Zirconia - Physical and Mechanical Property Comparison of the Different Types of Zirconias

 

 

Background

The fundamental properties of zirconia ceramics which are of interest to the engineer or designer are:

         High strength,

         High fracture toughness,

         High hardness,

         Wear resistance,

         Good frictional behaviour,

         Non-magnetic,

         Electrical insulation,

         Low thermal conductivity,

         Corrosion resistance in acids and alkalis,

         Modulus of elasticity similar to steel,

         Coefficient of thermal expansion similar to iron.

Types of Zirconias

There are many different types of zirconias. These have evolved as researchers and manufacturers sought to exploit the different properties of the various phases. Some of the phases are stable at high temperatures and need to be “frozen” in such that they can be used at room temperatures, while others exploit toughening mechanisms that are only found in these and few other materials. Some of these materials are listed below along with their typical abbreviations.

Table 1. The different types of zirconias.

Material

Abbrev.

Tetragonal Zirconia Polycrystals

TZP

Partially Stabilised Zirconia

PSZ

Fully Stabilised Zirconia

FSZ

Transformation Toughened Ceramics

TTC

Zirconia Toughened Alumina

ZTA

Transformation Toughened Zirconia

TTZ

Materials (oxides) added to stabilise or toughen the zirconia will also be noted as a prefix to the abbreviations listed in table 1. They will sometimes be used in conjunction with numbers which indicate the amount of the stabilising agent added. Typical examples include Y, Ce, Mg and A which correspond to yttria (Y2O3), ceria (CeO2), magnesia (MgO) and alumina (Al2O3) respectively. So a material denoted as 3Y-TZP would tetragonal zirconia polycrystal with an addition of 3mol% Y2O3 as a stabiliser.

Property Comparison

Table 2. lists properties for various grades of zirconia and has been compiled from a variety of sources. However, as with most ceramic materials properties are dependent on many factors such as starting powders and fabrication techniques. Most ceramic fabrication techniques have been applied to zirconias such as dry pressing, isostatic pressing, injection moulding, extrusion and tape casting. Addition of impurities during processing may also introduce flaws and degrade properties.

Table 2. Typical properties of various types of zirconia.

Property

Y-TZP

Ce-TZP

ZTA

Mg-PSZ

3Y20A

Density (g.cm-3)

6.05

6.15

4.15

5.75

5.51

Hardenss (HV30)

1350

900

1600

1020

1470

Bend Str. (MPa)

1000

350

500

800

2400

Compressive Str. (MPa)

2000

-

-

2000

-

Young’s Modulus (GPa)

205

215

380

205

260

Poisson’s Ratio

0.3

-

-

0.23

-

Fracture Toughness (MPa.m-1/2)

9.5

15-20

4-5

8-15

6

Thermal Exp. Co-Eff (x10-6 °C-1)

10

8

8

10

9.4

Thermal Conductivity (W.m-1.K-1)

2

2

23

1.8

3

 

 

Primary author: AZoM.com

 

Comments

  1. Kelly Loyd Kelly Loyd United States says:

    You speak about the different types of Zir. The Zirc Product by Nobel which uses a slurry of zirconia oxide upon an over sized die, is the same process as an In-Ceram? Also what properties are Procera restorations  made from: Ce-TZP, ZTA, Mg-PSZ or 3Y2OA?
    thx kel

  2. Smita Pandey Smita Pandey India says:

    what is modulus of elastisity of monoclinic zirconia

The opinions expressed here are the views of the writer and do not necessarily reflect the views and opinions of AZoM.com.

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