Abstract: The low Ta impurity content in pyrochlore ore makes it unnecessary to use a solvent extraction process to separate Nb from Ta. Consequently, niobium pentoxide powders using this ore can be produced at lower cost than competing mining/refining approaches, but in turn contain significant amounts of Ta impurities. SAW wafers are grown from melts produced by reacting niobium pentoxide powders containing Ta impurities at levels of 200 ppm or more by weight. Given proper amounts of starting powders, crystals can be grown with good yields and reproducible properties that satisfy typical SAW wafer specifications. The consistency across various lots of powders may be further improved by adding an appropriate amount of Ta pentoxide to the starting powders.

Abstract: A method is provided of growing crystals from compounds that melt congruently with negligible volatilization. The composition of one or more crystal samples is measured. A determination is made of a deviation of crystal composition from congruency. A determination is made of an initial melt composition and a source material composition correction relative to the deviation. Crystals are grown using the composition correction to yield reproducible material for surface acoustic substrate manufacturing.

Abstract: The low Ta impurity content in pyrochlore ore makes it unnecessary to use a solvent extraction process to separate Nb from Ta. Consequently, niobium pentoxide powders using this ore can be produced at lower cost than competing mining/refining approaches, but in turn contain significant amounts of Ta impurities. SAW wafers are grown from melts produced by reacting niobium pentoxide powders containing Ta impurities at levels of 200 ppm or more by weight. Given proper amounts of starting powders, crystals can be grown with good yields and reproducible properties that satisfy typical SAW wafer specifications. The consistency across various lots of powders may be further improved by adding an appropriate amount of Ta pentoxide to the starting powders.

Abstract: A method is provided of growing crystals from compounds that melt congruently with negligible volatilization. The composition of one or more crystal samples is measured. A determination is made of a deviation of crystal composition from congruency. A determination is made of an initial melt composition and a source material composition correction relative to the deviation. Crystals are grown using the composition correction to yield reproducible material for surface acoustic substrate manufacturing.

Abstract: Methods and apparatus for preconditioning a lithium niobate or lithium tantalate crystal. At least a portion of a surface of the crystal is covered with a condensed material including one or more active chemicals. The crystal is heated in a non-oxidizing environment above an activating temperature at which the active chemicals contribute to reducing the crystal beneath the covered surface portion. The crystal is cooled from above the activating temperature to below a quenching temperature at which the active chemicals become essentially inactive for reducing the crystal.

Abstract: Methods and apparatus for preconditioning a lithium niobate or lithium tantalate crystal. At least a portion of a surface of the crystal is covered with a condensed material including one or more active chemicals. The crystal is heated in a non-oxidizing environment above an activating temperature at which the active chemicals contribute to reducing the crystal beneath the covered surface portion. The crystal is cooled from above the activating temperature to below a quenching temperature at which the active chemicals become essentially inactive for reducing the crystal.