Low thermal expansion materials

thumb|Samples of Invar thumb|350px|right|The coefficient of thermal expansion of nickel/iron alloys is plotted here against the nickel percentage (on a mass basis) in the alloy. The sharp minimum occurs at the Invar ratio of 36% Ni.

type of glass with silica and boron trioxide as the main glass-forming constituents

thumb|300px|Opening of the European Extremely Large Telescope|ELT secondary mirror Zerodur blank mold containing the glass at first annealing at the [[Schott AG 4-meter blank annealing facility in Mainz, Germany.]] Zerodur is a lithium-aluminosilicate glass-ceramic manufactured by Schott AG. Zerodur has a near zero coefficient of thermal expansion (CTE), and is used for high-precision applications in telescope optics, microlithography machines and inertial navigation systems.

Glucydur is the trade name of a metal alloy with a low coefficient of thermal expansion, used for making balance wheels and other parts of mechanical watches.

alloy used in nuclear weapon pits