C
SECTION C — CHEMISTRY; METALLURGY
 C

Note(s)

  1. 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

  2. Section C covers :
    1. pure chemistry, which covers inorganic compounds, organic compounds, macromolecular compounds, and their methods of preparation;
    2. 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;
    3. 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;
    4. 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;
    5. metallurgy, ferrous or non-ferrous alloys.
  3. In all sections of the IPC, in the absence of an indication to the contrary, the Periodic System of chemical elements referred to is the one with 8 groups as represented in the table below. For example, group C07F 3/00 "Compounds containing elements of the 2nd Group of the Periodic System" refers to the elements of columns IIa and IIb. [2009.01]

    1. 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.
    2. 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 C03 and not by class F27.
    3. There are, however, some exceptions in which the mechanical (or non-chemical) aspect carries with it the chemical aspect, for example:
    4. 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:
    5. 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 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 D06M 11/00; decorating textiles by locally metallising D06Q 1/00); 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 H01C 17/06); INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL (treating metal surfaces or coating of metals by electrolysis or electrophoresis C25D, C25F)  [2]
 C23

Note(s)

In this class, the following expression is used with the meaning indicated:

 C23F
NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACES (working of metal by electro-erosion B23H; desurfacing by applying flames B23K 7/00; working metal by laser beam B23K 26/00; producing decorative effects by removing surface-material, e.g. by engraving, by etching, B44C 1/22; electrolytic etching or polishing 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 C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25 (inhibition or prevention of corrosion or incrustation during processing of hydrocarbons C10G 7/00, C10G 9/00, C10G 75/00)  [4]
 C23F

Note(s)

  1. This subclass covers inhibiting corrosion or incrustation in general, whether of or on metallic or non-metallic surfaces, subject to Note (2) below.
  2. This subclass does not cover:
  3. Processes using enzymes or micro-organisms in order to:
    1. liberate, separate or purify a pre-existing compound or composition, or to
    2. treat textiles or clean solid surfaces of materials
    are further classified in subclass 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 B41C; manufacture of printed circuits H05K)  [2]
 C23F 1/02
·  Local etching
 C23F 1/06
·  Sharpening files
 C23F 1/08
·  Apparatus, e.g. for photomechanical printing surfaces (photomechanical reproduction G03F)
 C23F 1/10
·  Etching compositions (C23F 1/44 takes precedence)  [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]
P:30 C23F 4/00
Processes for removing metallic material from surfaces, not provided for in group C23F 1/00 or 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 C09K 8/54; adding inhibitors to mineral oils, fuels or lubricants C10; adding inhibitors to pickling solutions C23G)
 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
P:40 C23F 13/00
Inhibiting corrosion of metals by anodic or cathodic protection
P:60 C23F 14/00
Inhibiting incrustation in apparatus for heating liquids for physical or chemical purposes (adding scale preventives or removers to water C02F 5/00)  [2]
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 C23 and at least one process covered by subclass C21D or C22F or class C25 (C23C 28/00 takes precedence)  [4]