Heat Exchanger, In Particular Exhaust Gas Heat Exchanger

Abstract

The invention relates to a heat exchanger, in particular an exhaust gas heat exchanger, having at least one surface which is impinged on by a medium, in particular exhaust gas, is made from metal, in particular aluminum or stainless steel, and is provided with a coating. In order to improve the properties of the coating, according to the invention, the coating comprises a coating material based on nanotechnology.

1 . A heat exchanger, in particular an exhaust gas heat exchanger, having at least one metal surface, in particular an aluminum or special steel surface, on which a medium, in particular exhaust gas, impinges and which is provided with a coating, wherein the coating comprises a coating material, which is based on nanotechnology. 
   
   
       2 . The heat exchanger as claimed in  claim 1 , wherein the coating comprises a main constituent, which is composed of an organic and an inorganic fraction. 
   
   
       3 . The heat exchanger as claimed in  claim 1  wherein the coating contains silicon. 
   
   
       4 . The heat exchanger as claimed in  claim 1 , wherein the coating contains titanium, zirconium and/or aluminum. 
   
   
       5 . The heat exchanger as claimed in  claim 1  wherein the coating contains magnesium, zinc and/or calcium. 
   
   
       6 . A method of manufacturing a heat exchanger, in particular an exhaust gas heat exchanger, as claimed in  claim 1 , wherein the coating is produced by a sol-gel process. 
   
   
       7 . The method as claimed in  claim 6 , wherein at least one sol is applied to the surface to be coated. 
   
   
       8 . The method as claimed in  claim 7 , wherein the sol is cured in order to form a cross-linked polymer layer. 
   
   
       9 . The method as claimed in  claim 6 , characterized by the following process steps:
 a) a heat exchanger to be coated is flooded with the coating material and drained;   b) the drained heat exchanger is heated in a drying oven and/or has a flow of hot gas, in particular hot air, passed through it.