公开(公告)号：US3647697A

公开(公告)日：1972-03-07

申请号：US3647697D

申请日：1969-05-26

Applicant: BELL TELEPHONE LABOR INC

Inventor： BALLMAN ALBERT A ,  CARRUTHERS JOHN R

IPC: C30B15/00 ,  C30B29/30 ,  G02F1/355 ,  C04B35/60 ,  B01J17/18

CPC classification number: G02F1/3551 ,  Y10S117/902

Abstract: A COMMERCIAL TECHNIQUE FOR GROWTH OF OPTICAL GRADE MATERIAL OF THE NOMINAL COMPOSITION BA2NANB5/15 IS DESCRIBED. THE USUALLY ENCOUNTERED CRACKING PROBLEM IS MINIMIZED BY FOLLOWING A CRITICALLY SLOW COOLING RATE OVER A SHORT TEMPERATURE INTERVAL OF FROM ABOUT 600*C. TO ABOUT 400*C. INITIAL COOLING FROM THE CRYSTALLIZING TEMPERATURE TO THIS INTERVAL AND FROM THIS RANGE TO ROOM TEMPERATURE IS NOT CRITICAL AND MAY BE RAPID.