Low Temperature Amorphous Al₂O₃ Coating

Al₂O₃ Coating on the polished Ti-6Al-4V disks, 16mm diameter, was carried out by HVLTS (High Voltage Low Temperature Sputtering)
The characterization of the coating was performed by the following methods:

Metallographic Examination
EDS analysis on the coated surface
HRSEM to reveal surface morphology.
Nano-hardness measurements.
Friction coefficient measurements.

The metallographic cross-section of the coated specimen is shown in Figures 1 and 2. The dense adherent coating with uniform thickness of 0.6µm was observed.
No discontinuities at the interface or within the coating were revealed.
EDS spectrum obtained from the surface revealed Al, O peaks and the substrate contribution of Ti, V peaks.
The surface morphology was revealed as featureless by High Resolution SEM examination at up to x200.000 magnification.
Nano- hardness measurements with the loading of L=5•10^-3N yielded hardness level of ~ 20 GPa. The friction experiments on Ti/Al₂O₃^- Ti pair are in processing.

The other physical properties of the coating are as follows:

Hydrophobic (contact angle 100-103^o)
Transparency band: γ from 0.3 to 8 µm.

Possible Applications:

Wear and Corrosion resistant coatings with solid lubricant properties
Insulation coatings

Fig 1: The metallographic cross-section of the coated sample - uniform thickness, adherent layer.

Fig 2: The same as in Fig 1 at higher magnification. The Al₂O₃coating thickness 0.6µm.

Fig 3: Spectrum EDS, obtained from the coated surface
Fig 4: The loading-unloading curves of nano-indenter. The measured hardness- 20 GPa L=5•10^-3N

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Last Updated on September 29th, 2005


Fig 1: The metallographic cross-section of the coated sample - uniform thickness, adherent layer.	Fig 2: The same as in Fig 1 at higher magnification. The Al₂O₃coating thickness 0.6µm.

Fig 3: Spectrum EDS, obtained from the coated surface	Fig 4: The loading-unloading curves of nano-indenter. The measured hardness- 20 GPa L=5•10^-3N