Unlike other ceramic materials, zirconium oxide (ZrO2 –also known as zirconia) is a material with very high resistance to crack propagation. Zirconium oxide ceramics also have very high thermal expansion and are therefore often the material of choice for joining ceramic and steel.
Zirconium oxide Related Data
| Main component | 99%Al2O3 | S-SiC | ZrO2 | Si3N4 |
Physical
Property | Density | g/cm3 | 3.9 | 3.1 | 6 | 3.2 |
| Water Absorption | % | 0 | 0.1 | 0 | 0.1 |
| Sinter Temperature | °C | 1700 | 2200 | 1500 | 1800 |
Mechanical
Property | Rockwell Hardness | HV | 1700 | 2200 | 1300 | 1400 |
| Bend Strength | kgf/mm2 | 3500 | 4000 | 9000 | 7000 |
| Compression Intensity | Kgf/mm2 | 30000 | 20000 | 20000 | 23000 |
Thermal
Property | Maximum working
temperature | °C | 1500 | 1600 | 1300 | 1400 |
thermal expansion
coefficient
0-1000°C | /°C | 8.0*10-6 | 4.1*10-6(0-500°C) | 9.5*10-6 | 2.0*10-6(0-500°C) |
| 5.2*10-6(500-1000°C) | 4.0*10-6(500-1000°C) |
| Thermal Shock resistance | T(°C) | 200 | 250 | 300 | 400-500 |
| Thermal Conductivity | W/m.k(25°C | 31 | 100 | 3 | 25 |
| 300°C) | 16 | 100 | 3 | 25 |
Electrical
Property | Resisting rate of Volume | ◎.cm | | | | |
| 20°C | >1012 | 106-108 | >1010 | >1011 |
| 100°C | 1012-1013 | – | – | >1011 |
| 300°C | >1012 | – | – | >1011 |
Insulation Breakdown
Intensity | KV/mm | 18 | semiconductor | 9 | 17.7 |
| Dielectric Constant (1 MHz) | (E) | 10 | – | 29 | 7 |
| Dielectric Dissipation | (tg o) | 0.4*10-3 | – | – | – |
Basic properties of the material
| Properties | Brand of material |
| ZROX-Y | ZROX-Mg | ZROX-Ca | ZROX-Al |
| Composition | ZrO2 + Y2O3 | ZrO2 + MgO | ZrO2 + CaO | ZrO2 + Al2O3 |
| Density, g/sm3 | 6,02-6,08 | 5,6-5,8 | – | 4,0-4,4 |
| Open porosity, % | 0 | 0 | 0 | 0 |
| Hardness, GPa | 12-13 | 12-13 | – | 14-18 |
| Flexural strength, MPa | 1000-1400 | 500-900 | – | 400-1400 |
| Compressive strength, MPa | 2000-2500 | 1600-1800 | – | 2700-3000 |
| Thermal conductivity at 20-100°С, W/mК | 2,0-2,5 | 2,0-2,5 | – | 15-30 |
| Coefficient of linear thermal expansion at 20-1000°С, 10-6К-1 | 10-11 | 10-11 | – | 7,0-8,5 |
| Maximum operating temperature | 1000 (modification up to 2000) | 850 | – | 1500 |
Zirconia (ZrO2) has an exceptional set of properties:
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high hardness;
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excellent corrosion resistance;
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CLTE is close to steels (it is possible to assemble with metal parts);
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highest crack resistance among ceramic materials;
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low thermal conductivity;
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stability in a wide range of temperatures;
All these combinations make the material irreplaceable in the production of corrosion-resistant, wear-resistant and heat-resistant products for the variety of industries.
There are two main types of zirconia:
Dense zirconia (ZrO2)
This material is used for the manufacture of responsible and mechanically loaded products, i.e. mainly as engineering and structural ceramics. The material has excellent corrosion-resistant, wear-resistant and heat-resistant properties, in addition to resistance to thermal shock. If a thermal shock is present during operation, it is recommended to use refractory materials.
There are several modifications of dense zirconia (ZrO2) depending on the content of the main phase and stabilizers (ZROX-Y, ZROX-Mg, ZROX-Ca, ZROX-Al).
The main applications are:
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bearings for pumps and compressors;
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ceramic plungers;
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balls for ball bearings;
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grinding bodies;
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elements of valves and isolation valves;
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lining for protection from wear and corrosion;
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sorting wheels of various grinding machinery;
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lining for cyclones and calciners for cement plants;
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shafts of extruders (screws), nozzles of extruders (cores);
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crucibles, boats;
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furniture and lining of furnaces;
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substrates, plates;
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products for the metallurgical industry;
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covers and tubes of thermocouples, rods;
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products for the glass industry;
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products for dentistry;
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positional and welding pins for the automotive industry;
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substrates, plates;
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products for the paper and printing industry;
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drags, eyes, dies, thread guides;
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prostheses;
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details of oxygen sensors.
