TITANIUM DIOXIDE - TITANIA ( TIO2)
| Property | Units (S.I.) | Minimum Value (S.I.) | Maximum Value (S.I.) |
| Atomic Volume (average) | m3/kmol | 0.0057 | 0.007 |
| Density | Mg/m3 | 3.97 | 4.05 |
| Bulk Modulus | GPa | 209.1 | 218.1 |
| Compressive Strength | MPa | 660 | 3675 |
| Hardness | MPa | 9330 | 10290 |
| Modulus of Rupture | MPa | 140 | 441.2 |
| Tensile Strength | MPa | 333.3 | 367.5 |
| Maximum Service Temperature | K | 1840 | 1910 |
| Melting Point | K | 2103 | 2123 |
| Thermal Conductivity | W/m.K | 4.8 | 11.8 |
| Thermal Expansion | 10-6/K | 8.4 | 11.8 |
| Dielectric Constant | 10 | 85 |
ZTA (Zirconia Toughened Alumina)
The main advantage of Zirconia Toughened Alumina (ZTA) is the additional strength and toughness over alumina with a lower cost than zirconia (YTZP, MSZ, CSZ).
The combination of aluminum oxide and 10-20% zirconium oxide provides a much higher strength, toughness, hardness and wear resistance than alumina alone.
The 20-30% increase in strength often provides the design criteria needed at a much lower cost than using zirconia.
A process called transformation toughening is the phenomenon that increases the fracture toughness of ZTA. When placed under stress, the zirconia particles change their crystal structure from a tetragonal to a monoclinic structure, causing a volume expansion that compresses the surrounding crack in the alumina matrix.
ZTA should be considered for any application where structural strength is needed that exceeds the standard alumina properties.
| Prime Features | |
| Higher strength than alumina | Lower cost than zirconia |
| High corrosion resistance | High erosion resistance |
| High fracture toughness | Capable of a very fine surface finish |
| Typical Applications | |
| Standoffs | Pump piston sleeves |
| Insulators | Instrument |
| Probe bodies | Sensor bulbs |
| Pump components | Valve seals |
| Bushings | Impellers |
| Fluid delivery system components | Analytical instrument columns |
| Application Limitations | |
| ZTA does provide a higher strength than alumina but the temperature limitation of 1500 C (2732 F) must be observed. Above this temperature the strength contribution of the zirconia is reduced. | Use in moist environments at temperatures above 250C also must be carefully considered as the zirconia is subject to low temperature degradation. |