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METHODS

Carrier Gas Hot Extraction Analyses (CGHE)

Carrier Gas Hot Extraction analysis (CGHE analysis) can be used to quantitatively determine carbon, sulphur, hydrogen, nitrogen, oxygen, and argon in metallic and non-metallic materials. The samples are melted under a specific gas atmosphere (carrier gas) for each element. Helium is used as the carrier gas for O, N and Ar analysis. In contrast, nitrogen is used as the carrier gas for the H measurement. In the C and S determination, carbon is oxidized to form CO2 and sulphur to form SO2. The quantitative determination is then carried out using selective infrared detection (O, C, S), via the change in thermal conductivity (H, N) or using a mass spectrometer (Ar).

According to which standards do we test?

Whenever possible, we carry out our testing services in accordance with or based on these international standards:

  • ASTM E1019: C, S, N, O in steel, iron, nickel/cobalt alloys
  • ASTM E1409: O, N in titanium and titanium alloys
  • ASTM E1447: H in titanium and titanium alloys
  • ASTM E1941: C in titanium and titanium alloys, tungsten, molybdenum
  • ASTM E2575: O in copper alloys
  • ISO 4491-4: O in steel powder
  • ISO 5842: Ar in components manufactured from metal powder,
  • ISO 14284: Sample preparation
  • Ironworks Alboratorium Manual: H in steel

Which devices do we use?

  • Leco CS 230 for carbon and sulphur analysis
  • Bruker G8 Galileo for oxygen, nitrogen and hydrogen analysis
  • Bruker G8 Galileo with ESD 100 mass spectrometer for argon analysis

What you should know about this method?

What needs to be considered with this method with regard to the samples?

CGHE is very suitable for metallic and non-metallic solids, chips or powders.
The material must be very clean (no contamination from cutting tools or other impurities).

A sample quantity of approx. 5 g is ideal. However, measurements are possible from a minimum quantity of 0.1 g.

What is the measuring range of this method?

The measuring range depends on the element to be determined:
C: 4 µg/g to 3.5 %
S: 4 µg/g to 0.4 %
O: 0.5 µg/g to 0.5 %
N: 0.5 µg/g to 0.5 %
H: 0.5 to 1000 µg/g
Ar: 10 ng/g to 1000 µg/g

The detection limits are:
C, S: 1 µg/g
O, N, H: 0.05 µg/g
Ar: 2 ng/g

What can be measured with the CGHE analysis?
  • Copper and copper alloys
  • Aluminum and aluminum alloys
  • Steel and iron alloys
  • Titanium and titanium alloys
  • Ar content in powder metallurgical steels
  • Hard metals
  • Ceramic materials
  • Further options on request
Are the analyses accredited?

Yes, the CGHE analyses offered are validated and accredited in accordance with ISO/IEC 17025.

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Who is your contact person?

Fabrizio Bigolin
Team Leader Analytics & Materials Testing
+41 32 644 2023