Ceramic Pigment

Ceramic Pigment is a range of colorants used in the manufacturing process of porcelain or glazed ceramic products. They can be applied directly to bisque fired clay bodies or applied to glazes and underglazes for brushing.

These pigments are produced by solid state reactions in the temperature range 800 – 1400C using metallic oxides or salts, generally in presence of mineralizers like halogenides of alkaline metals, borates, carbonates etc.

Origin

A ceramic pigment is a substance that can be colored. It can be natural or synthetic. The latter are produced industrially through appropriate chemical processes. These can be obtained through synthesis from oxides or carbonates and are usually more expensive than those produced by nature.

Pigments are the most important elements used in ceramic art, as they can be used to color tableware, sanitary ware, glazes and glass. They are very stable and do not decompose at high temperatures or react with or dissolve in the glazes.

They have been used since ancient times. They can give different colors depending on the crystal structures they possess. They are very popular in the production of glazed and enameled pottery.

Cobalt is one of the most famous pigments for ceramics and has been a very widely used substance in the history of art, as it imparts a great deal of colour to glazed and enameled pottery. It is also used in glass, paints and inks.

Another pigment that is very popular in the production of glazed and painted pottery is zinc oxide. It can be used to produce a variety of colors, such as blue, green, red and black.

Zinc oxide can be found in Ceramic Pigment many forms, such as rutile or zircon. These can be derived from various sources, such as iron and manganese.

These are all used to produce ceramic stains and they can be combined to give more complex colors, such as yellow, brown or black. These are very useful in the production of glazed and enameled pots, especially because they can be used in combination with other materials such as feldspar or kaolin.

They are extremely resistant and can withstand high temperature, which is required in the firing process. They are also very easy to work with and can be used in a variety of applications, such as on tiles, tableware or sanitary ware.

Titanium white was used as a ceramic pigment by the early modernists, but it had been used for yellow glazes in the ceramic arts before then. It was probably a fairly common pigment and it could be found in the shops of the marchands de couleur, or colour merchants, so that it would have been available to all the artists and craftsmen.

Color

Ceramic pigments are colorants used for the decoration of utilitarian and ornamental ware made of porcelain or glazed pottery. They are chemically inert and highly resistant to high temperatures, pressure and chemicals that may be present in the ceramic product or glaze.

They are available in many different colors and can be obtained by mixing individual pigments or through the use of several crystal structures. These colorants can also be formulated for specific applications such as glazes or underglazes.

Stains are usually granulated, but may be powdered or even fritted to help the colorants adhere to the clay better and make them more soluble in water. These stains can be added to dry glaze recipes, decorating slips and engobes, washes and even clay bodies for a unique look.

Most pigments are a mixture of different metallic oxides and carbonates, although the amount and variety of these oxides is variable. The color varies with the amount of each individual component and can also be affected by the percentage of each component.

Blacks are generally produced by combining several metallic oxides to produce a dark color. The amount of each component is controlled to produce a wide range of colors.

Other stains are made by micro-encapsulating coloring agents to prevent them from melting and burning out in the firing process. These stains can be used to achieve difficult reds and yellows in glazes.

In glazes, body stains are typically more finely ground than glazing pigments. They are also more prone to a partial solubility due to particle size which can have a dramatic impact on the coloring power.

These stains are often more expensive than glaze pigments and are generally used to color only small portions of a glaze. However, they can be very useful when a larger amount of color is needed in a specific application.

The most important aspect of a colorant is its solubility in the glaze or body that it is added to. A number of factors affect its solubility including granulometric sizes, the morphology of the colored elements and the chemical composition of the glaze or body.

Chemical structure

Ceramic Pigment is a solid inorganic compound which has a color and is used as an additive to glazes or body glazes. They are widely used in the production of ceramic tiles, sanitary ware and tableware.

In a glaze, pigments can be mixed in concentrations of 1-10%. However, this should be done with care because some pigments may react with materials Ceramic Pigment in the glaze. This can cause undesirable colors and effects.

There are a number of different compounds that can be used as ceramic pigments. They include idiochromatic compounds, allochromatic compounds and composite compounds.

For example, green uvarovite is an idiochromatic compound that is often used as a ceramic pigment. Similarly, zircon is an allochromatic pigment that can be used as a ceramic pigment.

Spinels are another type of chromate that can be used as ceramic pigments. These compounds can be synthesized by a chemical reaction, preferably using an acidic solvent such as aqueous solutions of a base metal.

Gallium-containing cobalt chromium spinels as ceramic pigments were prepared via a sol-gel process by adding Ga3+ to cobalt chromite with different substitutional levels (x = 0-2 with a step of 0.5). New CoCr2-xGaxO4 compositions exhibited phase purity, morphological properties, and color parameters. These pigments were characterized by XRD, SEM, and optical microscopy.

The color of these ceramic pigments was evaluated by the CIELab method in the 780-380 nm range. The L*, a*, and b* parameters were determined using a Perkin Elmer Lambda 950 spectrophotometer.

Several studies have been conducted on the preparation of gallium-containing cobalt chromium pigments. These compositions contain lutetium gallium garnet (CaxCrxLu3-2xGa5O12 up to x 0.2), chromium-gallium chromium spinels (CaxCrxGa3+xGa5O12 ranging from x 0.2), and perovskite-like purple inorganic pigments YGa1-xMnxO3 with x 0.10. In addition, a few studies have been conducted on the preparation of chromium-gallium chromate-rich chromio-phosphates such as cadmium chromite (CdCr3+) and chromio-chromium phosphate-rich chromio-calcium chromium phosphate-rich cadmium-gallium chromate (CaCr3+Ga3+xCa5O12) [24,27]. These pigments exhibit pink and red colors.

Production method

Ceramic pigments are inorganic powders obtained by a calcination process. This process produces a metal transition complex oxide that is thermally and chemically stable at high temperatures and maintains its identity when fired with glazes or ceramic bodies. This property of the pigment powder is very important for a wide variety of applications in the industry.

Some of the most common and well-known ceramic pigments include titanium oxide (TiO2), rutile white and brookite white. These pigments are used to color a wide variety of ceramic products, including porcelain, glass and stoneware. They are also used as a whitener and a coloring agent in glass.

A number of industrial wastes have been used in recent years to synthetize inorganic pigments for use on ceramic surfaces. These wastes can include titanium slag, electroplating sludge, municipal sewage ash, leather sludge and red mud.

The synthesis of these pigments requires a lot of energy, mainly for the rotary kilns that are used to produce the material. It is important to reduce this consumption and increase the efficiency of the synthesis process, as well as to lower the CO2 emissions associated with the production of these materials.

In the last few years there have been many new methods of reducing this consumption and increasing the efficiency of the pigment synthesis process. These include streamlined and efficient production processes that can reduce the amount of material required for each firing and the overall production costs of the material.

One of the most innovative methods that have been used is to encapsulate coloring oxides in a stable crystalline matrix that is then sintered or fired. This method allows the pigments to be reconstituted for a second firing and offers significant advantages over conventional methods, namely reduced production costs, improved quality and better stability of the pigment.

Another important development is the application of Life Cycle Assessment to the production of ceramic pigments. This approach aims to assess the environmental aspects of a production process by using an inventory of system inputs and outputs. LCA can be useful for all industrial sectors and can be a key tool for determining the most efficient and environmentally friendly way to produce the materials needed.