Functional, Medical and Electronic Coatings

Electroplated Coating Corrosion Resistance: Contact Angle Checks on the Substrate Before You Electroplate and on the Metal Coating After

Before you electroplate, a contact angle reading shows whether the base metal is clean enough to plate. After plating, it shows how water meets the electroplated coating. Read it alongside adhesion, coating thickness and corrosion testing, because wettability alone does not rank corrosion resistance.

Who this is for: Plating shop process and quality engineers, plating chemistry R&D teams and corrosion researchers working on electroplated and composite coatings.

Where it fits: Pre plating cleanliness checks, electroplating process development, and comparing coatings before salt spray and electrochemical tests.

What it does not do: It does not measure coating thickness, adhesion strength, corrosion rate or the coating's composition.

Method

Sessile drop water contact angle; two liquid surface energy for surface tension of solid coatings and substrates

Standard

Supports ASTM F22 water break checks with a number; ASTM D7490 for two liquid surface energy

Setup

About 2 minutes

Book a 15 minute demo Request a quote

Written by

Abhimanyu Bhandankar

Holds an MBA from Schulich School of Business and a BE in IT. He joined Droplet Lab in July 2019 and now leads sales and marketing.

CEO at Droplet Lab

Why plated coating surface checks matter

US$2.5 trillion

estimated global cost of corrosion, about 3.4% of global GDP in 2013; the study estimated that 15 to 35% of it could be saved with existing corrosion control practices.

NACE International, IMPACT study, 2016

69.7° vs 82.6°

the most corrosion resistant of four silver particle copper coatings read 69.7°, while the least wettable coating at 82.6° was not the best protected.

Yankova et al., C. R. Acad. Bulg. Sci. 79:479, 2026

162° to 152°

fall in water contact angle on a superhydrophobic Co Ni electrodeposit over 25 days in salt water, while its corrosion current density rose about eight times.

Wang et al., Coatings 12(2):222, 2022

Sources: NACE International, International Measures of Prevention, Application, and Economics of Corrosion Technologies (IMPACT) study, 2016; Yankova et al., Comptes rendus de l'Academie bulgare des Sciences, 2026; Wang S. et al., Long term durability of robust super hydrophobic Co Ni based coatings produced by electrochemical deposition, Coatings, 2022. Figures come from these sources, not from Droplet Lab measurements.

Quick reference

What this plated coating check does and what it does not

A quick reference for plating and corrosion teams checking fit before reading further.

Evidence Box

Problem this solves

In electroplating work, substrates plated after a pass or fail water break check, and coatings compared by eye, with no number to trend when adhesion or corrosion problems appear.

Standards

Adds a measured angle to the ASTM F22 water break test; ASTM D7490 covers surface energy of solid coatings and substrates from two liquids.

Peer reviewed method

The Dropometer drop shape method was validated against a KRUSS DSA100E in two peer reviewed papers, in Review of Scientific Instruments and Colloids and Surfaces A.

Customer case study

A plating chemistry maker runs fully automatic Dropometers with chemically resistant PTFE stage parts in two R&D labs, in Europe and the US.

Published research

A Bulgarian Academy of Sciences group found the least wettable of four electroplated copper and silver coatings was not the most corrosion resistant (2026).

Honest limit

Contact angle does not rank the corrosion performance of electroplated coatings on its own. Pair it with salt spray and electrochemical tests.

Who this is for

What plating question are you trying to answer?

Pick the card closest to your role. Each one points to the part of this page that answers it.

Plating process or quality engineer

You run the cleaning line and the electroplating process for nickel, zinc, copper or chromium on carbon steel, mild steel and copper parts that need corrosion protection and resistance to wear. A contact angle on the cleaned part before it enters the bath gives a number to trend, where the water break test gives only pass or fail.

Set your gate from parts that later passed adhesion testing, not from a generic value.

Plating chemistry R&D

You develop plating solutions, additives, cleaners and conversion coating chemistries. Contact angle and surface energy compare each coating applied by different coating methods, or a new electroplating method, on the same substrate, as one of the plating chemistry maker labs does with chemically resistant stage parts.

Report the substrate, current density, rinse and coating application method with every value.

Corrosion researcher

You study the corrosion behavior of electroplated coatings and superhydrophobic or composite coatings. Contact angle and sliding angle, read alongside corrosion current density and salt spray testing, show whether surface wetting explains the corrosion performance.

A high angle on day one does not prove long term corrosion protection.

Fit check

Is this the right check for your plating work?

It measures how water meets the substrate or the coating surface. It does not measure the coating itself in depth.

Good fit if

You want a number for cleanliness before you electroplate.

You compare cleaners, rinses or activation steps before plating.

You compare an electroplated coating, a composite coating or a conversion coating on the same substrate.

You develop superhydrophobic electrodeposits to prevent corrosion.

You compare corrosion inhibitor or sealer steps after plating.

Less relevant if

You need coating thickness or deposit composition.

You need adhesion strength; use ASTM B571 tests.

You need a corrosion rate; use electrochemical or salt spray tests.

Your parts are too curved or small to hold a drop.

Summary

How contact angle supports electroplating and corrosion protection

The answer in under a minute.

Measure water contact angle on the cleaned base metal before you electroplate, to confirm that oils and films are gone, and on the finished coating to compare surfaces. Set gates from your own adhesion and corrosion results, because the least wettable coating is not always the one with the highest corrosion resistance.

The Dropometer contact angle and surface energy kit runs the measurement. Our contact angle measurement guide and wettability glossary entry explain the basics, and the ASTM F22 water break test and ASTM D7490 pages cover the standards. A Bulgarian Academy of Sciences coatings group measured electroplated copper coatings, and a plating chemistry maker runs chemically resistant Dropometers in two labs. Our electrical and electronics guide covers plated contacts.

Expert Quote

Expert perspective on wettability

A contact angle is a thermodynamic property: fix the liquid and the solid and the same angle appears whether the drop sits on a plate or climbs a capillary.

The problem

Why plated coating problems are hard to catch early

Electroplating is a surface process. An electrochemical process deposits a metal coating from a plating solution containing metal ions onto the base metal, so the coating can only be as good as the surface underneath it. ASTM B322 puts it plainly: the performance and quality of electroplated articles depend upon the surface cleanliness and condition. Oils, oxide films and cleaner residue on the substrate cause poor adhesion, blistering, skip plating and pitting; one set of case studies traced blistering on zinc plated parts to inadequate pre treatment. The usual shop check, the water break test, is pass or fail and depends on the operator. After plating, teams want coatings with excellent corrosion resistance, wear resistance and electrical conductivity, and many now develop superhydrophobic or composite coatings to prevent corrosion. Each type of coating, from a zinc coating, or Zn coating, on a steel substrate to a Ni W coating on copper substrate, is judged by its electrochemical corrosion behavior: corrosion potential, corrosion current density and how the corrosion process develops in salt spray testing, along with the thickness of the coating, the morphology of the coating and the elements present in the coating. Many papers report superior corrosion resistance for a new coating; far fewer show how its surface and corrosion behaviour change in service. Water contact angle is a quick way to compare those surfaces, but it does not rank the corrosion resistance of coatings by itself. In one study the least wettable coating was not the best protected, and in another the contact angle of a superhydrophobic electrodeposit barely changed while its corrosion current density rose about eight times. Teams need a measured, repeatable surface check, read in context.

Blistering, peeling or poor adhesion after plating or baking.

Skip plating, pits or stains on part of a batch.

Water break results vary between operators.

A coating that repels water still fails salt spray testing.

Corrosion products or severe corrosion appear early in salt spray testing.

Troubleshooting

Why plated coating checks mislead and what to do

Why:

Drawing oils, rust preventives and fingerprints leave a hydrophobic film that blocks deposition and adhesion.

How to detect:

Water contact angle on the cleaned part stays high, or water breaks into beads.

Corrective action:

Review soak, electrolytic cleaning and rinse steps, and gate parts by contact angle before the bath. Our ASTM F22 page covers the water break test.

Why:

Poor rinsing leaves surfactant or salt residue that can lower the angle yet still harm adhesion.

How to detect:

Angles read unusually low or uneven across the part.

Corrective action:

Check rinse quality and dwell time, and compare against parts that passed adhesion testing.

Why:

Activated metal surfaces reoxidise if parts wait between the acid dip and the bath.

How to detect:

The angle rises with wait time between steps.

Corrective action:

Measure at fixed times after activation and set a maximum wait.

Why:

Corrosion properties depend on the content of the coating, porosity, thickness and defects as well as wetting.

How to detect:

The least wettable coating fails salt spray or electrochemical tests.

Corrective action:

Rank coatings by corrosion testing and use contact angle to explain the surface, as the Bulgarian Academy of Sciences study did.

Why:

A superhydrophobic coating acts as a corrosion barrier only while its trapped air lasts; during immersion the air is slowly replaced by solution, and the chloride ion reaches the metal.

How to detect:

Sliding angle rises before the static angle falls much. Our sliding angle guide covers the method.

Corrective action:

Track contact angle, sliding angle and corrosion current over immersion time.

Why:

Drop volume, timing and part handling change readings. Our guide to reproducible contact angle measurement covers fair comparisons.

How to detect:

A reference panel reads differently between shifts.

Corrective action:

Write the method down and measure a reference panel every shift.

Not sure where to set a cleanliness gate?

Send cleaned panels from good and failed batches, and we will compare them on a call.

Book a 15 minute demo

Lab records

What a plated coating surface record contains

Each check in the coating process produces a record you can file with the batch traveller or the test report. It can feed into your existing quality records.

Part and substrate

Part number, base metal, batch and the area measured.

Process stage

As received, after each cleaning step, after activation, or after plating, with times between steps.

Method settings

Liquid, drop volume, read time and number of spots.

Readings

Contact angle at each spot, the median and spread, and the gate result.

Decision

Plate, reclean, or hold for adhesion testing.

Drop images

Automatic edge and baseline detection gives the same reading from the same image, so a reviewer can recheck any result.

Measurements

What to measure before and after you electroplate

Before plating

Water contact angle on the cleaned substrate

Why it matters: It shows whether oils and films are gone before deposition, so the coating strongly adheres; a clean substrate is the first step in ensuring corrosion resistance.

How to interpret: A low, even angle suggests a clean surface. Set the gate per part family from your own correlation with adhesion results.

When it is not enough: It does not detect every residue; rinse residue can lower the angle.

After plating

Water contact angle on the electroplated coating

Why it matters: It describes one of the properties of the coating: the surface the environment will see.

How to interpret: Compare coatings on the same substrate and method, and evaluate the corrosion resistance by salt spray and electrochemical tests. A thicker coating or more uniform coating can change protection without changing the angle.

When it is not enough: It does not measure porosity, coating thickness or composition.

Repellency

Contact angle and sliding angle on superhydrophobic deposits

Why it matters: Roll off shows whether the protective air layer is intact.

How to interpret: Track both over immersion time with corrosion current density.

When it is not enough: A static angle can stay high while protection falls.

Surface energy

Two liquid surface energy

Why it matters: It separates polar and dispersive parts for coatings that are painted or bonded after plating.

How to interpret: Use the same liquids and model every time, as in ASTM D7490.

When it is not enough: Values from different models are not interchangeable.

Validation

Validated measurement approach for plated surfaces

How the Dropometer itself has been validated, and where plating and coating teams have used it.

Peer reviewed method

The Dropometer drop shape method is published in Review of Scientific Instruments and Colloids and Surfaces A. Contact angle was validated against a KRUSS DSA100E, with a published accuracy of 0.35°.

See the validation papers

Customer evidence on electroplated coatings

A coatings group at the Institute of Metal Science, Bulgarian Academy of Sciences, applied copper coatings with silver particles onto stainless steel, electroplated using acidic and alkaline baths. With the Dropometer, the group measured water contact angles from 69.7° to 82.6° and found the most corrosion resistant coating was not the least wettable one (C. R. Acad. Bulg. Sci., 2026).

Read the case study

QC Protocol

How to check substrate cleanliness and plated coatings

Six steps for one part family. Repeat for each new substrate, or each time you electroplate a new coating.

1

Lock the method

Fix the liquid, drop volume, read time and number of spots for each part family and plating metal.

2

Build a reference

Measure cleaned panels that later passed adhesion testing, and check readings against our contact angle reference values.

3

Set the gate

Set a cleanliness gate per substrate from your own good and failed batches.

4

Measure before plating

Measure the cleaned base metal at a fixed time after rinsing, then plate or reclean.

5

Measure the coating

After plating, measure the surface coating the same way and file it with salt spray and electrochemical results, so the effect on corrosion of each process change is recorded.

6

Review the trend

Review readings by shift and line, and against steps meant to improve the corrosion protection. Our guide to the best contact angle goniometer for industrial QA covers routine use.

We completed our gage R&R study on the unit and it performed very well.

Brandon Barbee

Corporate Quality Engineer, Zeus Industries, Polymer Manufacturing

Download the plated coating contact angle SOP

A two page SOP you can adapt for your plating line before you electroplate each batch, with the method lock, how to set a cleanliness gate against adhesion results, a troubleshooting table and a record sheet.

Contact angle measurement with the Dropometer

Example output

Example cleanliness and coating log for zinc plated steel

Example data only. Your values and gates will differ and must come from your own adhesion and corrosion results.

How to read this log

Example gate: cleaned steel at or below 20° goes to the bath. Panel 3 kept a film after a short soak and was recleaned. The zinc coating angles describe the plated surface only; corrosion resistance comes from the salt spray and electrochemical columns.

Example pre plating cleanliness log

Panel	Stage	Contact angle (°)	Water break	Result
1	As received, oiled	86	Breaks	Clean
1	After soak, electroclean and rinse	14	No break	Plate
2	After soak, electroclean and rinse	17	No break	Plate
3	After short soak and rinse	41	Breaks	Reclean
3	After reclean	15	No break	Plate

Example data, not customer data. Mild steel panels; 3 µL deionized water, read at 5 s, median of 5 spots.

Signal order

The order to check signals on plated parts

Check these in order. Each one rules out a cause before you look at the next.

1

Method and reference panel

Rules out drift in the measurement itself.

2

Cleaned substrate angle

Shows whether films are gone before plating.

3

Time between steps

Rules out oxide regrowth and drying marks.

4

Coating angle

Describes the electroplated coating surface.

5

Adhesion and corrosion tests

Confirm the decision; our mechanical and industrial guide covers related checks.

FAQ

Common questions about plated coating wettability

Questions plating and corrosion teams ask about contact angle.

Not on its own. In a 2026 Bulgarian Academy of Sciences study of four copper and silver coatings, the least wettable coating at 82.6° did not give the best corrosion protection; the coating with high corrosion resistance and the lowest corrosion rate of the coating, 0.028 mm/y, read 69.7°. Corrosion depends on composition, porosity, thickness and defects too. Use contact angle to describe the surface and corrosion testing to rank the corrosion resistance of the coating.

The ASTM F22 water break test detects hydrophobic films as pass or fail, judged by eye. A contact angle gives a number you can trend by line, shift and cleaner bath. Many teams keep the water break test and add contact angle where they need a recorded value or a tighter gate.

There is no universal value. Clean metal is usually well wetted, but the right gate depends on the base metal, the cleaning line and the time before plating. Measure parts that later passed and failed adhesion testing, and set the gate between them. ASTM B322 covers cleaning practice; it does not give a contact angle limit.

They can enhance corrosion resistance for a time. Zhou and colleagues reported a nickel and manganese coating on carbon steel at 161.9°, and its corrosion current density decreased from 1.39 × 10⁻⁵ to 5.89 × 10⁻⁷ A/cm² in salt water. Wang and colleagues saw protection fade over 25 days as the air layer was lost, while the angle barely moved.

Because roll off shows whether the trapped air layer is still there. In the Wang study the static angle stayed near 150° while the coating lost superhydrophobicity, and with it much of its resistance to corrosion, as corrosion current rose about eight times. Track sliding angle and immersion time with every corrosion test. Our sliding angle guide explains the method.

Yes. Measure water and a nonpolar liquid such as diiodomethane, and calculate polar and dispersive parts, as in ASTM D7490. This helps when the plated part is painted, bonded, sealed or treated for corrosion inhibition afterwards. Keep the liquids and model the same so results compare.

Standard stages are not designed for strong acids and cyanide solutions. A plating chemistry maker asked for PTFE stage parts in its two labs, and we built them. Rinse and dry parts before measurement, and tell us your chemistries when you configure a system.

A sessile drop instrument with fixed drop volume and timing, and a stage that holds flat panels and small parts, for each type of coating you electroplate. The Dropometer does this at the bench or on the line. Our industrial QA buying guide compares options, and our page on PCB surface preparation covers a related electronics check.

Business impact

What changes when you measure plated surfaces

Typical changes in how teams work. Benchmarks are given only where a published source exists.

Before and with plated surface checks

Metric	Before Dropometer	With Dropometer	Indicative Benchmark
Cleanliness check	Water break, pass or fail	Recorded contact angle against a gate	No published benchmark; track on your own lines
Adhesion failures	Found at bend, bake or field return	Dirty parts held before the bath	Blistering traced to inadequate pre treatment (Panossian and Ferrari, 2004)
Coating comparison	Visual and salt spray only	Surface wetting recorded beside corrosion results	Least wettable coating not the best protected (Yankova et al., 2026)
Cost of corrosion	Seen in warranty and rework	Surface checks inside corrosion control aimed at reducing the corrosion rate	About 3.4% of global GDP (NACE IMPACT, 2016)

See the measurement on your own parts

Send cleaned and plated panels. We will show the comparison on a call.

Book a 15 minute demo

Estimate avoided plating rework

Enter your own numbers. The result is an estimate, not a Droplet Lab claim.

Instrument cost ($) Each Dropometer unit is $5,000; the default models 1 unit.

Plating rework events per month

Avg rework cost per event ($) Your own average cost to strip, reclean and replate one part, rack or batch.

Failures caught by a cleanliness gate (%) No published benchmark. Use your own failure records; start low if unsure.

Scrap cost per event ($) Scrap cost per event from plating failures only, from your own records.

Other monthly savings ($)

Result

~0

Monthly savings

~0

Payback period

~0

First year net benefit

Monthly savings = preventable rework cost + preventable scrap cost + other monthly savings.

Limits

What contact angle cannot tell you about a plated coating

Honest limits, so you know when to reach for another test.

A surface that repels water is not necessarily resistant to corrosion.

Rinse residue can lower the angle on a part that is not clean.

Readings change with time after cleaning; lock the timing.

A static angle can stay high while superhydrophobic protection fades.

Coating thickness is controlled by current densities and time; the angle does not show it.

Gates must be set per substrate from your own adhesion results.

Contact angle shows how water meets the substrate or the electroplated coating. Coating thickness, adhesion, porosity, the elements on the coating surface and corrosion rate need their own tests.

Book a 15 minute demo Request a quote

How this page was created

Editorial and technical transparency notes for this page.

Transparency Details 4 checklist items

01

Drafting assistance

Drafted with Claude Opus 5.5 (Anthropic) using web search for sources, then edited by the Droplet Lab team.

02

Technical review

Reviewed and edited for technical accuracy by the Droplet Lab Team.

03

Verification steps

Standard identifiers, units, thresholds and key procedural claims are checked against cited sources before publication.

04

Updates

Reviewed every 12 months or when the underlying method changes.

Report a correction

Spotted an issue in this summary? Send a correction request and our team will review it.

Correction Request

We work hard to keep this page accurate and up to date. If you spot an error (wrong revision/year, missing requirement, incorrect interpretation, or broken link), tell us and we'll review it.

Contact us to report a correction

Sources

References

1.

NACE International. International Measures of Prevention, Application, and Economics of Corrosion Technologies (IMPACT) study, 2016. http://impact.nace.org/economic-impact.aspx

2.

Yankova et al. Comptes rendus de l'Academie bulgare des Sciences 79:479, 2026. See our case study. https://dropletlab.com/validation/case-studies/bulgarian-academy-of-sciences-plated-coatings-contact-angle/

3.

Wang, S., Xue, Y., Xue, Y., Lv, C., Jin, Y. Long term durability of robust super hydrophobic Co Ni based coatings produced by electrochemical deposition. Coatings 12(2):222, 2022. https://doi.org/10.3390/coatings12020222

4.

Zhou, Z.Y. et al. Superhydrophobic nickel and manganese alloy coatings on carbon steel with corrosion resistance and robustness capabilities prepared via one step electrodeposition. Journal of Iron and Steel Research International 32(5):1127 to 1138, 2025. https://doi.org/10.1007/s42243-024-01306-2

5.

Superhydrophobic and anti corrosion Cu microcones and Ni W alloy coating fabricated by electrochemical approaches. RSC Advances 5:103863 to 103868, 2015. https://doi.org/10.1039/C5RA20638C

6.

Hu, C., Xie, X., Zheng, H., Qing, Y., Ren, K. Facile fabrication of superhydrophobic zinc coatings with corrosion resistance via an electrodeposition process. New Journal of Chemistry 44(21):8890 to 8901, 2020. https://doi.org/10.1039/D0NJ00561D

7.

Panossian, Z., Ferrari, J.V. Case studies of blistering problems in zinc plated steel and zinc plated die cast zinc alloy parts. Plating and Surface Finishing, September 2004, 48 to 51. https://www.nmfrc.org/pdf/psf2004/090448.pdf

8.

ASTM F22-21. Standard test method for hydrophobic surface films by the water break test. See our ASTM F22 page. https://store.astm.org/f0022-21.html

9.

ASTM B322-99(2025). Standard guide for cleaning metals prior to electroplating. https://store.astm.org/b0322-99r25.html

10.

ASTM B571-23. Standard practice for qualitative adhesion testing of metallic coatings. https://store.astm.org/b0571-23.html

11.

ASTM B117-26a. Standard practice for operating salt spray (fog) apparatus. https://store.astm.org/b0117-26a.html

12.

ASTM D7490-13(2022). Standard test method for measurement of the surface tension of solid coatings, substrates and pigments using contact angle measurements. See our ASTM D7490 page. https://store.astm.org/d7490-13r22.html

13.

Chen, X. et al. Contact angle measurement with a smartphone. Review of Scientific Instruments 89(3):035117, 2018. https://pubs.aip.org/aip/rsi/article-abstract/89/3/035117/368179/Contact-angle-measurement-with-a-smartphone

14.

Surface tension measurement with a smartphone using a pendant drop. Colloids and Surfaces A: Physicochemical and Engineering Aspects. https://www.sciencedirect.com/science/article/abs/pii/S0927775717307744

15.

Droplet Lab validation papers

16.

Customer publications that cite the Dropometer

17.

Bulgarian Academy of Sciences case study

18.

Plating chemistry maker case study

Electroplated Coating Corrosion Resistance: Contact Angle Checks on the Substrate Before You Electroplate and on the Metal Coating After

Abhimanyu Bhandankar

Droplet Lab Team

Featured Studies & Publications

Why plated coating surface checks matter

US$2.5 trillion

69.7° vs 82.6°

162° to 152°

What this plated coating check does and what it does not

Evidence Box

What plating question are you trying to answer?

Plating process or quality engineer

Plating chemistry R&D

Corrosion researcher

Is this the right check for your plating work?

Good fit if

Less relevant if

How contact angle supports electroplating and corrosion protection

Expert perspective on wettability

Why plated coating problems are hard to catch early

Why plated coating checks mislead and what to do

Not sure where to set a cleanliness gate?

What a plated coating surface record contains

Part and substrate

Process stage

Method settings

Readings

Decision

Drop images

What to measure before and after you electroplate

Water contact angle on the cleaned substrate

Water contact angle on the electroplated coating

Contact angle and sliding angle on superhydrophobic deposits

Two liquid surface energy

Validated measurement approach for plated surfaces

How to check substrate cleanliness and plated coatings

Lock the method

Build a reference

Set the gate

Measure before plating

Measure the coating

Review the trend

Download the plated coating contact angle SOP

Example cleanliness and coating log for zinc plated steel

Example pre plating cleanliness log

The order to check signals on plated parts

Method and reference panel

Cleaned substrate angle

Time between steps

Coating angle

Adhesion and corrosion tests

Common questions about plated coating wettability

What changes when you measure plated surfaces

Before and with plated surface checks

See the measurement on your own parts

Estimate avoided plating rework

Estimate avoided rework from plating adhesion and corrosion failures.

What contact angle cannot tell you about a plated coating

Standards, evidence and related coating workflows

ASTM D7490

ASTM F22

Bulgarian Academy of Sciences

Plating chemistry maker

Dropometer

Functional, medical and electronic coatings

PCB surface preparation

Paint and powder coat adhesion

Electrical and electronics guide

How this page was created

Drafting assistance

Technical review

Verification steps

Updates

Report a correction

References