X-ray diffraction is a powerful laboratory technique often used in conjunction with microscopy and chemical analysis during materials characterization and failure investigations of construction materials.
Determination of bulk mineralogical composition of a concrete or mortar, including its aggregate and binder mineralogies; e.g.,
Quartz in sand, or
Calcite in sand or carbonated lime binder, or
Portlandite in binder;
Individual mineralogy and alteration products of aggregates at various size fractions, and binder phases;
Detection of dolomitic lime binder from brucite in the mortar;
Detection of lime (Portlandite), gypsum, or cement binders;
Detection of any potentially deleterious constituents, e.g., deleterious salts, or efflorescence deposits;
Detection of a mineral oxide-based pigmenting component; and,
Detection of components, which are difficult to detect by microscopical methods.
1st and 2nd Generations of D2 PHASER
For A Single Sample, or Up to 6 Samples
Rapid analyses of multiple samples by the groundbreaking Lynxeye detector
Rapid Analysis of Microgram Dust of Aggregates In 6-position Stage of 2nd Generation D2 Phaser
From Lapped Cross Section of A Concrete
In-situ Mineralogical Assessment of Aggregates Using Zero Background Sample Holder
A Powerhouse for Phase Identification
Before installation of Bruker's D2 Phasers, our X-ray diffraction studies used to be carried out in a floor-model Siemens D5000 Powder diffractometer (theta-2 theta goniometer) employing a long line focus Cu X-ray tube, divergent and anti-scatter slits fixed at 1 mm, a receiving slit (0.6 mm), diffracted and incident beam Soller slits (0.04 rad), a curved graphite diffracted beam monochromator, and a sealed proportional counter. Generator settings used are 45 kV and 30mA. The heart of D5000 is a goniometer precisely engineered for exact measuring results, yet flexible to accommodate a varietyof tasks. Its new, high-precision design features two independenlly controlled stepping motor drives. Representing the ultimate in flexibility, it operates in bolh horizontal and vertical modes (with the tube stand flanged to the goniometer housing foreesy change-over), and in either Thela-Two Theta or Theta-Theta geometry.
Sample is placed in a custom-made circular sample holder and excited with the copper radiation of 1.54 angstroms. Tests are run at 2-theta from 4° to 64° with a step of 0.02° and a dwell time of one second.
The resulting diffraction patterns are collected by DataScan 4 software of Materials Data, Inc. (MDI), analyzed by Jade software of MDI with ICDD PDF-4 (Minerals 2017) diffraction data. Phase identification, and quantitative analyses are carried out with MDI’s Search/Match, Easy Quant, and Rietveld modules, respectively.
BRUKER'S D2 PHASER
THE NEW MEMBER IN OUR XRD LAB
Rapid analyses of multiple samples by the groundbreaking Lynxeye detector
D2 Phaser, 2nd Gen, the world's best bench top XRD system has recently entered into our lab to accompany its big brother, Siemens D5000. Bruker's D2 Phaser delivers data quality at a speed that was once thought impossible from a bench top XRD system. The most powerful component is the state-of-the-art energy dispersive LYNXEYE detector capable of delivering data quality with virtual elimination of background from sample fluorescence and Bremsstrahlung scattering, with significantly improved peak to background boosting lower limits of detection and quantification, and clean diffraction line profile shapes without metal filter artifacts to improve peak fitting results and accuracy in quantitative phase analysis. The full-featured no-compromise DIFFRAC.SUITE software provides the easiest measurement method creation and most powerful and accurate analysis results. This portable all-in-one design needs no water cooling and no special power supply, making the D2 PHASER unmatched in its ability to bring powder XRD from the field to classroom to our laboratory.
INSTRUCTIONAL VIDEOS ON SIEMENS D5000 XRD FROM KS ANALYTICAL SYSTEMS WHO HAS INSTALLED OUR D5000 UNIT IN CMC
Resetting the coarse reference position on the Siemens D5000 goniometer
Siemens D5000 and D500 XRD Safety overview
XRD SAMPLE PREPARATION
A Sepor Mini Thor (Rocklab) tungsten carbide ring pulverizer is used to grind sample down to finer than 50-100 microns. Usually, a few drops of anhydrous alcohol are added to reduce decomposition of hydrous phases from the heat generated from grinding.
A McCrone micronizing mill is then used to further pulverize the sample down to finer than 44-micron grain size
Approximately 10 grams of sample is ground first in the Sepor pulverizer, from which about 8.0 grams of sample is selected, mixed with three binder tablets (total binder weight of 0.6 grams, for a fixed binder proportion of 7.5%), the mixture is then further ground in Sepor and McCrone pulverizer down to finer than 44 micron size.
Approximately 7.0 grams of thus-prepared binder-mixed pulverized sample is then weighed into an aluminum sample pan inserted in a stainless steel die to prepare the sample pellet.
A 25-ton Spex X-press is used to prepare a 32 mm-diameter pellet from the pulverized sample.
The same pellet is then used for XRD to determine the mineralogy and subsequently for XRF to determine the chemical composition.
MDI DATASCAN, JADE, SEARCH/MATCH, EASY QUANT, AND RIETVELD
State-of-the-art software for XRD data collection & interpretation
From data collection to interpretation, semi-quantitative estimation, and rigorous quantitative determination of phases, CMC's D 5000 XRD unit is integrated with the state-of-the-art software from MDI Materials Data with the following modules:
PDF-4+ 2018 contains 398,726 entries. It combines the world’s largest sources of inorganic diffraction data from crystals and powders into a single database. The result is a comprehensive collection of inorganic materials, produced in a standardized format that can be rapidly searched for unknown phase identification. Extensive data mining is facilitated with 125 display fields coupled with 72 searches.
PDF-4+ is designed to support automated quantitative analyses by providing key reference data required for these analyses. It also contains an array of tools that supplement conventional analyses, such as a full suite of data simulation programs enabling the analysis of neutron, electron, and synchrotron data, in addition to conventional X-ray data. PDF-4+ features digitized patterns, molecular graphics, and atomic coordinates. These features incorporated into PDF-4+ enhance the ability to do quantitative analysis using third party software by any of three methods: Rietveld Analysis, Reference Intensity Ratio (RIR) Method, or Total Pattern Analysis.
ICDD PDF4+ MINERALS
World’s largest database of inorganic diffraction data from crystals and powders
MATCH! SOFTWARE AND PDF4+ MINERALS AND/OR COD DATABASE FROM CRYSTAL IMPACT
A Powerful Phase Identification, Search-match, and Rietveld Refinement Program
Match! from www.crystalimpact.com is an easy-to-use software for phase identification from powder diffraction data. It compares the diffraction pattern of sample to a database containing reference patterns in order to identify the phases present. Additional knowledge about the sample e.g., known phases, elements or density can be applied easily.
In addition to this qualitative analysis, a quantitative analysis (using Rietveld refinement) can be performed as well.
APPLICATION OF XRD IN CONCRETE
Unsound constituents in aggregates
Cement hydration products
Bulk mineralogy of concrete
APPLICATION OF XRD IN MASONRY MORTAR
Mortar sand type
APPLICATION OF XRD IN HISTORIC MASONRY
Mortar From Fort Zachary Taylor, FL
Extensive Salt Contamination
Marine Shell as Sand
NaCl (41.6%) from Mixing Mortar with Sea Water
Equal Calcite and Aragonite (each 25-30%) from Carbonated Lime Matrix, and Sea Shells, respectively
Minor Quartz From Contaminant
APPLICATION OF XRD IN CEMENT
Mineralogical diversity in natural cement
Contrary to Portland cement that contains four common phases, alite, belite, aluminate, ferrite, and, the set-controlling phase, gypsum, natural cements (due to relatively low-temperature calcination) contain a large number of phases from various degrees of calcinations all of which can be identified by XRD:
(a) Calcined, air-slaked, and un-calcined products of calcite in limestone i.e. free lime, portlandite, and calcite, respectively;
(b) New minerals formed from calcination and lime-silica reactions i.e. periclase and larnite , respectively;
(c) Original phases from raw feed that has not been calcined or reacted, e.g., calcite, dolomite, and quartz;
(d) Added set-controlling phases, e.g., gypsum, anhydrite, bassanite.
APPLICATION OF XRD IN CEMENT MANUFACTURING
Mineralogical changes during successive heating of a dolomitic limestone raw feed to produce natural cement