Microstructure and Properties of Atmospheric Plasma Sprayed (Al,Cr)₂O₃-TiO₂ Coatings from Blends

Area of Science:

• Materials Science
• Surface Engineering
• Ceramic Coatings

Background:

• Chromium oxide (Cr2O3) coatings are crucial for wear and corrosion resistance.
• Improving Cr2O3 coating properties using (Al,Cr)2O3 solid solutions is underexplored.
• Atmospheric plasma spraying (APS) is a common method for applying ceramic coatings.

Purpose of the Study:

• To investigate the processability and properties of Cr2O3-rich (Al,Cr)2O3 solid solution coatings.
• To evaluate the effect of TiO2 additions on coating performance.
• To compare these coatings with plain Cr2O3 and TiO2 coatings.

Main Methods:

• Atmospheric plasma spraying (APS) of (Al,Cr)2O3 feedstock powders.
• Microstructural analysis using Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS), and X-ray Diffraction (XRD).
• Mechanical testing (hardness, sliding wear, abrasion wear), corrosion, and electrical property measurements.

Main Results:

• The (Al,Cr)2O3 solid solution coatings exhibited improved processability and properties compared to plain Cr2O3 coatings.
• The addition of 2 wt.% TiO2 to the (Al,Cr)2O3 coating resulted in the most balanced performance.
• The optimized coating demonstrated high sliding wear resistance, abrasion wear resistance, and corrosion resistance.

Conclusions:

• Cr2O3-rich (Al,Cr)2O3 solid solutions are viable for APS coatings, offering property enhancements over pure Cr2O3.
• A minor addition of TiO2 (2 wt.%) significantly optimizes the wear and corrosion resistance of these coatings.
• The developed (Al,Cr)2O3-TiO2 coatings show promise for demanding surface protection applications.