Overview
ISO 16525-5:2014 - Adhesives - Test methods for isotropic electrically conductive adhesives - Part 5: Determination of shear fatigue - specifies standardized test methods using miniature specimens to measure shear fatigue of glued joints made with isotropic electrically conductive adhesives and rigid adherends under defined conditions. The document defines required apparatus, specimen preparation, test procedures, judgement criteria and reporting for fatigue testing of conductive adhesive bonds used in electronic assemblies.
Key topics and technical requirements
- Scope: Fatigue testing of bonds formed by isotropic electrically conductive adhesives between rigid adherends (miniature specimens).
- Apparatus: Tensile/fatigue machine with specimen-holder jig, non-contact displacement detector, load cell, fall-of-potential (four‑terminal) ohmmeter, recorder and optional temperature control (Annex A). Preferred actuators: linear DC motors or piezoelectric actuators.
- Specimen and materials: Rigid adherends (typically class‑2 oxygen‑free copper per ISO 431) and specimen geometry consistent with the standard figure to ensure comparable results.
- Test procedure: Fix specimen without inducing preload, connect ohmmeter, set test temperature and displacement rate. Choose waveform (ramp/triangular preferred; sine or trapezoidal acceptable) and several displacement/shear‑strain ranges (recommended ~5 % to 0.5 % shear strain). Determine displacement rate from adhesive shear modulus so strain rate is approximately 0.1 %/s in the elastic range and verify by preliminary testing (Annex B).
- Measurements and judgment: Monitor maximum/minimum load, electrical resistance and displacement. Fatigue life is recorded as cycles to failure; failure can be judged by a decrease in maximum shear load (for example, 20% drop) or an increase in electrical resistance (for example, 20% rise) - electrical resistance is preferable when tests approach or exceed the adhesive glass transition temperature.
- Reporting: Test reports must reference ISO 16525-5 and include adhesive identification, adherend and surface treatment details, bonding/cure conditions, specimen dimensions, test apparatus, displacement rate, strain range, cycles to failure, resistance data and fracture modes (ISO 10365).
Applications and users
ISO 16525-5:2014 is used by:
- Adhesive manufacturers for product characterization and R&D
- Electronic assembly engineers and reliability test labs assessing conductive adhesive joints
- Quality and compliance teams specifying acceptance criteria for shear fatigue life
- Materials scientists evaluating fatigue behavior and design limits for conductive adhesive interconnects
Keywords: ISO 16525-5:2014, isotropic electrically conductive adhesives, shear fatigue, shear strain, shear fatigue tests, ohmmeter, shearing jig.
Related standards
- ISO 16525 (other parts): Part 1 (general), Part 2 (electrical characteristics), Part 4 (shear strength), Part 6–9 (impact, environment, electrochemical, signal transmission)
- ISO 291 (conditioning atmospheres), ISO 431 (copper adherends), ISO 10365 (failure pattern classification), ISO 17212 (surface preparation).
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