GB1061818A - - Google Patents

Abstract

A process for the production of vitreous enamelled substrates liable to corrosion comprises forming the vitreous coating agents on the substrate by applying to the surface in the presence of vitreous coating agents on said substrate a jet of flame formed by burning an inflammable liquid with a high heat of combustion and a calorific value of at least 6000 calories per gram. The vitreous coating agents are preferably applied to the substrate by means of said jet. The substrate may be metal, such as steel or aluminium, or a siliceous or other refractory substance. The vitreous coating agent may be a metal, alloy, metal oxide, silicate, boride, carbide or titanite, preferably aluminium or a combination of aluminium and butyl titanate and is suspended in the flame preferably with an enamel forming frit. It is desirable that the inflammable liquid is an organic compound of one of the metal constituents of the vitreous coating agent. Benzol mixed with paraffin is used in some of the examples, the coating agent being suspended in this liquid. The jet of flame is directed on to the substrate with a large radius of impact and may be used to preheat the substrate before the vitreous coating agent is suspended therein. Pre-heating may be carried out by using a high frequency current. The vitreous coating may also be applied by first applying a reactive coating (e.g. aluminium paint) to the substrate surface (e.g. a rusted iron surface) which upon heating with the flame reacts with the material of the surface to form the vitreous enamel coating, although usually there is suspended in the flame another enamel frit. The maximum variation in particle size of the frit is less than 0.1 mm. Before the application of the coating the surface may be pre-treated by sand blasting, etching or burnishing. Several examples of enamel frit compositions are given which may be suspended in a mixture of benzol and paraffin and which include a metal powder, or are mixed in an inflammable liquid suspension with aluminium and butyl titanate. The frit compositions fall within the ranges, quartz 10-45; borax 10-30.55; feldspar 8-26.73; sodium carbonate 5-7.64; cryolite 4-7.64; sodium nitrate 2-4.55; barium carbonate 3.8; boric acid 9-10; red lead 51; cobalt oxide 0.5; magnesium carbonate 3; titanium dioxide 0.18-18; alumina 21.64; ferrous oxide 0.08; calcium oxide 0.65; antimony trioxide 0.80; phosphorous pentoxide 0.06. Additionally 0.1 to 40% by weight of any one or a mixture of milled electrolytic copper, antimony powder, chromium oxide, aluminium powder or magnesium powder may be added to the frit in the flame. The inflammable liquid mixture may also be made from cerotin acid, cetyl ester and heavy benzol.ALSO:A process for the production of vitreous enamelled substrates liable to corrosion comprises forming the vitreous coating agents on the substrate by applying to the surface in the presence of vitreous coating agents on said substrate a jet of flame formed by burning an inflammable liquid with a high heat of combustion and a calorific value of at least 6000 calories per gram. The vitreous coating agents are preferably applied to the substrate by means of said jet. The substrate may be metal, such as steel or aluminium, or a siliceous or other refractory substance. The vitreous coating agent may be a metal, alloy, metal oxide, silicate, boride, carbide or titanite, preferably aluminium or a combination of aluminium and butyl titanate and is suspended in the flame preferably with an enamel forming frit. It is desirable that the inflammable liquid is an organic compound of one of the metal constituents of the vitreous coating agent. Benzol mixed with paraffin is used in some of the examples, the coating agent being suspended in this liquid. The jet of flame is directed on to the substrate with a large radius of impact and may be used to preheat the substrate before the vitreous coating agent is suspended therein. Pre-heating may be carried out by using a high frequency current. The vitreous coating may also be applied by first applying a reactive coating (e.g. aluminium paint) to the substrate surface (e.g. a rusted iron surface) which upon heating with the flame reacts with the material of the surface to form the vitreous enamel coating, although usually there is suspended in the flame another enamel frit. The maximum variation in particle size of the frit is less than 0.1 m.m. Before the application of the coating the surface may be pre-treated by sand blasting, etching or burnishing. Several examples of enamel frit compositions are given which may be suspended in a mixture of benzol and paraffin and which include a metal powder, or are mixed in an inflammable liquid suspension with aluminium and butyl titanate. The frit compositions fall with the ranges, quartz 10-45; borax 10-30.55; feldspar 8-26.73; Sodium Carbanate 5-7.64; cryolite 4-7.64; sodium nitrate 2-4.55; barium carbonate 3.8; boric acid 9-10; red lead 51; cobalt oxide 0.5; magnesium carbanate 3; titanium dioxide 0.18-18; alumina 21.64; ferrous oxide 0.08; calcium oxide 0.65; antimony trioxide 0.80; phosphorous pentoxide 0.06. Additionally 0.1 to 40% by weight of any one or a mixture of milled electrolytic copper, antimony powder, chorium oxide, aluminium powder or magnesium powder may be added to the frit in the flame. The inflammable liquid mixture may also be made from cerotin acid cetyl ester and heavy benzol.