Yttria Stabilized Zirconia, YSZ for Sale | Advanced Ceramic Materials

Yttria Stabilized Zirconia Structures

Yttria Stabilized Zirconia (YSZ) exhibits polymorphism, meaning it can exist in multiple crystal structures: monoclinic, tetragonal, and cubic. Each of these structures is stabilized under different conditions, primarily influenced by the yttria (Y2O3) content and temperature.

Asadikiya, Mohammad & Sabarou, Hooman & Chen, Ming & Zhong, Yu. (2016). Phase Diagram for Nano Yttria-Stabilized Zirconia System. RSC Advances. 6. 17438-17445. 10.1039/C5RA24330K.

Monoclinic Phase: In its pure form, zirconia (ZrO2) naturally exists in a monoclinic crystal structure at room temperature. This phase is characterized by a low symmetry and is less dense compared to the tetragonal and cubic phases. The addition of yttria disrupts this phase, stabilizing the zirconia in the tetragonal and cubic phases at lower temperatures. The monoclinic phase is seldom desired in YSZ applications due to its inferior mechanical properties and thermal stability.

Tetragonal Phase: The tetragonal phase of YSZ is stabilized at intermediate yttria concentrations (approximately 3 mol% to 8 mol% Y2O3) and is known for its significant toughness. This is due to the mechanism of transformation toughening, where stress-induced transformation from the tetragonal to monoclinic phase at the crack tip absorbs energy and slows crack propagation. The tetragonal phase is highly valued for applications requiring high strength and toughness.

Cubic Phase: At higher yttria concentrations (above 8 mol% Y2O3), the cubic phase becomes stable at all temperatures up to the melting point of the material. This phase exhibits a high degree of symmetry and is characterized by its high ionic conductivity, making it particularly useful for electrochemical applications such as electrolytes in solid oxide fuel cells (SOFCs). The cubic phase lacks the transformation toughening mechanism present in the tetragonal phase but offers superior thermal and chemical stability.

The ability to stabilize YSZ in these different phases through the controlled addition of yttria allows for the tailoring of material properties to suit specific applications, ranging from structural components requiring high toughness to electrochemical devices needing high ionic conductivity.

Yttria Stabilized Zirconia Specification

Physical Properties
Density	5.85 - 6.10 g/cc
Water Absorption	0.00%
Mechanical Properties
Hardness, Mohs	8
Modulus of Elasticity	200 - 210 GPa
Compressive Strength	2200 - 2500 MPa
Electrical Properties
Electrical Resistivity	>= 1e+12 ohm-cm
Dielectric Constant	29
Dielectric Strength	9.00 - 19.0 kV/mm
Dissipation Factor	0.001 - 0.002
Thermal Properties
Thermal Conductivity	2.20 - 2.50 W/m-K
Component Elements Properties
Y2O3	3 - 12 %
ZrO2	88 - 97 %

Yttria Stabilized Zirconia Applications

Yttria Stabilized Zirconia (YSZ) is renowned for its exceptional properties, including high strength, thermal stability, and resistance to wear and corrosion. These features make it a highly versatile material, leading to its application in various fields, from medical to industrial sectors. Below are expanded descriptions of its applications:

Dentistry: In the dental field, YSZ is widely used for the production of crowns and bridges due to its excellent biocompatibility, aesthetic qualities, and mechanical properties. Zirconia-based dental implants mimic the appearance of natural teeth while offering superior durability and resistance to fracture compared to other materials. Its ability to withstand the oral environment's corrosive effects without degrading makes it a preferred choice for long-term dental restorations.

Refractory Material: As a refractory material, YSZ excels due to its high melting point and low thermal conductivity, making it ideal for use in high-temperature applications such as kiln linings, furnace components, and crucibles. Its resistance to thermal shock allows it to maintain structural integrity under rapid temperature changes, extending the lifespan of refractory installations.

Production of Solid Oxide Fuel Cells (SOFCs): YSZ's high ionic conductivity at elevated temperatures makes it an excellent electrolyte material for SOFCs. These fuel cells convert chemical energy directly into electrical energy through oxidation processes at high temperatures, with YSZ enabling efficient oxygen ion transport across the electrolyte layer. This application is critical for developing cleaner, more efficient energy conversion technologies.

DIY Cement: In the realm of do-it-yourself (DIY) projects, YSZ is sometimes added to cement mixtures to enhance their mechanical properties and durability. The addition of YSZ can improve the wear resistance and longevity of cement-based projects, from countertops to outdoor fixtures, making it a valuable component for both aesthetic and structural enhancements.

Coating: YSZ coatings are applied in various industrial applications to protect surfaces from wear, corrosion, and high temperatures. These coatings are particularly valuable in aerospace and automotive industries, where they are used on components such as turbine blades to enhance their thermal barrier properties. YSZ coatings significantly extend the service life of parts exposed to extreme conditions by providing a durable layer that withstands harsh environments.

These applications of Yttria Stabilized Zirconia highlight its importance across multiple domains, leveraging its unique properties to improve the performance and durability of products and systems in demanding applications.

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FAQ

How Is YSZ Synthesized?

A: YSZ is typically synthesized using a process called solid-state reaction, which involves mixing zirconia and yttria powders in specific proportions and heating the mixture to a high temperature to promote chemical reaction and crystal growth. Other methods of synthesis, such as sol-gel and co-precipitation, are also used in some applications.

What Are the Main Applications of YSZ?

A: YSZ is used in a variety of industrial applications, including thermal barrier coatings, solid oxide fuel cells, oxygen sensors, refractory linings, and cutting tools. It is also used in biomedical applications, such as dental implants and artificial joints, due to its biocompatibility and high strength.

How Does the Level of Yttria Content Affect the Properties of YSZ?

The level of yttria content in YSZ can have a significant impact on its properties. Generally, increasing the yttria content leads to higher mechanical strength, lower thermal conductivity, and higher ionic conductivity. However, there is a trade-off between mechanical strength and ionic conductivity, as higher yttria contents tend to increase the grain size and reduce the number of grain boundaries, which can hinder the movement of oxygen ions in fuel cell applications.

What Is the Crystal Structure of YSZ?

A: YSZ has a crystal structure that varies with temperature and yttria content. At high temperatures, YSZ adopts a cubic crystal structure with a fluorite-type arrangement of oxygen ions. At lower temperatures, YSZ can transform into the tetragonal and monoclinic crystal structures, depending on the level of yttria content and the cooling rate.

Why Is Yttrium Oxide Used to Stabilize Zirconia?

Yttrium oxide is used because it effectively stabilizes the cubic phase of zirconia, preventing phase transitions that can lead to material degradation. This stabilization improves the material's mechanical strength and ionic conductivity.

How Does YSZ Perform in High-Temperature Environments?

YSZ excels in high-temperature environments due to its high melting point, thermal stability, and resistance to thermal shock, making it an ideal choice for refractory materials and thermal barrier coatings.

Is YSZ Biocompatible?

Yes, YSZ is biocompatible, making it suitable for medical applications such as dental implants and crowns, where it offers an aesthetically pleasing and durable solution.