BS EN ISO 27830:2013 pdf free
BS EN ISO 27830:2013 pdf free.Metallic and other inorganic coatings一Guidelines for specifying metallic and inorganic coatings
a) The coatings shall be designated by the symbols given in Table A.2, followed by a number designating the minimum local thickness of the coating in micrometres.
b) In the case of a binary alloy coating, the symbol shall be followed by a whole number, in parentheses,giving the nominal content of the alloying element in percent mass fraction. For example, NiP(10)15 designates an autocatalytic nickel-phosphorus alloy coating that is 15 um thick containing 10 % mass fraction phosphorus.
c) Metallic undercoats, when present, shall be designated by the chemical symbol(s) for the deposited metal(s) followed by a number specifying the minimum local thickness of the layer, in micrometres. See Table A.3 for the symbols of some common metallic undercoats.
d) Subsequent metallic coatings (top coats), e.g. chromium or gold electrodeposited upon the specified coating, shall be designated by the chemical symbols given in Table A.2.
e) The different types of coatings shall be designated by the lower case letters given in Table A.4.
f) Chemical conversion coatings and supplementary treatments (for example, those commonly used with zinc and cadmium coatings) shall be designated by the symbols in Table A.5 and Table A.6.
International Standards for metallic and other inorganic coatings shall provide specific examples to assist the user of the International Standard in understanding the designation system.Examples of designations are given in Annex B.
The coating thickness that is specified in the designation is the minimum local thickness which shall be measured at any point on the significant surface that can be touched by a ball 20 mm in diameter. The definitions and conventions for thickness are given in ISO 2064[2].
Thickness is an important dimension of the coating because thickness directly affects corrosion performance and the useful service life of the final product. Many of the standards on metallic and other inorganic coatings specify the minimum local thickness as related to different conditions of service. In general, corrosion performance improves as thickness is increased and the recommended minimum coating thickness is thus greater for severe service conditions than for mild ones. The severity of different service conditions has been standardized and is described in Annex C.BS EN ISO 27830 pdf download.
