SEM-EDS Analysis

What Is SEM-EDS Analysis?

SEM-EDS is a system in which an energy-dispersive X-ray spectrometer is added to a scanning electron microscope. When the electron beam excites the sample, each element emits characteristic X-rays at its own energy; the detector separates these energies to produce elemental information.

Purpose of SEM-EDS Analysis

The purpose is to determine not just how an imaged region looks but what it is made of. The source of a contaminant, residue or inclusion can often only be understood with this compositional information.

Which Products Is SEM-EDS Analysis Applied To?

Surface contamination and foreign-matter residues
Composition of coating layers
Compositional differences in weld and solder joints
Inclusions and segregation in metal
Corrosion products
Failure-source examinations on electronic boards

In Which Sectors Is SEM-EDS Analysis Used?

MetalPlasticsElectronicsAutomotiveConstructionDefenceAerospaceMedical Device

Standards Related to SEM-EDS Analysis

ISO 22309 (elemental analysis by EDS — quantitative approach)
ASTM E1508 (guide to quantitative analysis by EDS)
ASTM E2809 (forensic SEM/EDS examinations)

SEM-EDS Analysis Conditions

acceleration voltage: It is selected at a level that stimulates the characteristic lines of the elements sought.
Analiz modu: Point, line scan or elemental mapping
Analysis without standards: It gives semi-quantitative results; exact quantity requires certified standard
Hafif elementler: Sensitivity is limited for carbon and lower elements

Equipment for SEM-EDS Analysis

Scanning electron microscope
Energy-dispersive X-ray spectrometer (EDS)
Elemental mapping software
Sample preparation and coating infrastructure

Sample Requirements for SEM-EDS Analysis

The same preparation as SEM is required
Carbon coating is preferred; gold coating adds its own peak, complicating the analysis
The region to be analysed should be flat if possible — surface tilt affects the result
The sample must not be touched or cleaned in contamination examinations

Duration of SEM-EDS Analysis

A point analysis takes minutes. Elemental mapping can extend to hours depending on the area size.

SEM-EDS Analysis Procedure

1The sample is prepared for SEM and made conductive.
2The relevant region is imaged and analysis points are selected.
3Accelerating voltage is set per the elements sought.
4The X-ray spectrum is collected.
5Peaks are assigned to elements.
6A line scan or elemental map is produced if requested.
7Results are reported located on the image.

SEM-EDS Analysis Acceptance Criteria

Acceptability of the composition result is assessed against the compositional requirements in the material standard or customer specification.

Evaluation of Results

A standardless EDS result is semi-quantitative; the percentages are indicative and not a certified composition. If exact composition is needed, OES, ICP, or an EDS study calibrated with a certified standard is performed. Analysis depth is on the order of microns; the substrate signal can mix in for thin coatings.

SEM-EDS Analysis Report

Sample description and purpose of examination
Sample preparation and coating information
Instrument conditions and analysis mode
Images marking the analysis points
Spectrum and element list for each point
A statement that the result is semi-quantitative

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

Contract terms in failure analysis and supplier disputes
Particle and residue assessment requirements for medical devices

Pages Where This Method Is Used

Analytical Methods — What Does This Group of Methods Do?

The section below describes the field that the SEM-EDS 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

Related Tests

Frequently Asked Questions About SEM-EDS Analysis

Why are EDS results given as percentages but not exact?

In standardless analysis the instrument uses theoretical corrections. Surface roughness, tilt and coating distort these corrections. The result ranks composition correctly but is not taken as certified.

Can the source of a very small contaminant be found?

Generally yes. The contaminant's elemental fingerprint is matched against possible sources in the process (mould, tooling, plating bath, packaging).