denoted as wt.% henceforth), by adding the suggested 10wt.% of Al2O3 as internal standard;(3) ISM is not suggested to be used for quantifying the system containing less than 10w.t % of amorphous phases, and the wisely higher addition of internal standard, such as 20%, should be employed when it applied to quantifying the system with amorphous phases from 10wt.% to 50 wt.% in content.