Zircon
Zirconium Silicate
Chemistry
|
Links to Other Materials
- Tin Oxide - Related
- Zirconium Dioxide - Related
- Cache
Miscellaneous
- Family: Opacifier
- Region: None
- Mined At: Unspecified
- Raw Mineral: No
- Generic: No
Notes
Zirconium silicate or zircon powder is very refractory and acts as an opacifier in glazes for this reason. It is thus most effective at low temperatures. It is a major source for the production of zirconium oxide ZrO2.
Zirconium silicate is extremely stable and will survive to very high temperatures in a glaze melt without dissolving (although small amounts do dissolve). Up to 20% may be required to opacify some transparent glazes, amounts beyond this reach saturation where crystallization begins to occur. The exact amount needed varies between different glaze types.
Zircon has a low expansion, so it will tend to reduce crazing. In addition, it will increase melt viscosity, which means that crawling and pinholing can occur in glazes having a lot of zircon. These problems can normally be solved by cooling slower and taking measures to get a better bond between raw glaze and body during application.
Tin oxide is an even more effective opacifier than zircon and it has various advantages and disadvantages. See Tin Oxide for more information.
It is beneficial to add zircon to transparent glazes in amounts up to 3% to improve hardness and reduce thermal expansion. This is because small amounts can be taken into solution and will therefore not opacify.
Because of its high thermal stability zircon is also employed in making various hi-tech porcelain bodies and materials.
Properties
Body Thermal Expansion -
A very low expansion material.Glaze Opacifier - White
Zirconium silicate is by far the most popular opacifier in glazes. It is available from many manufacturers. Opax, Ultrox, Zircopax and Superpax are examples of trade names of zirconium silicate and zirconium oxide products. The finer the milling of the material the better the opacity and the cleaner the color that will be produced.
Data
- Solubility: Insoluble in water, weakly soluble in acids
- Hardness (Moh): 7.5
- Density: 4.3-4.7
- Melting Point (MP): 2550C
- Specific Gravity: 4.56
- Specific Gravity: 4.56
- Melting Point (MP): 2550C
- Density: 4.3-4.7
- Hardness (Moh): 7.5
- Solubility: Insoluble in water, weakly soluble in acids
URLs
- The Mineral Zircon - http://mineral.galleries.com/minerals/silicate/zircon/zircon.htm
Suppliers
- Generic
- Helmut Kreutz Gmbh
- Johnson Matthey (Blythe Matthey)
- Mario Pilato Blat SA
- TAM
Authors
- Tony Hansen (Owner)
XML
<?xml version="1.0" encoding="UTF-8"?>
<material name="Zircon" descrip="Zirconium Silicate" generic="0" rawmineral="0" searchkey="" loi="0.00">
<families>
<family name="Opacifier"/>
</families>
<oxides>
<oxide symbol="SiO2" name="Silicon Dioxide, Silica" status="" percent="32.790" tolerance=""/>
<oxide symbol="ZrO2" name="Zirconium Dioxide" status="" percent="67.210" tolerance=""/>
</oxides>
<references>
<reference name="seealso" reason=""/>
<reference name="seealso" reason=""/>
</references>
<suppliers>
<supplier name="Generic" country="" url="" label=""/>
<supplier name="Helmut Kreutz Gmbh" country="DE" url="http://www.kreutz-mahlwerke.de/" label=""/>
<supplier name="Johnson Matthey (Blythe Matthey)" country="UK" url="http://www.geocities.com/Athens/Agora/3542/blythe_colours.html" label=""/>
<supplier name="Mario Pilato Blat SA" country="ES" url="" label=""/>
<supplier name="TAM" country="" url="" label=""/>
</suppliers>
<notes>
<note>Zirconium silicate or zircon powder is very refractory and acts as an opacifier in glazes for this reason. It is thus most effective at low temperatures. It is a major source for the production of zirconium oxide ZrO2.
Zirconium silicate is extremely stable and will survive to very high temperatures in a glaze melt without dissolving (although small amounts do dissolve). Up to 20% may be required to opacify some transparent glazes, amounts beyond this reach saturation where crystallization begins to occur. The exact amount needed varies between different glaze types.
Zircon has a low expansion, so it will tend to reduce crazing. In addition, it will increase melt viscosity, which means that crawling and pinholing can occur in glazes having a lot of zircon. These problems can normally be solved by cooling slower and taking measures to get a better bond between raw glaze and body during application.
Tin oxide is an even more effective opacifier than zircon and it has various advantages and disadvantages. See Tin Oxide for more information.
It is beneficial to add zircon to transparent glazes in amounts up to 3% to improve hardness and reduce thermal expansion. This is because small amounts can be taken into solution and will therefore not opacify.
Because of its high thermal stability zircon is also employed in making various hi-tech porcelain bodies and materials.</note>
</notes>
<testdata>
<testitem testname="2" value="Insoluble in water, weakly soluble in acids"/>
<testitem testname="2" value="7.5"/>
<testitem testname="2" value="4.3-4.7"/>
<testitem testname="2" value="2550C"/>
<testitem testname="2" value="4.56"/>
<testitem testname="2" value="4.56"/>
<testitem testname="2" value="2550C"/>
<testitem testname="2" value="4.3-4.7"/>
<testitem testname="2" value="7.5"/>
<testitem testname="2" value="Insoluble in water, weakly soluble in acids"/>
</testdata>
</material>
Much more information with complete interlinking to many related Copyright 2003 http://digitalfire.com, All Rights Reserved Please support http://ceramicmaterials.info to improve this library |  |
INSIGHT is ceramic chemistry |