Tin Oxide
SnO2
Chemistry
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Links to Other Materials
- Zircopax -
- Zirconium Dioxide - Related
- Zircon - Related
- Cache
Miscellaneous
- Family: Opacifier
- Region: None
- Mined At: Unspecified
- Raw Mineral: No
- Generic: Yes
Notes
CAS 21651-19-4
Tin oxide is a white or off-white powder produced by oxidizing molten high grade tin metal. It is typically quite pure, some manufacturers have grades up to 99.999% purity.
Tin oxide has long been used to opacify glazes (make transparents opaque) at all temperatures. Hand decorated tin glazed earthenware of the 1700/1800s is the most famous use of tin in glazes (delftware-England, faience-France, maiolica-Italy). While many potters are keeping this tradition alive today most use zircon based opacifiers instead.
Thus any discussion about the use of tin oxide as an opacifier ends up comparing it with zircon products. Differences relate both to the different properties of the two and to the fact that twice as much zircon is required to produce the same level of opacity.
-Like zircon, tin melts at very high temperatures and thus does not go into solution in typical glaze melts.
-Zircon will stiffen the glaze melt more than tin.
-Zircon will likely produce a harder glaze surface.
-Zircon will reduce the thermal expansion of the glaze more than tin.
-The quality of the white color is different (tin tends to be more of a blue white, zircon a yellowish white).
-Tin is very expensive, this is likely the main reason for its much more limited use as an opacifier today.
-Zircon tends to have less of an effect on the development of metal oxide colors (e.g. tin reacts with chrome to make pink).
-Tin can react with titanium and rutile to variegate the glaze.
-If gloss is an issue, silica might have to be reduced to compensate for the silica introduced by a zirconium silicate opacifier being substituted for tin.
-While there are other products that produce varying degrees of opacity, none are as neutral and non-reactive as tin and zircon. Other opacifiers also tend to variegate the glaze.
-Copper red glazes require tin, with iron in oxidation tin makes a warmer shade of brown than zirconium does.
Properties
Glaze Opacifier - White
As little as 4-7% can produce brilliant white, although it is more typical to use 8-10% for full opacity. However, be aware that even tiny amounts of chrome in the kiln will volatilize and combine with the pink to produce pink shades.Surface Modifier - Variegation
Tin reacts with iron in fluid glazes to produce variegated surfaces. A good example is the Albany Slip 85, Tin 4, Lithium 11 glaze for cone 6.
Linked Articles
Stannous Chloride Toxicity
Overview by Edouard Bastarache
URLs
- The Mineral Cassiterite - http://mineral.galleries.com/minerals/oxides/cassiter/cassiter.htm
Suppliers
- Advance InOrganics
- Keeling & Walker Limited
- Pechiney Chemicals Division
Authors
- Tony Hansen (Owner)
XML
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<oxide symbol="SnO2" name="Tin Oxide, Stannic Oxide" status="" percent="100.000" tolerance=""/>
</oxides>
<references>
<reference name="seealso" reason=""/>
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<reference name="seealso" reason=""/>
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<supplier name="Keeling & Walker Limited" country="UK" url="http://www.keelingwalker.co.uk/" label=""/>
<supplier name="Pechiney Chemicals Division" country="US" url="http://www.pechiney-chemicals.com" label=""/>
</suppliers>
<notes>
<note>CAS 21651-19-4
Tin oxide is a white or off-white powder produced by oxidizing molten high grade tin metal. It is typically quite pure, some manufacturers have grades up to 99.999% purity.
Tin oxide has long been used to opacify glazes (make transparents opaque) at all temperatures. Hand decorated tin glazed earthenware of the 1700/1800s is the most famous use of tin in glazes (delftware-England, faience-France, maiolica-Italy). While many potters are keeping this tradition alive today most use zircon based opacifiers instead.
Thus any discussion about the use of tin oxide as an opacifier ends up comparing it with zircon products. Differences relate both to the different properties of the two and to the fact that twice as much zircon is required to produce the same level of opacity.
-Like zircon, tin melts at very high temperatures and thus does not go into solution in typical glaze melts.
-Zircon will stiffen the glaze melt more than tin.
-Zircon will likely produce a harder glaze surface.
-Zircon will reduce the thermal expansion of the glaze more than tin.
-The quality of the white color is different (tin tends to be more of a blue white, zircon a yellowish white).
-Tin is very expensive, this is likely the main reason for its much more limited use as an opacifier today.
-Zircon tends to have less of an effect on the development of metal oxide colors (e.g. tin reacts with chrome to make pink).
-Tin can react with titanium and rutile to variegate the glaze.
-If gloss is an issue, silica might have to be reduced to compensate for the silica introduced by a zirconium silicate opacifier being substituted for tin.
-While there are other products that produce varying degrees of opacity, none are as neutral and non-reactive as tin and zircon. Other opacifiers also tend to variegate the glaze.
-Copper red glazes require tin, with iron in oxidation tin makes a warmer shade of brown than zirconium does.
</note>
</notes>
</material>
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