BS ISO 22779 pdf download Metallic coatings — Physical vapour-deposited coatings of aluminium — Specification and test methods
6.1.2 Equipment and materials
a)The equipment, process and materials used to produce physical vapour-deposited aluminium shall becapable of producing a uniform coating, covering completely all significant surfaces,including roots of
threads, recesses, sharp corners, holes and other areas specified in the drawing, contract or purchaseorder.
NOTE Suitable rotating and revolving racks and fixtures may be used to ensure that all significant surfaces arecleaned and coated to the specified thickness limits.
b)High-purity argon (at least 99,995 % pure) shall be used during substrate conditioning and coating, asrequired.For sensitive material, ultra-high-purity argon (at least 99,998 % pure) shall be used.
c)The equipment shall be capable of producing a vacuum of 7× 10-+Pa, or better, in the coating chamber.Where water-cooled surfaces are present in the chamber, including chamber walls, then a means of heatingthe circulating water is to be used，to ensure that the chamber surfaces are warm enough to preventcondensation when open to the atmosphere.
d)The aluminium metal used as a source material shall contain not less than 99,95 % aluminium by mass.The composition of aluminium shall be determined by using chemical or other acceptable techniques. The
referee method is the mass spectrometry method.
e)Only items made of a similar basis metal shall be processed together.
f) The equipment and process shall be such that any temperature rise in the items will have no adverse
effects on the properties of the basis metal or the coating, or on the adhesion characteristics between thebasis metal and the coating [see 4 b)]-
a) Steels of tensile strength 1 000 MPa and greater shall be cleaned before the application of the coating,
preferably using non-electrolytic alkaline and anodic alkaline cleaners to avoid the risk of creatinghydrogen embrittlement problems as a result of the cleaning procedure.For titanium and titanium alloys,and for other materials,appropriate cleaning procedures,or procedures as specified in the drawing.contract or purchase order shall be followed.
b)Surfaces to be coated shall be smooth and free from oxides, tool marks,pitting, intergranular attack,or
)Abrasives used on any metal or alloy shall not have been used on any dissimilar metals or alloys.
Separate abrasive cleaning media shall be used for different alloy families, for example, iron and its alloys,aluminium and its alloys, etc. After abrasive cleaning， residues shall be removed from the surfaces ofarticles prior to subsequent processing.
d)Any shot peening of the basis metal or substrate shall be in accordance with ISO 12686 before final
cleaning and the application of the coating [see 4 b)].
6.2Stress-relief heat treatment before coating
Steel parts that have an ultimate tensile strength of 1 000 MPa and greater and that contain tensile stressescaused by machining, grinding or cold-forming operations shall be given a stress-relief heat treatment prior tocleaning and metal deposition.The stress-relief heat treatment shall be as specified in ISO 9587,or asspecified by the purchaser.