DE179997C - - Google Patents

Description

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IMPERIAL /

PATENT OFFICE.

CLASS 48 c -.-

of phosphoric acid.

The general use of cheap calcium phosphates as opacifiers for Glasses for direct enamelling on sheet iron stands in the way of the difficulty that any significant amount of calcium phosphate in. the silicate glasses on which one depends is, makes the latter unusable, melted and viscous. The one in the The basic enamels used in practice consist mainly of borosilicates of the alkalis, the Clay and lime, but the

C oxides are partially replaced by the fluoride. In order to be able to use phosphorus borosilicates, one must first avoid any major fluorine content, namely the presence of fluoroalkali (including cryolite) in the glassware; otherwise you will not get homogeneous glasses, and blistered, blind ones. or in the best case not very shiny

ao enamel coatings. The excessive fusibility and the viscosity of the calcium phosphate-containing glasses cannot be reduced by increasing the percentage the alkalis, generally the flux / or by reducing the content of Remove silica or alumina without the glasses becoming too easily decomposable.

However, it is possible to find usable enamel glasses and, by means of them, good ones that are heavily clouded To make enamel coatings in such a way that one can get into the composition for ordinary Ratios of indecomposable calcium phosphorus borosilicates introduces considerable quantities of oxides of iron or manganese or both metals, these oxides the basic constituents otherwise usual in enamel glasses, - if necessary also calcium compounds - partially replace. The glasses made in this way contain accordingly, in addition to the content required for turbidity, by no means insignificant Lime or calcium compounds contain considerable amounts of phosphoric acid and oxides of iron or manganese. Even if the lime content is significantly reduced, this falls. Opacity is just as strong as if lime and phosphoric acid were in those equivalent proportions is present which correspond to the composition of the tricalcium phosphate or pyrophosphate, and it will by introducing oxides of iron or manganese into the glass compositions achieved both the required easy fusibility and thin liquidity, as well as poor solubility of the glasses, because you are able to, in particular, the alkali, alumina and silica content in to regulate appropriately.

Compared to the common basic enamels, these glasses have the advantage that they are used in Burning take on a very similar appearance, especially the inevitable rust stains do not let the iron surface protrude that it does not even in thin places so easily darken, almost never pre-slag and that they remove the iron surface

protect much better from oxidation. They are also more elastic and adhere more firmly ■ to the iron. These advantages are based on the strong dissolving effect of phosphate glasses on oxides and metallic iron, on their opacity, on the lack of fluorine and on the presence of considerable amounts of heavy-duty glasses. metal and phosphoric acid, which increase the ίο elasticity and the expansion coefficient. _:

Because there are few incorrect places when using these emails and they can be used to produce glossy and light-colored coatings, It becomes further possible to produce uniform and pure in a single order and brand gray, brown or other customary colored goods, in particular also sprayed goods without producing a lot of waste.

The present method is explained below by means of some exemplary embodiments:

Gray email

Potash 4.5

Soda 16.4

Lime 6 ,,

Clay. 4.9

Iron oxide 5,3 manganese oxide

Nickel oxide 0.6

Phosphoric acid ... 8.0

Boric acid 15.2

Silica 39.0

100.00

Brown enamel Iron oxide 4.5 Blue email Blue email 4.5 Cobalt oxide 16.4 4.5 16.4 6 ,, 16.4 6 ,. 4.9 6 ,, 4.9 4.2 4.9 5-3 1.7 Manganese oxide 4.2 Ο, δ 'Q
0.0 Cobalt oxide 1-7 8.0 15.2 8, o 15.2 39th ° . 15.2 39. " 39. »

100.00 ΙΟΟ, οο

ΙΟΟ, οο.

Claims (2)

Patent Claims: i. Method of enamelling sheet metal articles using Phosphoric acid, characterized in that the base enamel is phosphorus borosilicate glasses are used, which are calcium compounds as essential components as well as considerable quantities of phosphoric acid and of oxides of iron or manganese or both metals usually in addition to clay or other things that are mainly found in enamel glasses existing bases included. 2. Embodiment of the method characterized in -Anspruch ι in in such a way that the glasses assembled according to this, instead of being actual Basic enamel to be used as the only complete coating applied to the ironware, the latter in other words be produced in a single brand.