ISO 7599:2018 pdf download – Anodizing of aluminium and itsalloys – Method for specifying decorative and protective anodic oxidation coatings on aluminium
ISO 7599:2018 pdf download – Anodizing of aluminium and itsalloys – Method for specifying decorative and protective anodic oxidation coatings on aluminium.
13.4 Specular gloss (medium or low gloss)
The determination of the specular gloss of surfaces which are semi-diffuse, or which are mainly diffuse, can be carried out as given in ISO 7668 by the measurement of
a) specular gloss at 60, using method C, b) specular gloss at 85°. usIng method 0, or c specular gloss at 45°, using method B.
The 60° method relies on a good general-purpose instrument applicable over the range of 30 gloss units to 70 gloss units and also classifies other surfaces as high or low gloss. On matt surfaces below 30 gloss units, the 45° or 85° geometry is more suitable. Above 70 gloss units, the methods given in 13.3 should be used.
13.5 Diffuse reflectance
By definition, the diffuse reflectance and the specular reflectance together give the total reflectance. It is not therefore an independent property and can be measured by the integrating sphere method specified in ISO 6719.
13.6 Image clarity
The determination of image clarity can be carried out using the method specified in ISO 10215, which describes a visual method using a simple apparatus, or the method specified in ISO 10216, which describes an instrumental method. If required by the customer, the test method and the performance requirement shall be agreed between the anodizer and the customer.
14 Electrical breakdown potential
If required by the customer, the electrical breakdown potential of the anodic oxidation coating shall be determined by the method specified in ISO 2376. The acceptable breakdown potential shall be agreed between the anodizer and the customer.
15 Continuity of coating
If required by the customer, the continuity of the anodic oxidation coating shall be determined by the method specified in ISO 2085. The requirements for continuity shall be agreed between the anodizer and the customer
16 Mass per unit area (surface density) of coating
If required by the customer, the mass per unit area of the anodic oxidation coating shall be determined by the method specified in ISO 2106 (see also Li.3). This isa destructive test.
WARNING — The method specified in ISO 2106 requires the use of a reagent containing chromlu,n(Vl), Chromkum(Vl) Is toxic and its solutions are hazardous to the environment and severely hazardous to waters.
The requirements for mass per unit area shall be agreed between the anodizer and the customer.
The pretreatment given before anodizing largely determines the final appearance and texture of the anodized aluminium surface. Different surface textures can be obtained by a variety of treatment processes.
Usually, the product, whether polished or unpolished, is subjected to a chemical etching procedure to provide a range of textures — from light satin with varying degrees of gloss to full matt — according to the type of etch used. Surface effects, such as corrosion which has occurred before pretreatment or different material characteristics, can become visible after etching.
Alternatively, the texture can be produced mechanically by brushes, abrasive belts or wheels to give a range of matt finishes which are lined or directional, in contrast with the essentially non-directional etched finishes. Mechanical finishes have good reproducibility and are less dependent on metal structure and composition than chemical pretreatments. Surface Irregularities. If not too deep, can be removed by mechanical means.
Aluminium can be mechanically polished to obtain a smooth or bright surface.
Chemical or electrochemical brightening can be employed with special aluminium alloys to obtain a very bright finish.
NOTE 1 Very rough surfaces, either chemically or mechanically produced, are best avoided In external applications as they tend to hold dirt and have an adverse effect on the durability olanodlc oxidation coatings.
NOTE 2 Surface preparation methods can result In the removal of considerable quantities of aluminium from the parts to be anodized. This aluminium cannot be easily recovered in metallic form. Often, the surface preparation method produces a waste that has no value and represents a cost for disposal, Thus, It Is Important to
use metal of good surface quality to minimize the extent of surface preparation and for the specifier to consider
the environmental Impact associated with the processes necessary to achieve the aesthetic effect sought.
B.2 Surface texture
The desired surface texture should be agreed between the anodizer and the customer, if necessary on the basis of agreed limit samples.