Molten salt synthesis of modified alkali niobate powders

Claim 1

A process for producing a modified alkali niobate having the formula (A 2x B 1-x )Nb 2 O 6 wherein A is alkali atom selected from the group consisting of Na, K and mixtures thereof, B is cation selected from the group consisting of Pb, Cd and mixtures thereof, and x has a value ranging from an effective amount up to but less than 1, which consists essentially of providing in stoichiometric amount an alkali oxide selected from the group consisting of Na 2 O, K 2 O and mixtures thereof or particulate precursor therefor, providing in stoichiometric amount cation oxide selected from the group consisting of PbO, CdO and mixtures thereof or particulate precursor therefor, providing in stoichiometric amount particulate Nb 2 O 5 or particulate precursor therefor, providing an alkali chloride salt selected from the group consisting of sodium chloride, potassium chloride and mixtures thereof, forming a mixture of said alkali oxide or precursor therefor, said cation oxide or precursor therefor, said Nb 2 O 5 or precursor therefor and said chloride salt solvent, said chloride salt being used in an amount of at least about 20% by weight of the total amount of said alkali oxide, cation oxide, Nb 2 O 5 and chloride salt, heating said mixture to a reaction temperature at least sufficient to melt said chloride salt, each said precursor decomposing completely at or below said reaction temperature to form said oxide and by-product gas, said chloride salt in molten form being a solvent for said alkali oxide, cation oxide and Nb 2 O 5 , maintaining said reaction temperature dissolving and reacting said alkali oxide, cation oxide and Nb 2 O 5 in said molten salt and precipitating said modified alkali niobate, and recovering said precipitated modified alkali niobate by dissolving said chloride salt and separating said precipitated modified alkali niobate from the resulting salt solution.