Cadmium Yellow pigments are the most durable yellow, orange and red inorganic pigments commercially available. They have excellent chemical and heat stability and can be used in chemically aggressive environments and durable applications without color fade.
Cadmium zinc sulfide pigments were developed in response to the need for stable, lighter shades of cadmium yellow. Cadmium and zinc salts of the same anion are used to form the pigment with up to about 25% zinc content.
Origin and History
When first introduced, there were few stable, bright pigments in the yellow to red range, with stable orange and bright red being very rare. The cadmium yellow pigments eventually replaced compounds such as mercury sulfide (vermilion) with improved lightfastness.
Cadmum sulfide was suggested as a pigment in 1819 by Stromeyer, but it was not commercially available until 1840s due to scarcity of metal required for its production.
About half the consumption of cadmium, which is about 2,000 tons annually, is used to produce colored cadmium yellow pigments. The principal pigments are a family of yellow/orange/red cadmium sulfides and sulfoselenides as well as compounds with metals other than cadmium.
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ENAMEL SUPPLEMENTS – For Medium Temperature Enamels for Copper, Gold, Silver, Low Carbon Steel, Window Glass, Stained Glass, Bulls-eye and Spectrum Glass, Effetre (Moretti), 400 Series Stainless Steel and Pottery (A.K.A. Ceramics)
Enamel Powder for Metal
A series of vitreous enamel powder for metal which fuse slightly below 1200ºF. Mix with your favorite painting medium.
The enamel powder for metal will attach to glass at 1250 degrees F. They will gloss between 1300 and 1400 degrees. F. They may be taken up to 1450 degrees F. without loss of color. Firing times and temperatures are only guides. Your actual experience may indicate the firing may need to be more or less time and temperature.
You may want to vent your kiln as it heats up to allow for any painting medium fumes to escape kiln.
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Porcelain is made from baked clay
Porcelain itself is a ceramic material made from a type of white clay called kaolin, plus feldspars, quartz, steatite, and other rocks. To make regular porcelain, the whole mixture is baked at 1300-1400 degrees. Porcelain enamel is made when the porcelain is melted together with a stronger metal. This makes porcelain enamel cookware both light and strong, with low porosity, so it is naturally non-stick.
Pay attention to porcelain coatings
Oddly enough, though, some companies seem to want to coat their porcelain enamel cookware with chemical non-stick coatings or to use potentially toxic heavy metals and other compounds in glazes and in the enamel mixture. It pays to be picky about porcelain enamel cookware and to ask questions of manufacturers if it’s not clear what they use in their pots and pans.
Unlike somewhat terrifying porcelain dolls that could be extras in a Stephen King movie adaptation, porcelain enamel cookware is a fun addition to the kitchen. That’s because it is available in a variety of colors and does not fade or peel when used according to instructions. My advice, though, would be to avoid porcelain enamel in reddish tones and to favor those that are blue, given that some Le Creuset models with a red tone have tested positive for lead and cadmium. The Signature Enameled Cast Iron Braiser (in a blue shade like Marseille or Marine) from Le Creuset is a good option for one-pot meals (View on Amazon).
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Those skilled in the enameling art have tried for years to produce multi-colored articles wherein the colors are overlapping or adjacent to each other by vitreous enamel coating and in a single firing operation, however, the best that has been accomplished before my invention is the production of articles which may have more than one color thereon, provided that such colors do not touch each other, or provided they are not overlapping or superimposed one on the other. .As heretofore practiced, the manufacture of multi-colored vitreous enameled articles has been carried out by a separate firing for each color when it is necessary to overlap or superimpose one color upon another. In the manner in which the colors have been applied in the past, if separate firings are not accomplished, then the finished article will be full of blisters and enamel defects and if separate firings are accomplished the finish will not be uniform, but will be stepped up, each subsequent color coating being higher than the last. Also every time a color coat is fired the color fades out so that the first color applied has changed to an undesirable shade after repeated firings and the colors lose the desired brilliance. Furthermore, there is a limit to the number of firings to which the first coat applied can be subjected, so that the prior process has serious limitations.
In the enameling art, as heretofore practiced, coatings averaged about 1% ounces per square foot of surface, (dry weight); some coatings may run as low as 1 ounce or may go as high as 1% ounces per square foot. The vitreous enamel coating in the present practice should pass through a 40 to 60 mesh screen and in some cases, such as for silk screen work, they are put through a screen as fine as 200 mesh.
A further object of my invention is to produce a multi-colored vitreous enameled article, or one having different hues, shades and different color tone in one firing and having a substantially smooth surface thereon free from blisters and blowholes and other enamel defects.
Another object of my invention is to reproduce vitreous enameled products of various colors, which may be superimposed, one upon the other, by a printing press. My invention generally comprises a wet enameling process wherein I start with a. metal base upon which one ground coat and one or two cover coats of enamel have been applied, this ground coat being a vitreous enamel coating 16 fused to the metal base. I then may apply a fine “wash coating” of frit over the surface to which other colors are to be applied; this wash coating may contain some coloring matter or it may be white. In the wash coating just referred to and in subsequent frits and colors applied to the article thereafter, the particles in the frit and coloring matter may be, and preferably are, of a size to belong to the class of dispersoids; that is, the solution is such that the particles range in size from 0.1 micron to one milli-micron, a micron being equal to .00003937 inch.
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When used with pigment white, Porcelain Powder achieves the look, feel, and texture of a porcelain casting.
- Use Porcelain Powder with flesh-toned dyes to duplicate one of a kind dolls and sculptures
- Use to make a part heavier
- Mix ½ of the total amount of powder into both A and B sides before mixing A and B together
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Synthetic industrial inorganic pigments are created through chemical manufacturing rather than by grinding and washing clays or minerals taken directly from the earth. The techniques for producing these substances on an industrial scale were developed after 1800, making them the first modern synthetic pigments of importance to artists.
The amazing story of these early industrial inorganic pigments is well told in Philip Ball’s Bright Earth. Nearly all synthetic inorganic pigments were discovered or identified in the grand European flowering of inorganic chemistry that occurred in the century after 1750, when European industries sponsored intensive minerological and metallurgical research, and early chemists isolated and identified many new metallic elements — cadmium, cobalt, chromium, zinc, manganese, magnesium, and so on. (These new puzzle pieces helped John Dalton to formulate modern atomic theory in around 1805.) Several synthetic inorganic pigments still used today, including iron blue, cobalt green, cobalt blue and zinc oxide, were discovered prior to 1800.
These manufactured pigment compounds generally have excellent chemical purity and color consistency, and are cheaper to buy and available in larger quantities than natural inorganic pigments. With very few exceptions, all inorganic pigments used in artists’ paints today are industrially manufactured. (Some dry powder natural inorganic pigments are available from specialty pigment retailers.)
As an artist, your primary concern is to understand the generic attributes of these industrial inorganic pigments across different manufacturers and different pigment hues (chemical or crystal variations) — that is, to see paints as physical substances rather than as “colors”. For example, the violet and blue ultramarines are typically granulating and moderately transparent; the many lemon yellow to deep red cadmiums are all powdery, permanent, opaque and quite staining; compounds made with mercury are poisonous and fugitive. The historical information can also help you to understand the rapid expansion in artists’ pigments that occurred in Europe between the 18th and 19th centuries.
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Industrial Enamel is a modified single pack urethane enamel made in a high gloss finish. It can be applied to a variety of surfaces including Concrete, Timber and Metal Surfaces that have been primed with a suitable Metal Primer. EPiC Industrial Enamel is for general purpose use.
EPiC Industrial Enamel has excellent durability for a single pack coating. It has very good corrosive and abrasive properties. It is hard-wearing when cured and has excellent Gloss and Colour retention.
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Chrome oxide green, also known as chromium oxide, chromium oxide green, chromium sesquioxide or chromia, is one of four oxides of chromium. It is commonly called chrome green or chromium green when used as a pigment. Chromium oxide is a crystalline green powder, which has been classified as Pigment Green 17 and C.I. 77288 by the Colour Index System.
Its basic chemical composition is Cr2O3. Chrome green is not soluble in water, acids and alkalis. It can be used to refer to a mixture of chrome yellow (Lead Chromate) and Prussian blue (Ferrocyanate). Chrome Oxide Green is used in a wide variety of applications because of its excellent opacity, outdoor durability and heat fastness. Its hardness is also highly valued for surface finishing, where Chrome Oxide Greens are used as abrasive components. They are also used as a base oxide to produce several other metal oxide based pigments.
Chrome oxide green is used as raw material in the preparation of pigments for porcelain, ceramic glazes, plastics, cements, roofing tiles, linoleum, industrial coatings, frits, colored glass, stainless steel electrodes, paints, industrial coatings, inks and as catalyst in the chemical industry. In addition to these areas, it is also used in the production of aerospace super-alloys and refractory bricks for glass and fiberglass industry.
In order to meet the requirements from customers in different lines, we produce several grades of high quality and stable quality chrome oxide greens, they are refractory and technical grade, metallurgical grade, pigment grade, coating grade, construction grade.
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Most cadmium pigments are used in plastics. These pigments disperse well in most polymers to give good colouring and high opacity and tinting strength. The pigments are insoluble in organic solvents, have good resistance to alkalis and in most cases will remain colour fast for the life of the plastic. As a result, cadmium pigments have been used in a wide range of plastic products. Nowadays, their greatest application is in complex polymers which are processed at higher temperatures and require the unique durability and technical performance of a cadmium pigment. Their use is almost mandatory in many nylon, acrylonitrile butadiene styrene (ABS), polycarbonates, high density polyethylene, silicone resins and other modern thermoplastic polymers processed at high temperatures which preclude the use of organic pigments and also most alternative inorganic pigments in the range of hues provided by cadmium. Cadmium pigmented engineering polymers such as ABS are widely used in products which include telephones, gas pipes and fittings, electricity cables, beverage crates and motor vehicle radiator fans. Pigments are usually incorporated in plastics in proportions of 0.01 to 0.75 per cent by weight.
(b) Specialist and industrial paints
Bright cadmium yellows, oranges and reds are major pigments for artists’ colours where their permanence and opacity are the accepted standards against which other pigments are judged.
Cadmium yellows and reds can have service temperatures well above 300 C and are used in coatings for process chemical and steam pipes. They can also be incorporated in latex and acrylic coatings.
Cadmium pigments are usually incorporated in these paints in proportions of 10 to 15 per cent by weight.
(c) Ceramics and glasses
The unique abilities of highly stable cadmium pigments to withstand high processing and service temperatures make them the only choice in much of their colour range for glasses, ceramic glazes and vitreous and porcelain enamels. In transparent glasses the cadmium pigment particles are colloidally dispersed to produce the colours by selective absorption and scattering. The addition of 0.5 percent by weight of cadmium pigment produces bright transparent glasses with colour ranging from intense yellow through to ruby red depending upon the composition.
The bright colours of cadmium pigments are ideally suited to ceramics, vitreous enamels for glass and porcelain enamels for iron and steel domestic products.
(d) Miscellaneous uses
Cadmium pigments have a number of other minor uses in rubber, paper and inks although these are small in terms of cadmium consumption.
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The invention discloses a lead-free transparent frit for ceramic preparation.
The lead-free transparent frit for ceramic preparation is made of, by weight, 60 parts of SiO2, 20 parts of Al2O3, 5 parts of MgO, 30 parts of CaO and 20 parts of K2CO3. The optimal composition and proportion are determined by screening from a great amount of tests according to the property requirements of the lead-free transparent frit.
Test results show that the lead-free transparent frit for ceramic preparation is scientific and reasonable in component proportion, and ceramic products prepared by the lead-free transparent frit are fine in glaze smoothness, excellent in enamel, especially transparent and bright, free of lead, environment-friendly and wide in application range.
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