Overview
EN ISO 9455-1:2022 - Soft soldering fluxes - Test methods - Part 1: Determination of non-volatile matter, gravimetric method - specifies a standardized gravimetric test to measure the content of non‑volatile matter in soft soldering fluxes. Adopted by CEN (as EN ISO 9455-1:2022) and applicable to liquid and paste fluxes of type 1 (see ISO 9454-1), the method gives a repeatable laboratory procedure for quality control, specification compliance and procurement.
Key topics and requirements
- Principle: Weigh a prepared flux sample, evaporate volatiles (boiling water bath + oven drying), cool in a desiccator and re-weigh; calculate non‑volatile matter as a percentage of the original sample.
- Apparatus: ordinary lab equipment including a thin-section glass Petri dish (≈100 mm), 20–25 ml weighing pipette for liquids, boiling water bath, drying oven maintained at (110 ± 2) °C, and a desiccator with silica gel.
- Procedure highlights:
- Perform the test in triplicate.
- Transfer sample to yield 0.5–1.0 g of expected non‑volatile residue; avoid volatile loss during weighing.
- Preliminary heating on a boiling water bath to remove bulk volatiles (can be omitted for low‑volatile samples).
- Dry in oven for 3 h at 110 ± 2 °C, cool in desiccator, and weigh to 0.001 g.
- Formula: Non‑volatile matter (%) = (mass of residue after drying / mass of sample taken) × 100.
- Notes on solvent/activator sensitivity:
- The 110 °C drying temperature is intended for solvents like isopropanol; alternative drying conditions can be agreed between purchaser and supplier for higher‑boiling solvents.
- Certain flux classes (e.g., classes 113, 123 with organic‑acid activators; classes 112, 122 with mixed organic/halide activators) may lose some activator content during the test.
- Precision: Results from an interlaboratory study (five labs) provide repeatability and reproducibility figures for representative non‑volatile contents (5 %, 15 %, 25 %). Reported reproducibility (R) ranges up to about 1.30 % at 25 % non‑volatile content.
- Test report requirements: sample identification; reference to ISO 9455-1:2022; any variations in drying temperature/time; results; unusual observations; optional operations used; test date.
Applications and users
- Flux manufacturers - product specification and batch quality control.
- Independent test laboratories - certified testing and conformity assessment.
- Electronics and metal-joining manufacturers - incoming inspection and process control for soldering operations.
- Purchasers and regulators - verifying supplier claims and ensuring material consistency.
- R&D and failure analysis teams - characterizing flux composition and behavior under thermal treatment.
Related standards
- ISO 9454-1 - Classification and requirements for soft soldering fluxes (used to identify flux type 1).
- ISO 5725-1 - Principles and definitions for accuracy (trueness and precision) of measurement methods (used for precision assessment).
Keywords: EN ISO 9455-1:2022, soft soldering fluxes, non-volatile matter, gravimetric method, test method, flux classification, ISO 9454-1, drying oven, precision, test report.