BS EN ISO 9455‑5:2020 pdf – Soft soldering fluxes — Test methods Part 5: Copper mirror test

BS EN ISO 9455‑5:2020 pdf – Soft soldering fluxes — Test methods Part 5: Copper mirror test.
1 Scope This document specifies a qualitative method for assessing the aggressiveness of a flux towards copper. The test is applicable to all fluxes of type 1 as defined in ISO 9454‑1. 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 this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 9455‑1, Soft soldering fluxes — Test methods — Part 1: Determination of non-volatile matter, gravimetric method ISO 9455‑2, Soft soldering fluxes — Test methods — Part 2: Determination of non-volatile matter, ebulliometric method 3 Terms and definitions No terms and definitions are listed in this document. ISO and IEC maintain terminological databases for use in standardization at the following addresses: — ISO Online browsing platform: available at https://www.iso.org/obp — IEC Electropedia: available at http://www.electropedia.org/ 4 Principle For flux samples in the form of a solid or paste, and for flux-cored solder, a flux test solution containing 25 % (m/m) of solids is prepared. For liquid flux samples, the liquid is used full strength as the flux test solution. The flux test solution is then evaluated in terms of its attack on a copper film previously vacuum deposited onto a glass plate (copper mirror). A rosin reference solution, which should not cause removal of the copper film, is used as a control. The object of the test is to determine the flux reactivity due to the presence of free halide activators. NOTE The presence of amines in the flux can cause misleading results in that the flux appears to pass the test, when in fact it has a highly reactive composition. 5 Reagents Use only reagents of recognized analytical grade and only distilled, or deionized, water. 5.1 Acetone. 5.2 Propan-2-ol. INTERNATIONAL STANDARD ISO 9455-5:2020 © ISO 2020 – All rights reserved
7.2 Preparation of copper mirrors for test Select two copper mirrors (see 6.2) free from visible defects. Immediately before carrying out the test in 7.3, immerse the copper mirrors in the EDTA (see 5.5) for not more than 5 s, to remove any copper oxide. Rinse immediately in running water, then in acetone (see 5.1) and dry using warm air. 7.3 Determination Place the two freshly cleaned copper mirrors (see 7.2) onto a clean horizontal surface, mirror side up. Place one drop (maximum 0,05 ml) of the flux test solution (see 7.1) on one of the mirrors and, at a distance of approximately 35 mm, one drop (maximum 0,05 ml) of the rosin reference solution (see 5.4). During this operation, the dropper shall not touch the copper mirror. Repeat the procedure with the second copper mirror. Place the two mirrors in a horizontal position in the temperature/humidity oven (see 6.1) and condition the mirrors at 25 °C ± 2 °C and (50 ± 5) % relative humidity for 24 h. Remove the mirrors from the oven and wash off the flux residues using propan-2-ol (see 5.2), or using the solvent used in 7.1. Dry the mirrors using a stream of warm air. Examine the copper mirrors against a white background. NOTE The presence of free halide activators in the flux test solution results in partial or complete removal of the copper film at the location of the drop, the copper mirror becoming progressively more transparent as the flux reactivity increases. The presence of amines in the flux can cause misleading results. 8 Assessment and expression of results The flux shall have passed the test if there is no removal of the film on either copper mirror by the flux test solution. Removal is defined as the complete penetration of the copper film over the whole or part of the area, which causes the white background to be visible. However, if the rosin reference solution (see 5.4) has failed the test, then repeat the determination using freshly prepared copper mirrors (see 7.2).