| 摘要 |
PURPOSE:To improve the transmissivity of the title material to about >=90% in max. as well as to increase the hardness thereof and to improve the durability thereof by providing an MgF2 film as an antireflection film on an aluminum oxynitride base material. CONSTITUTION:The magnesium fluoride film is formed on at least one surface of the light transparent aluminum oxynitride base material. The aluminum oxynitride base material may be a polycrystal body produced by a hot press method or atm. sintering method of sintering the material by adding a sintering assistant thereto in the same manner as heretofore. The magnesium fluoride film to be provided on the surface of the aluminum oxynitride base material may be formed by an ordinary thin film forming method such as vacuum deposition method, sputtering method or ion plating method. The composite material which is improved in the transmissivity to about >=90% in max., is simultaneously improved in the hardness and durability and is adequate as an optical window material for high-speed flying objects is thereby obtd. |
