| 摘要 |
1,258,833. Pack aluminizing aluminide coated Ni superalloys. UNITED AIRCRAFT CORP. Oct. 17, 1969 [Oct. 25, 1968], No.51020/69. Heading C7F. Aluminide coated Ni superalloy components which have been subjected to oxidation erosion e.g. gas turbine components, are repaired prior to coating failure by cleaning the component surface to remove oxides without stripping the aluminide coating and then pack aluminizing the components in a pack composition such that aluminides with an Al content in excess of that of the monoaluminide is formed. The components are than heat treated to convert at least some of the aluminides to aluminides having an Al content less than that of Ni 2 Al 3 . The pack mixture contains by weight 5-20% Al, 0À5-3% NH 4 , Cl, balance Al 2 O 3 and is heated to 649-871‹ C. in inert atmosphere with the components embedded in the mixture. A minimum coating thickness of 76À2 microns is formed, heat treatment is then effected at 1038‹-1204‹ C. Several different examples of Ni superalloys are given. |
