ISO 14916:2017

Overview

ISO 14916:2017 - "Thermal spraying - Determination of tensile adhesive strength" defines a standardized tensile adhesion test for thermally sprayed coatings. The procedure measures the tensile adhesive strength normal to the coating surface to enable comparable results across laboratories and production runs. The method applies to coating-to-substrate interfaces, internal interfaces (bond/top coat) and multi-layer systems, and is intended primarily for comparative quality control rather than predicting in-service durability.

Key topics and technical requirements

• Test purpose: Determine tensile adhesive strength (adhesive, cohesive or adhesive–cohesive failure) between coating layers and substrate; compare coatings produced with similar feedstock and spray processes.
• Specimen types: Form A (substrate block with coated face glued to a loading block) and Form B (test disc coated on one side glued between two loading blocks). Standard specimen diameters: 25.0 mm (or 25.4 mm) and 40 mm (25 mm preferred).
• Equipment: Use a calibrated tensile testing machine compliant with ISO 7500-1 (class 1) and a clamping system that avoids bending or torsion (ball joint/universal suspension). M16 threaded hole for load transfer is referenced.
• Specimen preparation: Strict control of substrate preparation, coating deposition, machining, centring and gluing to prevent bias from bonding-agent infiltration or misalignment. Guidance on fixtures (V-blocks), contact pressure, springs and gluing procedures (including use of foil bonding agents for porous coatings) is provided.
• Limitations: Not suitable for fused spray coatings deposited from self-fluxing alloys (inherently high adhesion). Results are comparative; they do not provide absolute service-life predictions.
• Measurement & reporting: Procedures cover number of specimens, measurement instruments, reading and evaluation, and documentation of test conditions to ensure repeatability and traceability.

Applications and users

ISO 14916:2017 is used for:

• Quality control in thermal spray manufacturing (monitoring consistency of spraying and bonding processes)
• Process development and optimization, evaluating the influence of substrate preparation and spray parameters
• Comparative testing of coatings, bond coats and top coats for R&D labs Typical users:
• Thermal spray service providers and coating manufacturers
• Materials and surface-engineering laboratories
• R&D teams in aerospace, power generation, automotive, and wear/corrosion protection sectors
• Quality assurance and inspection engineers

Related standards

• ISO 7500-1 - Calibration/verification of tensile machines
• ISO 14917 - Thermal spraying terminology, classification
• EN 13507 - Pre-treatment of metallic surfaces for thermal spraying
• ASTM C633-13, EN 13144, ISO 13779-4 - related tensile adhesion/test-fixture practices

Using ISO 14916:2017 ensures reproducible tensile adhesion testing for thermally sprayed coatings, helping engineers and quality teams make informed decisions about coating processes and materials.