BS EN 1965-2-2011 pdf download.Structural adhesives Corrosion Part 2: Determination and classification of corrosion to a brass substrate.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
EN 923:2005+A1 :2008. Adhesives — Terms and definitions
EN ISO 291, Plastics — Standard atmospheres for conditioning and testing (ISO 291:2008)
EN ISO 8044:1999, Corrosion of metals and alloys — Basic terms and definitions (ISO 8044:1999)
ISO 426 (all parts), Wrought copper-zinc alloys — Chemical composition and forms of wrought products
3 Terms and definitions
For the purposes of this document, the terms and definitions given in EN 923:2005+A1 :2008 and the following apply.
corrosion
destructive attack on metals which can be chemical or electrochemical in nature
NOTE The described method measures essentially an electrochemical attack.
4 Principle
Two brass electrodes are held in contact with a flat sample of the cured adhesive. The assembly is placed in
an environment with a relative humidity of 92 % at 42 °C and a direct current voltage of 100 V is applied
across the electrodes for four days. Following this the brass surface is examined and the extent of the tarnishing and/or corrosion decided on the basis of discolouration.
5 Products, materials and apparatus
5.1 Solvents.
Alcohol pure: for example propan-2-ol or ethanol.
5.2 Brass electrode, consisting of 0,1 mm thick brass, Ms63F45 or Ms63F55 of width 10 mm.
The length of the foil shall be adapted to the test equipment in accordance with ISO 426 (all parts).
5.3 Etching solution, consisting of 73 % concentrated sulfuric acid (98 %), 26 % concentrated nitric acid
(63 %). 0,5 % sodium chloride, 0,5 % carbon black.
5.4 Conditioning chamber, capable of maintaining a hotlhumid climate in accordance with EN ISO 291.
5.5 Direct current source (100 ± 5) V, e.g. a battery, or rectifying equipment with a maximum permissable
electrodyne alternating current not greater than 1 %.
5.6 Magnifier, with a magnification of 2.5 x
5.7 Electrode and clamping, in accordance with Figure 1.
This shall be constructed from Inert insulating materials which do not cause additional corrosion under the test conditions. The brass test foils shall make contact with the entire test area of the test specimen with a pressure of about 0,1 MPa.
6 Preparation of the brass substrate
Degrease strips of the foil, about 200 mm long and without any flash, with acetone solvent. Immediately afterwards immerse in the etching solution (5.3) (maintained at 15 °C to 25 °C) for 15 s. Rinse the foil under running water to remove the etching solution (5.3). Repeat this procedure as necessary until the brass foil has an even, dull lustre. Immediately afterwards immerse the brass foil in pure alcohol (5.1) dry with blotting paper and cut into pieces of suitable tength.
7 Test specimens
The thickness of the test specimens shall correspond to the relevant product thickness. The test surfaces shall be machined and flat and be at right angles to the edges. The material to be tested shall protrude a few tenths
of a millimetre beyond the holding plates. Remove any flash left following machining with a sharp knife. Finally clean the machined test specimens with pure alcohol.
NOTE The etchrg solution should be freshly made and used only once. The roughness of the brass surface has an influence on colouration and can lead to faulty assessments. An even, dull surface reveals more marked colourations than
a semi-matt or glossy surface.
CAUTION — The etching solution is corrosive.
A minimum of three test specimens shall be used for each evaluation.
8 Procedure
Ensure that the surface of the electrode in contact with the brass test foils is not discoloured.
Insert the test specimens and test folls in the test equipment using tweezers. Do not handle them under any circumstances.
Preheat the test equipment with test specimens and test foils in position to 42 °C to 45 °C and place it in the warm humid environment. This is to ensure that condensation on the test specimen is avoided. This is critical as liquid water in contact with the test specimens and foils can form an electrolyte, significantly increasing the rate of electrolytic corrosion.
Place the preheated, assembled, test fixture in the warm humid environment and connect to the direct current source.
Continue ageing under these conditions for four days.
On complebori of the above ageing, remove the test equipment from the humidity chamber and cool it to room temperature.BS EN 1965-2-2011 pdf download.