ISO 7599:2018 download free.Anodizing of aluminium and its alloys — Method for specifying decorative and protective anodic oxidation coatings on aluminium.
1 Scope
ISO 7599 specifies a method for specifying decorative and protective anodic oxidation coatings on aluminium (induding aluminium-based alloys). It defines the characteristic properties of anodic oxidation coatings. lists methods of test for checking the characteristic properties, provides minimum performance requirements, and gives information on the grades of aluminium suitable for anodizing and the importance of pretreatment to ensure the required appearance or texture of the finished work.
Iris not applicable to
a) non-porous anodic oxidation coatings of the barrier layer type.
b) anodic oxidation coatings produced by chromic acid or phosphoric acid anodizing.
c) anodic oxidation coatings intended merely to prepare the substrate for subsequent application of organic coatings or for the electrodepositlon of metals, and
d) hard anodic oxidation coatings used mainly for engineering purposes, for which abrasion and wear resistance are the primary characteristics (see ISO 10074).
2 Normative references
The following documents are referred to In the text In such a way that some or all of their content constitutes requirements of ISO 7599. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 1463, Metallic and oxide coatings — Measurement of coating thickness — Microscopical method
ISO 2085, Anodizing of aluminium and its allays — Check for continuity of thin anodic oxidation coatings — Copper sulfate test
ISO 2106. Anodizing of aluminium and its alloys — Determination of mass per unit area (surface density) of anodic oxidation coatings — Gravi,netric method
ISO 2128, AnodizIng of aluminium and Its alloys — Determination of thickness of aiwdic oxidation coatings — Non-destructive measurement by split-beam microscope
ISO 2143. Anodizing of aluminium and its alloys — Estimation of loss of absorptive power of onodic oxidation coatings after sealing — Dye-spot test with prior acid treatment
ISO 2360. Non-conductIve coatings on non-magnetic electrically conductive base metals — Measurement of coating thickness — Amplitude-sensitive eddy-current method
ISO 2376. Anodizing of aluminium and its alloys — Determination of electric breakdown potential
ISO 2931, AnodIzing of aluminium and its alloys — Assessment of quality of sealed anodic oxidation coatings by measurement of admittance
ISO 3210, AnodIzing of aluminium and its alloys — Assessment of quality of sealed anodic oxidation coatings by measurement of the loss of mass after immersion in acid solution(s)
For anodized aluminium, the degree or protection against pitting corrosion of the aluminium increases with an increase in coating thick ness. Thus, product lifetime is very dependent on the coating thickness. Specifiers should consider the full life cycle Impact of the product, including the energy expenditure associated with manufacture, in-service maintenance procedures and recycling.
6.3 Measurement of thickness
Thickness measurements shall be carried out by one or more of the following methods:
a) examination of cross-section using microscopy In accordance with ISO 1463 or ISO 9220;
b) eddy-current method in accordance with ISO 2360;
c) split-beam microscope method specified in ISO 2128.
When using method b), the measurement apparatus shall be calibrated In accordance with the manufacturer’s instructions using calibration standards before any measuring Is performed. Calibration standards are described in Annex 0.
In cases of dispute, method a) shall be the referee method.
Thickness measurements shall be made on the significant surfaces In accordance with Annex C. but no measurements shall be made within S mm olthe areas of anodic contact or In the Immediate vicinity of a sharp edge.
7 Quality of sealing
7.1 General
Scaling is a treatment applied to an anodic oxidation coating to reduce its porosity and absorption capacity (as defined in ISO 7583). In many applications, anodic oxidation coatings are expected to resist degradation by aqueous solutions. Sealing can provide that resistance. Where the retention of the initial appearance is important, for example, in outdoor architectural applications, sealing at the surface of the anodic oxidation coating is important. Where the anodized aluminium is expected to resist strongly acidic or alkaline conditions over a short time period, for example, car-wash fluids, sealing throughout the thickness of the coating can be important.
Hydrothermal sealing Is very well established and quality control methods have been developed for anodic oxidation coatings scaled using such treatments. These test methods can be appropriate where other sealing treatments are used.
7.2 Assessment of quality of hydrothermal sealing
7.2.1 Referee test
In cases of dispute, the quality of hydrothermal sealing of anodic oxidation coatings shall be determined by one of the test methods specified In ISO 3210, The necessity of prior acid treatment and maximum accepted loss of mass shall be agreed between the anodlzer and the customer.
The test should be carried out without prior acid treatment for Internal architectural and decorative coatings and with prior acid treatment for external architectural coatings.
These methods are surface-specific. They test the resistance of the surface of a sealed ano.dic oxidation coating to attack by certain acid solutions. They are not Intended to test the quality of the whole thickness of the coating,
NOTE The maximum accepted loss o4 mass of anodic oxidation coatings Is variously set at 30 mg)dmZ or 40 mg/dm2.
Anodized aluminium has the property of double reflection From the surface of oxidation byer and of the basis metal. Therefore, when matching colour samples, they shall be held in the same plane and viewed as near to nornial as Is practicable, with the direction of working (e.g. rolling, extrusions or machining direction) always the same. A diffuse source ofilluminatlon shall be placed above and behind the vlewer
Unless otherwise agreed, the colours shall be compared in diffuse daylight with the sun behind the viewer. If the coloured coatings are to be used in artificial light, this lighting shall be used for colour comparison.
The agreed colour limit samples shall be stored in a dry space in the dark.
8.3 Production control
For production control purposes, it can be convenient to use colour measuring instruments for recording or grading colours.
9 Corrosion resistance
if It Is required by the customer that the protection against corrosion of anodized aluminium be assessed, then the acetic acid salt spray (AASS) test method or the copper-accelerated acetic acid salt spray (CASS) test method specified in ISO 9227 shall be used. The choice of method, period of exposure and acceptance criteria shall be agreed between the anodizer and the customer.
ii required by the customer, the neutral salt spray (NSS) test according to ISO 9227 may be used.
The rating of corroded specimens shall be decided using the systems specified In ISO 8993 or ISO 8994.
AASS testing is more appropriate for assessing the corrosion resistance of anodized aluminium because its test conditions are more similar to the natural environment than those of the CASS test. It should be used as the referee test.
NOTh CASS testing is more effective than the AASS test for detecting defects in the anodic oxidation coating and to produce a test result in a shorter time (8 h for AA 51072 h (or AA 25). his useful isa production control test.
10 Abrasion (wear) resistance
Anodic oxidation coatings are very wear resistant, However, under aggressive conditions, they can suffer abrasive wear or erosive wear. ISO 8251 specIfies three methods:
a) abrasive-wheel wear test method;
b) abrasive et test method
c) falling sand abrasion method.
The abrasive-wheel wear test method assesses resistance to abrasive wear of the coating near its surface, or of the whole coating thickness, or of any selected intermediate zone. The abrasive let test method and the falling sand abrasion method assess resistance to erosive wear of the whole coating thickness. By convention, all three methods are said to assess abrasion resistance.
lispecitled by the customer, the abrasion resistance of the anodic oxidation coating shall be determined using the most appropriate method selected from those given In ISO 8251. The test to be carried out and the acceptable value for abrasion resistance shall be specified by the customer to the anodizer.
For abrasive-wheel wear tests In accordance with ISO 8251, the customer shall specify the method to be used and the values required, such as wear resistance, wear resistance coefficient, wear index or mass wear index, as appropriate. For abrasive jet tests in accordance with ISO 8251, the customer shall specify the mean specific abrasion resistance or the relative mean specific abrasion resistance.