Materials and Corrosion

The Materials and Corrosion division addresses materials issues of the energy and process technology sectors. The use of chemistry and energy based pedominantly on renewable resources comes with extreme corrosive, thermal and mechanical stresses for the materials. This presents numerous challenges for the researchers at DFI to develop solutions for the energy transition.

The division consists of three teams that work in their own research fields but in close collaboration with each other:

 

Teams

High Temperature Materials

acoustic_emission

The demand for environmentally and resources-friendly processes as well as higher efficiency in thermal plants and machinery requires an increase of operating temperatures. However, processes conducted at high temperatures and often in complex atmospheres lead to increasing demands on the high temperature corrosion resistance of the materials used. The main research objectives of the "high temperature materials" team at DFI are material analysis and development in the field of aggressive, high temperature environments. Within this research field, we focus on the development of metallic and ceramic protective coatings and innovative material systems appropriate for extremely aggressive service conditions (e.g. chlorine, sulphur, bromine, vanadium, and carbon-rich environments) and operation temperatures up to 1800 °C. The team also works on conceptionalising, developing and producing novel alloying systems that withstand more aggressive conditions.

Main Research Fields

  • Diffusion Coatings: modification of the material surface by enrichment with protective elements, which prevent substrate corrosion during high temperature exposure.
    Methods: Pack cementation (in-pack, out-of-pack, slurry).
    Examples: protective coatings for a better oxidation resistance of materials at high temperature in environments rich in water vapour, typical for gasification and combustion atmospheres, slurry-based coatings for application on-site in plants or on machine parts.
  • Computational modelling of coatings and their lifetime: prediction of material behaviour during manufacturing as well as their lifetime during operation at high temperatures.
    Examples: modelling of layer growth and phase formation in the pack cementation process, modelling the influence of defects on the mechanical properties of thermal barrier coatings and oxide layers.

  • Functional high temperature coatings: combining high temperature protective coatings with additional properties such as self-cleaning, thermal insulation or improved aerodynamics.
    Examples: self-healing "shark skin" coatings for turbines, foam-like ceramic thermal barrier coatings.

  • Development of novel high temperature alloys: refractory metal alloys (Cr base, Mo base), titanium aluminides (TiAl), high temperature lightweight construction.
  • Protective coating concepts particularly for novel alloying systems:
    development, application and testing of suitable protective coating concepts.
  • "Minimally-invasive" high temperature corrosion protection: targeted changes in the chemical metal_dustingcomposition near the surface for improved corrosion behaviour at high temperatures.
    Examples: development of stable and protective alumina layers by using the halogen effect, Sn-modified surfaces for catalytic poisoning in metal dusting environments, controlling chlorine corrosion by selective doping of coatings.

Methods

  • Isothermal, cyclic and thermogravimetric experiments in various environments
  • Production of customized alloy compositions in the electric arc furnace

  • Heat treatment, microstructure development and optimization

  • Extensive analytics for investigating metallic phases, alloy compositions, oxide scales, and reaction products
  • Pack cementation methods, slurry coatings

Electrolytic Corrosion

EC Cell AFM

The research team focusses on the one hand on the mechanistic investigation of corrosion processes of new materials as well as in various technologies. On the other hand the focus is on corrosion protection by different types of coatings. In both fields light alloys (aluminium, magnesium, titanium as well as high-strength steels) play an important role. Furthermore actual topics in the field of cathodic protection are adressed. Most profiting industrial branches are automotive, aviation, medical technologies, the structural-facings sector and pipeline construction.In addition the research team is responsible for corrosion investigations, materials selection tasks and corrosion failure analysis in the frame of the DECHEMA Corrosion Center.

Main Research Fields

Specific investigation methods used are:

Electrochemical measurements

  • Stationary current density – potential curves
  • Electrochemical Impedance Spectroscopy (EIS)
  • Rotating discs/cylinders and ring-disc electrodes
  • Hydrogen permeation measurements
  • Scanning Kelvinprobe (SKP) / Scanning Kelvinprobe Force Microscopy (SKPFM)

Materials characterisation methods

Ultrasound finger

  • Scanning Electron Microscopy (SEM) with EDX
  • Electron Beam Microanalysis (EBMA) with WDX
  • X-ray Diffraction (XRD)
  • Scanning Force Microscopy (AFM, EC-AFM)
  • Tribometry / Tribocorrosion
  • Contact angle measurements
  • Adhesion testing

Spectroscopic/analytical methods

  • Confocal Raman microscopy
  • FT-IR spectroscopy
  • Particle size analysis and Zeta potential measurement
  • Instrumental chemical analysis (AAS, GC-MS, IC, ICP-MS)

Innovative Ceramics

NanoMatFutur_MEOs

New materials that are stable at high temperatures in aggressive atmospheres over long periods of time are needed for more efficient and low-emission gas turbines, e.g. for aircrafts. Multicomponent equiatomic oxides (MEO), or high entropy oxides (HEO), are a promising new class of materials for this purpose, as they combine stability at high temperatures and low thermal conductivity. In addition, other attractive characteristics, such as ionic conductivity, reversible lithium storage, catalytic activity, and dielectric and magnetic properties, make HEOs an interesting class of materials.

Research topics of the junior research group

  • Material development for efficient energy conversion, storage and catalysis
  • New high-entropy oxides for high-temperature applications that are stable over long periods in aggressive atmospheres
  • Synthesis development for reproducible preparation of new compounds
  • Characterization of thermodynamic, thermophysical, mechanical and corrosion properties

The NanoMatFutur junior research group "High Entropy Oxides" is integrated in the funding line "From Material to Innovation" of the German Federal Ministry of Education and Research (BMBF). Within the framework of this research project, high entropy oxides for use as thermal barrier coatings (TBCs) are systematically developed and characterized in three successive PhD projects. Basic properties, such as phase stability, coefficient of thermal expansion and thermal conductivity, as well as application-relevant properties, such as thermocyclic resistance, mechanical and corrosion properties, are being investigated.

Current Project: Multicomponent equiatomic oxides as high performance materials for future thermal barrier coatings

ICE_en

Doctoral projects of the junior research group "High Entropy Oxides"

 

BMBF logo en

Grant No. 03XP0301

Methods

  • CZ6_2134aSynthesis of novel compositions using wet-chemical methods and solid phase sintering
  • Characterization of phases and chemical compositions using X-ray diffraction (XRD) with Rietveld refinement and microscopy
  • Analysis of thermodynamic and thermophysical properties using dynamic differential calorimetry (DSC), differential thermal analysis (DTA), thermogravimetry (TG) and dilatometry
  • Thermodynamic modelling and calculations using CALPHAD

 

We also do research on your behalf

Are our research topics of interest for you, or can we assist you with our comprehensive analytical capacity?

DFI_CorrosionCenter_Website_454x200_EN

The DECHEMA Corrosion Center provides more information and contact options.

Head of Division

Assoc. Prof. Dr.-Ing. Mathias Galetz

Telephone +49 69 7564-397

 

Research Teams

High Temperature Materials

Assoc. Prof. Dr.-Ing. Mathias Galetz

Telephone +49 69 7564-397

Dr.-Ing. Anke Silvia Ulrich

Telephone +49 69 7564-606

Electrolytic Corrosion

Prof. Dr. Wolfram Fürbeth

Telephone +49 69 7564-398

Innovative Ceramics

Dr.-Ing. Maren Lepple

Telephone +49 69 7564-439

Upcoming courses

Zuse-Mitgliedschaft

Become a benefactor