|  | C |
SECTION C — CHEMISTRY; METALLURGY

|  | C |
Note(s) In section C, the definitions of groups of chemical elements are as follows: Alkali metals: Li, Na, K, Rb, Cs, Fr Alkaline earth metals: Ca, Sr, Ba, Ra Lanthanides: elements with atomic numbers 57 to 71 inclusive Rare earths: Sc, Y, Lanthanides Actinides: elements with atomic numbers 89 to 103 inclusive Refractory metals: Ti, V, Cr, Zr, Nb, Mo, Hf, Ta, W Halogens: F, Cl, Br, I, At Noble gases: He, Ne, Ar, Kr, Xe, Rn Platinum group: Os, Ir, Pt, Ru, Rh, Pd Noble metals: Ag, Au, Platinum group Light metals: alkali metals, alkaline earth metals, Be, Al, Mg Heavy metals: metals other than light metals Iron group: Fe, Co, Ni Non-metals: H, B, C, Si, N, P, O, S, Se, Te, noble gases, halogens Metals: elements other than non-metals Transition elements: elements with atomic numbers 21 to 30 inclusive, 39 to 48 inclusive, 57 to 80 inclusive, 89 upwards Section C covers: pure chemistry, which covers inorganic compounds, organic compounds, macromolecular compounds, and their methods of preparation; applied chemistry, which covers compositions containing the above compounds, such as: glass, ceramics, fertilisers, plastics compositions, paints, products of the petroleum industry. It also covers certain compositions on account of their having particular properties rendering them suitable for certain purposes, as in the case of explosives, dyestuffs, adhesives, lubricants, and detergents; certain marginal industries, such as the manufacture of coke and of solid or gaseous fuels, the production and refining of oils, fats and waxes, the fermentation industry (e.g., brewing and wine-making), the sugar industry; certain operations or treatments, which are either purely mechanical, e.g., the mechanical treatment of leather and skins, or partly mechanical, e.g., the treatment of water or the prevention of corrosion in general; metallurgy, ferrous or non-ferrous alloys. In the case of operations, treatments, products or articles having both a chemical and a non-chemical part or aspect, the general rule is that the chemical part or aspect is covered by section C. In some of these cases, the chemical part or aspect brings with it a non-chemical one, even though purely mechanical, because this latter aspect either is essential to the operation or treatment or constitutes an important element thereof. It has seemed, in fact, more logical not to dissociate the different parts or aspects of a coherent whole. This is the case for applied chemistry and for the industries, operations and treatments mentioned in Notes (1)(c), (d) and (e). For example, furnaces peculiar to the manufacture of glass are covered by class Fulltext... Hierarchy... Expanded...C03 and not by class Fulltext... Hierarchy... Expanded...F27. There are, however, some exceptions in which the mechanical (or non-chemical) aspect carries with it the chemical aspect, for example: Certain extractive processes, in subclass Fulltext... Hierarchy... Expanded...A61K; The chemical purification of air, in subclass Fulltext... Hierarchy... Expanded...A61L; Chemical methods of fire-fighting, in subclass Fulltext... Hierarchy... Expanded...A62D; Chemical processes and apparatus, in class Fulltext... Hierarchy... Expanded...B01; Impregnation of wood, in subclass Fulltext... Hierarchy... Expanded...B27K; Chemical methods of analysis or testing, in subclass Fulltext... Hierarchy... Expanded...G01N; Photographic materials and processes, in class Fulltext... Hierarchy... Expanded...G03, and, generally, the chemical treatment of textiles and the production of cellulose or paper, in section D. In still other cases, the pure chemical aspect is covered by section C and the applied chemical aspect by another section, such as A, B or F, e.g., the use of a substance or composition for: treatment of plants or animals, covered by subclass Fulltext... Hierarchy... Expanded...A01N; foodstuffs, covered by class Fulltext... Hierarchy... Expanded...A23; ammunition or explosives, covered by class Fulltext... Hierarchy... Expanded...F42. When the chemical and mechanical aspects are so closely interlocked that a neat and simple division is not possible, or when certain mechanical processes follow as a natural or logical continuation of a chemical treatment, section C may cover, in addition to the chemical aspect, a part only of the mechanical aspect, e.g., after-treatment of artificial stone, covered by class Fulltext... Hierarchy... Expanded...C04. In this latter case, a note or a reference is usually given to make the position clear, even if sometimes the division is rather arbitrary.

METALLURGY

|  | C23 |
COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL (by metallising textiles Fulltext... Hierarchy... Expanded...D06M 11/83; decorating textiles by locally metallising Fulltext... Hierarchy... Expanded...D06Q 1/04); CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL (for specific applications, see the relevant places, e.g. for manufacturing resistors Fulltext... Hierarchy... Expanded...H01C 17/06); INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL (treating metal surfaces or coating of metals by electrolysis or electrophoresis Fulltext... Hierarchy... Expanded...C25D, Fulltext... Hierarchy... Expanded...C25F) [2]

|  | C23 |
Note(s) In this class, the following expression is used with the meaning indicated: "metallic material" covers: metals; [4] alloys (attention is drawn to the Note following the title of subclass Fulltext... Hierarchy... Expanded...C22C).

|  | C23F |
NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACES (working of metal by electro-erosion Fulltext... Hierarchy... Expanded...B23H; desurfacing by applying flames Fulltext... Hierarchy... Expanded...B23K 7/00; working metal by laser beam Fulltext... Hierarchy... Expanded...B23K 26/00; producing decorative effects by removing surface-material, e.g. by engraving, by etching, Fulltext... Hierarchy... Expanded...B44C 1/22; electrolytic etching or polishing Fulltext... Hierarchy... Expanded...C25F); INHIBITING CORROSION OF METALLIC MATERIAL; INHIBITING INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS Fulltext... Hierarchy... Expanded...C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS Fulltext... Hierarchy... Expanded...C21D OR Fulltext... Hierarchy... Expanded...C22F OR CLASS Fulltext... Hierarchy... Expanded...C25 (inhibition or prevention of corrosion or incrustation during processing of hydrocarbons Fulltext... Hierarchy... Expanded...C10G 7/10, Fulltext... Hierarchy... Expanded...C10G 9/16, Fulltext... Hierarchy... Expanded...C10G 75/00) [4]

|  | C23F |
Note(s) This subclass covers inhibiting corrosion or incrustation in general, whether of or on metallic or non-metallic surfaces, subject to Note (2) below. This subclass does not cover: protective layers or coating compositions or methods of applying them; these are classified in the appropriate places, e.g. Fulltext... Hierarchy... Expanded...B05, Fulltext... Hierarchy... Expanded...B44, Fulltext... Hierarchy... Expanded...C09D, Fulltext... Hierarchy... Expanded...C10M, Fulltext... Hierarchy... Expanded...C23C; mechanical devices or constructional features of particular articles for inhibiting incrustation; these are classified in the appropriate places, e.g. in pipes or pipe fittings Fulltext... Hierarchy... Expanded...F16L 58/00; articles characterised by being made of materials selected for their properties of resistance to corrosion or incrustation; these are classified in the appropriate places, e.g. turbine blades Fulltext... Hierarchy... Expanded...F01D 5/28. Processes using enzymes or micro-organisms in order to: liberate, separate or purify a pre-existing compound or composition, or to treat textiles or clean solid surfaces of materials are further classified in subclass Fulltext... Hierarchy... Expanded...C12S. [5]

|  | C23F |
Subclass index
ETCHING, BRIGHTENING, COMPOSITIONS THEREFOR | 1/00, 3/00
OTHER REMOVING OF METALLIC MATERIAL | 4/00
INHIBITING CORROSION OR INCRUSTATION | 11/00 - 15/00
MULTI-STEP SURFACE TREATMENTS | 17/00

P:20 |  | C23F 1/00 |
Etching metallic material by chemical means (manufacture of printing surfaces Fulltext... Hierarchy... Expanded...B41C; manufacture of printed circuits Fulltext... Hierarchy... Expanded...H05K) [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 1/10 |
· | Etching compositions (Fulltext... Hierarchy... Expanded...C23F 1/44 takes precedence) [4]

|  | C23F 1/12 |
· · | Gaseous compositions [4]

|  | C23F 1/14 |
· · | Aqueous compositions [4]

|  | C23F 1/16 |
· · · | Acidic compositions (Fulltext... Hierarchy... Expanded...C23F 1/42 takes precedence) [4]

|  | C23F 1/18 |
· · · · | for etching copper or alloys thereof [4]

|  | C23F 1/20 |
· · · · | for etching aluminium or alloys thereof [4]

|  | C23F 1/22 |
· · · · | for etching magnesium or alloys thereof [4]

|  | C23F 1/24 |
· · · · | for etching silicon or germanium [4]

|  | C23F 1/26 |
· · · · | for etching refractory metals [4]

|  | C23F 1/28 |
· · · · | for etching iron group metals [4]

|  | C23F 1/30 |
· · · · | for etching other metallic material [4]

|  | C23F 1/32 |
· · · | Alkaline compositions (Fulltext... Hierarchy... Expanded...C23F 1/42 takes precedence) [4]

|  | C23F 1/34 |
· · · · | for etching copper or alloys thereof [4]

|  | C23F 1/36 |
· · · · | for etching aluminium or alloys thereof [4]

|  | C23F 1/38 |
· · · · | for etching refractory metals [4]

|  | C23F 1/40 |
· · · · | for etching other metallic material [4]

|  | C23F 1/42 |
· · · | containing a dispersed water-immiscible liquid [4]

|  | C23F 1/44 |
· | Compositions for etching metallic material from a metallic material substrate of different composition [4]

|  | C23F 1/46 |
· | Regeneration of etching compositions [4]

P:10 |  | C23F 3/00 |
Brightening metals by chemical means [2]

|  | C23F 3/02 |
· | Light metals

|  | C23F 3/03 |
· · | with acidic solutions [4]

|  | C23F 3/04 |
· | Heavy metals

|  | C23F 3/06 |
· · | with acidic solutions [4]

P:30 |  | C23F 4/00 |
Processes for removing metallic material from surfaces, not provided for in group Fulltext... Hierarchy... Expanded...C23F 1/00 or Fulltext... Hierarchy... Expanded...C23F 3/00 [4]

|  | C23F 4/02 |
· | by evaporation [4]

|  | C23F 4/04 |
· | by physical dissolution [4]

P:50 |  | C23F 11/00 |
Inhibiting corrosion of metallic material by applying inhibitors to the surface in danger of corrosion or adding them to the corrosive agent (compositions for in situ inhibition of corrosion in boreholes or wells Fulltext... Hierarchy... Expanded...C09K 8/54; adding inhibitors to mineral oils, 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 11/173 |
Note(s) In groups Fulltext... Hierarchy... Expanded...Fulltext... Hierarchy... Expanded...C23F 11/12-C23F 11/173 in the absence of an indication to the contrary, a compound is classified in the last appropriate place.

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

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

|  | C23F 11/16 |
· · · | Sulfur-containing compounds

|  | C23F 11/167 |
· · · | Phosphorus-containing compounds [4]

|  | C23F 11/173 |
· · · | Macromolecular compounds [4]

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

P:40 |  | C23F 13/00 |
Inhibiting corrosion of metals by anodic or cathodic protection

|  | C23F 13/02 |
· | cathodic; Selection of conditions, parameters or procedures for cathodic protection, e.g. of electrical conditions [5]

|  | C23F 13/04 |
· · | Controlling or regulating desired parameters [5]

|  | C23F 13/06 |
· · | Constructional parts, or assemblies of cathodic-protection apparatus [5]

|  | C23F 13/08 |
· · · | Electrodes specially adapted for inhibiting corrosion by cathodic protection; Manufacture thereof; Conducting electric current thereto [5]

|  | C23F 13/10 |
· · · · | Electrodes characterised by the structure (Fulltext... Hierarchy... Expanded...C23F 13/16 takes precedence) [5]

|  | C23F 13/12 |
· · · · | Electrodes characterised by the material (Fulltext... Hierarchy... Expanded...C23F 13/16 takes precedence) [5]

|  | C23F 13/14 |
· · · · · | Material for sacrificial anodes [5]

|  | C23F 13/16 |
· · · · | Electrodes characterised by the combination of the structure and the material [5]

|  | C23F 13/18 |
· · · · | Means for supporting electrodes [5]

|  | C23F 13/20 |
· · · · | Conducting electric current to electrodes [5]

|  | C23F 13/22 |
· · · · | Monitoring arrangements therefor [5]

P:60 |  | 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...C02F 5/00) [2]

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

P:70 |  | C23F 15/00 |
Other methods of preventing corrosion or incrustation

P:0 |  | C23F 17/00 |
Multi-step processes for surface treatment of metallic material involving at least one process provided for in class Fulltext... Hierarchy... Expanded...C23 and at least one process covered by subclass Fulltext... Hierarchy... Expanded...C21D or Fulltext... Hierarchy... Expanded...C22F or class Fulltext... Hierarchy... Expanded...C25 (Fulltext... Hierarchy... Expanded...C23C 28/00 takes precedence) [4]