Polymer-Based Ceramic Coatings for Protecting Surfaces Against Fluoride Ions During a Cleaning Process

Abstract

A process for the gentle cleaning of partially corroded or oxidized surfaces with fluoride ions is provided. The parts of the surface which are not corroded or oxidized are coated with polymer-based ceramics before the start of the cleaning process. The coating process includes applying a precursor of the polymer-based ceramic and then ceramicizing the precursor.

1 .- 17 . (canceled) 
   
   
       18 . A process for the gentle cleaning of partially corroded or oxidized surfaces using fluoride ions, comprising:
 coating a non-corroded or non-oxidized part of a surface with a polymer-based ceramic layer before a cleaning process is started, the coating including:
 applying a precursor of the polymer-based ceramic, and 
 ceramicizing the precursor. 
   
   
   
       19 . The process as claimed in  claim 18 , wherein the precursor comprises silicon. 
   
   
       20 . The process as claimed in  claim 19 , wherein an SiC-forming and/or Si 3 N 4 -forming polymer-based ceramic is used. 
   
   
       21 . The process as claimed in  claim 19 , wherein the precursor comprises nitrogen. 
   
   
       22 . The process as claimed in  claim 19 ,
 wherein the precursor used does not comprise nitrogen, and   wherein the ceramicization is brought about by a pyrolysis in nitrogen.   
   
   
       23 . The process as claimed in  claim 19 , wherein the precursor used is selected from the group consisting of polysilane, polycarbosilane, polysilazane, polyborosilazane and polycarbosilazane. 
   
   
       24 . The process as claimed in  claim 19 , wherein a component is coated with the precursor by spreading, dripping or spraying the precursor in a liquid or a spreadable phase onto a plurality of parts of the surface of the component which are to be protected. 
   
   
       25 . The process as claimed in  claim 19 , wherein the plurality of parts of the surface which are to be protected are immersed in the precursor in a liquid phase of the precursor. 
   
   
       26 . The process as claimed in  claim 19 , wherein the precursor applied to the plurality of parts of the surface which are to be protected is crosslinked or partially crosslinked using a heat treatment. 
   
   
       27 . The process as claimed in  claim 22 , wherein the pyrolysis is used for the ceramicization. 
   
   
       28 . The process as claimed in  claim 27 , wherein the pyrolysis is carried out in a nitrogen atmosphere. 
   
   
       29 . The process as claimed in  claim 18 , wherein the polymer-based ceramic protective layer is removed in an alkaline bath once the cleaning process using fluoride ions has been completed. 
   
   
       30 . The process as claimed in  claim 29 , wherein the polymer-based ceramic protective layer is removed in an alkaline ultrasonic bath once the cleaning process using fluoride ions has been completed. 
   
   
       31 . The process as claimed in  claim 18 , wherein the component is a component of a gas turbine. 
   
   
       32 . The process as claimed in  claim 31 , wherein the component is a rotor or a vane of a gas turbine. 
   
   
       33 . A method of using polymer-based ceramic materials for protecting surface portions which are not to be cleaned against fluoride ions during a process for cleaning surfaces, comprising:
 providing a polymer-based ceramic material; and   protecting a plurality of surface portions of a component which are not to be cleaned against fluoride ions during a process for cleaning surfaces by coating the plurality of surface portions of the component which are not to be cleaned.   
   
   
       34 . The method as claimed in  claim 33 , wherein the coating material used is a silicon-containing polymer-based ceramic material. 
   
   
       35 . The method as claimed in  claim 34 , wherein the polymer-based ceramic material comprises SiC-forming and/or Si 3 N 4 -forming precursors. 
   
   
       36 . The method as claimed in  claim 35 , wherein a precursor present in the polymer-based ceramic material is selected from the group consisting of, polysilane, polycarbosilane, polysilazane, polyborosilazane and polycarbosilazane. 
   
   
       37 . The method as claimed in  claim 33 , wherein the component is a component of a gas turbine.