초록

where A.sup.4+ and A'.sup.4+ are Hf.sup.4+ or Zr.sup.4+, M.sup.6+ and M'.sup.6+ are W.sup.6+ or Mo.sup.6+, X is from 0 to 1, and Y is from about 0.05 to .ltoreq.2.

대표청구항 ▼

[ We claim:] [1.] A method for making substantially single-phase, crystalline NTE compounds having the formula: ]EQU11 ] re A.sup.4+ is Zr.sup.4+, Hf.sup.4+, or mixtures thereof, and M.sup.6+ is Mo.sup.6+, W.sup.6+, or mixtures thereof, the method comprising:forming a liquid mixture comprising stoic

[ We claim:] [1.] A method for making substantially single-phase, crystalline NTE compounds having the formula: ]EQU11 ] re A.sup.4+ is Zr.sup.4+, Hf.sup.4+, or mixtures thereof, and M.sup.6+ is Mo.sup.6+, W.sup.6+, or mixtures thereof, the method comprising:forming a liquid mixture comprising stoichiometric amounts of (1) a soluble source of Zr.sup.4+, Hf.sup.4+, or mixtures thereof, and (2) a sodium-ion-free tungstate salt, a sodium-ion-free molybdate salt, or mixtures thereof;adding an acid to the liquid mixture to acidify the liquid mixture;refluxing the liquid mixture at ambient pressures for a period of about 48 hours or more, or at pressures greater than ambient for a period of from about 1 to about 24 hours;separating a solid fraction from the mixture; andheating the solid fraction to a temperature within the temperature range of from about 500.degree. C. to less than 700.degree. C. to form a compound having the formula ]EQU12 ]