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PAINT & COATINGS MANUFACTURING: ENAMELS

PORCELAIN ENAMEL POWDER IN THE

21ST CENTURY

Production smelter.

By Stewart M. Hackler
and Cullen L. Hackler

orcelain enamel is a glass coating fused on a metallic Technical Basics
substrate at extremely high temperatures, providing a hard, Porcelain enamel is produced from natural, inorganic, raw materials.
Pdurable, and extremely heat and corrosion resistant product. It is not only an exceptionally durable finish, it is also 100 percent
Key features and benefits of a porcelain enamel finish include recyclable and as such an inherently environmentally-friendly
abrasion, acid, and corrosion and temperature resistance, as well as product. A blend of minerals is melted in much the same manner as
it being a colorfast and sanitary finish. common window or container glass; this is the beginning of
While porcelain enamel has been used throughout history on the process. Once all of the ingredients are fully melted – at
gold, silver, bronze, copper, iron, steel, and aluminum, enamel is pri- temperatures over 2,000 deg. F – the molten mixture is poured from
marily used on today’s home appliances, water heaters, bathtubs, a smelter and quenched between water-cooled rollers. This process
sinks, barbecue grills, architectural panels, waste treatment is known as “fritting.” The quick-cooled ribbon of glass is then
tanks/piping, whiteboards, and many other applications. Porcelain shattered into flakes, or frit. The chemical composition of the
enamel use remains strong in these and related industries despite frit/glass is tailored to the end-product performance requirements
conversion of porcelain to stainless steel for aesthetics and to and metal substrate used.
powder paint or plastics for cost reasons in the last quarter of the For the frit formulator, there are a few key things the enamel
20th century. Let’s take a look at the basics of the porcelain enamel coating must accomplish. For a ground coat, the first layer of glass on
process as well as some innovative porcelain materials and applica- the metal, the porcelain enamel glass must 1) adhere to the metal
tions that are giving designers reason to change back to powder (bond), 2) match the thermal expansion of the metal substrate, and
porcelain enamel in several applications. 3) have a smooth, defect-free surface. For the second layer, the cover
coat, the enamel must 1) have the desired surface color and texture,
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