Lead-free glass

Crystal glasses were traditionally melted in pot furnaces, but nowadays small continuous tank furnaces are used. Lead glasses are conveniently melted in Unit-Melter furnaces, lead-free glasses in all-electric furnaces with a daily output of several tons (cf. Fig. 102). Machine forming is being gradually introduced even for these types of glass. 

Standard Dithizone Solution Dissolve 10 mg of dithizone in 1000 mL of chloroform, keeping the solution in a glass-stoppered, lead-free bottle suitably wrapped to protect it from light and stored in a refrigerator. 

The copper methyl is unstable at the temperature of reaction and soon decomposes to metallic copper and free methyl radicals, the latter being identified by their ability to wipe off a mirror of lead on glass (the Paneth test). This decomposition occurs in about 0.003 second... 

I. Campbell, Lead and cadmium free glasses and frits, Glass Technol., 39(2) 38—41 (1998). 

Many other systems have subsequently been found to display anion conductivity. The electrical conductivity of lead fluoroborate and fluorogermanate glasses is similar to that of the lead fluorosilicate glasses. Calcium fluoroaluminate glasses also conduct by fluorine migration. Fluorophosphate glasses have also proven to be good anionic conductors. All of these systems are free of alkali ions. 

If carrier-free samples are required,then special-care must be taken with purity of reagents and lead-free boroslllcate glass or silica should be used throughout. 

A new LTCC material was designed to be able to sinter under 1000°C because of co-firing with copper conductor. The LTCC is composed of lead-free, Si02—AI2O3—MgO—ZnO—B2O3 system glass and ceramic fillers. In order to satisfy electrical and thermal properties, we adjusted the amount of crystalline phases precipitated after sintering [8]. 

IR-absorbing sealing glass for NiFe, lead-free, slow-evaporating (reed switches)... 

The internal transmittance of lead- and arsenic-free glasses, in which lead has been replaced by other elements, is markedly less than in the lead-containing... 

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