Process for improving the reflectivity of reflective surfaces of antennas

Abstract

The present invention refers to a novel process of coating the reflective surfaces of antennas made of composite material. In particular, it refers to the reflective surfaces made of carbon fiber impregnated with epoxy resins of parabolic antennas. The present invention further refers to the surfaces and to the antennas thus obtained.

1 . A process of coating the reflective surfaces of parabolic antennas, wherein said reflective surfaces are made of a composite material consisting in carbon fibers in epoxy resin matrix and wherein said epoxy resin matrix has a surface thickness comprised between 10 and 30 μm, comprising the following steps:
 a) performing a step of abrasion by shot peening on said reflective surface so as to remove a surface layer of epoxy resin of at least 3 μm; 
 b) performing a step of metal deposition on the reflective surface prepared at a) by thermal wire spray technique with one or more phases of cooling on the acceleration current of the metal particles and/or on the surface of the parabolic dish of said antenna. 
 
     
     
         2 . The process according to  claim 1 , wherein said carbon fibers have an areal weight comprised between 190 and 210 g/m 2  and a thickness comprised between 210 and 290 μm. 
     
     
         3 . The process according to  claim 1 , wherein said step of metal deposition is performed by imparting at the same time a rotational speed to said antenna in the range of 40-400 rev/min. 
     
     
         4 . The process according to  claim 1 , wherein said cooling consists in blowing compressed air with crystals of solid CO 2 . 
     
     
         5 . The process according to  claim 1 , wherein in said step of coating are used oxide-acetylenic nozzles or nozzles for oxygen mixed with combustible gases. 
     
     
         6 . The process according to  claim 1 , wherein said metal coating is of a metal or metal alloy selected from the group of Al, Zn, steel, Cu, SbSn Ag, Au, Ti, Cr, Ni molybdenum, Inconel, Monel, nickel/aluminum, bronze. 
     
     
         7 . The process according to  claim 1 , wherein the surface thickness of said epoxy resin is comprised between 15 and 20 μm. 
     
     
         8 . The process according to  claim 1 , comprising a further step c) of grinding said reflective surfaces. 
     
     
         9 . The process according to  claim 1 , wherein said carbon fibers are of T300 3K type. 
     
     
         10 . The process according to  claim 1 , wherein the removed surface layer of epoxy resin is comprised between 3 and 6 μm. 
     
     
         11 . The process according to  claim 1 , wherein the step of abrasion by shot peening is performed by glass microspheres of a diameter comprised between 1 and 10 mm. 
     
     
         12 . Reflective surface for parabolic antennas with a metal coating obtainable by the process of  claim 1 . 
     
     
         13 . Parabolic antenna comprising a reflective surface according to  claim 12 .