BS EN ISO 2376:2019 pdf free download.Anodizing of aluminium and its alloys — Determination of breakdown voltage and withstand voltage.
BS EN ISO 2376:2019 specifies test methods for the determination of the breakdown voltage and withstand voltage of anodic oxidation coatings on aluminium and its alloys, on flat or near-flat surfaces and on round wire. The methods are applicable to anodic oxidation coatings used primarily as electrical insulators.
The methods are not applicable to coatings in the vicinity of cut edges, the edges of holes, or sharp changes of angle on, for example, extruded shapes.
4 Principle
The electric voltage at which current first passes through an anodic oxidation coating is measured. These breakdown voltage and withstand voltage are a function of the dielectric characteristics and the insulation properties of the anodic oxidation coatings. The breakdown voltage and withstand voltage depend upon the thickness of the coating, as well as on many other factors, particularly the composition of the basis metal, its surface condition, the effectiveness of sealing, the dryness of the test specimen anti the degree of ageing.
5 Apparatus
5.1 Power supply, from a suitable 50 Hz or 60 Hz source.
5.2 Transformer (AC), having an output with a waveform as nearly sinusoidal as possible, capable of producing the voltage required.
5.5 Voltage-measuring device, which gives r.m.s. values, expressed in volts.
5.6 Electrode probe, made from conducting material, suitably insulated for handling purposes, free
to move as required and adequately supported. The contact surface shall be spherical with a diameter of
3 mm to 8 mm and shall be maintained in a smooth, untarnished condition. The design of the probe shall
be such that, when the spherical surface is placed on the surface of the anodized test specimen, the total
force exerted on the coating is 0,5 N to 1,0 N (a probe of mass 50 g to 100 g is suitable).
5.7 Contact plate, for testing flat test specimens, having a smooth, bright, metallic surface, or a contact probe or clip which is capable of breaking through to the basis metal (7d).
5.8 Twisting machine, for testing round wire, having two sets of jaws 400 mm apart, with one set of jaws fixed, while the other set is free to rotate. The jaws shall be mounted so as to prevent lateral movement of the jaws when the twisting operation is carried out (7.2).
