DE1953891B2 - High temperature resistant putty material - Google Patents

Description

SiO ₇ 9-26 B ₂ O ₃ 9-36 Al ₂ O ₃ 0-16 CaO + SrO + BaO + MgO 9-56 ZnO + CdO 9-56

where the sum of

CaO + SrO + BaO + MgO + ZnO + CdO is equal to or greater than 50 mol%

The invention relates to a cement material, in particular for use in cement connections between metal and a ceramic material, between two metals or between two ceramic materials.

Such putty connections are often high in the operation of the equipment in which they are used Exposed to operating temperatures and it is desirable to manufacture them at relatively low temperatures in order to avoid any change in the constituent parts (deformation, brittleness, etc.).

It is known for putty connections between one ceramic material and metal or between glass and metal to use stable types of glass that correspond to the Type of the so-called "long" types of glass, d. H. Glass types whose viscosity remains high over a wide temperature range and whose silicon content is high.

The adhesion between glass and metal is brought about by a chemical bond which is produced by the after the layer of oxide remaining between the material and the glass is obtained in the cement; a long" Type of glass that has a high viscosity at the temperature required to produce the cement joint has made it difficult to dissolve the oxide layer.

In connection with the wider temperature range in which the viscosity of such cement compounds however, the maximum operating temperature in the table will change

Devices in which these cement compounds are used are well below the cement temperature.

In addition, the composition of a glass of this type is such that its specific resistance

■ j stand decreases rapidly with increasing temperature

In US Pat. No. 3,113,878, a putty material is described which consists of devitrifiable types of glass from "Short" type is composed of a relatively low silicon content.

In terms of these types of glass described is such that the sum of the three oxides ZnO + B ₂ O ₃ + SiO _{2 is} at least 90%

i) types of glass is relatively narrow which makes the Applications are limited.

The purpose of the invention is to provide a new putty material which can be used for many purposes, in particular for higher temperatures, can be applied, whereby the favorable mechanical and electrical properties are retained.

The invention relates to a high-temperature-resistant cement material, in particular for the production of a Connection between materials, their expansion coefficient between about 45 and 100 - 10- ⁷ / ° C, which consists of a devitrifiable glass from the "short" type on the basis of the oxides of aluminum, boron, silicon, zinc and, optionally, cadmium and further oxides containing the network-changing ions provide , how

jo alkaline earth oxide or magnesium, with that mentioned Material is characterized in that the quantities of the starting components in MoI - ° / o within the the following limits are:

SiO ₂ 9-26

B ₂ O ₃ 9-36

Al ₂ O ₃ 0-16

CaO + SrO + BaO + MgO 9-56

ZnO + CdO 9-56

4u where the sum of

CaO + SrO + BaO + MgO + ZnO + CdO

is equal to or greater than 50 mol%.
Because of their high content of network-changing ions, these types of glass only slightly attack the oxide layer that causes the adhesion between the glass and the metal. For example, various starting compositions of putty materials according to the invention are given in the table below:

Composition in mol% 1 2 3 4th 5 6th 7th 8th 9 10 U 12th 13th 14th 15th 16 number 15th 15th 15th 35 15th 15th 35 15th 15th 15th 35 15th 15th 20th 15th 15th O 20th 20th 20th 10 20th 20th 10 20th 20th 20th 10 20th 20th 15th 20th 15th B ₂ O ₃ 35 5 5 5 5 10 15th 5 SiO ₂ 10 15th 15th 20th 20th 20th 25th 25th 25th 25th 45 40 55 Al ₂ O ₃ 10 40 CaO 5 25th SrO 5 BaO 50 45 50 35 40 45 30th 35 40 35 30th 10 40 10 25th 10 MgO ZnO 50 10? 53 57 61 64 65 69 70 72 74 76 80 82 83 86 90 99 x ° C- ' Between 20 47 and 320 ⁰ C

In certain cases it can be beneficial if at least part of the zinc oxide is replaced by cadmium oxide is replaced.

For example, 50% of the zinc oxide in compositions 5 and 7 can be replaced by cadmium oxide will.

These compositions correspond to devitrifiable glasses of the short type, borosilicate systems and borosilico zinc aluminate systems with alkaline earth ions which, if they contain a sufficient number of network altering ions, retain the oxide layer necessary to produce a good bond. They are processed according to the generally known glass technology at temperatures between 1200 and 1450 ^° C.

The resulting molten glass is then converted into a frit, e.g. B. by having it in water is hardened, after which it is ground; it can then be used as a putty material. The cement connection is made by the usual techniques in an atmosphere that depends on the nature of the parts to be connected to each other is selected and set.

Due to the selected starting composition and the fine distribution of the ground Putty material transforms the glasses into glass ceramic products, which consist of a vitreous network exist, in which there are finely divided microcrystals of one or more crystal phases. By the The presence of the latter has a favorable effect on the mechanical properties of the connection. Of the Content of crystal phase depending on the starting composition and the temperature at which the compound is produced is dependent, but must remain low in order to achieve that the material between the ) The seams of the parts to be joined together can flow.

The time and the temperature of the production of the cement connection are therefore not only dependent on the type of parts to be connected, but also in

ίο Dependence on their geometry, their wetting properties and chosen their river

The mechanical properties of the obtained joints, determined by the flexural strength are below for various

ι> Tests given in which certain compositions of the table can be used.

The initial composition is chosen so that the expansion coefficient of the cement material the body to be connected is adapted to the conditions under which the connections are made are determined by the duration and temperature

example 1

With the help of powders with compositions 0,1,2, 4, 5, 6, 7 and 9 according to the table are cylindrical test tubes from Fernico in a 25% hydrogen containing and saturated with water vapor of room temperature nitrogen atmosphere with each other

soldered in.

composition
0 1

Treatment 10 min. At ( ⁰ C)
Flexural strength in kg / mm- ²

950 1100 1050 950 1050 1100 900 1050 18.1 19.1 17.5 18.1 21.9 18.2 103 8th

The flexural strength is still high even if the expansion coefficient of the connection is from the of the material to be connected is different. From a mechanical point of view excellent results will be achieved achieved with putty materials with coefficients of expansion between 47 and 69 · 10-'.

Example 2

With the help of the compositions 1, 2, 3, 5, 6 and 9, cylindrical test tubes are made of sintered Aluminum oxide cemented together with the end faces in a non-reducing atmosphere

composition

12 3 4 5 6 9

Treatment 10 min. At ( ⁰ C) 1100 1050 1100 950 1050 1100 1050 Flexural strength in kg / mm- ² 20.9 16.8 29.3 28.0 27.9 27.8 19.5

In fact, the intrinsic strength of the connection is greater than in most of the performed Tests, particularly with compositions 3, 4, 5 and 6, occurred in the alumina fracture.

Example 3

With the help of the compositions 1, 2, 3, 4, 5, 6 and 9 and with water vapor at room temperature Cylindrical aluminum oxide rings were soldered to a cylindrically saturated nitrogen atmosphere see femicore rings containing 25% hydrogen

composition
1 2

Treatment temp. in ⁰ C 1000 1050 1100 900 1050 1100 1050 Flexural strength in kg / mm- ² 22.0 15.2 16.5 16.0 16.3 143 13.1

The electrical properties of the connections determined by the resistivity as a function of Temperature determined are given in the table below, with measurements using Fernico connections on Fernico with the help of putty materials according to the invention with some compositions the table.

In the last column comparatively di <results of the measurements of the specific resistance that of Fernico connections applied to Fernico with the help of a long type glass. At this Compounds, the resistivity increases much faster with increasing temperature.

material 2 5 Manufacturing temperature in ° C 1050 1050 - - 6th 9 Glass from 1 1000 Log. of the spec. Resistance in Ω · cm 11th 11.5 "Long" type 10 10.5 1100 950 11.4 9.1 9.6 950 10 8.2 8.8 Measurement temperature in "C 9.1 7.4 8.1 - n / A 300 8.2 6.9 7.5 - 10.0 8.1 350 7.4 _ 7.0 10.7 8.9 7.6 400 6.9 6.0 9.8 8.0 - 450 6.5 9.0 7.3 - 500 6.2 8.3 6.6 - 550 7.7 6.0 - 600 7.2 - - 650 6.1 - 700

For example, some parts cemented together with the above-mentioned materials are in the Drawings shown. It shows

F i g. 1 connections in a high-voltage bushing, namely a connection 1 between metal and metal, a connection 2 between metal and aluminum oxide and a connection 3 between

Alumina and metal;

F i g. 2 a connection 4 between a window 5 made of corundum and a Fernico frame 6 and

F i g. 3 a connection 7, between metal 8 and aluminum oxide 9, the different connections were vacuum-tight.

1 sheet of drawings

Claims (1)

Claim: High-temperature-resistant cement material made from devitrifiable glass of the "short" type based on the There is oxides of aluminum, boron, silicon, zinc and possibly cadmium and that too Contains oxides which supply network-changing ions, characterized in that the composition in mol% is within the following limits: