Solder glass

Most industrial glasses have linear thermal expansion coefficients between 30 10 /K (thermal shock resistant borosilicate gla.ss) and 80 to 90 lO /K (window gla.ss). In composite systems, such as used in the electronics industry for fusing (soldering) glasses to metal conductors or casing components, the thermal expansion coefficients of the glass and the metal have to be precisely matched. 

Protective and decorative enamels, solder glasses for glass-to-glass or glass-to-metal seals, and a variety of sintered glass products are made from finely crushed ground glass... 

Glass ceramics based on the Pb0-Zn0-B203-Si02 system are used as solder glasses that is, they fuse at low temperatures ( 450°C) and can bond other glasses and... 

Lead has a low melting point (326°C). It is a soft, malleable metal, i.e., it can be easily formed into a variety of shapes. It can form alloys with many other metals. Other important industrial products containing Pb include pipes, paints, solders, glass, pottery glazes, rubber, plastics, and insecticides. 

The burners described here are meant to obtain temperatures of the order of 1000-1200°C. But a whole range of burners also exists, which are meant to produce lower temperatures of the order of 500 as well as blow-torches for very different uses machine blow-torch, oxy-arc cutting, soldering, glass blowing, jewellery. 

As the separator, an insulating membrane having a large ion transmittance and a predetermined mechanical strength is used. As a material for use in the reflow soldering, glass fibers are the most stable. 

Lead oxide has been widely used in the glazing of pottery in flint -type glasses and in solder glasses, but these materials contain no carbon and have no visible structure In the process being reported, carbon contained in the cotton is required for formation of the new chemical structure and for retention of the fabric weave pattern and shape in the new products ... 

Alumino-silicate glasses have been found useful for work up to 750 C by Enderby and co-workers. These glasses combine a high softening point (800°C) with a medium coefficient of expansion (42.5 X 10 deg.C ) and it is therefore possible to use a lower melting point solder glass with the same expansivity as an adhesive. 

Alloys of Pb—Li are attractive in some nuclear shielding apphcations due to their ability to thermalize neutrons. Lead containing more than 0.5 wt% In wets glass, and Pb—In alloys with up to 5 wt% In can be used for soldering glass over a narrow temperature range. Additions over 25 wt% of In are made to Pb—Sn solders to increase their alkali resistance. An addition of 1 - 2 wt% In in Pb—Ag solders increases their strength. Indium is also used in multi-component fusible aUoy systems. 

One must distinguish between vitreous solder glasses and devitrify ing solder glasses, according to their behavior during the soldering process. 

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