| 摘要 |
1,137,746. Ceramic-metal seals. PHILIPS ELECTRONIC & ASSOCIATED INDUSTRIES Ltd. 7 June, 1966 [10 June, 1965], No. 25345/66. Heading B3V. A method of hermetically sealing a body of tungsten, molybdenum or rhenium &c. to a ceramic body, e.g. alumina, spinel or synthetic sapphire, comprising applying a suspension of a molybdenum oxide and/or tungsten oxide in an organic vehicle between the surfaces to be bonded, applying an aqueous suspension of a bonding material comprising alumina over exposed surfaces of a spongy metal layer formed by reducing the molybdenum oxide and/or tungsten oxide or over the dried organic matrix, and then heating the assembly in a non-oxidizing atmosphere so as to melt the material comprising alumina and form a hermetic bond which solidifies on cooling. The bonding materials are those disclosed in Specification 1,019,821 for bonding to a metal body. In an example for securing a disc of Mo to the end of an alumina tube, a suspension of molybdenum oxide in a solution of nitrocellulose in amyl acetate was applied to the surfaces and the assembly heated at 1650‹ C. for 10 minutes in wet hydrogen. The assembly was cooled and the surface of the porous Mo formed was covered with the bonding material comprising an aqueous suspension of Al 2 O 3 and CaCO 3 . The assembly was then heated at 1650‹ C. for 20 minutes to flow the bonding material into the pores of the porous Mo. Alternatively, the MoO 3 suspension may be allowed to dry, after which the aqueous suspension of A1 2 0 3 and CaCO 3 is applied over the dried layer and the assembly fired once, in wet hydrogen at 1650‹ C. for 20 minutes. |
