DE1646735B1 - FLAME MOLD - Google Patents

Description

The invention relates to improvements in spraying of copper- and silver-containing flame spraying compounds. In particular, it relates to an improved one Flame spraying compound containing copper and / or silver, on a method for spraying a conductive coating on a ceramic surface using this flame spray material and on ceramic material which has such a sprayed-on surface.

The known flame spraying process is practiced largely in an economical manner; it exists therein, a flame-spraying compound consisting, for example, of metal or refractory material, to temperatures to heat, in which it is at least softened in the warmth, and then against a To hurl the basis in order to form a coating on this. The spraying is generally carried out using known flame spray guns; in the case of powder spray guns, the flame spraying compound is used in the form of a powder, while in the case of wire-type guns, the flame spray material is used in the form of a wire or rod.

To ensure that the sprayed-on coating is firmly bonded to the substrate adheres, it is generally necessary to sufficiently penetrate the surface to be sprayed To pretreat roughening or to ensure a satisfactory bond in some other way, for example by spraying on a molybdenum bonding layer. For many purposes it is desirable to have a To coat the ceramic surface with a coating of silver or copper. For example, comes this is particularly in question in electronics, where one often has an electrically conductive copper or Silver coating is required on a ceramic body or one with a ceramic surface. That However, spraying copper coatings onto such ceramic surfaces has not been found to be practical proven. Difficulties arose when the ceramic surface was sufficiently roughened by mechanical means, as you would in order to ensure a perfect binding of the sprayed Materials needed. A surface roughness of 8 microns, preferably with scratches (undercuts), is generally for a satisfactory bond between the flame-sprayed Coating and the underlay requirement. However, you can achieve this with the usual sandblasting treatment a roughening of this extent is not attributable to the hard nature of the ceramic material is. In addition, mechanical roughening of the surface is not permitted for many purposes in this way the required tolerances can be disturbed.

It is known from the literature section WADC TR 59-415, p. 9, tungsten surfaces with a layer to be coated with borosilicate glass. The spraying of glass mixed with copper and / or silver is not specified here, but rather the coating of sprayed-on tungsten coatings with a glass coating. First of all, it is mentioned here that a coating made of tungsten with zirconium oxide and / or aluminum oxide is to be coated by flame spraying. It is then also described that a tungsten wire is used can be covered with borosilicate glass by spraying the glass. From a common splash There is no mention of tungsten with glass as part of a mixture.

The German patent specification 258 505 describes a method for producing dense metallic coatings by flame spraying, whereby it is also mentioned that the light liquid of the coating material is used can be increased by adding flux to the metals.

The addition of fluxes to the metal has been a matter of course in flame spraying technology for a long time Years known. Above all, what is common in spray welding is the spraying on of metals already carried out with a flux for different combinations. In this context However, the task of adding fluxes is quite different from that of the invention, where it is a matter of extremely firmly adhering to a base made of ceramic mass and also apply conductive coating. It has been found that the spraying the conductive material itself does not give satisfactory results. In neither of the two There is some evidence found in publications that the addition of glass works surprisingly result in an extremely strong increase in the adhesive strength of the conductive metals could. According to the invention, it is thus possible in a very simple way to produce conductive metals with bases to apply from ceramic masses while maintaining the conductivity in an extremely strong connection.

Even if it had been known, other materials such as tungsten with glass had good adhesive strength to apply to documents, this could not suggest that mixtures of Glass with copper and / or silver in the simplest way eliminates the problem of adhesive strength while maintaining the solve the desired conductivity. In this context it is very important that, as in Example 1 shows that copper wires could be soldered to the surface coated according to the invention, without the need for an additional layer. The soldered wires and the inventive Cover were very firmly connected to each other, while the connection between the cover and isolator had not been adversely affected in any way.

The invention relates to the application of conductive copper or silver coatings to a ceramic Surface with the help of the flame spraying process, whereby the disadvantages mentioned do not occur.

Furthermore, it is possible according to the invention to spray firmly adhering copper or silver coatings onto ceramic surfaces without having to make use of the customary roughening methods.
The flame spraying composition of the invention contains copper and / or silver as the conductive metal and is characterized in that it contains 4 to 5 percent by volume of glass in a form which can be melted together with the metals in the flame spraying process. According to the invention, tenaciously adhering conductive coatings are obtained on the substrate, even on dense, smooth ceramic surfaces.

The spraying of the mass of the invention can be with a copper and / or silver as well as glass containing Mass take place, which has somehow been prepared in the usual way as flame spraying material. Accordingly metal and glass can be used in the form of a conventional flame spray powder, the a mixture of metal powder and glass powder

3 4

represents. The powder is intended to pull out individual particles of the usual desired diameter. In the same

To have size, for example, should be particle-wise, wires can be made of silver and glass

sizes between 3 and 150 microns are preferred.

between 15 and 105 microns, although the flame spraying surface, which contains metal and glass Particle size and the associated tolerances 5 mass of the invention is particularly suitable for Aufvon the special type of flame spraying device spray onto ceramic surfaces such as those made of hang. The numbers mentioned for particle sizes aluminum oxide, quartz, steatite, forsterite, zirconium or and tolerances are within the range of the tech cordierite. The sprayed material is then in nik usual. The mixture can produce 4 to 50 volume-tough bonds with the backing, even if percent glass and preferably 20 to 45 volumes whose surface is dense and relatively smooth, percent glass, but in particular should, as is the case with a surface roughness, for example 35 percent by volume of glass is present. As far as the case of less than an average of 0.3 microns Percentage by volume glass is spoken of, refers to it. This was done according to the USA standard method this information on the real volume (in contrast to B 46.1-1955 measured. It was measured with a to the bulk volume), based on the total cutoff distance of 0.75 mm and the volume of copper and / or silver and glass on the 0.75 micron (maximum) scale with a roughness mixture, measuring device (profilometer) worked by the

Copper can be obtained in the form of the well-known Copper Micrometrical Manufacturing Co., Ann Arbor, Michi-

Flame spray powder are present, which is also made from particles.

a copper alloy, which mainly consists of copper. like brass, beryllium — copper, copper — high to be cleaned. The sprayed-on coatings Nickel, copper-chromium and tin-bronze, for example, have a thickness of 50 to can. 250 microns before. Despite the presence of glass

In the same way, the silver can be shaped, the coatings are electrically conductive to a high degree

known silver flame spray powder or SiI-25 and easy to solder, so that wires or electrical

Alloy flame spray powder particles are present. Elements immediately using normal

Mixtures of copper and silver can be combined in all tin soldering

desired proportions are used. can.

The glass should be any familiar and flame-sprayed. It is also possible to start with the

Be barable glass, preferably one uses silica 3 ° mass of the invention sprayed-on pad an over-

Acid-containing glasses, in particular borosilicate flame spray material based on metal or on

To spray on melting glasses, glasses containing cobalt oxide or the base of refractory substances, so that

usual soda lime glasses. there is sufficient adhesive strength. The crowd

Instead of a powder mixture, the flame spraying device of the invention can serve as a binding intermediate powder urform of a mass, each of which has 35 layers. For example, the first with Individual particles contain both the metal or metals and glass coated with a glass-containing base. Correspondingly, the individual layers of copper or silver can be applied directly to powder particles without glass from fused aggregate syringes so that the ceramic base becomes one Gates of copper and glass consist of body, copper or silver plating, while the glass pern, the layer containing a copper core with a glass coating 40 as a connecting intermediate layer contain or a glass core with a copper overlap. On the initially applied, glass withdrawal. The component enveloping the core can leave other substances in the holding layer, such as In the form of a real glass or copper layer in front of platinum, tin, solder, aluminum oxide, etc. But it can also spray out of smaller particles.

Coating compound such as copper or glass, 45 The invention is particularly suitable for the manufacture

with the help of a binding agent to the core of materials for the electrical or

who have been. Example: A binder that is electronic sector, for example one can be a

decomposes at the flame spray temperatures, e.g. B. an electrically conductive copper layer on a smooth

phenolic varnish. Spray on the same components as a grain-tight insulator, e. B. an aluminum

men of course also consider silver. 50 oxide isolator. In this way, z. B. Boards

The flame spray powder of the invention can be produced in accordance with the invention with a printed circuit, Usually with a powder flame spray gun by passing the circuit diagram through a template spray on, for example one that has a compound on a high density base, for example Combustion and the combustion sustaining gases sprayed onto those of aluminum oxide. the such as hydrogen and oxygen, or one of 55 electricity-consuming elements, such as capacitors, Plasma flame spray gun. The powder can also be used in resistors, transistors etc. that can easily be applied to the Form of a rod or wire incorporated sprayed-on coating to be soldered. The invention be, for example with the help of one made of polyethylene can also be used for spraying bridges or existing binder, and in the usual way with connections between previously laid parts of sprayed with a flame spray gun. That 60 circuits use it to ensure electrical continuity conductive material made of metal and glass to effect. Individual components such as PoUeitungsisola invention can also be sprayed directly to a flame torch for soldering Spray wire have been deformed, for example to facilitate the required metal parts. Condensation Incorporation of a compact mix of capacitors can be done by spraying on the counter-glass and copper powder in a copper sheath. Here 65 overlapping sides of a ceramic plate can be made a copper jacket can be formed with the powder mixture. The sprayed-on coverings can Fill out of glass and copper, the end can also be used for heat transfer to weld and the jacket on the z. B. uniform warmth of the surface of a ceramic

Claims (7)

5 6 micbodies or to derive the radiation from this example 4 area. The bonding of the metal-glass coating on Example 1 was repeated, but instead of the base, the base of the glass used here does not require any heating. In this case, too, other unfavorable effects on this were given equally good results, are switched. R. . 1 The following examples illustrate the example invention. Example 1 was repeated with the exception that. ίο that spraying with a Metco type 2M example is a game! Plasma flame spray gun was carried out using a copper powder (round individual particles of high Ε nozzle was used. Nitrogen was used as Pias purity with a particle size between 44 and magas under a pressure of 3.5 kg / cm2 and a 88 micron) about 38 percent by volume, based on an amount of 2.83 m3, while hydrogen is applied to the total volume of borosilicate glass at 3.5 kg / cm2 pressure and 140 l / h. was used, mixes. (Borosilicate glass = Corning Glas Comp. The gun works at 75VoIt and 250 Ampere No. 7052 Covar Sealing Glass with about 15 to 140 microns at an application speed of 3.18 kg / hour - and a spray distance of 7.5 to 10 cm. A glazed surface of a sintered aluminum coating was formed, an electrically highly conductive coating, oxide base of high density was cleaned by light blasting of the coating obtained according to example 1 with aluminum oxide powder of the grain size 60; was treated with example 6 1.4 kg / cm ² air pressure at a distance of 15.2 cm. This surface had a surface texture - Example 1 was repeated with the exception that i.e. from about 0.25 to 0.40 microns. The pad 25 is a silver powder with a particle size of 44 was preheated to about 121 ° C, water condensed to 125 microns in place of copper to remove saturated moisture. The splash that was. The coating adhered and was excellent Powder mixing is carried out with the Metco 2P thermo-electrically conductive. spray gun using a P7 metal ". -17 jet; Hydrogen was at a pressure of 30 eispie 1.05 kg / cm ² in an amount of 4.2 m ² / h., Sauer- Example 1 was repeated with the exception, substance under a pressure of 1.05 kg / cm ² and that the spraying on different bases amount of 8501 / h applied; the carrier gas was carried out, including beryllium oxide, zirconium oxide, control device was set to 14 notches; Application quartz, steatite, forsterite, zircon and cordierite.
speed: about 2.7 kg / hour. A 35 -r · · 1 s was obtained 127 micron thick topping of excellent adhesion- Example 8
strength. The covering was electrically conductive since Example 1 was repeated with the exception of a standard ohmmeter showing that the 125 micron thick copper-glass covering could be substantially less than 1 ohm resistance over a 250 micron aluminum oxide layer 7.5 cm pavement surface 40 thickness was covered. The appearance of aluminum was flame-sprayed. Metco No. 101 type copper oxide powder was soldered to the coated surface with a ferrule without an additional oversize particle size of 15 to 44 microns; stratification was used; the soldering was carried out with a thermal spray gun of the Metco 2 P type with common tin-lead solder and an iron using a P 7-C ceramic nozzle. Acetylene soldering iron made. The soldered wires 45 were put together under a pressure of 0.84 kg / cm ² and the coating was very tightly combined with each other at a rate of 7901 / hour. and oxygen under an inhibited been during the bond between the coating and pressure of 1 kg / cm ² and an amount of the insulator in no way adversely affected 1.33 m ^s / h. applied. The carrier gas control regulator was. works with 12 notches, the application ^{speed, for example, 2 5} ° ^ etru S 1.02 kg / hour. The flame-sprayed aluminum-oxide coating was firmly coated on the copper glass Example 1 was repeated with the exception that a ceramic base was bonded and placed on top that on a glazed aluminum oxide base on the electrically conductive copper-glass layer was injected, with equally good results on electrical insulation. fell. 55 _,. . , _n Example 9 Example 1 was repeated with the exception Example 1 was repeated with the exception that the copper was replaced by a mixture of copper that instead of Covar sealing glass (a glass with powder and 50 percent by weight tin powder a low thermal expansion) has been replaced with a ^{particle size of 6o} from 44 to 105 microns, high thermal expansion was applied. based on the total content of copper plus tin. This glass belonged to the genus of the high-SiO ₂ -containing- Equally good results were obtained gen glasses, which, along with other components, have one. contain a small percentage of cobalt oxide and claims: which are generally used in porcelain enamelling 65 1. Flame spraying compound, which is copper and / or be used to contain a good silver as an electrically conductive metal on steel substrates, d a - Ensure adhesion of colored top coats. characterized in that they are about 4 Equally good results were obtained. up to 50, in particular 20 to 45 percent by volume Glass in a joint flame-sprayable with the metals Contains shape. 2. Flame injection compound according to claim 1, characterized in that it is in the form of a powder mixture of metal and glass is present. 3. Flame injection compound according to claim 1 and 2, characterized in that the glass is a borosilicate fused glass is. 4. Flame injection compound according to claim 1 to 3, characterized in that it is about 35 percent by volume Contains glass. 5. Flame injection compound according to claim 1 to 4, characterized in that the individual PuI- represent grains of particles that contain the conductive metal and glass together. 6. flame injection compound according to claim 1, 3 and 4, characterized in that it is in the form of a flame spray wire is present, in particular one whose sheath consists of the conductive Metal and its core consists of conductive metal and glass powder. 7. A method for flame spraying using the flame spraying composition according to claim 1 to 6, characterized in that the mass is based on a ceramic, in particular a those made of aluminum oxide, sprayed on. Ί09 542/214