BORON ROD FOR FLOATING-ZONE PURIFICATION AND ITS PRODUCTION

摘要

PURPOSE:To obtain a desired boron rod for floating-zone purification method by molding boron powder at high temp. under high pressure and specifying the packing density of the boron rod to a certain range. CONSTITUTION:The boron rod of this purpose is to be used for a floating-zone purification method, and has =50 % packing density (apparent density/true density X 100 %). This rod is produced by molding boron powder in a boron nitride die 10 under desired pressure at desired temp. for more than 0.1 hour in vacuum or in a gas atmosphere of VIII group elements in the periodical table. Pressure and heating temp. for molding relate to each other and are specified to satisfy that 1,500=X=1,950 and (a)=Y=500, wherein X is temp.( deg.C), Y is pressure (kg/cm2), and (a)= -0.0004496X2 + 1.2883X - 708.3. They are maintained for 0.1 - 1 hour.