Silicon Carbide (SiC) is an extremely hard and tough material often found in abrasive products, and boasts low expansion properties making it useful as kiln elements.
Granular SiC is a great way to produce blistered textures in glazes during oxidation firings, due to its carbon content acting to reduce metallic oxides such as iron and copper oxides.
Crater and Foam Glazes
Crater glazes (also referred to as foam glazes) are an effective way to add texture to ceramic pieces, and are extremely popular among both functional and art pottery makers. Their distinctive crater effect is created by mixing silicon carbide powder into the glaze recipe; when exposed to silica in the glaze mixture it reacts with it to produce gasses that create the characteristic “crater effect” seen on ceramic surfaces resembling volcanic or icy terrains on their surfaces.
This process is quick and simple, producing stunning results that will draw customers in. Many recipes for glaze can be found online.
Add silicon carbide to a glaze to create an eye-catching bubbly or frothy effect during firing and you have yourself an eye-catching ceramic surface! Silicon carbide glazes are used both decoratively and functionally and come in an assortment of colors that you can make use of as decoration.
Silicon carbide has numerous applications in glazes, including as an abrasive; wear resistant material; and refractory. It is also used as an effective reducing agent during oxidation firings of stoneware to help decrease metallic oxides such as iron and copper oxides, while celadon glazes often benefit from its use by producing reduction effects through lower melting point silica particles.
Oxidation Firings
If you want a bubbling, textural glaze, try creating a lava glaze at cone 6 with fine silicon carbide powder. This material releases vapors during firing to form bubbles and craters that create these types of glazes; excessive bubbles may break off leaving razor sharp surfaces; thus you should consider decreasing your silicon carbide usage in your recipe to prevent such instances from occurring.
Silicon carbide can also be used in oxidation firings to produce reduction effects. When combined with oxygen, carbon dioxide forms and can reduce metallic oxides like iron and copper oxides to create reduction effects that enhance glaze colors – particularly copper red glazes.
Silicon carbide can also be utilized in low-fire glazes to mitigate thermal stresses between ceramic and metal substrates that arise due to variations in coefficients of expansion between materials. By including an underglaze of silicon carbide, these stresses can be alleviated, prolonging product durability.
Kiln furniture can help enhance your ceramics in many different ways, and you should select the type that meets your specific needs. Heavy zirconia kiln shelves have historically been preferred due to their long heat endurance and resistance against abrasion; however, more advanced silicon carbide material has emerged due to its lower expansion and superior heat resistance properties.
Lava Glazes
Silicon carbide when added to glaze recipes creates the unique surface textures known as lava or crater glazes, often known as bubbling and textured surfaces known as “lava or crater glazes.” Crater glazes can be quite striking when made using coarser grit such as 400 to 800, providing striking surface textures suitable for ceramic art work. Although traditionally produced using cone 6 oxidation firings, these types of glazes can also be produced and used at any temperature and for any ceramic firings.
SiC powder reacts by taking in oxygen from other oxides in glaze and burning at high temperatures, producing carbon dioxide which bubbles up into craters in an electric kiln, with as little as 5-percent SiC addition usually providing this effect; more will cause severe blistering.
Silicon Carbide (SC) is an extremely durable non-oxide ceramic material with multiple uses. Often found as an ingredient in abrasives, wear-resistant mechanical parts, refractories, and wear resistant flooring due to its hardness, heat resistance, and low thermal expansion rates; SC can also be found used as a semiconductor material and for its conductivity properties in electronics applications.
Granular SiC is readily available in various sizes, though it must be ground down into micron-sized particles for ceramic use. Frit is also an option. Silicon carbide is one of few ceramic materials which will remain strong at very high temperatures – hence its popularity for use as kiln shelf insulation or high-heat applications such as thermal shock resistance.
Texture
Texture glazes add depth and dimension to ceramic art pieces through creativity and the right recipe. Most recipes that produce crater, foam and lava textures (commonly known as fat lava glazes) use silicon carbide powder; this material generates gases during firing that cause surface tension to increase and bubbles to form, collecting in various surface contours for an engaging visual texture.
SiC particles also act as a reductant during oxidation firings of stoneware, helping metallic oxides to deplete and facilitate color development in copper glazes, while providing reduction effects in celadons.
Because these reactions happen at a molten state, it is impossible to accurately predict their outcomes using only chemical knowledge alone. Because of this uncertainty, glaze chemists are constantly experimenting with various materials in order to find those which work well with specific purposes and firing conditions.
When choosing raw materials, it’s essential to understand their chemical composition, common name and mesh size. This information allows us to correctly identify mineral or powder products in ceramic supplier catalogs and packaging; any mis-identification could lead to sending the incorrect product directly to a potter’s studio or adding too much glaze recipe ingredients at once. The graph below compares Loss on Ignition for six commonly used raw materials during 1700F melting; this serves as a reminder that some materials become gassier faster, leading to blisters, pinholes or crawling at lower temperatures than others – this serves as an illustration that some materials become gassier sooner, leading to problems like blisters pinholes or crawling at other temperatures.