Chemical properties of porcelain enamel powder

1) porcelain enamel powder often is applied as a paste, and may be transparent or opaque when fired; vitreous porcelain enamel powder can be applied to most metals. It has many excellent properties: it is smooth, hard, chemically resistant, durable, can assume brilliant, long-lasting colors, and cannot burn. Its disadvantages are its tendency to crack or shatter when the substrate is stressed or bent. Its durability has found it many functional applications: early 20th century advertising signs, interior oven walls, cooking pots, exterior walls of kitchen appliances, cast iron bathtubs, farm storage silos, and processing equipment such as chemical reactors and pharmaceutical chemical process tanks. Commercial structures such as gas stations, bus stations and even Lustron Houses had walls, ceilings and structural elements made of porcelain enamel powderl steel.

2) Color in porcelain enamel powder is obtained by the addition of various minerals, often metal oxides cobalt, praseodymium, iron, or neodymium. The last creates delicate shades ranging from pure violet through wine-red and warm gray. Porcelain enamel powder can be either transparent, opaque or opalescent (translucent), which is a variety that gains a milky opacity the longer it is fired. Different porcelain enamel powder colors cannot be mixed to make a new color, in the manner of paint. This produces tiny specks of both colors; although the eye can be tricked by grinding colors together to an extremely fine, flour-like, powder.

This article comes from reade edit released

Vitreous enamel information

You will recognise vitreous enamel as the material used to produce the now highly collectable advertising signs produced during the early 20th Century. The ‘Hovis’ and ‘Virol’ signs were part of the everyday street scene. Your cooker will almost certainly have a vitreous enamelled oven and the higher quality cookers will use it on the outer parts. Your cast iron or steel bath will have been vitreous enamelled. Less obvious are the storage silos on farms, usually blue or green; they tower over the surrounding countryside. Carl Faberge used enamel for his unique eggs and jewellery and the Battersea enamellers are famous for their copper enamelled boxes. These are just two of the better known groups of highly skilled artists who used this very special material.

The word enamel comes from the High German word ‘smelzan’ and later from the Old French ‘esmail’. The Collins English Dictionary defines enamel as ‘a coloured glassy substance, transparent or opaque, fused to the surface of articles made of metal, glass etc. for ornament or protection’. Vitreous enamel is specifically on a metal base. It is thus defined as a vitreous, glass like coating fused on to a metallic base. In American English it is referred to as Porcelain Enamel.

It should not be confused with paint, which is sometimes called ‘enamel’. Paints cannot be enamel. They do not have the hardness, heat resistance and colour stability that is only available with real vitreous enamel. Beware of companies or products implying the use of enamel. Check their credentials and warranties.

The glass will be applied to the metal by a various methods either as a powder or mixed with water. This is followed by heating in a furnace to a temperature usually between 750 and 850 degrees Celsius. This ‘firing’ process gives vitreous enamel its unique combination of properties.

The smooth glass-like surface is hard; it is scratch, chemical and fire resistant. It is easy to clean and hygienic.

Vitreous enamel can be applied to most metals. For jewellery and decorative items it is often applied to gold, silver, copper and bronze. For the more common uses, it is applied to steel or cast iron. There are some specialised uses on stainless steel and aluminium.

The durability of the early advertising signs, still showing the brilliance of the original colours after a hundred years, is one of the best examples of the long-term colour stability of vitreous enamel. Compare them to signs, for example road signs, produced in less durable materials which fade and become shabby. Some of the early vitreous enamelled relics date back to the 13th Century BC and the colours are still as vibrant as the day they were produced (see our page on Enamelling History). If you want something where the colour will never fade – use vitreous enamel.

Following the disastrous King’s Cross fire, where combustible materials underground were the major cause, the specification of vitreous enamel for both decorative and functional parts in underground applications is now universal. It cannot burn, in contrast to paints and plastics. The famous London Underground station signs and maps are instantly recognisable uses of this unique product.

This article comes from iom3 edit released

A short history of jewellery enamelling process

The art of enamelling jewellery is an ancient one. The earliest archaeological finds from ancient Greece date from 1600 BC. Enamelling process on metal is very hot work. The process requires temperatures in excess of 500 degrees centigrade which melts the enamel creating an impermeable bond, a smooth surface and brilliant colours.

For centuries enamelling process would be used primarily for the creation of religious objects and most of the oldest artefacts involved enamelling process on gold (Cloisonné technique). The museum of Cyprus in Nicosia houses a golden sceptre (1100 BC) which was found near Episkopi and its spherical top is enamelled in white, lilac and green.

From the 5th century BC the La Tene culture of Western Europe produced enamel objects on bronze usually of a bright red colour. The Greek writer Philostratus of Lemnos witnessed that the northern Barbarians of the ocean regions applied colours on hot bronze (Champlevé technique).

The early middle ages from the 5th century AD onwards saw a new impulse of Celtic-roman art in what is today known as Ireland, England and Scotland. One of the most beautiful and well known pieces to be created in this period in Ireland is the Ardagh chalice. The chalice is elaborately decorated with layers of gold thread one on top of the other and at intervals are set cloisonné enamel bosses of blue and red.

Another very important and famous piece created in the period 400 AD to 800 AD is the Iron Crown. Originating in the time of Constantine (350 AD) it was Charlemagne who restored this crown of gold and added 21 of the 24 enamel plates and wore the crown at his coronation in 800 AD. Since then the Iron crown has been worn by 32 kings and emperors including Napoleon Bonaparte on the 2nd of December 1804. Today the crown is in the possession of the Monza Cathedral in Northern Italy.

During the late Middle Ages (1100 to 1500 AD) schools dedicated to Cloisonné enamelling process sprung up in Liège, Cologne, Limoges and Silos. New Techniques were perfected such as “Translucent relief” and “Bas-relief”. Bas-relief is the filling of engraving or chisel marks with enamel.

The Renaissance period (15th-16th Century) saw the beginning of enamel painting and the first work considered to be a true painted enamel is by Nardon Penicaud (1470-1542) in 1503. Leonardo Da Vinci wrote in his “treatise on Painting” – “A painting on thick copper, covered with enamel on which it is painted with enamel colours and then put into the furnace again and fired, far exceeds sculpture in durability”.

The Grisaille (cameo) technique appears in 1530 and consists of firing dark enamel on a copper surface covered with white enamel figures completed with bas-relief firings. It is well suited to miniatures and snuff boxes and cameo pendants were popular at the time. The Guilloche technique is introduced where gold or silver sheet is covered by fired layers of transparent enamel. Faberge would later use this technique so famously at the end of the 19th century and early 20th century.

The art deco period from 1920 to 1930 would see enamelling process make a resurgence in many different art forms. Enamel art jugs created by Faure Atelier are highly sought after today.

Here we feel we are continuing this 3,500 year old art of enamelling process and producing our own unique style of jewellery which we hope will be enjoyed by people long after we have moved on too.

This article comes from meabenamels edit released

Vitreous enamel

Vitreous enamel, also called porcelain enamel, is a material made by fusing powdered glass to a substrate by firing, usually between 750 and 850 °C (1,380 and 1,560 °F). The powder melts, flows, and then hardens to a smooth, durable vitreous coating. The word comes from the Latin vitreum, meaning “glassy”.

Enamel can be used on metal, glass, ceramics, stone, or any material that will withstand the fusing temperature. In technical terms fired enamelware is an integrated layered composite of glass and another material (or more glass). The term “enamel” is most often restricted to work on metal, which is the subject of this article. Enamelled glass is also called “painted”, and overglaze decoration to pottery is often called enamelling.

Enamelling is an old and widely adopted technology, for most of its history mainly used in jewelry and decorative art. Since the 19th century, enamels have also been applied to many consumer objects, such as some cooking vessels, steel sinks, enamel bathtubs, and stone countertops. It has also been used on some appliances, such as dishwashers, laundry machines, and refrigerators, and on marker boards and signage.

The term “enamel” has also sometimes been applied to industrial materials other than vitreous enamel, such as “enamel” paint and the polymers coating “enamelled” wire.

The word enamel comes from the Old High German word smelzan (to smelt) via the Old French esmail, or from a Latin word smaltum, first found in a 9th-century life of Leo IV. Used as a noun, “an enamel” is usually a small decorative object coated with enamel. “Enamelled” and “enamelling” are the preferred spellings in British English, while “enameled” and “enameling” are preferred in American English.

This article comes from wikipedia edit released

Premium Cobalt Blue Paint for Composites

Premium cobalt blue paint is a high gloss coating which does not require a base coat or clear coat. It is designed to protect composite and metal substrates providing an extremely durable, high gloss finish which builds quickly and requires fewer coats to achieve full hiding. This premium cobalt blue paint is easy to mix, easy to spray and fast drying. ChromaGlast™ was developed with the latest polyurethane coating technologies to provide ultimate performance and durability. It is compatible with polyester, epoxy and vinyl ester resin systems as well as SMC and most metals. It can be used with new work or repairs with a formula trusted by OEM’s worldwide. Cobalt blue paint is a low VOC formulation (2.8 VOC max.).

We offer cobalt blue paint both in kits, including the correct quantities of our Drying Accelerator and Paint Hardener, and as stand-alone mixed colors. Please note that if stand-alone mixed colors are purchased, Drying Accelerator and Paint Hardener are required. Thin up to 10% using Exempt Solvent.

Features

  • High solids, first-class formula provides a beautiful rich finish
  • Single stage system is easy to use, and delivers incredible gloss
  • Suitable for automotive, fleet, aerospace use, or above-the-waterline marine
  • Does not sag on edges or rivets
  • Outstanding corrosion and chemical resistance
  • Low VOC formula (2.8 Max)
  • Requires #5025 Drying Accelerator and #5027 Paint Hardener

This article comes from fibreglast edit released

Processing of porcelain enamel powders for electrostatic spraying

Following a brief review on current technology of electrostatic spray for enameling, the requirements on powder properties were discussed.

The use of poly (siloxanes) or poly (silanes) as encapsulants for producing electrostatic porcelain enamel powders with appropriate electrical resistivity, hydrophobicity and fluidity was analyzed from a mechanistic standpoint.

Experimental results were presented to illustrate typical processing problems such as the change of powder properties on aging as a result of differential encapsulation of glass components. Various measures were proposed for improving the stability of powder properties. Optimization of powder processing parameters by means of experimental design technique was described.

This article comes from sciencedirect edit released

Metal Pigment Powders

These metal pigment powders give the ultimate metallic leafing finish in resin & you will want to use them continuously.

It is available in 4 shades, sold in one size container which carry the same volume though each metal pigment powders weight is different.

Using only a smalll amount into your resin mix you can achieve the most amazing of metal looking finishes.

Copper Fine 36 (50g) – Is a beautiful copper metallic with an amazing finish that can be achieved to look like real copper.

Rich Gold Fine 36 (50g) – Is a beautiful rich gold metallic with an amazing finish that can be achieved to look like real gold.

Rose Gold fine 36 (50g) – Is a beautiful rose gold colour which will be a perfect addition to add that wow to your art work.

Aluminium Bright (15g, same volume as the others, its just very light) – This is a brilliant silver leafing grade offering a reflective sparkle to your work (not suitable for polyurathane resins – epoxys only)

This article comes from arttreecreations edit released

Chemical and Physical Properties of Inorganic Pigments

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Inorganic pigments play double-duty as fillers that provide a greater benefit than simple coloration of a formulation; they also impact physical properties of the film during application and throughout the product lifecycle. Pigments in coatings protect the resins and binders from electromagnetic or thermal degradation due to their reflectance of short-wave IR radiation, which also helps to keep the materials containing said pigments cooler.1

Why We Use Pigments

Before we can understand best practices for dispersing materials containing pigments, it is important to understand what a pigment is, and the chemical and physical reasons why we use pigments. Inorganic pigments are transition metal complexes,2 primarily oxides of crystalline or semi-crystalline repeating units of ceramic crystal lattice structure.

The d-orbital of the metal ions is responsible for a multitude of inorganic pigment properties, including color, reactivity, strength (as in Mohs hardness) and weatherability. Pigments are unique as fillers in that they are composed of transition metals surrounded by ligands (functional groups). The way in which the d-orbital of the metal ion interacts with the various ligands to which it is bonded also influences pigment properties; ligand substitution results in modified pigment characteristics.

As an interesting aside, the metal ion-ligand coordination complexes of pigments used in coatings function (that is to say, provide a visible output color) much like light-harvesting complexes in photosynthetic pigments. Drawing from the Stark-Einstein law, we will take this full circle. The law states that an absorbed photon will initiate a primary chemical or physical reaction within the system.3 For coating pigments, this means that the d-orbital of the transition metal experiences excitation; the degree to which this excitation increases the energy gap dictates corresponding perceived color of the material. For example, the transition metal Vanadium can form complexes of four different ionization states (i.e., V2+, V3+, V4+, V5+), which offer pigments of different hues from purple (V2+) to yellow (V5+).4

That is to say, to reduce agglomerates to aggregates requires one-tenth the energy of reducing aggregates to primary particles; aggregates are chemically bound. Surfactants physically bond to aggregates/primary particles and prevent the reformation of pigment agglomerates by disruption of the London-Van der Waal forces. It must be noted that the geometry of the particles plays a role in the extent to which these forces are felt over a specific distance. Surface defects and aspect ratios other than one result in an increased surface area-to-volume ratio, which entails a greater Van der Waal force of attraction than simple spheres; the probability of the geometry leading to mechanical interlocking is also increased.

Understanding Dispersion

Dispersion is a physical process that tends to increase the entropy of a system. A poorly stabilized dispersion will tend to flocculate; a state that decreases the potential number of conformations of the system (i.e., reduced entropy or randomness). This is largely due to the randomized Brownian motion of the dispersed particles, which are attracted (i.e., tend to agglomerate) via short-range London-Van der Waal forces.

For adequate dispersion it is essential that the surface tension of the liquid(s) be less than the surface free energy of the pigment (and other solids, such as fillers). If a specific solvent, resin or other liquid is to be used with a solid that it does not have an affinity for -in the sense of it being difficult to incorporate and wet out -surfactants are utilized to mitigate de-wetting and prevent floccules from forming.

This article comes from pcimag edit released

Porcelain Enamel History

Down through the ages, artists, inventors and scientists have searched for materials that are both beautiful and enduring.

The Egyptians inlaid glass in metal frames in 2000 BC. Greek craftsmen advanced the art form by applying sufficient heat to fuse the metal and glass. With the expansion of the Roman Empire, the technology spread throughout Europe.

The continued existence of these artifacts fashioned centuries ago, is testimony to the timeless beauty and permanence of Porcelain Enamel.

Though all of us use porcelain enamel products everyday, it is something that few of us are aware of on a conscious level. We bathe in porcelain enamel bathtubs. Use porcelain enamel sinks, lavatories, stoves, ovens, washing machines, dryers and water heaters without a thought about that beautiful, glassy finish.

We walk through buildings sheathed in porcelain enamel and read signs of porcelain enamel. The operating rooms of many hospitals are porcelain enamel. Our children write on porcelain enamel boards at school, and we barbecue on porcelain enamel grills. It is present in an amazing number of applications that we encounter in our daily schedule.

Porcelain Enamel Cookware

Pots and pans made of materials, such as cast iron or aluminum that have had porcelain enamel applied as a coating. It prevents them from corroding or reacting with the food being cooked in them. A pan coated with porcelain should not be used for sautéing or frying but will work as a saucepan or roaster.

To care for porcelain enamel cookware, wash with hot soapy water. A nylon scouring pad, nylon scraper, or nonabrasive cleaner can also be used to help remove stuck on food. Porcelain enamel can be cleaned occasionally in the dishwasher unless it has a non-stick interior surface, but dishwasher use should be limited to avoid dulling the enamel surface.

This article comes from recipetips edit released