Alternate Names: TiO2
|If this formula is not unified correctly please contact us.|
|DENS - Density (Specific Gravity)||4.26|
|HMOH - Hardness (Moh)||6.5|
|GSPT - Frit Softening Point||1830C|
TiO2 occurs in many silicates in nature, accounting for over 1% of the earth's crust. Thus it is manufactured using a variety of materials and processes.
Although titanium is the strongest white pigment known for many uses, in ceramics the whiteness (and opacity) it imparts to glazes is due to its tendency to crystallize during cooling. While titanium dioxide is used in glazes as an opacifier, it is not as effective and easy-to-use as tin oxide or zircon. It can be used as an additive to enliven (variegate, crystallize) the color and texture of glazes (rutile works in a similar manner). In moderate amounts it encourages strong melts, durable surfaces and rich visual textures.
Titanium is available both as raw and surface treated products. Non-pigmentary grades flow more freely in the dry state. Self opacified enamels are made by adding titanium during smelting to super saturation. Upon firing the enamel, the titanium crystallizes or precipitates to produce the opacity. Titania is also used in dry process enameling on cast iron appliances for its effect on acid resistance, color and texture. In glass, non-pigmentary titanium dioxide increases refractive index, intensifies color.
Glaze Crystallization - Crystallization
TiO2 dissolves into the melt during firing but normally re-crystallizes (or acts as a crystallization catalyst) during cooling (with rutile structure).
Glaze Matteness - Crystal Matte
Titanium can be used in glazes to produce a matte surface with increasing amounts of crystallization in amounts up to 25%. The effect works in most stoneware glazes and is better when the glaze is slow cooled.
Glaze Opacifier - White
Titanium is a crystalline mineral and encourages crystal development during cooling and freezing of the glaze melt. This generally produces opacity. However, titanium opacified glazes have a much different character than zircon or tin types. The latter produces a much more even and bright white coloration. When used as an opacifier the batch amount can range to 10% or more of the recipe.
Glaze Variegation - Titanium
Smaller amounts of titanium dioxide (i.e. 5%) added to colored or opacified recipes can variegate the surface and make it more interesting (e.g. it alters the shape of crystals, shade of colors).
The referred to surface is the outside of this large bowl. The base glaze (inside and out) is GA6-D Alberta Slip glaze fired at cone 6 on a buff stoneware. The thinness of the rutile needs to be controlled carefully, the only practical method to apply it is by spraying. The dramatical effect is a real testament to the variegating power of TiO2. An advantage of this technique is the source: Titanium dioxide instead of sourcing TiO2 from the often troublesome rutile.
The first is on GA6-A, the rest are on GA6-C (Alberta slip glazes). The last has been applied too thickly, the brown band is dry and blistered.
Out Bound Links
Rutile is the mineral name for natural crystals of titanium dioxide. It is a very hard (6-6.5 Moh) and heavy titanium mineral mined in Australia, Africa, Norway, Canada, and in Florida and NY in USA. ...
A mineral form on titanium dioxide.
A glaze additive that transforms an otherwise transparent glaze into an opaque one. Common opacifiers are tin oxide and zircon compounds. Opacifiers typically work by simply not dissolving into the melt, the white suspended particles thus reflect and scatter the light. Since they do not participate ...
Hazards of this material in the ceramic industry and process
A mineral form of titanium dioxide.
In Bound Links