Patent ID: 6844283

Claim:
A process for producing a zero thermal expansion material; the process comprising mixing a negative thermal expansion material and a positive thermal expansion material, followed by firing; said negative thermal expansion material comprising a double oxide containing at least partly a compound represented by the chemical formula: RQ 2 O 8 wherein R is Zr, Hf or a tetravalent metallic element represented by a mixture system of these, and Q is a hexavalent metallic element selected from W and Mo; and said positive thermal expansion material comprising a material containing at least partly a compound represented by the chemical formula: MQX 4 wherein M is Mg, Ca, Sr, Ba, Ra or a divalent metallic element represented by a mixture system of any of these, Q is a hexavalent metallic element selected from W and Mo, and X is an element selected from O and S.