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A ceramic material in the lithium aluminosilicate (LAS) system, having a negative coefficient of thermal expansion and improved mechanical properties, the material having a stoichiometric composition of Li.sub.1+X AlSiO.sub.4+X/2, where 0.ltoreq.x.ltoreq.0.1. The ceramic material can be made by mixi

A ceramic material in the lithium aluminosilicate (LAS) system, having a negative coefficient of thermal expansion and improved mechanical properties, the material having a stoichiometric composition of Li.sub.1+X AlSiO.sub.4+X/2, where 0.ltoreq.x.ltoreq.0.1. The ceramic material can be made by mixing silicon and aluminum oxides (SiO.sub.2 and Al.sub.2 O.sub.5) with lithium carbonate (Li.sub.2 CO.sub.3) and calcining the mixture. Alternatively, the ceramic material can be made by mixing silicon oxide (SiO.sub.2), lithium aluminate (LiAlO.sub.2), and, if desired, lithium carbonate (Li.sub.2 CO.sub.3), and calcining the mixture. Alternatively, the ceramic material can be made by mixing spodumene (an inexpensive mineral with a nominal composition of LiAlSi.sub.2 O.sub.6), lithium aluminate (LiAlO.sub.2), and the required amounts of other constituents (Li.sub.2 CO.sub.3, Al.sub.2 O.sub.3, or SiO.sub.2), and calcining the mixture. Alternatively, the ceramic material can be made by mixing spodumene (nominally LiAlSi.sub.2 O.sub.6) and the required amounts of other constituents (Li.sub.2 CO.sub.3, Al.sub.2 O.sub.3, or SiO.sub.2), and calcining the mixture. The ceramics of this invention exhibit negative thermal expansion, and improved mechanical properties, which allow them to be used as components of thermostats and other products.

대표청구항

[ What is claimed is:] [1.] A ceramic material of the lithium aluminosilicate (LAS) system in which the material has a stoichiometric composition of Li.sub.1+X AlSiO.sub.4+X/2, where X>0.

[ What is claimed is:] [1.] A ceramic material of the lithium aluminosilicate (LAS) system in which the material has a stoichiometric composition of Li.sub.1+X AlSiO.sub.4+X/2, where X>0.