| 摘要 |
PURPOSE:To easily produce a W single crystal nearly free from gain boundaries and having improved processability by adding a specified amount of ZrO2 to W doped with Al2O3, K2O or SiO2 and subjecting them to pressing, a sintering and heat treatment at a specified temp. CONSTITUTION:Doped W powder contg. 0.01-1.0wt% one or more among Al2O3, K2O and SiO2 is mixed with 0.01-0.05% ZrO2 powder. The powdery mixture is compacted, sintered in hydrogen or the like, machined to a prescribed size and heat treated at >=2,600 deg.C. By this method, the grain boundaries of fine recrystallized grains are vanished and a large W single crystal is grown.
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