About Zirconia Ceramics

Zirconia generally refers to zirconium dioxide with a chemical formula of ZrO2. It is the main oxide of zirconium. It is usually white, odorless and tasteless crystals, and is hardly soluble in water, hydrochloric acid and dilute sulfuric acid.
Unlike traditional ceramics, which tend to harden and become brittle, zirconia has high strength, wear resistance and flexibility, far surpassing most other technical ceramics. Zirconia is a very strong industrial ceramic with excellent properties in terms of hardness, fracture toughness and corrosion resistance.

Available Grades of Zirconia:

There are several grades of zirconia, the most common being yttria partially stabilized zirconia (Y-PSZ) and magnesium oxide partially stabilized zirconia (Mg-PSZ). Its unique resistance to crack growth and high thermal expansion make it an excellent material for joining ceramics and metals such as steel. Due to the unique properties of zirconia, it is sometimes referred to as “ceramic steel”.

Yttrium oxide partially stabilized zirconia (Y-PSZ) doped with yttrium oxide (Y2O3) as a stabilizer, it strengthens and stabilizes the internal grain structure and changes the material from a monoclinic phase to a tetragonal phase to enhance the strength of the material. It is a fine-grained material with the highest bending strength among all ceramic materials. It has very high impact resistance and abrasion resistance, while providing low thermal conductivity, usually making it a suitable material to replace metals. The addition of yttria (Yttria) enables the material to undergo phase transformation toughening, thereby achieving high toughness. As the material is under pressure, the crystal structure becomes energetically more conducive to the transition from the tetragonal phase to the monoclinic phase, resulting in a 3% – 5% increase in the highly localized volume. This increase in volume puts the crack in a compressed state, thereby reducing its ability to grow and propagate into more cracks. This characteristic explains the material’s low sensitivity to stress fatigue and high bending strength.

Although Y-PSZ is very suitable for demanding mechanical applications, it may not be suitable for very high temperature applications because it will undergo a crystal phase change: when exposed to a high temperature environment for a long time, the material will change from a strong tetragonal phase to a weaker one. In monoclinic phase. Likewise, it may not be suitable for warm and humid conditions, because when it is exposed to water vapor, its performance will decrease. Therefore, Y-PSZ is most suitable for operation under dry and moderate temperature conditions.

Magnesium Oxide Partially Stabilized Zirconia Using magnesium oxide (MgO) as a stabilizer for zirconia, the crystal structure after molding is cubic, which is more stable. Magnesium zirconium has better resistance to high temperature and humidity because it is not affected by phase migration. Even in a humid and high temperature environment where the mechanical properties of yttria partially stabilized zirconia begin to deteriorate, magnesium zirconium can maintain its strength.

Zirconia Toughened Alumina (ZTA) is a co-stabilized zirconia-based ceramic with an alumina matrix, which is reinforced by self-grown alumina substrate crystals. ZTA has better fracture toughness and thermal shock resistance than zirconia, while still having excellent mechanical strength and hardness properties.

Zirconia Ceramic Performance Parameters

  • The density is relatively high;
  • High bending strength and hardness;
  • Excellent fracture toughness;
  • Very resistant to wear and tear;
  • Resistant to acid and alkali corrosion;
  • Modulus of elasticity is similar to steel;

Mechanical Properties

Properties Unit Y-PSZ

Mg-PSZ

ZTA
Colour —— White Yellow White
Density g/cm³ 6.05 5.7 4.1~4.38
Hardness GPa 12.5 11.8 15
Compressive Strength MPa 2100 1750 2350
Flexural Strength MPa 850 900 700
Fracture Toughness MPa・m1/2 4~5 >7.0 3.5
Modulus of Elasticity GPa 200 200 310
Poissons Ratio —— 0.30 0.30 0.26

Thermal Properties

Properties Unit Y-PSZ

Mg-PSZ

ZTA
Maximum Use Temperature ℃(No load) 1000 1000 1500
Thermal Conductivity @ 25°C W/(m・K) 2 2.2 20
Thermal Expansion a at 20–400°C 1 x 10-6/°C 10 10.2 8
Specific Heat J/(kg・K) 460 400 720
Thermal Shock Resistance ℃(Put in water) 300 350 300

Electrical Properties

Properties Unit Y-PSZ

Mg-PSZ

ZTA
Dielectric Constant 1MHz 30 28 10.2
Dielectric Strength(6.35mm) ac-kV/mm 9.0 9.4 9.0
Dielectric Loss 1MHz 16 x 10-4 10 x 10-4 20 x 10-4
Volume Resistivity @ 25°C Ω・cm >1013 >1012 >1014
Volume Resistivity @ 500°C Ω・cm >103 >103 >104

*The values are typical material properties and may vary according to products configuration and manufacturing process. For more details, Please feel free to contact us.

What is the use of zirconia ceramics?

  • Wire forming/drawing dies
  • Insulating rings in thermal processes
  • Precision shafts and axles in high wear environments
  • Furnace process tubes
  • Wear resistance pads
  • Thermocouple protection tubes
  • Sandblasting nozzles
  • Refractory material
  • Extrusion dies
  • Bushings and caps
  • Kiln furniture crucible
  • Fiber optic ferrules and sleeves
  • Knives and blades
  • Fuel cell parts
  • Bearings & rollers
  • Welding nozzles & pins
  • Laser parts
  • Gas igniters
  • Electric insulator
  • Ceramic guiders
  • Oxygen sensors
  • Medical and surgical component
  • Mechanical seals
  • Pumps, pistons, and liners

Zirconia Machining & Grinding

Zirconia machining and grinding involves using various techniques to shape and finish zirconia, a very hard ceramic material. The same design features common to alumina ceramics, such as blind holes and threads, can be easily produced in zirconia. However, the grinding time required is approximately 50% longer than that of most alumina.

The post-mill surface finish of zirconia is significantly better than that of most aluminum oxides. Zirconia is denser, finer grained and stronger than alumina ceramics. These physical properties make zirconia an excellent material choice when strength and wear resistance are required.

Zirconia can be specified for applications requiring extremely tight dimensional tolerances and a high-quality surface finish. Grinding methods for zirconia involve standard machine equipment for all functions, such as surface grinding, cylindrical grinding, centerless grinding and belt grinding.

Our zirconia ceramics service

Great Ceramic is an expert in the production of technical ceramics. Since 2013, we have participated in and provided more than 3,000 precision ceramic products to hundreds of companies.

We can provide you with ceramic processing, ceramic raw materials, ceramic mold forming and other services. We are committed to only providing products and services that meet or exceed customer quality requirements.

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Great Ceramic is your Zirconia machining specialist for your precision ceramic prototyping & manufacturing needs; we are always happy to use our many years of advanced ceramics experience to provide advice on materials, design, and application. If you would like to buy zirconia plates, rods, tubes or custom machined components, please contact us and one of our experts will be happy to assist you.