| 摘要 |
851,267. Coating with metals. GENERAL MOTORS CORPORATION. March 25, 1959 [April 28, 1958], No. 10321/59. Class 82(2) [Also in Group XXVI] In an axial-flow compressor, the inner surface of the stator casing opposite each row of rotor blades has a coating which is abradable by the rotor blade tips in motion and is made of porous metal, such as aluminium, bronze or zinc, impregnated with a thermosetting synthetic resin which fills the pores. This ensures minimum clearances between the blade tips and the casing. The surface of the casing opposite the tips of rotor blades 5 is roughened by cutting shallow threads 19 in it or by grit- or shot-blasting it, and is then preferably heated to 175-200‹F., after which a porous metal coating is sprayed on, the temperature being maintained at 150-200‹F. as by applying a hot air blast to the opposite side. For a magnesium casing, a coating of 0.003 to 0.005 inch thickness of porous bronze is used. For a steel casing, a coating of stainless steel of about 0.002 to 0.005 inch thickness is followed by a porous aluminium coating of about 0.030 to 0.035 inch thickness. Bronze, zinc or copper may be used instead of stainless steel. At least two coats of a high-temperature resistant thermosetting resin, such as an epoxy or silicone resin, in a solvent or thinner are applied by brushing, spraying, dipping or rolling, to fill the pores of the metal. Drying and curing is effected by baking at about 150 T. for at least half an hour and then baking at about 450‹F. for one hour. A final bake at about 625‹F. for about three hours may be given. |
