Optical emission spectrometry basics

An industry-standard analytical solution for metallurgical applications, optical emission spectrometry is well-established for the analysis of a large range of metals and alloys (from Ag to Zn). It is the ideal technology for process and quality control in metal production and is routinely applied directly in-the-field for foundry production. Optical emission spectrometry offers the possibility to analyze elemental composition of alloys down to the trace level with minimal impact on operating throughput, ensuring precise and reliable readings for up to 40 individual alloying elements in a single minute. It is also possible to investigate non-metallic inclusions using advanced optical emission spectrometry methods.

 

If you would like to learn more about using optical emission spectrometry in your application area, speak with one of our expert sales personnel.


Optical emission spectrometry fundamentals

What is optical emission spectrometry?

Optical emission spectrometry is a tried-and-tested analytical technique that is widely used to measure the elemental composition of metals and alloys. It is often referred to as spark OES as electrical sparks are used to ablate surface material from metal samples so that it can produce characteristic optical emissions. This introduces the first of two primary components in a typical OES analyzer: the electrical source.

 

An electrode is typically used in Optical emission spectrometry systems to generate a high voltage electrical discharge that causes surface material to heat to the point of ablation. Vaporized molecules then become excited by the argon plasma generated by the electrical arc, or sparks. This causes them to emit element-specific light in the ultraviolet and visible range – although multiple emission lines will be present, comprising a full spectrum of wavelengths determined by the elements present in the sample and their concentration. Making sense of this spectrum requires the second primary component: the optical system.

Light generated by the spark process is directed towards the optical system and is dispersed through a vacuum region within the spectrometer housing using a diffraction grating. These signals are acquired and converted into electrical signals using either CCD (charge-couple device) detectors or PMTs (photomultiplier tubes). CCD detectors typically obtain signals from wavelengths of interest directly from collected spectra, while PMTs transform photons into electrical signals and transform those into concentrations using calibration curves.

 

Spark Optical emission spectrometry analysis provides the fastest possible determination of all the elements in metals of interest with outstanding accuracy and precision. Among the many metals and alloys that spark OES is ideal for analyzing are: iron (Fe) and steel, aluminum (Al), copper (Cu), cobalt (Co), iron (Fe), magnesium (Mg), nickel (Ni), tin (Sn), titanium (Ti), zinc (Zn), and various precious metals. Alongside this exceptional precision, spark OES is also the most commonly used analytical technique in metallurgical facilities due to their ease-of-usability and maintenance. Sample preparation is quick and easy, typically performed using a standard grinding or milling machine, which can facilitate extremely high throughput (up to 400 samples a day).

 

Each of these integrated components is critical to making spark OES one of the highest reliability techniques in the analysis of metallic samples. It is routinely used to test finished and semi-finished goods from metals production (plates, sheets, tubes, etc.) and can be used in the field for interrogating melt samples from both primary and secondary metal production processes.


Optical emission spectrometry periodic table of elements

Understanding the elemental composition of your metals can help you adapt to new challenges unique to your market sector. We offer the products, services, and technologies to help you understand your metals.

Optical emission spectrometry videos


Optical emission spectrometry instruments

Spark optical emission spectrometry is a central technology to the metals and alloy manufacturing chain, providing crucial insights into the chemical content of solid metallic samples throughout the production cycle. With a choice of robust, high-precision Optical emission spectrometry spectrometers under the innovative ARL product line, our products can satisfy the unique demands of analytical roles from the foundry to the rolling mill.

 

Among our proprietary optical emission spectrometry product offerings are the ARL easySpark and ARL iSpark Plus Series. Each is adapted to the harsh working environments of iron and steel foundries and casting mills, providing the speed and accuracy required to meet your quality requirements and productivity objectives.

From routine elemental analysis to metals research and development, the Thermo Scientific ARL iSpark Plus Optical Emission Spectrometer provides the solution that primary metals producers, foundries, fabricators in the automotive, aviation and appliance industries, contract laboratories and metal recyclers look for. Adapted to the harshest environments, ARL iSpark Plus metals analyzers offer a high degree of functionality and features to achieve productivity and quality objectives.

The Thermo Scientific ARL easySpark Metal Analyzer is designed to meet the challenges and demands of small-to medium-sized plants and laboratories in the metal industry that require high-quality, yet cost-effective OES analysis to produce parts for automotive, aviation, aerospace and consumer products, among other industries.

Optical Emission Spectrometry Quick Guide and Periodic Table

Learn more about OES basic theory, technology, and applications with our Optical Emission Spectrometry Quick Guide and Periodic Table posters.

10 Reasons Steel Industry Uses the ARL iSpark Spectrometer with Spark-DAT Inclusion Analysis

Always present in steel, inclusions are often undesirable, because of deleterious effects on the properties of the steel and the running of the manufacturing process, and considerable costs that this entails for the steelworks. The effects can, for example, lead to failure of the end product, which is especially critical when steel is used in buildings, infrastructure, cars, airplanes, and many other objects where safety is paramount.