XRD Analysis | EUROLAB

What Is XRD Analysis?

X-ray diffraction is based on X-rays directed at a crystalline material being diffracted at specific angles by regular atomic planes. The resulting diffraction pattern is a fingerprint specific to the crystalline phases in the material.

Purpose of XRD Analysis

The purpose is to determine PHASE composition, not elemental composition. Chemical analysis tells you the sample contains calcium and carbon; XRD tells you whether it is calcite or aragonite. This distinction directly affects material behaviour.

Which Products Is XRD Analysis Applied To?

Cement, clinker and construction binders
Ceramic and refractory materials
Mining and ore samples
Polymorph determination in pharmaceutical active ingredients
Metal coatings and thin films
Corrosion products and deposit analyses

In Which Sectors Is XRD Analysis Used?

MetalPlasticsElectronicsAutomotiveConstructionMiningPharmaceuticalsCeramics

Standards Related to XRD Analysis

ISO 9277 and related powder diffraction application standards
ASTM E3294 / E975-type diffraction methods
European Pharmacopoeia 2.9.33 (solid-state characterisation)

XRD Analysis Conditions

Radyasyon: Generally Cu Kα; Different anode can be selected according to the sample
Scan range: 2θ range to cover reflections of expected phases
Step and duration: Longer counting time is required for phase ratio determination
Phase identification: Comparison with reference diffraction database

Equipment for XRD Analysis

X-ray diffractometer
X-ray tube and monochromator
Sample spinner and automatic changer
Phase database and Rietveld analysis software

Sample Requirements for XRD Analysis

Fine, homogeneous grinding is required for powder samples
A few grams of powder is generally sufficient
The surface of a solid piece must be flat and clean
Amorphous materials do not give a diffraction pattern; the method is for crystalline phases
Phase search is faster if the expected composition of the sample is stated

Duration of XRD Analysis

A routine phase identification scan is generally under an hour. Quantitative phase analysis by Rietveld method requires both a longer measurement and a separate calculation stage.

XRD Analysis Procedure

1The sample is ground and placed in the sample holder without disturbing surface flatness.
2Scan parameters (range, step, time) are selected.
3The diffraction pattern is recorded.
4Phases are identified by comparing peaks against the reference database.
5Phase proportions are calculated by the Rietveld method if requested.
6Amorphous content, if present, is assessed with an internal standard.

XRD Analysis Acceptance Criteria

The acceptability of phase composition comes from the product standard or specification; e.g. clinker phase proportions in cement are defined in the relevant product standard.

Evaluation of Results

Phase identification relies on the measured peak positions and intensity ratios agreeing with the reference pattern. Since preferred orientation and particle size can distort intensity ratios, sample preparation directly determines result quality.

XRD Analysis Report

Sample description, receipt date and laboratory number
Method applied and reference standard, if any
Instrument and measurement conditions
Sample preparation steps
Measurement results and units
Measurement uncertainty (if requested)
A statement that the results relate only to the sample submitted for testing

Accreditation

EUROLAB holds internationally recognised accreditation obtained from accreditation bodies party to the IAF and ILAC multilateral recognition arrangements, under ISO/IEC 17025 for laboratory testing, ISO/IEC 17020 for inspection and surveillance, and ISO/IEC 17021-1 and ISO/IEC 17065 for system and product certification. This chain ensures the reports and certificates issued are accepted worldwide.

Whether this test can be offered within accredited scope depends on your product and the standard applied; since accreditation is method-based, the scope is confirmed in writing at the quotation stage.

Scope and authorisations

Related Regulations

Product standards under EU 305/2011 CPR for construction materials
Solid-state characterisation requirements in pharmaceutical registration dossiers

Pages Where This Method Is Used

Analytical Methods — What Does This Group of Methods Do?

The section below describes the field that the XRD Analysis test belongs to; the conditions and acceptance criteria of this particular test are given in the sections above. The scope specific to your product is confirmed in writing at the quotation stage.

Analytical method pages are pages about a MEASUREMENT TECHNIQUE rather than about a test. The difference matters: "salt spray testing" is a test and answers one question; "ICP-MS" is a technique and is used in dozens of different tests. Sometimes the user is looking not for the test but for the technique — because the method name is what appears in their specification.

This distinction becomes decisive in choosing a laboratory. When a customer asks for "heavy metal analysis", the real question is by which technique it will be done: XRF is fast and non-destructive but does not distinguish compounds; AAS is economical for a single element; ICP-OES screens multiple elements; ICP-MS sees trace levels. The same sample gives results with different detection limits and different uncertainties across the four techniques.

Method selection is made against three criteria. DETECTION LIMIT: is the concentration sought within the range the method can see? MATRIX COMPATIBILITY: is the sample matrix (plastic, food, soil, metal) one the method can handle, and is pre-treatment required? SPECIFICATION LINK: does the product standard or legislation mandate a particular method? The third often overrides the first two — the specification binds the method.

Method pages build a CHAIN. A technique is linked to the test pages where it is used, to the standards those tests rest on, to the legislation those standards are tied to and ultimately to market access regimes. The example chain in the source document works like this: XRF → metal analysis → RoHS compliance → heavy metal restriction → coating pages. Whichever link the user enters from, they reach the others.

Sample preparation is the invisible half of the result in this family and is a greater source of error than the technique itself. The digestion method, degree of grinding, extraction solvent and dilution ratio change the result markedly. The same sample on the same instrument gives a different result with different preparation; the definition of the method therefore covers preparation too.

Calibration and verification are the third determining component. An instrument is calibrated with certified reference material, the calibration curve is verified periodically and a control sample is run in each batch. Without these steps, a number produced is not traceable even if the instrument is working correctly.

Method groups in this field

Elemental analysis
ICP-OES, ICP-MS, AAS and XRF. They differ in detection limit, matrix tolerance and multi-element capacity.
Chromatography
GC, GC-MS, HPLC, LC-MS/MS and ion chromatography. It separates a mixture into its components and measures each separately.
Spectroscopy
FTIR, Raman, UV-Vis and optical emission. For material identity, functional group identification and alloy composition.
Thermal analysis
DSC, TGA, DMA and dilatometry. Transition temperatures, composition, decomposition and dimensional behaviour.
Microscopy and imaging
Optical microscopy, SEM-EDS, radiography and tomography. Structure, defects and elemental distribution.
Classical (wet) chemistry
Titration, gravimetry and colorimetry. Used as a reference method and in confirming instrumental results.

Commonly confused in this field

XRF is a screening tool; it sees elements and does not distinguish compounds. A decision on a restricted compound requires confirmation by wet chemistry.
The phrase "not detected" is not proof of absence; it is read together with the detection limit of the method.
The specification binds the method. A technically better method is not accepted if the specification calls for another.
Sample preparation is part of the result; a report that does not state the preparation is not reproducible.
Results obtained by different techniques cannot be compared directly; their detection limits and uncertainties differ.
A method page is not a test page; which method applies to which test comes from the product standard.

Which decisions these results support

Matching the method written in the specification to the laboratory's scope
Method selection according to detection limit and matrix compatibility
Confirming an instrumental result with a reference method
Eliminating deviations arising from sample preparation

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Frequently Asked Questions About XRD Analysis

What is the difference between XRD and XRF?

XRF tells you which elements are present; XRD tells you which compound and crystal structure those elements are in. The two are complementary.

Can an amorphous material be analysed?

Non-crystalline structures do not give sharp peaks; they form a broad hump. The amorphous fraction can be estimated with the internal standard method, but phase identification cannot be performed.