Plasma Alumina-Titania
A&A Coatings Plasma sprayed Alumina-Titania was developed to produce extremely wear resistant ceramic coatings which take excellent finishes. The coatings are heat resistant to about 540°C (1000°F), are resistant to most acids and alkalies, and have high dielectric strength.
Coatings of Alumina-Titania are very dense, and exhibit little evidence of through porosity when sprayed .25-.38mm (.010-.015″) thick. Bond strength is high, interparticle bond is high, and a very smooth finish can be obtained. The coatings resist heat to about 540°C (1000°F). They resist corrosion by dilute solutions of alkalies. They also resist wetting by common aqueous solutions. (Coatings of other ceramics absorb these liquids.)
Material Powder Characteristics
| Typical Composition: | Titanium Dioxide (13%) Aluminum Oxide (Balance) |
| Typical Size Range: | -270 mesh +15 microns-53 +15 microns |
| Melting Point: | 1840°C (3340°F) |
Physical Properties of Coating
| Texture, as sprayed, (microinches aa): | 250 – 350 |
| Finish, ground (microinches aa): | 10 – 20 |
| Finish, Lapped (microinches aa): | 2 – 4 |
| Macrohardness: | Rc63 |
| Cross-Sectional Hardness (DPH300): | 850 – 1000 |
| Dielectric Strength (Volts/Mil): | 300 |
| Density (g/cc): | 3.5 |
| Coating Weight (lb/ft2/.001″): | .018 |
Porosity
The porosity of all coatings of A&A Coatings Plasma sprayed Alumina-Titania is negligible. Sealing of coatings recommended for corrosive chemical environments. However, unsealed coatings were exposed to 2% salt solution for five weeks with no indication of penetration to the base material.
Thickness Limitation
A&A Coatings Plasma Sprayed Alumina-Titania was designed for use in thin coatings, not more than 0.5mm – 0.63mm (0.020″ – 0.025”) thick. If sprayed thicker, the probability of cracking and delamination will increase rapidly, as is the case of thick coatings of all fine powders.
Service Temperature
A&A Coatings Plasma Sprayed Alumina-Titania should not be used at temperatures above 540°C (1000°F). At temperatures higher than 540°C (1000°F), the coating undergoes a phase transformation resulting in embrittlement and cracking.
Surface Preparation
A&A Coatings Plasma Sprayed Alumina-Titania can be applied to most substrates which have been cleaned to remove surface oxides. This cleaning is accomplished with a light grit blast. Additionally, a “Bond coat” is required in most cases. Please contact us for substrate specific requirements
Finishing
A&A Coatings Plasma Sprayed Alumina–Titania can be ground to required finish size and polished to a 6 – 8 surface finish.
