Glass-to-metal seal absorb the stresses from thermal expansion mismatches. Due to its very low vapor pressure, indium finds use in glass-metal seals used in vacuum technology. Gallium is a soft metal with melting point at 30 °C. It readily wets glasses and most metals and can be used for seals that can be assembled/disassembled by just slight heating. It can be used as a liquid seal up to high temperatures or even at lower temperatures when alloyed with other metals (e.g. as galinstan). Mercury is a metal liquid at normal temperature. It was used as the earliest glass-to-metal seal and is still
Temperature dependence of liquid viscosity and applies over a large temperature and viscosity range: where "T" is absolute temperature in kelvins, formula_26 is the kinematic viscosity in centistokes, formula_27 is the zero order modified Bessel function of the second kind, and "A" and "B" are liquid specific values. This form should not be applied to ammonia or water viscosity over a large temperature range. For liquid metal viscosity as a function of temperature, Seeton proposed: Temperature dependence of liquid viscosity The temperature dependence of liquid viscosity is the phenomenon by which liquid viscosity tends to decrease (or, alternatively, its "fluidity" tends to increase) as its