Process for preparing lead tungstate crystal

Abstract

The invention discloses a method for preparing lead tungstate crystal, and contains the following steps: pre-treating the raw material PbWO3, pouring into the growing crucible containing crystallon with a space of 0.1-0.6 time of the crystal length at the top, packaging, sealing, vacuumizing, reinjecting oxygen of one atmospheric pressure, placing in a descent furnace for inoculating and growing, keeping the furnace temperature at 1200-1250DEG C, descending at a speed of 1mm / h, cooling to 950DEG C at a speed of 30DEG C / h, annealing for 5h, heating the lead tungstate crystal in an annealing furnace to 1000DEG C at a speed of 30DEG C / h, keeping the temperature for 5h for annealing, cooling to room temperature at a speed of 30DEG C / h, cutting according to the settled specification, and polishing to obtain the final product.

Description

technical field [0001] The present invention relates to a crystal preparation method, in particular to a preparation method of lead tungstate crystal Background technique [0002] The invention patent (Application No. 94114075.X) describes a growth technique for simultaneously growing 2, 4 or 8 pure PWO crystals at a time using a vertical multi-crucible growth technique in a conventional atmospheric atmosphere. This technology is a successful extension of the traditional Bridgman technology, which improves the crystal growth efficiency. However, when this technology grows lead tungstate crystals, an extra space of 0.6 times the length of the crystal is left in the crucible containing the raw materials, that is, the crucible for crystal growth needs to use a crucible that is 1.6 times the length of the required growth crystal. This part of the space is used to ensure The content of ambient oxygen in the crystal growth process, the PWO crystals grown by this method often rely...

AI Technical Summary

Problems solved by technology

At the same time, a larger space is reserved, and a large amount of PbO and WO will be produced during the high temperature process of crystal growth. 3 Non-measured volatilization, the result is that the tail of the growing crystal inevitably appears yellow, and it is necessary to extend the crystal growth length and cut off the yellow part of the tail of the crystal, so that the yield of the crystal is difficult to be guaranteed.