ISO 9455-17:2024

Overview

ISO 9455-17:2024 - "Soft soldering fluxes - Test methods - Part 17" defines standardized test methods to evaluate the electrical and electrochemical effects of flux residues left after soldering or tinning. The standard covers the Surface Insulation Resistance (SIR) comb test and the electrochemical migration (ECM) test applied to flux residues from type 1 and type 2 fluxes (per ISO 9454-1) in liquid, solid, flux‑cored wire, preform or solder‑paste forms. Tests are applicable to both lead-containing (Sn/Pb) and lead‑free solders (for example Sn95,5Ag3Cu0,5), with soldering temperatures adjustable by agreement.

Key topics and requirements

• Objective: Characterize degradation of electrical resistance and electrochemical migration on printed wiring coupon specimens exposed to flux residues.
• Test conditions: High humidity, elevated temperature and applied bias voltage to accelerate SIR degradation and migration phenomena. The updated edition extends ECM test duration to 1 000 h (previously 21 days).
• Test specimens: IPC B53 test pattern per IEC 61189-5-501 is specified; detailed comb geometries (line widths, spacings, square counts) are provided for reproducible SIR measurement.
• Sample types: Liquid, solid, flux‑cored solder wire, preforms and solder paste, including lead-free formulations agreed between user and supplier (see ISO 9453).
• Reagents and cleaning: Use analytical-grade reagents and deionized water (conductivity < 0.05 µS/cm). Propan-2-ol (isopropyl alcohol) and manufacturer‑recommended cleaning solvents are referenced.
• Apparatus and measurement:
  • EMC‑shielded cabling and low‑current measurement capability (picoampere range).
  • Connector specifications and coupon mounting details to ensure ≥10^12 Ω pin‑to‑pin insulation under test conditions.
  • Measurement repeatability and precision per ISO 5725-2.
• Documentation: Procedures for sample prep, soldering, optional cleaning, SIR measurement, ECM testing, assessment and test reporting. Annexes provide guidance and a qualification test report template.

Applications and users

ISO 9455-17:2024 is intended for:

• Flux manufacturers validating residue behavior of new formulations.
• PCB and electronic assembly manufacturers assessing whether flux residues require removal.
• Reliability and quality engineers setting acceptance criteria for flux residues and cleaning processes.
• Test laboratories and OEMs performing comparative evaluations of leaded and lead‑free fluxes. Practical outcomes include improved board reliability, informed cleaning decisions, and supplier qualification based on standardized SIR and ECM data.

Related standards

• ISO 9454-1 (flux classification)
• ISO 9453 (solder composition)
• IEC 61189-5-501 / IPC B53 (SIR test coupon geometry)
• ISO 5725-2 (measurement repeatability and reproducibility)

Keywords: ISO 9455-17:2024, soft soldering fluxes, surface insulation resistance, electrochemical migration, flux residues, SIR test, IPC B53, flux testing, lead-free solder.