ISO 4517:2025

Physical vapor deposition (PVD) coatings - Contact angle measurement of metallic hydrophobic PVD coatings

This document specifies the requirements for the contact angle measurement of metallic hydrophobic thin film coatings deposited by the physical vapor deposition (PVD) method, including thermal evaporation, sputtering and ion plating. This document does not apply to non-metallic coatings, paints or varnishes.

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General Information

• Status: Published
• Publication Date: 08-May-2025
• ICS: 25.220.40 - Metallic coatings
• Technical Committee: ISO/TC 107/SC 9 - Physical vapor deposition coatings
• Drafting Committee: ISO/TC 107/SC 9 - Physical vapor deposition coatings
• Current Stage: 6060 - International Standard published
• Start Date: 09-May-2025
• Due Date: 22-Sep-2025
• Completion Date: 09-May-2025

Overview - ISO 4517:2025 (PVD coatings, contact angle measurement)

ISO 4517:2025 specifies standardized requirements and procedures for measuring the water contact angle of metallic hydrophobic thin films produced by physical vapor deposition (PVD) methods (thermal evaporation, sputtering, ion plating). The standard targets metallic PVD coatings only (not polymeric coatings, paints or varnishes) and defines how to evaluate wettability quantitatively using the sessile-drop contact angle technique and related surface characterization.

Key topics and technical requirements

• Measurement principle: Static sessile-drop contact angle measured with a contact angle goniometer; tangent at the three‑phase boundary yields the water contact angle (θ). Hydrophobic: θ > 90°; superhydrophobic: θ > 150°.
• Droplet procedure: Place droplet with syringe, record at least five measurements on different positions and report the average. Typical droplet extrusion example: 2 μL; recommended droplet volume range 1–5 μL to avoid gravity/evaporation effects.
• Timing since deposition: Metallic PVD coatings evolve in wettability due to hydrocarbon adsorption in air. Measure contact angle at least 7 days after deposition when values stabilize (example: ~100° reported after ~168 h).
• Environment control: Perform measurements in ambient air with controlled temperature 20–30 °C and relative humidity 40–60 %; avoid vibrations, strong air flows or bright light during measurement.
• Surface quality & morphology: Examine coating topography using AFM, SEM, profilometer. Indicative quality: RMS roughness R < 20 nm within a 5 μm × 5 μm AFM scan; inspect defects at ~300× SEM magnification.
• Chemical composition analysis: Use surface-sensitive techniques such as XPS (X-ray photoelectron spectroscopy), EDS, EPMA, Auger to characterize surface chemistry (carbon often present).
• Surface free energy: Determine via multiple probe liquids and static contact angles using models such as OWRK; combine with Young’s equation and Wenzel/Cassie–Baxter models to interpret roughness and composite wetting states.

Applications and who uses this standard

ISO 4517:2025 is useful for:

• PVD process engineers and R&D teams developing metallic hydrophobic coatings for electronics, aerospace, automotive and construction.
• Quality assurance and laboratory personnel performing contact angle testing, surface energy analysis and failure investigations.
• Materials scientists and surface chemists comparing wettability across PVD recipes, substrate preparations and post‑treatments. Practical uses include validating hydrophobic performance, optimizing deposition parameters for durability, and ensuring repeatable, comparable wettability data across labs and suppliers.

Related standards and resources

• ISO 4517:2025 contains no normative references; users should consult national standards bodies and ISO resources for related guidance on surface analysis and instrumentation. Recommended characterization techniques include AFM, SEM, XPS and contact angle goniometry best practices.

Keywords: ISO 4517:2025, PVD coatings, metallic hydrophobic PVD coatings, contact angle measurement, water contact angle, sessile drop, surface free energy, Wenzel, Cassie-Baxter, AFM, XPS.

Standards Content (Sample)

International
Standard
ISO 4517
First edition
Physical vapor deposition
2025-05
(PVD) coatings — Contact
angle measurement of metallic
hydrophobic PVD coatings
Reference number
© ISO 2025
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
or ISO’s member body in the country of the requester.
ISO copyright office
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Phone: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 1
5 Samples for contact angle evaluation . 2
6 Contact angle measurement . 3
6.1 General .3
6.2 Contact angle measurement environment .3
6.3 Droplet size .3
6.4 Contact angle measurement time since deposition .4
6.5 Surface quality requirements .4
6.6 Chemical composition .5
6.7 Surface free energy.5
Bibliography . 7

iii
Foreword
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This document was prepared by Technical Committee ISO/TC 107, Metallic and other inorganic coatings,
Subcommittee SC 9, Physical vapor deposition coatings.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.

iv
Introduction
A hydrophobic surface is defined as a solid surface with a water contact angle higher than 90°. A hydrophobic
surface tends to repel water droplets. Hydrophobic coatings have drawn much interest in electronic devices,
aerospace engineering and construction industries. This is because of their self-cleaning, anti-icing and
corrosion resistance properties. Among current hydrophobic coatings, polymer-based materials are the
most commonly used due to their low surface energy. However, they are relatively soft with low durability
when applied in harsh environments.
Metal-based hydrophobic physical vapor deposition (PVD) coating is a promising candidate for realizing the
practical use of hydrophobic surfaces due to their outstanding mechanical durability. However, the surface
wettability of metallic PVD coatings goes through a time evolution under ambient air exposure due to the
adsorption of hydrocarbons. This makes it difficult to evaluate the wettability and apply this kind of coating
for hydrophobic use. It is thus essential to evaluate how wettable metallic hydrophobic PVD coatings are for
the further development and applications of metallic hydrophobic PVD coatings.

v
International Standard ISO 4517:2025(en)
Physical vapor deposition (PVD) coatings — Contact angle
measurement of metallic hydrophobic PVD coatings
1 Scope
This document specifies the requirements for the contact angle measurement of metallic hydrophobic thin
film coatings deposited by the physical vapor deposition (PVD) method, including thermal evaporation,
sputtering and ion plating.
This document does not apply to non-metallic coatings, paints or varnishes.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
physical vapor deposition
PVD
vacuum deposition method for producing thin films or coatings on a substrate by a physical reaction
3.2
hydrophobic coating
coating that repels water droplets
3.3
water contact angle
angle formed by a liquid at the three-phase boundary, where a liquid, gas and solid intersect
3.4
adsorption
process by which molecules of a substance from a gas or liquid attach to a surface
4 Principle
The contact angle is a quantitative measure of the wetting state of a solid. It is an angle formed by a liquid
at the three-phase boundary, where a liquid-vapor interface meets a solid surface (see Figure 1). When θ
< 90°, the surface is hydrophilic, which means that wetting is favoured on this surface and water tends to
spread and maintain the maximum contact area. When θ > 90°, the surface is hydrophobic, which means it
is difficult to wet the surface, water tends to shrink and maintain the minimum contact area. If θ > 150°, the
surface is superhydrophobic.
...