Zirconia Boards and Cylinders, Type ZYFB

TYPE ZYFB

FEATURES

  • Rigid and Machinable
  • High Purity Zirconia Bonded
  • Two Densities Available 30 pcf & 60 pcf
  • Extreme High Temperature Stability
  • Fibers Stabilized with ~10 wt% Yttria
  • Low Thermal Conductivity
  • Can be Cemented with Zircar Zirconia Cement Type ZR-CEM
  • Can be Surface Hardened with Zircar Zirconia Rigidizer Type ZR-RIG
  • Pre-fired and Organic Free

Type ZYFB Boards, Discs and Cylinders are rigid, refractory structures composed of
yttria-stabilized zirconia fibers that do not undergo the usual phase transitions associated
with pure zirconia. Type ZYFB is ideally suited for thermal insulation applications under
conditions of ultra-high temperatures and in a variety of severe environments. ZYFB is
fired at a high temperature to impart good dimensional stability up to 1650°C and can be
used at higher temperatures where some additional sintering can be tolerated. It has good
hot strength up to 1400°C and can be used as a self supporting setter for loads equal to
twice its own weight up to this temperature.

ZYFB is available in two densities. ZYFB-3 has a bulk density of 30 pcf and possesses
extremely low thermal conductivity. ZYFB-6 has a bulk density of 60 pcf and is stronger
than ZYFB-3. Both are zirconia bonded and have exceptional resistance to oxidizing and
reducing atmospheres at high temperatures. Zirconia does, however, lose a small amount
of oxygen at very high temperatures in vacuum and inert or reducing atmospheres. This
reaction results in a color change from white to gray while most other properties remain essentially
unchanged and insulation effectiveness is not impaired.

ZYFB has exceptional resistance to most corrosive environments. It undergoes little attack
by molten alkali metal chlorides and carbonates at temperatures up to 700°C and withstands
aqueous solutions of alkali metal hydroxides at temperatures as high as 230°C.
ZYFB will also tolerate exposure to inorganic acids at their boiling point for short lengths of
time.

Shown below are SEM micrographs of ZYFB-3 (left) and ZYFB-6 board surfaces. Both
materials are made by vacuum forming zirconia fibers and sintering at a high temperature.
The fibers used in ZYFB-6 are shorter than those used in ZYFB-3 resulting in a higher density,
lower porosity and higher strength.

CHEMICAL COMPOSITION

Zircar Zirconia’s type ZYFB is nominally 90 wt% ZrO2 + HfO2 and 10 wt% Y2O3. 1 – 2 wt%
hafnia, HfO2, occurs naturally with zirconia, ZrO2, and does not affect performance. Only
the highest purity starting materials are used to make type ZYFB minimizing trace oxides.

Trace Oxide Typical Wt%
SiO2 0.12
TiO2 0.14
CaO 0.09
MgO 0.03
Fe2O3 0.04
Trace Oxide Typical Wt%
Al2O3 0.01
Na2O 0.01
SnO2 0.001
Cr2O3 0.0005
Ag2O 0.0005

MACHINING INFORMATION

Zirconia Type ZYFB has the consistency of soft chalk and can be cut or machined with a
very wide range of tooling. For manual cutting, place the ZYFB part on a smooth clean
surface and hold it in place with gentle finger pressure. When close tolerances are not required
and the amount of cutting is limited, small holes can be drilled by hand with a standard
high speed steel twist drill rotated between the fingers and boards can be cut with a
back saw. If closer tolerances are needed, holes can be drilled using a drill press and
boards can be cut with a radial arm saw. Table saws are not recommended without a carrier
board since the motion of the material over the saw bed will tend to abrade away the
material. For very close tolerances and large amounts of cutting, CNC machining with solid
carbide or carbide tipped tooling is recommended. While quite soft, Type ZYFB is very
abrasive and will cause rapid wear of high speed steel tooling which over time could result
in an out of tolerance condition. ZYFB boards can be held in place for CNC machining
with a vacuum hold down set up. Hot glue can also be used to fixture ZYFB but will generally
form a very strong bond that will pull away material from the machined part. Crystal
Bond ™ which burns away cleanly when heated has also been used to fixture ZYFB.

PROPERTIES & CHARACTERISTICS

ZYFB-3 ZYFB-6
Bulk Density, g/cc (pcf) 0.48 (30) 0.96 (60)
Porosity, % 92 84
Melting Point, °C (°F) 2590 (4694) 2590 (4694)
Flexural Strength, (Parallel to thickness) MPa (psi) 0.60 (85) 2.10 (300)
Compressive Strength, (Parallel to thickness) @ 10% Compression MPa (psi) 0.29 (42) 1.59 (230)
Outgassing in Vacuum Nil Nil
Dilatometric Softening Temperature °C (°F) at 10 psi 1180 (2156) 1240 (2264)
Thermal Expansion Coefficient (Perpendicular to Thickness) Room Temperature to 1180°C (2156°F) 10.7 X 10-6/C (6 X 10-6/F) 10.7 X 10-6/C (6 X 10-6/F)
Linear Shrinkage (Perpendicular to Thickness), %
1 hour at 1650°C (3002°F) 1.2 1.0
24 hours at 1650°C (3002°F) 2.8 1.7
Thermal Conductivity, (Parallel to thickness)
W/mK (BTU/hr ft2 °F/inch) at 400°C (752°F) 0.08 (0.6) 0.16 (1.2)
W/mK (BTU/hr ft2 °F/inch) at 800°C (1472°F) 0.11 (0.8) 0.19 (1.3)
W/mK (BTU/hr ft2 °F/inch) at 1100°C (2012°F) 0.14 (1.0) 0.22 (1.5)
W/mK (BTU/hr ft2 °F/inch) at 1400°C (2552°F) 0.19 (1.3) 0.25 (1.7)
W/mK (BTU/hr ft2 °F/inch) at 1650°C (3002°F) 0.24 (1.7) 0.27 (1.9)
 Specific Heat (BTU/lb°F)  0.18  0.18

APPLICATION INFORMATION

  • ZYFB is used as a high temperature, machinable hot face insulation in glass melting furnaces.
  • ZYFB is used as high temperature heat shielding. It can replace or reduce the number of conventional refractory metal shields needed in many vacuum furnace applications and is not restricted to non-oxidizing conditions.
  • ZYFB is used as insulation in directional solidification furnaces for jet turbine blades.
  • ZYFB Boards and Discs are excellent setter and fixturing materials. ZYFB’s ready machinability, dimensional stability and low heat capacity favor its use as a setter in both continuous and batch processes.
  • Zircar Zirconia Cement Type ZR-CEM can be used to bond ZYFB boards and shapes together to build up complex fixtures. Custom shapes for your particular application may be easily machined out of these products.
  • ZYFB can be treated with surface coatings to meet your needs. Please inquire.

ORDERING INFORMATION

Zircar Zirconia Insulation Type ZYFB is available in standard sized Boards and Discs,
which are listed on page 6 with their ordering item number. The stocked standard items
are in bold typeset. Please contact our Sales Department for Pricing and Availability.

  • To order one of our standard sized Boards or Discs specify the Quantity you wish to order, Product Type, Item #, and Size. For example: 12 each, ZYFB-6, Item # AB312, 12″ DIA. x 1.50″ TK
  • Our forming process and machining capabilities allow a wide variety of custom sized parts to be made (such as: boards, discs, cylinders and other shapes ). Please contact us with your special requirements and we’ll be happy to provide you with a quotation.
Standard Sizes ZYFB-3 Item No. ZYFB-6 Item No.
Board, 6″ X 6″ X 0.25″ TK AA00.01 AB00.01
Board, 6″ X 6″ X 0.50″ TK AA00.02 AB00.02
Board, 6″ X 6″ X 0.75″ TK AA00.03 AB00.03
Board, 6″ X 6″ X 1.00″ TK AA00.04 AB00.04
Board, 6″ X 6″ X 1.50″ TK AA00.05 AB00.05
Board, 12″ X 12″ X 0.50″ TK AA009 AB009
Board, 12″ X 12″ X 0.75″ TK AA010 AB010
Board, 12″ X 12″ X 1.00″ TK AA011 AB011
Board, 12″ X 12″ X 1.50″ TK AA012 AB012
Disc, 8″ DIA X 0.50″ TK AA301 AB301
Disc, 8″ DIA X 0.75″ TK AA302 AB302
Disc, 8″ DIA X 1.00″ TK AA303 AB303
Disc, 8″ DIA X 1.50″ TK AA304 AB304
Disc, 10″ DIA X 0.50″ TK AA305 AB305
Disc, 10″ DIA X 0.75″ TK AA306 AB306
Disc, 10″ DIA X 1.00″ TK AA307 AB307
Disc, 10″ DIA X 1.50″ TK AA308 AB308
Disc, 12″ DIA X 0.50″ TK AA309 AB309
Disc, 12″ DIA X 0.75″ TK AA310 AB310
Disc, 12″ DIA X 1.00″ TK AA311 AB311
Disc, 12″ DIA X 1.50″ TK AA312 AB312

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