Surface Technology
Environmental Corrosion and Hydrogen

Main activity

Essential competences include the evaluation of the influence of specific media acting on the surface with regard to the stressability of materials and service properties of components. The range of services includes the performance of standardized tests and individual corrosion tests adapted to the respective application.

Environmentally induced cracking is defined as a superimposed mechanical-corrosive complex stress, which requires a holistic consideration and testing of the respective corrosion system. In the development and implementation of new individual testing methods, the test-accompanying application of electrochemical measuring methods is also possible on customer request.

The focal points include:

  • Vibration crack corrosion
  • stress corrosion cracking
    • – anodic stress corrosion cracking
    • – cathodic/hydrogen-induced stress corrosion cracking (production-related/operational)
  • Creep rupture testing

The applied investigation methods are e.g.:

  • Load increase tests (step load test according to DIN 50969 part 2 and part 3, ASTM F 1624-12) up to 100 kN in air and/or under the influence of a corrosive medium as well as under cathodic hydrogen loading
  • Slow strain rate tests (DIN EN ISO 7539-Part 7, ASTM G129-00) up to 100 kN in air or under the influence of a corrosive medium as well as under cathodic hydrogen loading
  • Creep tests up to 100 kN in air or under the influence of a corrosive medium as well as under cathodic hydrogen loading (e.g. 4-point bending)
  • Vibration crack corrosion tests according to individual load curve up to 100 kN and 100 Hz under the influence of a corrosive medium
  • Vibration crack corrosion tests at temperatures up to 300 °C in autoclaves
  • Fatigue tests using rotating bending under the influence of a corrosive medium (up to 200 °C)

Environmental simulation involves comparative testing of components against a defined corrosive environmental load. In addition to the standardized corrosion tests, we have a great deal of expertise in carrying out individually adapted investigations. Within the scope of individual corrosion tests, the corrosion system (materials, medium, environment) is first analyzed in cooperation with the customer and, based on this, a test method is developed that is individually tailored to the respective requirements.

An excerpt of the test and investigation methods that can be carried out is as follows:

  • Salt spray test (DIN EN ISO 9227, ASTM B117, ASTM B368, DIN EN 60068-2-11, DIN EN 60068-2-52)
  • Condensation water atmosphere (DIN EN ISO 6270-2, DIN 50017)
  • Harmful gas atmosphere, simulation of acid rain, the so-called “Kesternichtest”, test with sulfur dioxide under general humidity condensation (DIN EN ISO 6988, DIN 50018)
  • Climatic alternating stresses (VDA 233-102 (“VDA new”), DIN EN ISO 11997-1)
  • Tests according to company-specific test sheets (e.g. VW PV 1210, Nissan CCT 1, Renault ECC1, Volvo STD 423_0014, SWAAT, …)
  • Alternating immersion test (e.g. ASTM G47)
  • Immersion test (e.g. ASTM F483-09)
  • Evaluation of the degree of rusting according to DIN EN ISO 4628-3
  • Evaluation of the degree of blistering (DIN EN ISO 4628-2)
  • Cross-cut test (DIN EN ISO 2409)
  • Bunch test (DIN EN ISO 3651-2)

In addition to the possibility of holistic material testing in a complex environmental system, it is often also possible to perform supplementary material qualification using electrochemical tests. In addition to simple tests in beakers (up to 90 °C) in variable test solutions and different gassing conditions, tests can be carried out with directly heated specimens (up to 130 °C) or in situ using electrochemical measurement devices (e.g. electrochemical impedance spectroscopy during a fatigue test). Electrochemistry activities also include characterization of hydrogen breakthrough behavior (determination of diffusion coefficients, evaluation of trapping behavior).

The investigation methods applied are:

  • Potentiodynamic measurements (iE curve)
  • Permeation tests (DIN EN ISO 17081)
  • Impedance spectroscopy (EIS)
  • Measurement of the free corrosion potential (OCP)
  • Determination of breakdown potential and redox potential
  • Potentio- and galvanostatic measurements
  • Noise measurements
  • Spatially resolved electrochemical measurements using a scanning Kelvin probe (resolution 150 µm)