The soldering of graphite with copper

Connections of graphite with copper apply by manufacture of brushes of electric motors, removal of the current devices and other products. Difficulties at the soldering of graphite with copper are connected to practically absent chemical interaction between them and essential distinction of physicomechanical properties.

The soldering of these materials is carried out due to application of intermediate layers and the solders containing metals, superficially active to carbon (the titan, zirconium, nickel, stainless steel).

The contact-reactive soldering of graphite with copper is successfully carried out. The soldering of graphite with copper solders on the basis of copper or silver can be carried out and on air, using standard gumboils № 200, 201, 209.

The soldering of graphite with graphite

Connection of graphite details among themselves is required at creation from them blocks or at manufacturing products from graphites with various physicomechanical properties.

Artificial graphite since 400 °С is easily oxidized, loosened and loses durability. For preservation of its properties the soldering carry out in vacuum or neutral environments (argon, helium, nitrogen, etc.).

Coal-graphite materials solder with application carbide-form solders (the titan, zirconium, tantalum or niobium) due to formation эвтектики MeC - C.

Enriched silicon graphite possesses high heat resistance, chemical stability the fused metals and other excited environments. Of it make thermocouples of immersing, roller conveyors burn furnaces.

IV The soldering of glasses with metals

The junctions of metal with glass can be coordinated and unmatched. Coordinated junctions are formed between glass and metal with equal or close temperature factors of linear expansion (TFLE) in all an interval of temperatures from 20 °С up to temperature of the soldering. Unmatched junctions are formed between glass and metal with sharply various TFLE. Maintenance of durability in this case is reached by constructive decisions of a metal detail which should be deformed freely after deformation of a glass.

At a choice of metal for connection with glass besides TFLE (depending on type of junction and its designs) the important role play its such properties, as temperature of fusion, elasticity of vapours in vacuum, gas evolution, electro- and heat conductivity, magnetic properties, chemical stability{resistance}, mechanical properties, обрабатываемость cutting and pressure, an opportunity of welding and the soldering, presence аллотропических changes, etc. Necessity of maintenance of constant electric parameters for devices as makes demands a condition of their reliability and durability to structure of metal in a working interval of temperatures.

At the soldering of metal with glass use gas heating, induction, in furnaces, resistance.

Gas heating apply for bead-like and tape junctions, to manufacturing scallop-like and flat legs. These kinds of connections are carried out at radiating heating by a torch in furnaces, with the help of simple adaptations or on universal horizontal - welding machine tools for glass-blowing works.

Induction heating is expedient for applying to manufacturing рантовых, disk and other types of connections. Thus use generators capacity up to 30 kw and the special equipment.

For fusing a layer of the glass paste rendered on a surface of metal for its prevention oxidation, having heated make in муфельных, tunnel and conveyor furnaces. Oven heating is expedient for the soldering of details of a simple configuration (глазковых, окошечных junctions, the coaxial inputs compressed junctions, flat legs).

Heating of glass is carried out due to heat conductivity of the metal which has been heated up at drive through it of a current. This way of heating provides batching heat and does not demand high qualification of the operator.

Connection of a glass with metal probably due to use of enamel. On connected details render a layer enamel pastes and a junction heat up to temperature of its fusion. At this way of connection internal pressure decrease, oxidation metal and reception of demountable vakuum-dense connections is provided.

After connection of a glass with metal make отжиг connections for decrease in internal pressure. A mode отжига choose with account TFLE of connected materials and designs of junction. With same purpose apply also an optimum mode отжига or coolings to maintenance of identical volumetric compression of metal and a glass during cooling.

To connection of a glass with other materials are applied gallium pastes. In tab. 3 combinations of materials for which connection with application gallium solder of structure (mass fractions) is received, % are resulted: 39,6 Ga; 4,4 Sn; 56 Cu (powder).

Table 3

Combination material when soldering the microcircuits with using the gallium pastes

Existing ways of the soldering of a quartz glass (quartz) with metals differ depending on a modular condition of quartz during the soldering. Quartz can be soldered, leading up it before fusion, at high temperature as well as glass or to conduct process at lower temperatures when quartz is in a firm condition.

At the soldering of quartz from it оплавлением use transitive glasses with various TFLE which, being alloyed with each other, form gradual transition from metal to quartz so that pressure on separate borders between glasses did not exceed allowable values. As metal to input apply, as a rule, tungsten or molybdenum.

This way of the soldering of quartz with metals is labour-consuming, junctions have the significant sizes, mechanical durability and a thermal capacity are insignificant.

More progressive consider a way soldering in a metal foil directly in quartz (tape junctions). Thus as metals use tungsten, molybdenum, tantalum, platinum. However the sizes of a foil are limited (width about several millimeters, thickness 0,01 - 0,05 mm). This restriction is connected to big difference TFLE of connected materials. Sometimes simultaneously solder in some single thin inputs.

There is a way of the soldering of quartz with the help of active metals. In this case on a surface of quartz the layer of the titan or zirconium is rendered, the soldering is made by the solders containing fusible metals - tin, indium, gallium. As constructional metal use copper, silver, gold.