C23F - Definition 
Definition statement
This subclass covers:
Methods, compositions and apparatus for etching of metallic materials by chemical means.
Regeneration of etching compositions, including apparatus for regenerating etching agents.
Methods, compositions and apparatus for chemical polishing (brightening) of metals.
Other non-mechanical processes for removing metallic material from surfaces, e.g. by plasma or sputter etching, and compositions therefor.
Simultaneous chemical and mechanical removal of metallic material from surfaces.
Inhibiting corrosion of metallic material by applying inhibitors to the surface in danger of corrosion.
Inhibiting corrosion of metallic material by adding inhibitors to the corrosive agent.
Inhibiting corrosion of metals by anodic or cathodic protection.
Other methods of preventing corrosion, e.g. by removing the corrosive agent from the medium or rendering it non corrosive by neutralizing it.
Inhibiting incrustation.
Corrosion and incrustation inhibitors per se.
Other apparatus for executing the methods mentioned above as far as they are specially adapted for treating metallic material.
Multi-step processes for surface treatment of metallic material involving at least one process provided for in class C23 and at least one process covered by subclass C21D or C22F or class C25.
Relationship between large subject matter areas
Protective layers or coating compositions or methods of applying them are not classified in this subclass but in the appropriate places, e.g. B05, B44, C09D, C10M, C23C.
Mechanical devices or constructional features of particular articles for inhibiting incrustation are not classified in this subclass but in the appropriate places, e.g. in group F16L 58/00 for inhibiting incrustations in pipes or pipe fittings.
Articles characterised by being made of materials selected for their properties of resistance to corrosion or incrustation are not to be classified in this subclass but in the appropriate places for such articles, e.g. in group F01D 5/28 for turbine blades.
References relevant to classification in this subclass
This subclass does not cover:
Working of metal by electro-erosion | B23H |
De-surfacing by applying flames | B23K 7/00 |
Working metal by laser beam | B23K 26/00 |
Adding scale preventives or removers to water | C02F 5/00 |
Electrolytic etching or polishing | C25F |
Preventing formation of scale in cooking vessels | A47J 36/42 |
Producing decorative effects by removing surface-material, e.g. by engraving or by etching | B44C 1/22 |
Mechanical methods for preventing fouling in hull protection | B63B 59/04 |
Preventing incrustations during destructive distillation of carbonaceous materials | C10B 43/14 |
Inhibition or prevention of corrosion or incrustation during processing of hydrocarbons | C10G 7/10, C10G 9/16, C10G 75/02 |
Use of additives to fuels or fires for minimising corrosion or incrustation | C10L 10/04 |
Adding corrosion inhibitors to lubricants | C10M, C10N 30/12 |
Adding corrosion inhibitors to pickling solutions | C23G |
Preventing incrustation in pipes | F16L 58/00 |
Informative references
Attention is drawn to the following places, which may be of interest for search:
Methods for preventing fouling | B08B 17/00 |
Manufacture of printing surfaces | B41C |
Surface treatment of glass by etching | C03C 15/00, C03C 25/68 |
Etching of natural or artificial stone or ceramics | C04B 41/53, C04B 41/72, C04B 41/91 |
Polishing compositions | C09G |
Etching, surface-brightening or pickling compositions in general | C09K 13/00 |
In situ inhibition of corrosion in boreholes or wells | E21B 41/02 |
Photomechanical reproduction | G03F |
Discharge tubes with the provision for introducing objects or materials to be exposed to the discharge, e.g. for plasma treatment | H01J 37/00 |
Chemical or electrical treatment, e.g. etching, of semiconductor bodies | H01L 21/306 |
Manufacture of printed circuits | H05K |
Glossary of terms
In this subclass, the following terms or expressions are used with the meaning indicated:
| Alloys | include: metallic composite materials containing a substantial proportion of fibres or other somewhat larger particles;ceramic compositions bonded by free metal, containing free metal bonded to carbides, diamond, oxides, borides, nitrides or silicides, e.g. cermets, or other metal compounds, e.g. oxynitrides or sulfides, other than as macroscopic reinforcing agents. |
| Applying corrosion inhibitors | Applying corrosion inhibitors to a metallic surface layer is not considered to be applying a protective coating. |
| Corrosion | Deterioration of a metallic material due to a change of valence state caused by reactions with its environment. |
Synonyms and Keywords
In patent documents the expression "chemical polishing" is often used with the meaning of "brightening".