| 摘要 |
A process of protecting Be metal against oxidation comprises (a) coating the Be metal to a maximum thickness of 1/32 inch with a slurry comprising a lacquer solution and crushed Be/Si alloy containing from 35 to 50 atom percent Si, (b) heat-treating the coated Be metal at 950-1000 DEG C at a pressure not greater than 10-4 mm Hg, (c) introducing an inert atmosphere of superatmospheric pressure, e.g. of A or He, (d) heating the coated Be metal to a temperature in excess of the liquidus of the alloy but less than 1200 DEG C until the coating has uniformly covered the Be metal, and (e) cooling the coated metal. The slurry is prepared by mixing Be and Si, arcmelting the mixture obtained, cooling the product, crushing the product, and suspending the product in the lacquer. Nitrocellulose lacquer may be used or a solution of 1% by volume of cellulose acetate butyrate in acetone. Prior to coating, the Be may be etched in an aqueous solution containing sulphuric, phosphoric and chromic acids in concentrations of 7 fl. oz/U.S. gal; 121 fl. oz/U.S. gal.; and 1 lb/U.S.gal. Si/Be alloys containing 33 to 70 atomic percent of Si are referred to but only those containing 35 to 50 atomic percent of Si are suitable for the present invention. |
