Zirconia ceramic has a number of unique properties that make it excellently suited for various applications. However, when using Zirconium Oxide, it must be considered that different fields of application require different modifications of the Zirconia ceramic. These modifications are described at the bottom. Here are some of the most important properties of Zirconia ceramics in general:

High Fracture Toughness:

Zirconia ceramics exhibit exceptional fracture toughness, making them resistant to crack propagation and applicable for high loaded mechanical applications.

High Hardness:

Zirconia has a high hardness, which contributes to its wear resistance and makes it perfect material for cutting tools and wear-resistant components.

Thermal Stability:

Zirconia ceramics can withstand high temperatures without significant degradation, making them suitable for high-temperature applications like thermal barrier coatings and refractories.

Ionic Conductivity:

Due to its oxygen ion conductivity, Zirconium Oxide is an important component in fuel cells, enabling efficient energy generation with low emissions.

Low Thermal Conductivity:

Zirconia has low thermal conductivity and this makes it an effective thermal barrier material, protecting underlying structures from extreme heat.

Biocompatibility:

Zirconia is biocompatible, that is no immune response will be caused by its presence in the body. This property makes it first choice for dental and orthopedic implants.

Chemical Inertness:

Zirconia shows a very good chemical resistance to many substances, making it suitable for harsh chemical environments.

High Strength:

Zirconia ceramics have high mechanical strength, which contributes to their durability and reliability in various applications.

Aesthetic Properties:

Zirconia can be polished to a high finish and its tooth like appearance makes it ideal for dental restorations.

These properties make Zirconia ceramics a versatile and valuable material for many industries, from medical implants to high-temperature furnace applications. Dependant on the different varieties for stabilization current applications are for example:

Wear-Resistant Components:

Zirconia’s remarkable hardness and wear resistance make it ideal for components exposed to abrasive conditions, such as pump seals, valve seats, and bearings.

High-Temperature Applications:

Zirconia’s high-temperature resistance makes it suitable for refractory linings, thermal barrier coatings, and insulation material for furnaces and kilns.

Cutting Tools:

The combination of hardness and toughness in Zirconia ceramics makes them best suited for cutting tools, particularly for machining of hard materials.

Dental Implants and Prosthetics:

Zirconia is widely used in dental restorations, including crowns, bridges, and implants, due to its biocompatibility, strength, and aesthetic appearance.

Orthopedic Implants:

Zirconia ceramics are used in orthopedic implants, such as hip and knee replacements, as result of both their wear resistance and biocompatibility.

Solid Oxide Fuel Cells (SOFCs):

Zirconia ceramics are crucial components in solid oxide fuel cells, enabling efficient energy generation with low emissions.

Oxygen Sensors:

Zirconia is used in oxygen sensors for automotive and industrial applications due to its high ionic conductivity.

Watch Components:

Zirconia’s durability and aesthetic qualities make it suitable for high-end watch components.

Stabilization of Zirconia ceramics:

Y-TZP (Yttria Stabilized Zirconia)
Yttria Stabilized Zirconia (Y-TZP) is a ceramic characterized by the incorporation of Yttrium Oxide (Y2O3) as a stabilizer, generally in concentrations ranging from 2% to 3% by atomic fraction. Higher Yttrium Oxide contents of i.e. 8% are leading to a very good high oxygen ion conduction (applications i.e. lambda oxgen sensors, SOFCs – solid oxide fuel cells). Y-TZP exhibits a relatively low sintering temperature, typically within the range of 1,400°C to 1,550°C, which facilitates its processing. Y-TZP is recognized for its remarkable mechanical properties at room temperature, with a bending strength exceeding 1,000MPa up to 1,500MPa. The fracture toughness of Y-TZP is generally between 10 to 15MPa•m1/2. In addition, Y-TZP demonstrates superior wear resistance, corrosion resistance, and biocompatibility, rendering it one of the most promising advanced ceramic materials. The optimal mechanical performance is achieved with a stabilization concentration of approximately 3.5% Y2O3.

However, a significant limitation of Y-TZP is its susceptibility to low-temperature degradation, particularly within the range of 100°C to 400°C. Prolonged exposure to this temperature range can induce an isothermal phase transition from tetragonal (t) to monoclinic (m) phases, leading to a substantial reduction in mechanical properties – a phenomenon known as low-temperature aging. This aging effect is most pronounced between 200°C and 300°C, and is further accelerated in humid or aqueous environments.

Mg-PSZ (Magnesia Partially Stabilized Zirconia)
Magnesia Partially Stabilized Zirconia (Mg-PSZ) offers significant advantages over Y-TZP, particularly in terms of mechanical properties and creep resistance at elevated temperatures, making it suitable for structural applications below 800°C. However, the application of Mg-PSZ is hampered by two critical challenges: the solid solution temperature of MgO in the lattice of ZrO2 is approximately 1700°C, which requires a high sintering temperature of 1,700°C to 1,800°C. This imposes significant difficulties in material preparation and industrial scalability. In addition, at temperatures above 1,000°C, Mg-PSZ tends to have phase transformation of the tetragonal phase, which impairs its mechanical strength. Thats why the application of Mg-PSZ is limited.
Ce-TZP (Ceria Stabilized Zirconia)
Ceria Stabilized Zirconia (Ce-TZP) utilizes Cerium Oxide (CeO2) as a stabilizer, and has advantageous behaviour similar to Y2O3. CeO2 can form a solid solution with zirconia over a wide range of compositions. Notably, the initial phase transition temperature from tetragonal to monoclinic can be significantly lowered; for instance, the phase transition temperature for 3.5Y-TZP is around 560°C, while 20Ce-TZP can reduce this temperature to below 25°C. The critical grain size necessary for phase transformation in Ce-TZP is larger than that in Y-TZP, enabling the production of superior zirconia ceramics without the need for ultrafine powders.

In comparison to Y-TZP, Ce-TZP exhibits higher fracture toughness and enhanced resistance to hydrothermal aging at low temperatures. However, it is characterized by lower hardness and strength. Ce-TZP is sensitive to sintering conditions, as reducing atmospheres can cause grain coarsening, adversely affecting its mechanical properties. Research indicates that the maximum flexural strength of Ce-TZP can reach 800MPa when the atomic fraction of CeO2 is between 10% and 20%. The mechanical characteristics of Ce-TZP are closely tied to grain size, with larger grains promoting a more favorable phase transformation at crack tips, thereby enhancing toughness. Hence, the effective preparation of Ce-TZP ceramics hinges on the precise control of crystal grain growth to achieve optimal mechanical performance.

The technical specification of the material will be provided on request, as the precise determination depends on the particular application and is in accordance with our customers.