BS ISO 22779 pdf download – Metallic coatings Physical vapour-deposited coatings of aluminium——Specification and test methods

BS ISO 22779 pdf download – Metallic coatingsPhysical vapour-deposited coatings of aluminium——Specification and test methods.
I the requirement for coating adhesion (see 6.3.3 and Annex C).
j) the requirement for special test specimens and for the type of test method, for example, destructive or non-destructive (see 6.6):
k) sampling and inspection requirements (see Clause 7 and Annex 0).
5 Designation
The designation shall appear on engineenng drawings, in the purchase order, the contract or in the detailed product specification. The designation specifies the basis material, the requirements for stress relief before vapour deposition, the nominal conosition and thickness of the vapour-deposited aluminium coating, the type of chromate conversion coating and other supplementary treatment, and the heat treatment to reduce suscep1ility to hydrogen embrittlement.
5.1 General
The designation shall comprise the following:
a) the term: vapour-deposited coating:
b) the number of this International Standard, ISO 22779;
C) a hyphen;
d) the chemical symbol of the basis metal:
e) a stroke (i);
f) symbols for the aluminium coating, as well as any coatings that may be applied prior to and after deposition, separated by strokes for each stage in the coating sequence in the order of application. The coating designation shall include the thickness of the coating, in micrometres.
5.2 Basis metal
The basis metal shall be designated by its chemical symbol, or its pnnclpal constituent, It It Is an alloy. For example:
— Fe for iron and steel;
— Zn for zinc alloys:
— Cu for copper and copper alloys.
– Al for aluminjm and aluminium alloys;
— Ti for titanium and titanium alloys.
The specific alloy may be derititied by its standard designation (for example. its LJNS number, or Its national or regional equivalent) placed between the symbols. ‘>,for example. Fe. See Reference (4] In the Bibliography.
6.3.1 Appearance
The coating shall be present on all significant areas and shall be smooth, continuous, urWform, adherent, fine-grained and free from starns, burns, blisters, pits, nodules, cracks, porosity, non-coated areas, edge build-up o other detects. The aluminium coating shall show no indication of contamination or improper operation of equipment, such as powdered or darkened area& The coating shall extend Into holes and recesses to a distance as specified in the drawing, contract or purchase order [see 4 c)J.
All masking material is to be removed from the non-significant surfaces, and the masked areas shall be clean and free from any defect and aluminium coating. The line of demarcation between the coated and non-coated areas shall be clear-cut. Lifting of the deposit at the edge shalt not be acceptable.
Approved samples of artefacts shall be used to control the appearance of the twial finish (see ISO 16348).
NOTE Unavoidable rack marks may be permitted it specified in the clraerng, contract or purchase order, or Mlh the
prior agreement ot the purchaser.
6.3.2 Thickness
The coating thickness specified in the designation shall be the mmimum local thickness. The minimum local thickness shall be measured at any point on the significant surface that can be touched by a ball 20 mm in diameter. Thickness shall comply with the requirements In Table 1.
The minimum local thickness of the vapour-deposited aluminium coaling shall be measured by one of the following methods: ISO 1463, ISO 2360, ISO 3497, ISO 3543, ISO 3882. ISO 3892. ISO 4518 ci ISO 9220. The referee methods are specified in ISO 1463, ISO 3497. or ISO 9220. For the determination of the average thickness of the aluminium coating (ISO 3892), see Annex B.
6.3.3 Adhesion
The coating shall adhere to the basis metal without chipping, flaking, or other coating damage and shall
conform to the minimum requirements given in Annex C.
6.3.4 CoatIng composition
The coating shall contain not less than 999% aluminum by mass. The referee method is the mass specirometry method.
6.4 Supplementary treatments
Prior to the application of any supplementary coating, the aluminium-coated surface may require solvent
degreasing. No other form of cleaning shalt be allowed.
6,4.1 Treatment with glass beads
If required. the physical vapour-deposited coating may be peened with glass beads Isee 4 e)].
NOTE The process can wnprove the compactness of the coating, give additional corrosion resistance arid provide a check for the adhesion ci the ooatir. For example, peerwig may be carried out by using glass beads 50 irn to tOO pm In diameter, at a pressure oh 28 s 10 Pa to produce a satin fWIh on the surface. Thicker coatings deposited at relatively high pressure often develop a coarsegramed structure which can be converted to a tine-grained structure by glass•bead peen.