NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE

**Definition:** This place covers:

Methods, compositions and apparatus for etching of metallic materials by chemical means ( C23F1/00 - C23F1/44 ).

Regeneration of etching compositions, including apparatus for regenerating etching agents ( C23F1/46 ).

Methods, compositions and apparatus for chemical polishing (brightening) of metals ( C23F3/00 - C23F3/06 ).

Other non-mechanical processes for removing metallic material from surfaces, e.g. by plasma or sputter etching, and compositions therefor ( C23F4/00 - C23F4/04 ).

Simultaneous chemical and mechanical removal of metallic material from surfaces, e.g. by laser ablation ( C23F4/02 , C23F4/04 ).

Inhibiting corrosion of metallic material by applying inhibitors to the surface in danger of corrosion ( C23F11/00 - C23F11/188 ).

Inhibiting corrosion of metallic material by adding inhibitors to the corrosive agent ( C23F11/00 - C23F11/188 ).

Inhibiting corrosion of metals by anodic or cathodic protection ( C23F13/00 - C23F13/22 ).

Inhibiting incrustation in apparatus for heating liquids for physical or chemical purposes ( C23F14/00 ), in polymerisation reactors ( C23F15/005 ).

Corrosion inhibitors per se ( C23F11/12 - C23F11/18 ).

Incrustation inhibitors per se ( C23F14/02 ).

Other methods of preventing corrosion or incrustation, e.g. by removing the corrosive agent from the medium or rendering it non corrosive by neutralizing it ( C23F15/00 ).

Other apparatus for executing the methods mentioned above as far as they are specially adapted for treating metallic material, e.g. apparatus for regenerating etching agents; apparatus for anodic or cathodic protection, apparatus for executing the processes of the other groups, but only if they have at least one feature which is specifically designed for treating metallic material ( C23F1/00 , C23F3/00 ; C23F4/00 , C23F13/00 , C23F14/00 , C23F15/00 ).

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 ( C23F17/00 ).

**Limiting references (this place does not cover):** - Methods for preventing fouling -> B08B17/00 - Working of metal by electro-erosion -> B23H - Desurfacing by applying flames -> B23K7/00 - Working metal by laser beam -> B23K26/00 - Adding scale preventives or removers to water -> C02F5/00 - Polishing compositions -> C09G - Etching process and compositions for silicon or germanium -> C09K13/00 - Adding corrosion inhibitors to pickling solutions -> C23G - Electrolytic etching or polishing -> C25F

**Glossary:** - Metallic material: covers metals and alloys - 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. - Inhibiting corrosion: Inhibiting corrosion is a specific form of preventing corrosion, the words are not synonyms - Corrosion: Deterioration of a metallic material due to a change of valence state caused by reactions with its environment. - Incrustation: Accumulation of deposition /precipitation of undesired solid /dense products on a metallic surface in systems in which a fluid circulation takes place, preferably a water-based fluid, e.g. deposition /precipitation of compounds of calcium, magnesium, barium or strontium (carbonates/ sulphates, oxalates, phosphates, fluorides, silica, silicates, naphtelenates), iron /lead / zinc sulphide, zinc /cadmium carbonates (white rust).