Enamel firing

Enamel firing temperature is dictated by the coating composition, metal thickness, and the type of metal used. Enamels for aluminum are fired at... 

Firing of Enamels. Firing can be carried out in intermittent box-type furnaces or continuous furnaces. The dryer and the furnace form one continuous unit or function as separate units in the continuous firing process. Most industrial furnaces are fiber-lined (low thermal mass), which lowers cost and downtime between firing schedules. 

Decorating Firing or Enamel Firing. The process of firing pottery-ware after the... 

Enamel Colour. A ceramic colour for the on-glaze decoration of pottery. Enamel Firing. In the British pottery industry this term is synonymous with DECORATING FIRING (q.V.)... 

Fig. 1. Concentrations of anatase and rutile in enamel fired at 780°C. Points are experimental data curves are calculated from Eqs. (17) and (18).

For temperatures up to 100°, a water bath or steam bath is generally employed. The simplest form is a beaker or an enamelled iron vessel mounted on a suitable stand water is placed in the vessel, which is heated by means of a flame. This arrangement may be used for non-inflammable liquids or for refluxing liquids of low boiling point. Since numerous liquids of low boiling point are highly inflammable, the presence of a naked flame will introduce considerable risk of fire. For such liquids a steam bath or an electrically-heated water bath, provided with a constant-level device, must be used. If the laboratory is equipped with a... 

Alloys suitable for castings that ate to be bonded to porcelain must have expansion coefficients matching those of porcelain as well as soHdus temperatures above that at which the ceramic is fired. These ate composed of gold and palladium and small quantities of other constituents silver, calcium, iron, indium, tin, iridium, rhenium, and rhodium. The readily oxidi2able components increase the bond strength with the porcelain by chemical interaction of the oxidi2ed species with the oxide system of the enamel (see Dental materials). 

Structural, Al alloy Oxidation catalyst Fluxes, enamel frit Glass, ceramics Detergents Fire retardants Rubber catalyst Photographic Antiknock agents Medicinals Fertilizers... 

Adhesion of Enamel to Steel. Cobalt compounds are used both to color and to enhance adhesion of enamels to steel (55). Cobalt oxide is often incorporated into the ground frit at rates of 0.5—0.6 wt %, although levels from 0.2 to 3 wt % have been used. The frit is fired for ten minutes at 850°C to give a blue enamel that is later coated with a white cover coat. 

The resistance of these materials to firing temperature is definitely limited. They can be fired to about 1000°C. Hence, they are limited to use in porcelain enamels and in low firing artware gla2es. 

Two-coat—one-fire enameling processes have also reduced the need for heavy-metal etching and nickel flashing (nickel replacement) for direct-on enamel apphcation to decarburized steels. 

The level of moisture ia the furnace atmosphere is also of importance ia the development of good fired surface appearance. The range of moisture normally associated with good enameling practice is 1—2 vol % of moisture (21). Levels below 1 vol % may result ia reduced gloss of the glass surface levels above 2 vol % may result ia blistering or a scummy surface. Wiater conditions usually cause dry furnace atmospheres, and summer conditions may result ia excessive moisture if the furnace is not properly vented. 

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