Electroplating, also known as electrochemical deposition or electrodeposition, is a process for producing a metal coating on a solid substrate through the reduction of cations of that metal by means of a direct electric current. The part to be coated acts as the cathode of an electrolytic cell; the electrolyte is a solution of a salt of the metal to be coated; and the anode is usually either a block of that metal, or of some inert conductive material. The current is provided by an external power supply.
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. The powder melts, flows, and then hardens to a smooth, durable vitreous coating. The word vitreous comes from the Latin vitreus, meaning "glassy".
Gilding is a decorative technique for applying a very thin coating of gold over solid surfaces such as metal, wood, porcelain, or stone. A gilded object is also described as "gilt". Where metal is gilded, the metal below was traditionally silver in the West, to make silver-gilt objects, but gilt-bronze is commonly used in China, and also called ormolu if it is Western. Methods of gilding include hand application and gluing, typically of gold leaf, chemical gilding, and electroplating, the last also called gold plating. Parcel-gilt objects are only gilded over part of their surfaces. This may mean that all of the inside, and none of the outside, of a chalice or similar vessel is gilded, or that patterns or images are made up by using a combination of gilt and ungilted areas.
Cloisonné is an ancient technique for decorating metalwork objects with colored material held in place or separated by metal strips or wire, normally of gold. In recent centuries, vitreous enamel has been used, but inlays of cut gemstones, glass and other materials were also used during older periods; indeed cloisonné enamel very probably began as an easier imitation of cloisonné work using gems. The resulting objects can also be called cloisonné. The decoration is formed by first adding compartments to the metal object by soldering or affixing silver or gold as wires or thin strips placed on their edges. These remain visible in the finished piece, separating the different compartments of the enamel or inlays, which are often of several colors. Cloisonné enamel objects are worked on with enamel powder made into a paste, which then needs to be fired in a kiln. If gemstones or colored glass are used, the pieces need to be cut or ground into the shape of each cloison.
Plating is a finishing process in which a metal is deposited on a surface. Plating has been done for hundreds of years; it is also critical for modern technology. Plating is used to decorate objects, for corrosion inhibition, to improve solderability, to harden, to improve wearability, to reduce friction, to improve paint adhesion, to alter conductivity, to improve IR reflectivity, for radiation shielding, and for other purposes. Jewelry typically uses plating to give a silver or gold finish.
Gold plating is a method of depositing a thin layer of gold onto the surface of another metal, most often copper or silver, by chemical or electrochemical plating. This article covers plating methods used in the modern electronics industry; for more traditional methods, often used for much larger objects, see gilding.
Verre églomisé is a French term referring to the process of applying both a design and gilding onto the rear face of glass to produce a mirror finish. The name is derived from the 18th-century French decorator and art-dealer Jean-Baptiste Glomy (1711–1786), who was responsible for its revival.
Metallizing is the general name for the technique of coating metal on the surface of objects. Metallic coatings may be decorative, protective or functional.
Ormolu is the gilding technique of applying finely ground, high-carat gold–mercury amalgam to an object of bronze, and for objects finished in this way. The mercury is driven off in a kiln leaving behind a gold coating. The French refer to this technique as "bronze doré"; in English, it is known as "gilt bronze". Around 1830, legislation in France had outlawed the use of mercury for health reasons, though use continued to the 1900s.
Silvering is the chemical process of coating a non-conductive substrate such as glass with a reflective substance, to produce a mirror. While the metal is often silver, the term is used for the application of any reflective metal.
Christofle is a French silverware and tableware company founded in Paris in 1830 by Charles Christofle.
Mercury glass is glass that was blown double walled, then silvered between the layers with a liquid silvering solution, and sealed. Although mercury was originally used to provide the reflective coating for mirrors, elemental mercury was never used to create tableware. Silvered glass was free-blown, then silvered with a solution containing silver nitrate and grape sugar in solution, heated, then closed. Sealing methods include metal discs covered with a glass round or a cork inserted into the unpolished pontil scar. "Mercury" silvered glass was produced originally around 1840 until at least 1930 in Bohemia, Germany and was also manufactured in England from 1849 to 1855.
Corinthian bronze, also named Corinthian brass or aes Corinthiacum, was a highly valuable metal alloy in classical antiquity. It is thought to be an alloy of copper with gold or silver, although it has also been contended that it was simply a very high grade of bronze, or a kind of bronze that was manufactured in Corinth. It is referred to in various ancient texts, but no certain examples of Corinthian bronze exist today. However, it has been increasingly suggested that a number of artefacts previously described as niello in fact use a technique of patinated metal that may be the same as Corinthian bronze and is similar to the Japanese Shakudō.
Depletion gilding is a method for producing a layer of nearly pure gold on an object made of gold alloy by removing the other metals from its surface. It is sometimes referred to as a "surface enrichment" process.
Lacquerware is a Japanese craft with a wide range of fine and decorative arts, as lacquer has been used in urushi-e, prints, and on a wide variety of objects from Buddha statues to bento boxes for food.
Keum-boo is an ancient Korean gilding technique used to apply thin sheets of gold to silver, to make silver-gilt. Traditionally, this technique is accomplished by first depleting a surface of sterling silver to bring up a thin layer of fine silver. Then 24 carat gold foil is applied with heat and pressure—mechanical gilding—to produce a permanent diffusion bond.
Glass-to-metal seals are a type of mechanical seal which joins glass and metal surfaces. They are very important elements in the construction of vacuum tubes, electric discharge tubes, incandescent light bulbs, glass-encapsulated semiconductor diodes, reed switches, glass windows in metal cases, and metal or ceramic packages of electronic components.
Angel gilding is gilding glass or gold plating by electroless chemical deposition.
The Middle Ages was a period that spanned approximately 1000 years and is normally restricted to Europe and the Byzantine Empire. The material remains we have from that time, including jewelry, can vary greatly depending on the place and time of their creation, especially as Christianity discouraged the burial of jewellery as grave goods, except for royalty and important clerics, who were often buried in their best clothes and wearing jewels. The main material used for jewellery design in antiquity and leading into the Middle Ages was gold. Many different techniques were used to create working surfaces and add decoration to those surfaces to produce the jewellery, including soldering, plating and gilding, repoussé, chasing, inlay, enamelling, filigree and granulation, stamping, striking and casting. Major stylistic phases include barbarian, Byzantine, Carolingian and Ottonian, Viking, and the Late Middle Ages, when Western European styles became relatively similar.
Traditional metal working in Mexico dates from the Mesoamerican period with metals such as gold, silver and copper. Other metals were mined and worked starting in the colonial period. The working of gold and silver, especially for jewelry, initially declined after the Spanish conquest of the Aztec Empire. However, during the colonial period, the working of metals rose again and took on much of the character traditional goods still have. Today, important metal products include those from silver, gold, copper, iron, tin and more made into jewelry, household objects, furniture, pots, decorative objects, toys and more. Important metal working centers include Taxco for silver, Santa Clara del Cobre for copper, Celaya for tin and Zacatecas for wrought iron.
