|  | C |
SECTION C — CHEMISTRY AND METALLURGY

METALLURGY

|  | C23 |
WORKING OR TREATMENT OF METALS, OTHER THAN BY MECHANICAL MEANS; COVERING MATERIALS WITH METALS (decorating textiles by metallising Fulltext... Hierarchy... Expanded...D06Q 1/04); INHIBITING CORROSION OR INCRUSTATION IN GENERAL (treating metal surfaces or coating of metals by electrolysis or electrophoresis Fulltext... Hierarchy... Expanded...C25D, Fulltext... Hierarchy... Expanded...C25F)

|  | C23F |
CHEMICAL SURFACE TREATMENT OF METALS NOT COVERED BY SUB-CLASSES Fulltext... Hierarchy... Expanded...C23D, Fulltext... Hierarchy... Expanded...C25D; INHIBITING CORROSION OR INCRUSTATION IN GENERAL

|  | C23F |
Note(s) This sub-class is the general place for inhibiting corrosion or incrustation in general, whether of or on metallic or non-metallic surfaces. It does not include, however: protective layers or coating compositions or methods of applying them; these are classified in the relevant class, e.g. Fulltext... Hierarchy... Expanded...B05, Fulltext... Hierarchy... Expanded...B44, Fulltext... Hierarchy... Expanded...C09D; mechanical devices or constructional features of particular articles; these are classified in the relevant class, e.g. pipes, pipe fittings Fulltext... Hierarchy... Expanded...F16L; articles characterised by being made of materials selected for their properties of resistance to corrosion or incrustation; these are classified in the relevant class, e.g. turbine blades Fulltext... Hierarchy... Expanded...F01D 5/28.

|  | C23F 1/00 |
Etching metals by chemical means (manufacture of printing surfaces Fulltext... Hierarchy... Expanded...B41C; etching compositions Fulltext... Hierarchy... Expanded...C09K 13/00; electrolytic etching Fulltext... Hierarchy... Expanded...C25F 3/00) [2]

|  | C23F 1/02 |
· | Local etching

|  | C23F 1/04 |
· · | Chemical milling

|  | C23F 1/06 |
· | Sharpening files

|  | C23F 1/08 |
· | Apparatus, e.g. for photomechanical printing surfaces (photomechanical reproduction Fulltext... Hierarchy... Expanded...G03F)

|  | C23F 3/00 |
Brightening metals by chemical means (brightening compositions Fulltext... Hierarchy... Expanded...C09K 13/00) [2]

|  | C23F 3/02 |
· | light metals

|  | C23F 3/04 |
· | heavy metals

|  | C23F 5/00 |
Forming coloured layers on metal surfaces (Fulltext... Hierarchy... Expanded...C23F 7/00 takes precedence)

|  | C23F 5/02 |
· | with inorganic colouring matters

|  | C23F 5/04 |
· | with organic colouring matters

|  | C23F 7/00 |
Forming non-metallic layers on metals by surface reactions (diffusion processes Fulltext... Hierarchy... Expanded...C23C)

|  | C23F 7/02 |
· | Forming oxide layers

|  | C23F 7/04 |
· · | on iron or steel

|  | C23F 7/06 |
· · | on light metals

|  | C23F 7/08 |
· | Forming phosphate layers

|  | C23F 7/10 |
· · | on iron or steel

|  | C23F 7/12 |
· · | on copper, brass, zinc, or tin

|  | C23F 7/14 |
· · | on light metals

|  | C23F 7/16 |
· · · | on magnesium

|  | C23F 7/18 |
· | Forming oxalate layers

|  | C23F 7/20 |
· · | on iron or steel

|  | C23F 7/22 |
· · | on light metals

|  | C23F 7/24 |
· | Forming sulphide layers

|  | C23F 7/26 |
· | Forming chromate layers

|  | C23F 9/00 |
Passivating metals

|  | C23F 9/02 |
· | iron or steel

|  | C23F 11/00 |
Inhibiting corrosion by applying inhibitors to the surface in danger of corrosion or adding them to the corrosive agent (adding inhibitors to mineral oil, fuels, or lubricants Fulltext... Hierarchy... Expanded...C10; adding inhibitors to pickling solutions Fulltext... Hierarchy... Expanded...C23G)

|  | C23F 11/02 |
· | in air or gases by adding vapour phase inhibitors

|  | C23F 11/04 |
· | in markedly acid liquids

|  | C23F 11/06 |
· | in markedly alkaline liquids

|  | C23F 11/08 |
· | in other liquids

|  | C23F 11/10 |
· · | using organic inhibitors

|  | C23F 11/12 - C23F 11/12 |
Note(s) A compound is classified in the last appropriate place.

|  | C23F 11/12 |
· · · | oxygen-containing compounds

|  | C23F 11/14 |
· · · | nitrogen-containing compounds

|  | C23F 11/16 |
· · · | compounds containing sulphur or phosphorus

|  | C23F 11/18 |
· · | using inorganic inhibitors

|  | C23F 13/00 |
Inhibiting corrosion of metals by anodic or cathodic protection

|  | C23F 14/00 |
Inhibiting incrustation in apparatus for heating liquids for physical or chemical purposes (adding scale preventives or removers to water Fulltext... Hierarchy... Expanded...C02B 5/00) [2]

|  | C23F 14/02 |
· | by chemical means

|  | C23F 15/00 |
Other methods of preventing corrosion or incrustation

|  | C23F 17/00 |
Multi-step processes for chemical or physical, i.e. non-mechanical, surface treatment of or with metals, in which at least one step is a process covered in Fulltext... Hierarchy... Expanded...C21D, Fulltext... Hierarchy... Expanded...C22F or Fulltext... Hierarchy... Expanded...C23