Optical emission spectroscopy
Spectroscopy (OEM) is used to determine the material composition, i.e. the elements of which the material at hand is composed in percentage terms, and a Determination of originality and dating of the component can be carried out.
Spectroscopy - physical basics
In principle, the term Spectroscopy A wide-ranging group of experimental methods that uses the spectral decomposition of emitted light from a light source. The light that is visible to us only represents a small range of the entire electromagnetic wave spectrum. This range covers a wavelength of approx. 400 to 700 nm, but radioactive gamma rays with a wavelength of 0.01 nm and radio waves with a wavelength of up to 1 km also belong to the electromagnetic wave spectrum.
This allows the age of the material, based on the elements and the manufacturing process, to be determined to within a decade at best. The method is based on the fact that steel has changed considerably in its elemental composition over the years. The reason for this is the different manufacturing processes. Over the years, purification processes have been developed that optimise the proportion of steel contaminants and, through the addition of alloying elements, the molten steel. These fine differences - we are talking about thousandths of a millimetre here - can be seen in the measured values of a spectroscopic examination (OES) and can be assigned to specific periods of time, so that it is possible to date components. For this purpose, a comparison with reference values is indispensable.
mobile & non-destructive
Spectroscopy, as a forensic / scientific method of authenticity testing (originality examination) of a vehicle, has been used in our engineering office since 1998. For 11 years now, we have been able to determine the material composition in the required quality / thousandths range, almost non-destructively and mobile. This means that we can carry out a corresponding investigation at any time, both nationally and internationally. To date, we have been able to expand our experience on the west and east coasts of North America, South America, Tokyo, Moscow, northern Italy, England, Belgium, the Netherlands, Switzerland and in Austria.
The collected measured values are compared with the manufacturer's specifications. Examples of this would be original construction plans or technical drawings of the examined vehicle type. The steel grade used for individual components is often noted in these, and their elemental composition can be researched using steel keys. It is important to note that the material composition of steel grades changes over time. However, this usually concerns the deoxidising agents, which can also give an indication of the age of the steel.
With this method, all common metallic materials can be analysed:
- Cast iron
- unalloyed steels
- Low alloy steels
- Low-alloy and high-alloy stainless steels
- Aluminium materials and aluminium alloys
- Copper materials and copper alloys
- Nickel-based alloys
- Titanium material
Devices & procedures
Our high-precision mobile spark emission spectrometer from Spectro is used for the precise qualitative and quantitative determination of chemical elements in metals, using the optical emission spectrum of atoms or atomic ions. It determines all elements used in the metal industry, including trace analysis of carbon, phosphorus, sulphur and nitrogen.
- Accredited methods:ASTM E 1086 2014 Standard Test Method for Analysis of Austenitic Stainless Steel by Spark Atomic Emission Spectrometry
- ASTM E 1999 2018 Standard Test Method for Analysis of Cast Iron by Spark Atomic Emission Spectrometry
- ASTM E 415 2017 Standard Test Method for Analysis of Carbon and Low-Alloy Steel by Spark Atomic Emission Spectrometry
- DIN EN 14726 2019-06 Aluminium and aluminium alloys - Determination of the chemical composition of aluminium and aluminium alloys by optical emission spectrometry with spark excitation
- ASTM E 2209 2013 Standard Test Method for Analysis of High Manganese Steel by Spark Atomic Emission Spectrometry
- DIN EN 15079 2015-07 Copper and copper alloys - Analysis by spark-excited optical emission spectrometry (F-OES)
XRF / XRF vs. OES
You would like XRF / XRF use? X-ray fluorescence is a method for analysing the elemental composition of materials. However, XRF has limitations in terms of the elements that can be measured... Optical emission spectroscopy (the spectroscopy we use and the only one that provides the information needed to be able to "date" the material) is a method to detect almost all types of elements, especially those that are crucial for our analysis and "dating" -> XRF can NOT detect these elements!
This is due to the fact that the detection limits of certain elements in XRF are too high, with the result that it is not possible to make a statement about the age of the steel. These are mainly elements with a low atomic number, such as carbon, phosphorus, sulphur and aluminium. These elements emit too weak a characteristic energy when X-ray radiation arrives. The reason for this is, among other things, energy loss due to scattering effects at the atom, the Compton effect and the photoelectric effect. The Compton and photo effects in particular depend on the atomic number of the atom and weaken the emitted energy as the atomic number of the atom decreases.
The information you get is not very helpful! The OEM is non-destructive and also portable, so there is absolutely no need for XRF, which then does not give you the information you need. So please be careful here.
We will also be happy to advise you by telephone on +49 (0) 2206 95 900.