Yttria Stabilized Zirconia (YSZ)

As a professional, you may have learned that yttria-stabilized zirconia (YSZ) plays an indispensable role in modern engineering materials. Are you curious about YSZ? Reading this article will give you a comprehensive understanding of this material and help you make a more informed choice for your material application!

What Is Yttria Stabilized Zirconia (YSZ)

YSZ is made by adding a specific proportion of yttrium oxide to zirconium oxide. Its chemical composition mainly includes two key components, namely zirconium oxide (ZrO2) as the matrix and yttrium oxide (Y2O3) as the stabilizer. According to Depending on your application needs, the added content of yttrium oxide is usually between 3-8 mol%.

In the field of engineering, YSZ is known by many names, including：

Yttria Stabilized Zirconia

Y2O3 Stabilized ZrO2

Yttrium Stabilized Zirconium Oxide

Zirconium Oxide Yttria Stabilized

No matter which name is used, they all refer to the material YSZ.

YSZ Crystal Structure Characteristics

If you want to study the performance of YSZ in depth, then understanding its crystal structure first will be of great help to you in understanding the performance of YSZ. Pure zirconium oxide has a unique phase transition property. At room temperature, it presents a monoclinic phase structure. When the temperature gradually rises, it will undergo two phase transitions. This phase transition behavior may affect your application.

At room temperature -1170℃, zirconium oxide presents a monoclinic phase(Monoclinic)

1170-2370℃, zirconia presents tetragonal phase(Tetragonal)

At ＞2370℃, zirconia exhibits cubic phase(Cubic)

At this time, adding yttrium oxide can stabilize the mechanism. The principle is: when you introduce Y2O3 into the zirconia lattice, Y3+ ions will replace some Zr4+ ions, and at the same time, oxygen vacancies will be generated to maintain charge balance.

Adding yttrium oxide helps you achieve two important goals：

1.Stable preservation of high temperature phase structure at room temperature

2.Effectively prevent the generation of harmful phase change stress

YSZ Properties

YSZ has many superior properties. Whether you need high strength, high temperature resistance or chemical inertness, YSZ can meet your needs. When selecting the appropriate YSZ specification, we recommend that you carefully weigh these performance parameters against your specific application.

Mechanical Properties

YSZ has excellent mechanical properties. Its main mechanical properties are as follows：

Density：The density of YSZ is 6.02 g/cc. The relatively moderate density ensures the strength of the material without placing an excessive burden on your equipment.

Hardness：YSZ has a Mohs hardness of 8.5, it has very strong wear resistance and is very durable.

Bending Strength：YSZ has a flexural strength of up to 976 MPa (142,000 psi), allowing you to use it in extremely harsh mechanical environments.

Fracture Toughness：The fracture toughness of YSZ is very superior, which is mainly due to its unique phase transformation toughening mechanism.

Thermal Properties

YSZ is an ideal material for high temperature applications. Its thermal properties are as follows:

Melting Point：Over 2700℃, which means YSZ can be used in extreme high temperature environments.
Thermal Conductivity：The thermal conductivity at room temperature is 2.0-2.3 W/m·K, making it an excellent thermal insulation material.
Coefficient Of Thermal Expansion：10.7-11.2 × 10-6/℃ (RT-900℃)
Thermal Shock Resistance：YSZ has very superior thermal shock resistance and can withstand some rapid temperature changes.
Melting Point：Over 2700°C, making it ideal for extreme environments
Thermal Conductivity：2.0-2.3 W/m·K (room temperature)，This low thermal conductivity makes it an excellent thermal insulator
Coefficient Of Thermal Expansion：10.7-11.2 × 10^-6/°C (RT-900°C)，This moderate coefficient of thermal expansion helps reduce thermal stress
Thermal Shock Resistance：Excellent thermal shock resistance enables it to withstand rapid temperature changes

Chemical Properties

The chemical properties of YSZ in industry are mainly reflected in its excellent stability. It is corrosion-resistant and oxidation-resistant, not easily corroded by strong acids and alkalis, and can be kept stable in high-temperature oxidation environments. In addition to this, it is biocompatible, making it ideal for medical implants.

These performance characteristics make YSZ an ideal choice for your demanding applications. Whether you need high strength, high temperature resistance or chemical inertness, YSZ can meet your needs. When selecting the appropriate YSZ specification, it is recommended that you carefully weigh these performance parameters with your specific application requirements.

YSZ Selection Guide

When you choose YSZ, you need to understand the characteristics of different types and suitable application scenarios. According to the content of yttrium oxide (Y2O3), the YSZ market is mainly divided into three series.

3mol% YSZ

3mol% YSZ is the most popular partially stabilized zirconia product on the market. It is the first choice for some high-performance structural applications. Partially stabilized zirconia mainly presents a tetragonal phase structure at room temperature. Its main mechanical properties are as follows:

Bending Properties–1200 MPa
Fracture Toughness–10 MPa·m1/2
Wear-resistant and impact-resistant
If your application needs to withstand high stress and frequent mechanical shock, 3mol% YSZ is your ideal choice.

5mol% YSZ

5mol% YSZ has more balanced performance and processability. It has excellent rheological properties, outstanding molding properties and good sintering activity.

If your product requires precise processing details and complex processing shapes, the excellent processing performance of 5mol% YSZ can better help you achieve your design goals.

5mol% YSZ is very suitable for the following processes：

Strip casting process
Injection molding
Precision structural parts manufacturing

8mol% YSZ

8mol% YSZ achieves complete stabilization of zirconium oxide and is an ideal material for ion conductive applications. It exhibits a pure cubic phase structure at room temperature. Fully stabilized zirconia is characterized by excellent oxygen ion conductivity and outstanding high temperature stability.

In some applications requiring high ionic conductivity such as solid oxide fuel cells，it’s your ideal choice！

Application of YSZ

Industrial Applications

In the industrial field, YSZ has a wide range of applications and its performance is excellent: corrosion resistance, wear resistance, high hardness, low friction, and high toughness. You can find the advantages of this material in the following scenarios：

Pump Body Components
Cutting Tools
Valve System
Bearing Components
Wear-Resistant Coating

Medical Field

YSZ has good biocompatibility and mechanical properties, making it an ideal choice for implant materials

In dentistry, it is beautiful and durable all-ceramic crowns and implants
In orthopedic applications, it is a high-strength, durable joint prosthesis
In medical equipment, it is a reliable medical equipment component

Energy Sector

In energy applications, YSZ can be used as electrolyte for solid oxide fuel cells (SOFCs), thermal shielding coatings for gas turbines, and oxygen sensor materials for high temperature environments.

Aerospace

In aerospace, YSZ’s high-temperature performance and durability are very important. It can be made into a thermal protection system for engine hot parts, and it can also be seen in some high-temperature structural parts.

Conclusion

Yttria-stabilized zirconia has a wide range of uses in all walks of life. I hope you will gain something different by reading this article.

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