DE2739919A1 - METHOD OF APPLYING A GLASS-LIKE COATING OR AN ENAMEL COATING TO AT LEAST ONE SURFACE OF A CARRIER - Google Patents

Description

-M-

description

The invention relates to a method for applying vitreous coatings and the products obtained by this process.

It is already an industrial process for applying a glassy coating on a surface of a support is known, which consists in applying a cold glass powder on the surface to be coated and then heating the carrier to a temperature between 500 and 100O ⁰ C to derive to produce a vitreous coating. However, this method of enamelling or glazing the surface of a support has several difficulties; On the one hand it is found that in most of the coatings applied in this way, blistering occurs, in particular of the type that one is generally forced to apply coatings of a considerable thickness, sometimes thicker than 1 mm, while on the other hand it is impossible in most cases, to heat the entire beam to elevated temperatures without causing significant and undesirable changes, especially when using beams made of concrete, plaster of paris, fired clay or analogous materials. A number of references have also suggested spraying (spraying) a glass powder onto the surface of a material to be coated, but experience has shown that it is impossible to obtain a useful coating unless a number of Respects conditions with regard to the wearer on the one hand and in relation to the glass on the other hand, and finally also with regard to working conditions; this is in

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This is also the reason why such a process is currently not used in industry.

The present invention now relates to the conditions which must be met in order to do this in principle known methods for coating a carrier by spraying on (spraying) a glass powder are industrially applicable close. The basic conditions that apply when applying a glass-like coating by spraying on (spraying on) of a glass powder must be adhered to are the following:

- the surface to be coated must be clean and preheated,

- The glass powder or the vitrifiable mixture used must have a certain particle size distribution to have,

- The burner used must be designed in such a way that it heats up completely (up to the center) of the means of the burner sprayed (sprayed) glass particles allowed, so that molten particles with a low Viscosity can be obtained.

Each of these conditions is analyzed below.

The surface to be coated must be clean; this is generally achieved by pointing to the to be cleaned Surfaces a combination of the known methods of Degreasing, washing, applying treatment with a sandblasting fan or with steel grit. If For example, the surface of a material such as concrete, asbestos cement, gypsum, stone, baked clay or marble, wants to coat, the surface to be coated is cleaned by sandblasting or treatment with steel grit; the treatment with a sandblasting blower (or with steel gravel) serves to remove more or less degraded surface

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to remove surface layers to which the applied glass-like coating does not adhere well, since these surface layers in turn adhere poorly to the underlying material. If you want to coat a metallic material, it is generally advisable to apply degreasing and then treatment with steel shot, one after the other. The surface to be coated must be preheated to a temperature of at least 250 ° C. The type of preheating and the temperature to be achieved obviously depend on the type of substrate. If you want to coat the surface of a material such as concrete, asbestos cement, plaster of paris, stone, burnt earth or marble, preheating to temperatures between 250 and 35O ⁰ C is carried out, since beyond these elevated temperatures one more during the duration of the coating process or less severe decomposition of the carrier material occurs. In other carriers, such as those made of metal, it is possible and even desirable to preheat surface to be coated to a temperature which 35O exceeds ⁰ C significantly and from 550 to 600 ° C and even 900 reach up to 1000 ° C can. As explained in more detail below, the need to preheat the surface to be coated is related to the fact that the sprayed-on (sprayed-on) glass, after it has come into contact with the surface, must spread strongly, ie must have a temperature such that its log M is at most 2.2.

The preheating can be effected by the temperature of the entire wearer increases evenly, or by the fact that the heating on the surface or on surface parts of the surface to be coated

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limited; in the latter case, it is expedient to use rapid heating by means of a planrae.

It is important to the present invention to use glass particles which have characteristic dimensions. This dimension of the particles is characterized by two parameters: the grain size distribution and the specific surface, whereby the mean grain size distribution must be between 40 and 100 microns, but with 0% residue on a sieve with a mesh size of 15 ° micron, and the specific surface must be between 800 and 3000 cm / g. This suitable dimensioning of the granules is necessary on the one hand to allow a suitable and regular introduction into the burner (a regular flow of the possibly pneumatically assisted granules) and on the other hand to allow a complete melting (up to the center) of each of the granules during its flight path in to achieve the flame of the burner. The burner used must be such that it allows the glass to be given a very low viscosity when the glass comes into contact with the surface to be coated. The essential criterion is that the glass, when it is brought into contact with the surface to be coated, has a temperature such that its viscosity - * ή , expressed by log «^, is less than or at most equal to V / ert 2, 2 is. In order to achieve this goal, two essential parameters can be used, the burner and the quality of the glass.

The best embodiment of the process according to the invention is that which consists in using an oxygen-acetylene burner used, of which it is known that the flame reaches a temperature of 2400 to 2900 ° C. It it is desirable that the mixture of flame-glass particles be a

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is of sufficient quality in terms of both quantity and duration. Those skilled in the art must also take into account, when selecting the burner, the quality and the quantity of flame particle mixture, that the technology of the burner allows it to be used for a period of time during which the glass particles are in the flame before they strike the support to be coated with these particles. If, for example, a burner is used which has a flame on the one hand, and a mechanical or pneumatic device for dispersing the glass particles on the other, the relative speeds of the burning gases and the number of movement of the particles must be coordinated so that the latter is appropriately supported by the Gas are entrained in order to melt at a given distance from the nozzle, which in any case and necessarily lies outside the nozzle; the width and length of the flame can also be changed if necessary. The METCO 6 P type thermospray gun with P7 AB or AD nozzles is particularly suitable for spraying on (spraying) molten glass particles, but this is only one example to which the invention is in no way limited. A plasma torch can also be used if the coating is to be carried out with glass that is difficult to melt. In this case, however, it is advisable to control the temperature of the plasma very precisely so that the glass used does not decompose; it is well known that in such plasma burners, the temperature inside of the nozzle must be of the burner between '6000 and 10 000 ⁰ C.

As stated above, the composition of the glass plays an important role in finding a suitable one

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To achieve viscosity of the glass when it comes into contact with the surface to be coated. The for the present invention Particularly suitable glasses are, at least if an oxygen-acetylene burner is used, the glasses, which have a viscosity whose logarithm (log) is below 2.2 at a temperature of 1400 ° C.

For supports whose surface changes when their temperature exceeds 350 ° C., fusible glasses are expedient used, i.e. glasses that have the following properties:

- the log η = 2.2 at temperatures not exceeding 920 ° C,

- the softening temperature is between 250 and ^ 8O ⁰ C.

Such glasses can be considered to be known per se, even if they have not been a large industrial one in general Have found application. The following are examples the possible compositions of fusible glasses of this type indicated:

P ₂ O ₅ 0-50 %

SiO ₂ 0 - 35%

V ₂ O ₅ 0-30 %

B ₂ O ₅ 0-60 %

Al ₂ O ₃ 0 - 8 %

Na ₂ O 0 - 30 %

K ₂ O 0-30 %

Li ₂ O 0 - 5 %

35-90 %

₂ 0 - 10 %

TeO ₂ 0-20%

Tl ₂ O 0 - 5 %

HgO 0 - 5%

GdO 0 - 5%

CaO-SgO BaO 0 - 5 %

SnO ₂ 0 - 5 %

NiO 0 - 5%

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- 10 - 0 - 5 % 2739919 ZnO 0 - 10 Vo ZrO ₂ 0 - 10 % other Colorants

These "fusible glasses" must preferably contain oxides of large or strongly polarizable cations (such as K, Pb ⁺⁺ , Te ⁺ ) which, as is known, are capable of giving the glasses the lowest possible surface tension at a given temperature to rent. Ordinary silica-soda-lime glasses can be used with an oxygen-acetylene burner. However, since the log Y of such glasses is 2.2 only at elevated temperatures (of the order of 1360 to 1440 ° C.), it is recommended to add known fluxes to the glasses to facilitate the production of the vitreous coating. The glasses then have the following composition: ordinary silica-soda-lime glass 80 - 95 / ■> flux (LiNO ,, NaNO,) 5 - 20 %

A plasma torch must therefore be used for glasses whose log -) j at 1400 ° C. is very clearly above 2.2. In practice it should be borne in mind that the present invention is carried out in such a way that on the one hand the relationship between the temperature and the viscosity of the glass at the given temperature is determined and on the other hand, by means of a probe, for example, the temperature of the surface layer of the material to be coated is measured (e.g. the temperature in the material to be coated at a distance of 50 or 100 microns from the surface). The temperature reached by this surface layer must then be such that the log> y (where Yj represents the viscosity of the glass at this temperature) is at most 2.2. One can also qualitatively measure the impact of the molten glass particles on the one to be coated

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Examine the carrier and find that when the glass particles have melted and one is sufficient have high temperature, they expand widely (spread) and mix rapidly with the other particles to form a continuous coating.

In addition to these "basic conditions" for carrying out the invention, it is also appropriate to use "specific conditions" to be observed, which are not necessary, but which facilitate the implementation of the invention.

First, efforts must be made to select the coating glass so that the glass has a coefficient of expansion which is sufficiently close to the coefficient of expansion of the support; The rule to be applied here is as follows: if the expansion coefficient of the carrier is denoted by α, which is usually provided with a factor of 10 'and is in the temperature range between 0 and 300 ° C, then one uses for a glass coating that only consists of a single glass, a coefficient of expansion that is between α and a-10. If the glass coating consists of several glasses, a coefficient of expansion between α and oc + 10 is chosen for the "bulk glass" or for the anchoring glass. For each of the other applied glasses, a coefficient of expansion is selected which lies between α ¹ and α ¹ -10, where α ^{1 is} the coefficient of expansion of the carrier glass. In addition, it is often desirable to choose the experimental conditions under which the coating is carried out so that a certain ion exchange takes place between the support and the applied glass. Such ion exchange is known and it is known that it generally facilitates anchoring of the glass to a support. For example, if one wishes to coat steels, it is generally desirable to do so in such a way that the

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treatment according to the invention nickel, cobalt, manganese (or more of these metals) are present; it is known that these metals make it easier for the vitreous coatings to adhere to steel. These metals can be applied to the carrier itself (if a steel containing at least one of these metals is used) or by applying a thin metal layer to the surface of the carrier prior to glazing (this application can be carried out using any known method) Surface of the support or by using a glass which contains at least 1 % nickel oxide or cobalt oxide or manganese oxide (or these oxides) are provided. Finally it is clear that

- The glasses used can contain various additives and in particular colorants (dyes) and

- It is possible for the glass coating produced according to the invention to give specific properties by treating the surface of the coating with oxides (e.g. TiOp, SiOp, SnOp) or treated with resins (e.g. silicone resin); this treatment is preferably carried out immediately after the application of the glass coating carried out while the surface of the coating is still a suitable temperature Has.

The carriers, their surfaces when applying the invention can accommodate a vitreous coating (glass coating) are of very different nature; suitable examples are all materials that are used in construction or public works, such as concrete, asbestos concrete, Plaster of paris, fired clay, stone and marble that allow the application of decorative or protective coatings allow (against wear and tear or degradation by sea water) on different materials; wood is also suitable, Metals, glass and even certain plastic materials,

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provided that they can withstand the preheating.

In numerous cases, using the inventive Procedure also two parts are united with each other; It is sufficient to use the coating according to the invention to be applied to the surfaces of the two parts and these coated surfaces in contact with one another while the coating is still warm, or just applying the coating to the surface of a part and bringing the preheated surface of another part into contact with the coating while it is still warm. The inventive Coating can be carried out in the form of one or more layers, with the average thickness of a layer is about 30 to about 60 microns. The inventive Coating has remarkable properties on, in particular the following:

- it has great homogeneity and perfect adhesion,

- it is repairable,

- it is free from blistering.

The fact that the coatings according to the invention are repairable means that when the coating has received an impact and when the carrier has been locally exposed is, by using the method according to the invention continuous coating can be restored; it is even possible to carry out repairs on glass-like coatings or enamel coatings made using other known glazing processes are; it should be noted, however, that when repairing any vitreous coating it is generally It is necessary to take special precautions for preheating the surface to be repaired to be hit.

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In addition, it was found that the enamel coatings applied using the known methods or vitreous coatings (glass coatings) have strong blistering, which is evident, for example, in microscopic Investigation of these coatings or in electrical Tests shows. This blistering is explained by the fact that the used enamels or glasses are brought to such a temperature that their viscosity is too high; the enamel grains or glass grains mix insufficiently with each other and between the grains and the surface Significant amounts of gas are trapped in the carrier. Thicker coatings are used to remedy this difficulty on, wherein the glass layers can usually reach thicknesses of 1 to 2 mm; this is how you get there however, too brittle (fragile) coatings.

The extraordinary quality - the lack of blistering - of the coatings according to the invention is explained by this the fact that each of the granules during its Aufsprit zens (spraying) on the carrier completely (up to Core) is melted and that a slight mixture between the melted particles occurs on this carrier because of the low viscosity of these particles. These are essential for the vitreous coatings according to the invention Property is shown in dielectric control at high voltage. This dielectric attempt, also called electrostatic test is carried out at voltages that vary from 1000 to 20,000 volts, the enamelled part has the potential 0, with its temperature corresponding to the voltage applied can vary. This is a real breakdown test to which the glass-like layer is exposed is where all weak points are detected by the formation of a characteristic white arc.

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A vitreous layer 130 to 200 microns thick, produced using traditional enamelling techniques and brought to a temperature of 350 ° C., will not withstand a voltage of more than 1200 to 1400 volts. At a higher temperature, the voltage must be reduced. A glass-like layer produced according to the invention with a thickness of 130 to 200 microns, which has been brought to a temperature of more than 50O ⁰ C, shows no weakness at a voltage of 3000 V. When used as anti-acid and anti-base coatings, there must be no weakness in the vitreous layer at ordinary temperature even at a voltage of 20,000 volts. In order to meet these requirements, the vitreous layer produced using traditional enamelling processes must be 1.5 to 1.8 mm thick.

The invention is illustrated in more detail by the following examples, but without being limited to it.

example 1

A prefabricated concrete element measuring 80 cm × 40 cm × 2 cm, 1/3 of which consists of "cement CPA" and 2/3 of sand, is subjected to a treatment. 8 days after its shaping, this element is subjected to a light sandblasting treatment in order to remove the milky coating. It is then placed on iron rods (one chain), and which is to be coated surface of this element preheated to 290 ⁰ C, either by using a burner or preferably using Strahlungserhit zungsröhr s. The surface heated in this way is then provided with a glass coating using a METCO 6P gun equipped with a P7 AD nozzle and reciprocating. After the coating, the glass layer is smoothed by touching it

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Layer subjected to the radiation of a heating tube.

The sprayed glass has the following properties

- 92 Vo of the granules are between 40 and 100 microns in size

- the residue on an oieb with a mesh size of 150 microns is 0%,

- the specific surface size is 2000 cm / g. The applied glass coating consists of:

28.2% SiO ₂
52.6 % PbO
2.5 % TiO ₂

0.8% ^A1 2 ° 3

1.8 Vo Li ₂ O

1.2% Na ₂ O + K ₂ O

6 % B ₂ O ₅

0.2 % ZrO ₂

1.7% ZnO

5 % CuO

Such a glass has a transformation temperature of 4-75 ° C and a log ') at 920 ⁰ C of 2.05.

The spraying (spraying) is carried out in such a way that the glass at the moment of contact with the coating surface reaches a temperature of at least 1000 ° C and is largely and evenly this surface spreads. The spraying is carried out in an oxidizing environment. In this way a coating 100 microns thick of a sky blue color is obtained. Even after being stored in one Drying cabinet at 4-5 ° C and 100% relative humidity the vitreous coating undergoes no change for a period of one year.

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Example 2

One uses an element made of asbestos cement with the same dimensions, on which one has the same treatment as on using the element of Example 1, charging the gun with the same mixture, spraying but is carried out in a reducing environment. After this treatment, the item has one on the Carrier fully adhering red colored coating.

Example 3

A concrete element is used analogous to the one used Example 1, which is subjected to the same treatment. After preheating to 305 ° C., this element is subjected but superficial hydration with pressurized water vapor, then a coating is applied using a vitrifiable mixture containing the has the following properties:

- 88 % of the granules are between 40 and 100 microns in size,

- the residue on a sieve with a mesh size of 150 microns is 0 % and

- the specific surface size is 2400 cm / g.

The vitrifiable mixture used consists of: 87% soda lime glass

3 % boric acid

6 % sodium nitrate and

4 % cobalt oxide.

Such a glass has a log '·. * Of 2.2 at 320 ° C .; It is advisable to ensure that the glass on the surface to be coated reaches a temperature of at least 1320 ^° C. The coating obtained has after smoothing at 380 ° C the surface skin with radiation heating tubes

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a thickness of about 80 microns and a blue color that The carrier does not experience any change.

Example 4

Treating a concrete facade element of a pale yellow color on a construction site. First you grind the one to be treated Surface of the support lightly, then it is heated. Then you bring a first layer of a vitreous Then a second layer of the same coating, but thinner and with a larger gap from the carrier, and finally smoothing is carried out. The glazing geciinch used has the following physical properties:

- 80% of the granules have a size between 40 and Micron,

- the residue on a sieve with a mesh size of 150 microns is 0 %

- the specific surface area is 19OO cm / g. The glazing unit used consists of:

27 % ₂ 50 % PbO 4.5 % Al ₂ O ₃ 2 % Li ₂ O 9.5> i B ₂ O ₅ 2.5% ZrO ₂ 2.5 % ZnO 2 %

The glass has a transformation temperature of 475 ⁰ C and at 92o ° C has a log η of 2.12. In this way a fully adherent anti-reflective coating is obtained.

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Example 5

According to the invention, elements made of fired clay are treated during their cooling phase, their surface still being at a temperature of approximately 500.degree. One uses randomly one of the glasses described in the preceding examples, to which ΐ ', αη about 20 wt .- / j corundum grains with an average grain size of 30 microns are added. In this way it is easy to obtain a material coated with a well-adhering, homogeneous glass layer between 200 and 300 microns thick.

To achieve an anti-reflective effect. analogous to that as described in example M- , the coating is carried out in the form of two superimposed glass layers using zv / ei oxygen-acetylene guns, which operate successively at different distances, for example at a distance of 15 to 20 cm for one and from 30 to 55 cm for the other.

Example 6

In this example, the application of a glass-like, transparent, colorless anti-reflective coating on a Marble slab in order to protect it against atmospheric attacks, in particular those caused by to protect.

Initially treating the surface to be coated with a sand blast, then subjecting the surface to a flame treatment, has reached to the temperature of this surface is about 350 to 4-00 ⁰ C. The method according to the invention is then applied, using the METCO flame burner, type 6P, nozzle P7 AD.ein a glass powder with the

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provides the following properties:

- Grain size distribution: 87% of the grains have a diameter between 40 and 100 microns and 0 % of the grains remain on a sieve with a mesh size of 150 microns,

- the specific surface area is 2150 cm / g.

The composition of the glass powder is as follows: SiO ₂ 4 Vo PbO 71 %

B ₂ O ₅ 16 % K ₂ O 9%

The expansion coefficient of the glass at 0 to 50 ° C is 121 χ 10 " ⁷ ,

the log 'ij at 820 ^° C. is 1.9 and the softening temperature T _R is 385 ^° C.

The working conditions (amount of gas charged to the burner, amount of glass, distance between the burner and the surface to be coated) are selected so that the glass reaches ^{a temperature of at least 950 to 1000 ° C. on the surface to be coated.} In this way, the treated marble surface is provided with a uniform, firmly adhering coating of the glass; the thickness of the applied first layer is about 0.05 mra; a second layer of the same glass is then applied to this first layer (after the surface has been heated to about 350 ° C.) with a thickness of about 0.05 mm, this second layer also adhering very well. The surface is dusted with a thin layer of ethyl silicate.

It should be noted that it has heretofore been difficult to coat a marble layer with a glass coating because the marble decomposes in the presence of water vapor at a temperature below 900 ° C with the formation of Calcium ions, which have the property of clouding every glass coating.

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Example 7 Treatment of a wooden surface

After degreasing with ethyl acetate, a 30 µ thick layer of tin metal is applied using a METCO 1 OE gun. The material treated in this way is preheated by irradiation to about j>€> 0 ° G and then, using a METGO 6P gun, a vitreous coating of a glass is applied which has the following properties:

Composition:

SiO ₂ 20 % HgO 5 % CuO 4- %

B ₂ O ₃ 6 % Tl ₂ O 5 % PbO 60 %

This glass has the following properties:

- grain size distribution: 80 % of the grains are between 40 and 100 microns, the residue on a sieve with a mesh size of 150 microns is 0%,

- the specific surface area is 2050 cm / g

- The characteristic thermal softening temperature T ⁰ is 373 ⁰ C, the log y. at 820 ° C is 1.82.

The applied, green colored glass-like coating is after smoothed after application with a flame.

Example 8

Treatment of a low-density asbestos-cement carrier for the production of solar energy coils

The following work is carried out with a hemispherical dome made of asbestos cement:

- treatment with a sandblasting machine,

- application of a steel metal coating,

- applying a glass coating according to the invention,

- Application of a TiOp layer.

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The coating of steel with glass is carried out according to the method of the invention using two Glass powders with an average grain size of 80 microns, one of which (which forms the first layer) has the following composition:

SiO ₂ 33 % PbO 58 % B ₂ O ₅ 5 % TiO ₂ 4 % and of which the other (which the second layer builds up) has the following composition: SiO ₂ 55 % K ₂ O 2 ^ Al ₂ O ₅ 1.5 % ZnO 2.5 % ^B 2 ° 3 13% PbO 14% ZrO ₂ £ Z. / θ Example 9

Application of a glass coating to the V7and of a metal container for the storage of wine

The container to be coated inside has a cylindrical shape, a diameter of 10 m and a height of 8 m, its walls are 20 mm thick.

First, the inner surface of the container is degreased and then treated with steel shot. Then she will coated using a rotating device which translates helically so that one after the other all points of the surface are exposed to the effect of:

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- a * heating ramp consisting of a series of compressed air / Pron.pn burners to preheat the surface to a temperature of 5OC ⁰ C,

- A device for spraying (Aufsn ühen) of glass powder, the composition of which is given below, which cuts immediately on the so pre-wormed carrier, the temperature of the glass when it hits the carrier 1000 to T-SOO ⁰ C, depending according to the glasses used, can achieve

- a second propane / compressed air burner ramp and

- a ramp of IiETCO pin oils of the type 6P with the Diine P? AD, which inject the same molten GD ns onto the carrier, which has the following network:

17%

B ₂ O ₃ 5 Vo

HiO 2 V>

Na ₂ O 5 vol

K ₂ O 5 VS

PbO 65 95

LInO 1, ^%

CoO 1, S %

- an atomization ramp, which advised on the surface - still warm glass of isopropyl titanate dusted.

Under the same working conditions, glasses of the following compositions "can be used with success:

A) SiO ₂ 28 V>

PbO 52 %

TiO ₂ 2 %

IC 0 7 * 9 /

B ₂ O ₅ S %

ZrO ₂ 2%

CdO 3

CoO 6

/O

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a such a glass has a softening temperature of 470 ⁰ C and a log) 'at 92o ° C of 2.10;

B) SiO ₂ 55 vol

PbO 41 %

Li ₂ O 5 ^L / o

GDP ₅ 7%

SnO ₂ 4 previous year

ZrO ₂ 2 Vo

NiO 2 %

CoO 1%

K ₂ O 4 Vo

such a glaze has a softening temperature of 480 ° C and a log ij at 920 ° C of 2.15;

B ₂ O ₃

X v. '' / -> 46 Vo 8th Vo 1 Vo 2 % 2 % 5 % 5 Vi

ZrO ₂
Zno "
CdO

such a glass has a softening temperature of 480 ⁰ C and a log η at 920 ° C of 2.10;

D) TeO ₂ 15%

Tl ₂ O 5 Vo

₂ 1 ^c , j

PbO 74/3

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such a glass has a softening temperature of 280.degree. C. and a log »· at 920.degree. C. of 0.2.

Example 10

On a plate made of ordinary steel (carbon content 0.17 / ό) a glass-like anti-acid and anti-base coating is applied on. You work as follows:

- the surface to be coated is degreased with Vrichlorethylene and then treated;

cleaned with steel grit;

- the plate is preheated to 800 ° C,

- with an M CTOO-GP brand oxygen-acetylene gun apply a smooth primer about 40 microns thick on which you then have a glass cover, not a thickness of about 20 microns,

- then you do a smoothing with the fla rie of the pistol by.

The glasses used have the following properties: Grain size distribution: - Grinding glass: 86 % of the grains have a diameter between 40 and 100 microns,

- Cover glass: 90 % of the granules have a diameter between 4µ and 100 microns,

- specific surface size: priming glass 2350 cmVg

Cover glass 2150 cm ^ / g

Chemical composition (in% by weight):

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Primer class Cover slip 62 3 17th Ί 8th 7th 1 1 0.5 1 0.5 1

^B 2 ° 3
ZrO ₂

MnO ₂

Li ₀ O

Na ₂ O 15

At sj X

A glass of the addition indicated below is used nriL'ie ns c t tion:

SiO ₀ 68; '.:

7 ^ 12%

ZrO ₂ 7 '

CaO 1 %

MgO 1%

ZnO 1>

This glass is used in the form of a powder, its Particles have a diameter between 40 and 100 microns and their specific surface area 23CK) was ~ / g punished.

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BATH ORIGINAL

■ ... from right

One coats a marble using the above specified powder by doing the following operations carries out:

- Treatment nit a I3 'ndstrahlgebläRe _t?.

- Preheating the material to about 3 (H) ⁰ C,

- spraying of the powder using an} innermost gun, which has the following properties:

electrical energy consumption 7 kV / h

The amount of plasma-forming gas supplied,

(Nitrogen) 0.85 m / h

Hydrogen feed rate 0.2 m / h

Cooling water 0.4 nr / h

The angle of introduction of the powder into the nozzle is 0 °

The distance from the gun to the surface to be coated is 1 ^ cm.

Under these conditions, a homogeneous draw 40 microns thick is made in a single Du ¹¹ Ch; : nec

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BATH ORIGINAL

Claims (1)

PATENTAh ¹ W * LT KLAUS D. KIRSCHNER OIPL.-PHYSICIST BAVARIARINO 38 D-BOOO MDNCHEN 2 YOUR SIGN: VOUR REFERENCE: MY CHARACTER: MV REFERENCE: B 999 K / ÜK Andre BISCH F-67370 Truchtersheim / France Date: September 5, 1977 Method for applying a vitreous coating or a Enamel coating on at least one surface of a carrier Claims 1, Method of applying a vitreous coating or an enamel coating on at least one surface of a carrier, characterized in that that he - cleans the surface to be coated, - The surface to be coated is preheated to a temperature of at least 250 ° C and - The glass forming the coating is sprayed onto the surface to be coated (sprayed on), v / obei using the glass in the form of a powder, the particles of which have an average particle size distribution between 40 and 100 microns with C % residue on a sieve with a 809810/0975 original inspected have a clear mesh size of 150 microns and a specific surface area between 800 and 3000 cm / g, the spraying (spraying) being carried out using a device which is able to completely remove the glass particles during the spraying (spraying) (up to the center ) to melt, and the spraying (spraying) is carried out under such conditions that the temperature reached by the glass at the moment of formation of the surface layer is at least equal to the temperature for which log <y is at most 2.2, where ' ■ ': represents the viscosity of the glass at the temperature under consideration. 2. The method according to claim 1, characterized in that the glass used for the coating has a coefficient of expansion which is close to the expansion coefficient of the carrier. 5. The method according to any one of claims 1 and 2, characterized characterized in that the spraying (spraying) and the melting of the glass powder using a Oxygen-acetylene burner is carried out and that a glass with such a viscosity -: ■ at 1400 ° C used that log>. is below 2.2. 4. The method according to claim 3, characterized in that that a carrier is coated, the surface of which can change when the temperature of this surface is 35O ° C exceeds, in particular a beam made of a material that can be used in construction, and that one uses a glass whose softening temperature is between 250 and 480 ° C and whose logr is 920 ° C is below 2.2. 5. The method according to any one of claims 3 and 4, characterized characterized in that a fusible glass is used as the glass, which preferably contains cations with large dimensions or contains highly polarizable cations or fluxes. 809810/0975 6. The method according to claim 3, characterized in that that one coated a metal support. 7. The method according to claim 6, characterized in that that one coated a steel beam, which one preheated to a temperature above 550 C, and that one the coating is carried out in the presence of a metal, that is selected from the group consisting of nickel, cobalt and manganese. 8. The method according to any one of claims 1 and 2, characterized in that the spraying (spraying) and the melting of the glass powder is carried out using a plasma torch whose temperature inside the nozzle is between 6000 and 10,000 ° C and that one Glass is used whose viscosity rf at 1400 ° C is so high? is that log "η > 2.2. 809810/097 !, ORIG.NALiNSPECTED