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:

 C23D
ENAMELLING OF, OR APPLYING A VITREOUS LAYER TO, METALS (chemical composition of the enamels C03C)
 C23D
Subclass index
TREATMENT PRIOR TO ENAMELLING 1/00, 3/00
ENAMELLING 5/00 - 11/00
AFTER-TREATMENT 13/00, 15/00, 17/00
P:80 C23D 1/00
Melting or fritting the enamels; Apparatus or furnaces therefor
 C23D 3/00 - 
C23D 7/00
Coating with the enamels
P:40 C23D 3/00
Chemical treatment of the metal surfaces prior to coating (cleaning or de-greasing of metallic objects C23G)
P:60 C23D 5/00
Coating with enamels or vitreous layers  [4]
P:50 C23D 7/00
Treating the coatings, e.g. drying before burning
 C23D 9/00 - 
C23D 11/00
Firing the enamels
P:70 C23D 9/00
Ovens specially adapted for firing enamels
P:30 C23D 11/00
Continuous processes for firing enamels; Apparatus therefor
 C23D 13/00 - 
C23D 17/00
After-treatment
P:20 C23D 13/00
After-treatment of the enamelled articles
P:0 C23D 15/00
Joining enamelled articles to other enamelled articles by processes involving an enamelling step
P:10 C23D 17/00
De-enamelling