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 D06Q 1/04); INHIBITING CORROSION OR INCRUSTATION IN GENERAL (treating metal surfaces or coating of metals by electrolysis or electrophoresis C25D, C25F)
 C23F
CHEMICAL SURFACE TREATMENT OF METALS NOT COVERED BY SUB-CLASSES C23D, 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:

  1. protective layers or coating compositions or methods of applying them; these are classified in the relevant class, e.g. B05, B44, C09D;
  2. mechanical devices or constructional features of particular articles; these are classified in the relevant class, e.g. pipes, pipe fittings F16L;
  3. 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 F01D 5/28.

 C23F 1/00
Etching metals by chemical means (manufacture of printing surfaces B41C; etching compositions C09K 13/00; electrolytic etching 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 G03F)
 C23F 3/00
Brightening metals by chemical means (brightening compositions C09K 13/00)  [2]
 C23F 3/02
·  light metals
 C23F 3/04
·  heavy metals
 C23F 5/00
Forming coloured layers on metal surfaces (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 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 C10; adding inhibitors to pickling solutions 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 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 C21D, C22F or C23