ZYC and ZYZ Zirconium Oxide Composites

Overview: ZYZ and ZYC Zirconium Oxide Composites

Zirconium Oxide Boards Type ZYZ and ZYC are rigid, refractory structures composed of yttria stabilized zirconia fibres that are bonded with silica. This unique composition provides ZYZ insulation with the low thermal conductivity of zirconia fibres combined with the strength and machinability of a silica bonded material. ZYZ is evenly bonded, allowing it to be machined to tight tolerances and intricate shapes.

ZYBF fibre is the result of the Zircar Process which transforms an organic fibre into a ceramic one. The new fibre usually has a diameter of 6 to 10 μm and a serrated outer surface.

Manufacturing

All zirconia bulk fibres are made of nearly 100 % zirconia phase stabilized with 10 % yttria. The yttria stabilizes the tetragonal/cubic structure by preventing the monoclinic to tetragonal crystal transformation that occurs at 1,170 °C in pure un-stabilized or insufficiently stabilized zirconia. This undesirable transformation causes an 11 % volume change in the crystal unit cell size that can cause micro-cracking and reduced physical strength in the bulk solid.

Yttria stabilized zirconia is an electrical semiconductor at elevated temperatures. This conductivity arises from the different valences of ionic Zr4+ and Y3+. Electricity is conducted at elevated temperatures (700-800 °C) as oxygen ions are induced to flow through the stabilized zirconia structure. This phenomenon forms the basis of zirconia oxygen sensors.

Available ZYZ and ZYC Zirconium Oxide Composites


ZYC

Zirconium oxide cylinders type ZYC are firm, rigid, free standing refractory structures composed of yttria stabilized zirconia fibers evenly bonded with amorphous silica, allowing intricate shapes to be machined to tight tolerances. These products do not require organic binders and will produce no smoke or odor when heated.

ZYC cylinders possess low thermal conductivity and good resistance to thermal shock. ZYC is manufactured using a proprietary vacuum forming technique. It is dimensionally stable to 1,650 °C.

ZYC is resistant to attack by most molten metals and has a high resistance to reactions with other oxide materials.

Applications

  • Induction ovens
  • Electric ovens
  • Radiation shielding
  • High temperature insulation

Main Characteristics

  • Made of ZYBF fibre
  • Dimensionally stable to 1,650 °C
  • Very good hot tensile strength at 1,350 °C
  • Phase stabilized with 10 wt % yttria
  • High purity
  • No organic binders, no odor, no smoke
  • Low thermal conductivity
  • Excellent in corrosive, oxidizing and reducing atmospheres


ZYZ

ZYZ boards are rigid and refractory in nature. Their composition includes yttria-stabilised zirconia fibres and a silica binder. Like all products in this range, they have low thermal conductivity and can be machined into complex shapes to high tolerances. ZYZ is resistant to 1,400 °C and remains dimensionally stable up to 1,650 °C. The material is ideal for oven racks with loads twice its weight.

ZYZ boards are available at two different densities:

• ZYZ-3 is our lowest density product at 0.48 g/cm3 and benefits of an extremely low thermal conductivity.

• ZYZ-6 is medium density product at 0.96 g/cm3 and has a better mechanical strength than ZYZ-3 products.

Applications

  • Induction ovens
  • Electric ovens
  • Radiation shielding
  • High temperature insulation

Main Characteristics

  • Made of ZYBF fibre
  • Dimensionally stable to 1,650 °C
  • Very good hot tensile strength at 1,400 °C
  • Phase stabilized with 10 wt % yttria
  • High purity
  • No organic binders, no odor, no smoke
  • Low thermal conductivity

Technical Data of ZYZ and ZYC Zirconium Oxide Composites

Property

Unit

ZYC

ZYZ-3

ZYZ-6

Nominal Composition

ZrO2*

Wt. % 

85

85

85

Y2O3

10

10

10

SiO2

5

5

5

Colour

white

white

white

Bulk Density

g/cm3

0.48

0.48

0.96

Porosity

%

91

91

85

Thermal Properties

Max. Operating Temperature**

°C

1,650

1,650

1,650

Peak Temperature

°C

1,700

1,700

1,700

Melting Point

°C

2,200

2,200

2,200

Dilatometric Softening Temperature at 10 psi

°C

950

1,250

1,275

Thermal Conductivity

at 400 °C

Wm-1.K-1

0.08

0.08

0.16

at 800 °C

0.11

0.11

0.20

at 1,100 °C

0.14

0.14

0.23

at 1,400 °C

0.19

0.19

0.25

at 1,650 °C

0.23

0.23

0.27

Mechanical Properties

Flexural Strength 

MPa

0.55

0.28

1.74

Compressive Strength at 10 % compression

MPa

0.21

0.39

0.92

Thermal Expansion Coefficient (20 – 1,425 °C)

10-6.K-1

9

9

9

Linear Shrinkage (⊥ to thickness)

1 hr at 1,650 °C

%

2.5

1.7

1.6

24 hrs at 1,650 °C

4

2.3

2.6

Chemical Properties

Outgassing in Vacuum

Nil

Nil

Nil

*1-2 % weight hafnia (HfO2) occurs naturally with zirconia (ZrO2) and does not affect performance.
**Maximum use temperature is dependent of variables such as chemical environment and stresses; both thermal and mechanical.

Available ZYZ and ZYC Zirconium Oxide Composites

ZYC Zirconium Oxide Cylinder

Cylinder

Length

152.4 mm

304.8 mm

Inner and Outer Diameter

mm

from 25.4 x 50.8 mm

to 304.8 x 330.2 mm

inch

from 1″ x 2″

to 12″ x 13



ZYZ Zirconium Oxide Board

Dimension

Thickness

Board

304.8 x 304.8 mm

12.7 mm

19.0 mm

25.4 mm

38.1 mm

The dimensions depend on the article number.
Customized designs are available on request.



Physical variables included in this documentation are provided by way of indication only and do not, under any circumstances, constitute a contractual undertaking. Please contact our technical service if you require any additional information.

Zirconium Oxide Fibre (313.68k)

Technical datasheet: Zirconium Oxide Fibre


ZYZ and ZYC Zirconium Composite (224.63k)

ZYZ and ZYC Zirconium Composite


Composite Materials (363.96k)

Composite Materials