DE1571409A1 - Bonding compounds and processes for the high-vacuum-tight and high-temperature-resistant bonding of objects made of ceramic and / or glass-ceramic material with extremely low thermal expansion - Google Patents

Description

Connection compounds and methods for high-vacuum, tight and high-temperature-resistant connection of objects made of ceramic and / or glass-ceramic material with extremely low thermal expansion called ceramic material) extremely low thermal expansion, ie with an expansion coefficient (1K) 0-L = i0.10-7deg-i and below up to negative values, @ where the ceramic material is the main component. contains the three-soft system 1120-A1203-Si02 and the main mineral components $ ukryptite, spodumene and petalite either alone or in combinations.

2e, methods for joining objects made of ceramic material are already known. In this process, an adhesive bond was established between ceramic bodies with an AK o2 it 30.10-7deg-i and above using bonding compounds such as s, 11, Notallote or U% Iäeer. So z. B. Parts res noröeer Poreterit-Reramik connected with each other with the help of a glass Z1lsa from Zucke the Binbauee in sheet metal tubes . The previously known soldering glasses are not suitable for ceramic materials with an AK a, 10.10-7degree-1 and below, such as eucryptite, 3podumene and petalite ceramic materials. Because of the different AKs of the materials to be connected and the different compositions, a normal glass connection cannot be established. When the connection produced at a higher temperature cools, biting occurs at the connection seam. Suitable soldering glasses or bonding compounds were not previously known for bukryptite etc. ceramics.

The purpose to be achieved by the present invention is the elimination of the deficiencies in the state of the art in terms of manufacturing High vacuum and high temperature resistant connections for ceramic materials extremely low thermal expansion.

The invention is based on the object of finding a connection device, if necessary a method, with the aid of which it is possible to produce connections between objects made of the ceramic material with extremely low thermal expansion, the connections being stable up to a temperature of 100,000 a pressure of, for example, 10-4 Torr high vacuum tight bind. It was found that Verbindmsen are suitable for the required purpose, the same as Bmptkoaponenten contain "linking nuclear waste away both body, but in deep @ @ ISPEX Atarin, ®chnelsen than the material to be joined. = is beer praying. Marshalling that the U of the connection area of the AK does not have to be adapted to the m werbindedern l @ ile. The compounds have the following composition Zi20 10 to 25% by weight, A1203 5 to 30 wt. 9b, SiO2 50 to 85 wt%. For example, the following compositions have proven to be particularly advantageous : Composition in weight: -L Zi20_ A1203 Si02 melting point in 0C 13.5 7.0 79.5 980 15.85 8.75 75.4 975 19.4 15.1 65.5 1026 21.0 23.0 56.0 1065 A melting point which is at least 5000 below the deformation temperature of one of the objects to be joined, and a viscosity of at most 106 poise at the melting point are essential for the selection of the suitable composition of the joining compound.

The compound masses have a coefficient of expansion between 20 and 70,000 a- = 50 ... 70degrees-1 and at 1000 or 11000C a viscosity of about 103 to 105 Poise. Connection seams, made with these masses according to the present process, are high vacuum tight; a vacuum of e.g. 10-4 Torr can be maintained.

As a result of their composition, the compounds constitute one electrical insulator.

The compound masses can be produced by simply melting them. The melts obtained are to be poured into water for reasons of expediency (to be granulated) and brought to a particle size by grinding which is below 60 bum lies. The powder obtained in this way can be used directly as such or as a paste with a content of up to TO% by weight of powder, using as a suspending agent those are used which are used before the melting temperature of the connecting materials can be removed without leaving any residue, e.g. 8. Water or nitrocellulose binder.

A method has also been found for the high-vacuum-tight, high-temperature-resistant joining of objects made of ceramic material with extremely low thermal expansion using the joining compounds according to the invention. The respective connecting surfaces of the parts of the objects to be connected are affected by unevenness, e.g. B. by grinding, frees one of the connecting surfaces with bonding compound, maximally 0.5 mm thick, evenly coated, assembling the pre-treated connecting surfaces, the connecting surfaces, depending on the thickness of the parts of the objects carrying the connecting surface, at a speed of preferably between 1 and 100 ° C per minute up to 200 ° C above the melting point of the connecting mass and leaving the whole thing at this temperature until the connection between the connecting mass and the objects to be connected react. The cooling of the joined parts to room temperature is preferably carried out at the same rate that was necessary for heating the joining surfaces. The connection thus obtained is so tight and strong that breakage by impact does not occur along the connection surface.

The high-temperature-resistant and high-vacuum-tight connection to the connection surface of the objects to be connected made of the ceramic material can be explained primarily by the fact that part of the molten connection compound diffuses into the ceramic material and that the ceramic material reacts with the connection compound at the connection surface and the reaction layer represents a .Art transition layer between the bonding compound and the ceramic material. The heating of the connection surfaces with the applied connection compound must generally take place quickly enough so that the connection compound melts and opens up. well distributed over the surface before the reaction between the surface and the bonding compound and thus crystallization occurs. 3o lines that are, for example, 5 mm: thick, can easily be heated at a rate of 10,000 per minute; For parts that are several centimeters thick, the speed of heating is to be kept lower for reasons of expediency, for example: for 3 cm thick parts about 10o0 per minute.

With) eleven of the connecting compounds according to the invention and the method it is now possible to connect objects made of the ceramic material with east's low thermal expansion in a highly vacuum-tight manner and at high temperatures. 8o the Verbinen up to a temperature of 1000 ° 0 temperature resistant and keep Z.8. a vacuum of 10-4 torr.

The present invention is explained in more detail by the following exemplary embodiments. Example 1 Two rods made of a ceramic material are to be connected, which by controlled crystallization of a glass of added composition (in% by weight) 51.1 3i02; 3496 A7.203; 101.2 L; 20; 398 T; 02 .; 093 1, and which has an A8 Qt = 3.10m7 / 00 (between 20 and 70,000) .

Dimensions of the bars: 5 x 5 x 50 am.

The two bars should be connected to each other in a T-shape. They are ground flat at the connection point. One of the connection surfaces with a powder with a particle size of up to 60 μm and a compound composition of the composition which melts at 975 ° C. (in% by weight): 15985 L.20; 8.75 A1203; 75.4 9i02 evenly coated with a thickness of 0.5 mm and the connection surface of the other rod brought together with the IPI surface of the first rod while pressing firmly. The whole thing is now placed in an oven at room temperature, which is brought to a temperature of 1150 ° C at a rate of about 2000 per minute. Bin .d for sufficient reaction between the Verbindungesaaea and the material to be bonded, of the @ xiauten about 30, this temperature is maintained and then with about the same G.go, miadigkeit Arie previously on Rauat "ebgekUhlt temperature. To test its temperature resistance, the T-piece was placed in an oven in such a way that the attached 50 mm long rod was suspended under the force of the impact. The oven was heated up at 200C per minute. The attached rod part peeled off at 1130 ° C. Example 2 Two pieces of pipe made of the same material as specified in Example 1 are to be connected. One of the two pipe sections is closed on one side. Dimensions of the pipe sections: 30 mm outer diameter 1.5 mm wall thickness 30 mm effort The connection of the two pipe pieces is carried out in the same way and with the same connection compound as described under Example 1, in such a way that a 60 mm long pipe closed on one side is produced. To test for vacuum tightness, the open side of the body was connected to a vacuum system by means of Picein. A vacuum of 10-4 torr was applied and the system was sealed off. Over the course of 14 days, it was checked several times with a Tesla vacuum tester for a release of the vacuum.

No change could be found.

Claims (3)

Claims: 1. Connection compounds for high vacuum tight and high temperature resistant Joining of objects made of ceramic and / or glass ceramic material extremely low thermal expansion, characterized in that the connecting compounds consist of 10 to 25% by weight of Zi20, 5 to 30% by weight of A1203 and 50 to 85% by weight of SiO2. 2. Connection compounds according to claim 1, characterized in that they are with a Particle size below 60 µm either as powders or as pastes with a content up to 70% by weight of powder are present, the pastes containing suspending agents, which can be removed without leaving any residue before the bonding compound has reached its melting temperature are. 3. Process for the high-vacuum-tight and high-temperature-resistant connection of Objects made of ceramic and / or glass ceramic material extremely lower Thermal expansion with the use of a connecting compound according to Claims 1 and 2, characterized in that characterized in that, after removing unevenness on the connecting surfaces of the parts of the objects to be connected, a connection surface with connection compound is evenly coated in a thickness of no more than 0.5 mm, the connecting surfaces pretreated in this way composed and depending on the thickness of the bearing surfaces Parts of the objects, at a rate of preferably between 1 and 100 ° C heated up to 200 ° C per minute above the melting point of the compound, whereupon the whole thing up to the reaction between connecting mass and to be connected Leave objects at this temperature and the connected parts with a Rate of preferably between 1 and 100 ° C per minute to room temperature is cooled.