PTC composite material
AssigneeNGK Insulators, Ltd.
InventorYoshihiko Ishida
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Abstract
A PTC composite material including a matrix of ceramic material having one of a cristobalite crystal structure and a tridymite crystal structure, each doped with an oxide of at least one of Be, B, Mg, Al, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge and W, and a conductive phase dispersed throughout the matrix. The conductive phase includes at least one of a metal, silicide, nitride, carbide and boride.
Claims39
A PTC material comprising a matrix material having one of a cristobalite crystal structure and a tridymite crystal structure, each doped with an oxide of at least one of Be, B, Mg, Al, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, and W, and a conductive phase dispersed throughout said matrix, said conductive phase comprising at least one of a metal, silicide, nitride, carbide and boride.
A PTC material comprising (i) a matrix of at least one of cristobalite phase SiO2, tridymite phase SiO2, cristobalite phase AlPO4, and tridymite phase AlPO4, each doped with 0.1 mol % to 20 mol % of an oxide of at least one of Be, B, Mg, Al, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, and W, and (ii) a conductive phase dispersed throughout said matrix, said conductive phase comprising at least one of a metal, silicide, nitride, carbide and boride, wherein the resistivity of the composite material at 250° C. is at least 10 times greater than the resistivity of the material at 30° C.
Dependencies are inferred from the claim text.