| 摘要 |
PROBLEM TO BE SOLVED: To obtain a polycrystalline MgO vacuum-deposition material capable of forming a MgO film having an approximately uniform thickness substantially without generating a splash, even when subjected to a vacuum-deposition treatment by an electron beam method. SOLUTION: This polycrystalline MgO vacuum-deposition material comprises sintered pellets 11 having a MgO purity of >=99.5% and a relative density of >=96% and formed in a spherical shape. The crystal particle diameters of the pellets are 1-500 μm. Si and Al impurities are contained it the pellets 11 in element concentrations of <=200 ppm and <=200 ppm, respectively. Ca, Zn and Fe impurities are also contained in element concentrations of <=250 ppm, <=150 ppm and <=50 ppm, respectively. Cr, V and Ni impurities are also contained in element concentrations of <=10 ppm, <=10 ppm and <=10 ppm, respectively. Na, K and C impurities are more also contained in element concentrations of <=20 ppm, <=20 ppm and <=70 ppm, respectively. |
