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Chrome / Chromium Carbide Coating (CrC-TDH)

Case Study Characterization of CrC Coating:


  • Low carbon steel


  • Steel strip (1”x1”x0.03”)

The Characterization Included the Following Methods:

  • SEM analysis of surface morphology
  • Metallographic examination
  • Microhardness testing
  • X-ray diffraction
  • High resolution SEM


  • The surface morphology of sample 1 is shown in Figure 1 and is characterized by spherical particles 7-8 µm in diameter
  • The microstructure in the cross-section of sample 1 in Figure 2 reveals a uniform coating thickness of 12 µm from both sides
  • No defects, such as porosity or contamination, are revealed within the coating or at the interface
  • The base material has a ferrite microstructure
  • Higher magnification photos of the microstructure appear in Figures 3 and 4
  • The micro-hardness indentations are seen in Figure 3. The micro-hardness level was found to be 3000-3500HV within the coating
  • High Resolution (HR) SEM was applied to examine the grain structure of the coating from the surface. Figures 5 and 6 confirm the nanostructure of the coating to be 20-30nm

Other Characteristics:

  • Phase content of the coating: Cr7C3 + Cr23C6
  • Micro-hardness of the layer: 2,000 – 2,200 HV
  • Micro-hardness of the base metal: 700 – 800 HV
  • Layer thickness: 0.0004” – 0.0006”
  • Very low coefficient of friction
  • No coarsening of the base metal