What is Dacromet coating for automotive parts

Ever wondered why those thin gray finishes on bolts survive winters, salt, and grime? Put simply, Dacromet is a family of zinc and aluminum flake coatings applied without electroplating to shield steel in tough environments. It is typically deposited from a water-based slurry and baked to form a tightly bonded, thin dry film. Even at single-digit micron thickness, it demonstrates strong salt-spray corrosion resistance, thanks to both barrier and sacrificial action Fasto Screws.

How Dacromet protects steel in harsh environments

Sounds complex? The science is practical. The zinc-aluminum flakes create a barrier that keeps moisture and salts away from the base metal, while zinc oxidizes sacrificially to protect exposed steel. Because the process is non-electrolytic and cured thermally, it avoids the hydrogen embrittlement risks commonly associated with electroplating on high-strength steel. Coatings can also be paired with topcoats to tune friction for consistent torque-tension on fasteners DECC.

Sacrificial protection means the zinc-rich coating corrodes first so the steel does not.

Where Dacromet fits in automotive assemblies

You will see dacromet coated fasteners and hardware anywhere thin, uniform protection is needed without swelling threads or edges. Typical parts include:

• Bolts, screws, and washers for controlled assembly torque
• Springs and clips exposed to splash and road salt
• Brake hardware, brackets, and small stampings
• Hose clamps and underbody retainers

Key terms you will see in specifications

• Zinc flake basecoat: A zinc and aluminum flake layer that provides barrier and sacrificial protection.
• Topcoat or sealer: Optional layer to adjust friction, appearance, and added chemical resistance.
• Non-electrolytic application: Applied by dip-spin or spray, then thermally cured to a uniform dry film.
• Thickness control: Thin films help preserve thread fit and tight tolerances on precision parts.
• Salt spray and adhesion: Common lab checks used to benchmark corrosion performance and coating integrity.
• Environmental aspect: Modern water-based systems and process controls aim to reduce ecological impact Shengenfab.

What is Dacromet coating at a glance? A proven zinc-flake, non-electrolytic system for durable, thin-film protection on steel parts used throughout the vehicle. In the sections ahead, we will walk through the application steps shop teams follow, the tests engineers use to verify results, how this finish compares with galvanized and plated alternatives, and practical guidance for purchasing, quality control, and troubleshooting.

Inside the Dacromet coating process from prep to cure

Ever watch raw steel parts enter a line and imagine how they come out with a thin, uniform, corrosion-tough film? The dacromet coating process follows a repeatable, shop-friendly flow that you can dial in for consistency.

From surface prep to cure

1. Incoming prep: Inspect, sort, and remove burrs or trapped oils. Keep similar geometries together for even coverage.
2. Clean the base metal: Use alkaline and or mechanical cleaning such as blasting to remove oils and scale, improving adhesion Yude Metal.
3. Mask critical areas: Protect bearing faces, press fits, or electrical contact points as required by the print.
4. Slurry readiness: Agitate the water based zinc flake slurry until homogeneous. Verify viscosity and solids before coating.
5. Apply the coating: For bulk parts, dip then spin to shed excess. For large or delicate parts, use controlled spray or dip drain spin Greenmetafin.
6. Drain or centrifuge: Promote even film by managing spin speed, time, and part orientation.
7. Air dry flash off: Let solvents water carrier evaporate uniformly before baking Yude Metal.
8. Thermal cure: Follow the licensor’s cure window. Representative examples appear below. Some systems also use a first set bake followed by a final cure.
9. Optional second coat and or sealer: Add a topcoat when friction control or extra chemical resistance is specified Greenmetafin.
10. Cool and inspect: Controlled cooling helps avoid cracking and preserves adhesion Yude Metal.

• Log for traceability: slurry batch ID, solids and viscosity, dip time or spray settings, spin rpm and time, load mass, hang or drain time, oven setpoint, part PMT and time at PMT, part orientation, and measured dacromet coating thickness DFT per checkpoint.

Controlling dry film thickness without overbuild

Think thin and even. DFT rises with higher solids, slower spin, longer dip, and lower drainage. It falls with faster spin or leaner slurry. Keeping DFT inside the specified band avoids thread interference, preserves press fits, and helps hit friction windows on fasteners. For example, dacromet 320 coating is often targeted in the single digit micron range to balance protection and fit, while optional sealers fine tune torque tension behavior Greenmetafin. Verify dacromet coating thickness at edges, roots, and flats, not only on easy to reach faces.

Masking and fixturing best practices

Mask threads or bearing faces when prints call for bare metal or a separate friction treatment. Use racking that spaces parts so the slurry can drain freely. Point blind holes downward to prevent pooling. Keep basket loads consistent so spin off is repeatable. For mixed material assemblies, avoid direct contact with copper, magnesium, nickel, and stainless steel mating parts because of contact corrosion concerns Shisheng. The zinc aluminum flake system is designed to work well against aluminum or steel substrates when properly specified and cured.

Process done right sets you up for proof. Next, see how to confirm corrosion resistance, adhesion, friction, and DFT with standardized tests.

Performance validation and test methods

How do you prove a thin zinc flake film will survive road salt, heat, and tightening torque? You validate it with the right tests, then tie the results back to your drawing and the dacromet coating standard named in your specification.

Interpreting salt spray and adhesion results

For corrosion resistance, many automotive teams use neutral salt spray per ISO 9227, and in global programs ASTM B117 is also widely accepted. ISO 9227 exposes parts to a fine salt mist in a controlled chamber to generate comparative data on coating performance ISO 9227 overview. Report hours to first white corrosion and to red rust exactly as your licensor or coater defines them. Pass or fail should be judged against the specific product data sheet, not a generic benchmark.

Salt spray compares coatings; it does not predict service life.

Run an adhesion check using a recognized cross-cut or tape method per your chosen ASTM or ISO practice. Document lot, surface prep, cure, and any topcoat used so you can trace root cause if flaking or undercutting appears later.

Friction targets for threaded fasteners

Assembly torque must translate into clamp load, so coefficient of friction needs a window that matches your joint design. Real-world conditions can shift friction significantly. Research on zinc flake coated fasteners shows storage history matters, with hot humid or sub-zero conditioning changing friction and under-head friction sometimes dropping by up to 47 percent zinc flake friction study. That means you should:

• Test on representative hardware with the specified topcoat or sealer.
• Control and record storage conditions, humidity, and handling before testing.
• Correlate torque, angle, and achieved clamp load on a sample size defined in your spec.
• Retest after aging or thermal exposure if your use case demands it.

When you need numeric targets, cite licensor documents, for example nof metal coatings dacromet data sheets that define the friction window and mating hardware conditions.

Documenting dry film thickness

DFT is both a performance driver and a fit control. Measure it with an ASTM D7091 compliant gauge and follow the standard’s guidance on instrument selection, calibration, and frequency of readings relative to coated area ASTM D7091 summary. Record readings at edges, roots, and flats on critical features like threads and bearing faces. Keep a log that links DFT back to slurry condition, spin or spray settings, and cure parameters so you can adjust before parts reach the line.

• If your customer calls up a dacromet coating standard astm reference, tie each requirement to a specific method, for example DFT per ASTM D7091 and salt spray per ISO 9227 or ASTM B117.
• For heat resistance and thermal cycling, reference the licensor’s technical data rather than assuming salt spray performance alone covers it.
• When available, cite nof metal coatings dacromet product literature for validated hours-to-red-rust ranges and recommended DFT bands.

With your validation toolkit in place, the next step is selecting the right coating for each use case, so let’s compare this finish with galvanized, plated, and other alternatives.

How Dacromet compares with alternative coatings

Choosing a finish for bolts, clips, and brackets? Imagine balancing corrosion hours, thread fit, friction control, heat, and cost. Below, we break down dacromet coating vs galvanized and dacromet coating vs zinc plating so you can pick what fits your joint design and environment.

Trade-offs that matter to fastener engineers

• Corrosion vs thickness: Dacromet zinc flake builds a thin film yet can deliver strong salt spray performance. A 4–8 µm layer is reported at 600–1000 hours, while hot-dip galvanized is much thicker at roughly 50–100 µm and zinc plating ranges about 48–200 hours depending on passivation Zhuocheng Hardware comparison.
• Hydrogen embrittlement risk: Non-electrolytic zinc flake avoids the embrittlement concerns associated with electroplating. HDG can be problematic on very high-strength fasteners, and electroplated zinc requires dehydrogenation on high-strength grades, per industry guidance in the sources above.
• Heat resistance: Zinc flake systems are cited for withstanding around 300 °C and above, while zinc coatings degrade around 250 °C in typical references within the sources above.
• Fit and appearance: Thin zinc flake preserves thread tolerances. HDG’s thicker, rougher build can affect engagement on fine threads. Zinc plating provides a smooth, aesthetic finish suitable for small precision parts Fasto Screws outdoor guide.
• Cost and maintenance: Zinc plating is generally the most cost-effective. Zinc flake can be higher cost but offers strong protection and avoids embrittlement. Plated parts may use chromate conversion to boost resistance where needed Pioneer Metal overview.

Where galvanized still wins

If you need rugged, long-life protection outdoors or near marine exposure, HDG’s thick zinc-iron layer is a proven option. The trade-off is thickness and surface roughness, which can affect thread engagement on precision fasteners, and caution is advised on high-strength grades Fasto Screws outdoor guide.

When to choose zinc plating or stainless steel

Zinc plating fits indoor or mildly corrosive environments where appearance and cost matter. It is common to add a chromate-conversion finish when more resistance is needed, while zinc flake coatings are noted for fewer white corrosion byproducts and better extreme temperature resistance in many applications Pioneer Metal overview. Stainless fasteners avoid coating wear-off entirely but cost more and may require anti-galling practices. You will also see programs weigh e coat vs dacromet for large assemblies and threaded parts, and zinc flake families such as Geomet may be specified based on licensor guidance.

With the pros and cons clear, the next section turns these choices into a shop-floor process control plan you can run every day.

Actionable application and process control guide

When a bin of mixed bolts, clips, and brackets lands at your line, where do you start? Use this shop-floor routine to apply a thin, even film on dacromet coating fasteners and small hardware with fewer surprises and rework.

Shop-floor checklist from prep to pack

1. Surface preparation and verification: Remove oils and cutting fluids. Use mechanical or chemical pretreatment to promote adhesion. Fine abrasive blasting creates a micro-profile for better bond, and many flows add a phosphate or chromate pretreatment where permitted. Rinse per licensor spec, using deionized water if required, then dry thoroughly to avoid flash rusting Sinteredfilter Dacromet guide.
2. Masking and fixturing: Mask threads or bearing faces called out on the print. Rack or basket parts so slurry can drain freely; avoid deep nests that trap liquid. Keep load mass and part orientation consistent from lot to lot.
3. Slurry make-up and maintenance: Agitate until homogeneous. Check viscosity and solids content. Filter out agglomerates. Record adjustments and lot IDs before production.
4. Apply the coating: For bulk parts, dip then centrifuge to shed excess and build a uniform film in recesses and internal threads. For large or delicate parts, use controlled HVLP spray or rack-dip-drain methods to hit the target thickness while avoiding runs.
5. Drainage and flash-off: Let the water-borne carrier evaporate evenly to reduce pinholes and pooling, especially on blind holes and fine threads.
6. Cure and verify: Follow the licensor cure window, then confirm with part-mounted thermocouples and oven load mapping. Thermal profiling documents time-at-temperature on the part, not just the air setpoint, which prevents under- or over-cure Powder Coating Online on thermal profiling.
7. Optional topcoat: Apply specified sealers or friction modifiers and recure per their data sheets to tune torque-tension behavior.
8. Cool, unmask, and pack: Cool in still air to avoid shock. Unmask carefully. Label trays and racks with lot, recipe, and inspection status to prevent mix-ups.

The following reference targets are taken from an industry overview of Dacromet technology and process controls Sinteredfilter Dacromet guide.

Dip-spin versus spray considerations

• Dip-spin excels on small, complex shapes, evenly coating recesses, internal threads, and tight geometries while shedding excess via centrifuging.
• Spray is better for large brackets or assemblies where you need directional control and cosmetic consistency, often in two light passes to avoid runs.
• Rack-dip can balance throughput and coverage for mid-size parts; orient blind holes downward and maintain a repeatable drain angle.
• For dacromet coating bolts, control thread fill with spin speed and hang time so engaged threads do not bind at assembly.

In-line QA controls that prevent rework

• DFT checkpoints: Measure dry film thickness with a magnetic or eddy-current gauge on flats, edges, thread roots, and bearing faces. Adjust spin, solids, or spray settings before the next load if values drift.
• Adhesion and appearance: Cross-cut or tape test on a witness panel or sacrificial part from the load. Scan for pinholes, runs, and color inconsistency.
• Torque-tension correlation: On representative hardware, verify the coefficient of friction window and torque-to-clamp-load behavior. Many coaters use surrogate bolts and document torque-tension alongside DFT and cure data SWD Inc. dip-spin overview.
• Thermal cure proof: Attach thermocouples to the heaviest and lightest parts in the load to profile time-at-temperature and tune conveyor speed, airflow, and setpoints, reducing undercure risk and energy waste Powder Coating Online on thermal profiling.
• Bath health log: Record slurry batch ID, viscosity, solids, filtration changes, dip time, spin rpm and duration, hang or drain time, and oven parameters for traceability.
• High-strength fasteners: For a490 bolts with dacromet coating, prefer non-electrolytic zinc-flake systems to mitigate hydrogen embrittlement concerns noted with electroplating in industry discussions of the technology.

Run this playbook consistently and your dacromet coating fasteners will hit thickness, adhesion, and friction targets before they reach final inspection. Next, we will formalize acceptance criteria and a measurement plan your team can copy into drawings, control plans, and RFQs.

QA templates and acceptance criteria for your dacromet coating specification

Want language you can paste into drawings and RFQs without guesswork? Use the acceptance wording and measurement plan below to keep your dacromet coating specification tight, testable, and supplier friendly.

Sample acceptance criteria you can copy

• Appearance: Coating shall be silvery gray and continuous, free of leakage, bubbles, flaking, cracks, pockmarks, and inclusions. No discoloration is allowed, though small yellow spots are acceptable when noted in the standard GB/T18684-2002 and related test methods.
• Dry film thickness DFT: Measure by metallographic microscope per GB/T6462 or by dissolution weighing per the zinc chrome coating method. Target range to be defined by licensor data sheet and drawing.
• Adhesion: Tape test. Either follow GB/T5270 with no peeling or exposure of substrate, or use ASTM D3359 Method B with a minimum 3B classification per the published acceptance guidance in a general coatings standard ANSI/SDI A250.3-2007.
• Salt spray resistance: Conduct per GB/T10125. Report hours to red rust and grading per the standard’s scheme. Assign pass/fail against the licensor’s product data and the drawing GB/T18684-2002 and related test methods.
• Water resistance: Immerse in deionized water at 40 °C ±1 °C for 240 h. After drying, adhesion shall still meet the chosen tape test criterion GB/T18684-2002 and related test methods.
• Damp heat: 40 °C ±2 °C, 95% RH ±3%, up to 240 h with no red rust for specified coating levels. Reposition samples at each check interval and record results GB/T18684-2002 and related test methods.
• Sampling and retest rule: For each test, randomly select three samples from the batch. If any fail, select three more for the same test. If any fail again, the batch is nonconforming GB/T18684-2002 and related test methods.
• Document control: Include a dacromet coating standard pdf in your files. If your program relies on Chinese standards, request GB/T18684-2002 Technical Conditions of Zinc Chrome Coating by title and revision. For general acceptance of ASTM-based methods, also store ANSI/SDI A250.3-2007 for coating test procedures ANSI/SDI A250.3-2007.

Attach licensor or coater data sheets to your Control Plan and RFQ.

Measurement plan and sampling strategy

• Pre-production PPAP: Generate data from a significant production run, typically 300 consecutive pieces using production tooling and staff. Submit the full PPAP element set as required by the buyer Supplier PPAP Manual.
• Ongoing lots: At minimum, follow the three-sample rule and retest logic for each coating test in the batch. Increase frequency for special characteristics called out on the drawing GB/T18684-2002 and related test methods.
• DFT checkpoints: Verify DFT on flats, edges, and thread roots with microscope sections or dissolution weighing. Tie readings to load ID, slurry lot, and cure profile.
• Performance data: For fasteners, request torque–tension correlation as a Performance Test Result within PPAP, aligned to your joint’s friction window Supplier PPAP Manual.

What to ask for in lab certifications

• Independent lab work: Use an external lab accredited to ISO 17025. Include the accreditation certificate, company letterhead results, test dates, and the standards used Supplier PPAP Manual.
• In-house testing: Provide scope of tests performed, personnel competency, equipment list, and calibration methods for any on-site measurements Supplier PPAP Manual.
• For dacromet coating suppliers, require batch-level traceability: slurry lot, cure profile, DFT records, and complete salt spray or damp heat reports that match the drawing’s acceptance.
• Make your RFQ explicit: reference the exact dacromet coating specification, the sampling plan above, and the file names of the dacromet coating standard pdf you expect in the submission.

With clear criteria and proof packages defined, you are ready to spot issues fast. Next up, we will cover defect troubleshooting and compliance checkpoints so problems do not reach customers.

Troubleshooting defects and Dacromet coating RoHS compliant checks

Seeing pinholes, flaking, or early rust after cure? Imagine catching those issues at in-process audit instead of at your customer. Use the guide below to link visible symptoms to credible causes and practical fixes, then lock in compliance so your lots ship with confidence.

Common defects and what causes them

Most coating problems trace back to surface prep and environmental control. A concise overview of coating defects and their root causes highlights how prep, humidity, temperature, and application discipline drive outcomes coating defects and causes.

Fix prep and environment first; most coating defects start there.

Rework rules that protect base metal

• Quarantine and document lots before touching parts; confirm the defect and its extent.
• Do not bury defects. Remove defective film using an approved method, then re-clean and dry promptly to avoid flash rust.
• Stabilize humidity and part temperature before re-application to reduce pinholes and blistering.
• Protect edges and functional faces during handling to prevent underfilm corrosion starts.
• After rework, repeat adhesion and appearance checks on witness panels or sacrificial parts from the load.
• If high-strength fasteners underwent electrochemical steps upstream, coordinate hydrogen management requirements such as bake-out with your fastener or OEM standard before release.

Environmental and compliance checkpoints

Regulations target substances, not trade names. Under RoHS, hexavalent chromium is restricted, and trivalent chromium is widely used as a compliant alternative; thresholds and limited exemptions can apply, and documentation often focuses on substance content and passivation details RoHS and REACH summary. Under the EU REACH framework, substances of very high concern include hexavalent chromium, lead, and cadmium, while zinc is not on the SVHC list. Suppliers may be asked to confirm that their articles do not exceed SVHC thresholds.

What does that mean for zinc-flake programs? Ask your coater to declare the chemistry and passivation stack so you can show the system is dacromet coating RoHS compliant for your scope of use. If you run into online claims like "dacromet coating banned" or "dacromet coating discontinued," validate the specifics against substance restrictions and your customer standard rather than headlines, and file the supporting declarations in your control plan.

Use these defect maps and compliance checks during supplier audits and RFQs. Next, we will translate them into a procurement checklist and a simple scorecard you can apply to qualify a Dacromet-capable supplier.

Procurement checklist and supplier qualification

Sounds complex? When you source zinc flake finishes for automotive parts, a tight RFQ and a focused audit save time and avoid rework. Use the toolkit below to qualify a coater who can deliver repeatable DFT, friction, and corrosion performance.

RFP language that avoids ambiguity

• Coating callout: Specify ASTM F1136 type zinc aluminum dispersion coating and require licensor authorization for the named system. Note that this standard covers zinc flake families such as DACROMET and GEOMET IBECA research report.
• Dry film thickness: State the target DFT band and require thickness checks with a magnetic induction gauge per ASTM D1186 at defined checkpoints.
• Friction window: If fasteners are in scope, define the coefficient of friction window and test it per ISO 16047 concepts on your hardware stack. Ask the coater to name the topcoat or sealer used to achieve that window Wurth surface protection overview.
• Corrosion and adhesion: Require neutral salt spray per ISO 9227 or ASTM B117 and adhesion by ASTM B571 or D3359, with full lab reports.
• Traceability: Request batch-level logs for slurry lot, viscosity, filtration, spin or spray settings, oven profile, and DFT results.
• Compliance: Ask for chromium(VI)-free declarations and REACH and RoHS statements aligned to your program.
• Capacity and speed: Include expected lot sizes, takt, capacity, and sample turn time for PPAP or FAI.
• Regional sourcing: Use precise searches to build your vendor list, for example "dacromet coater in nc", "dacromet coating uk", "dacromet coating india", "dacromet coating canada", or "dacromet coating australia" to find local licensor-authorized applicators.

What to verify during supplier audits

• Process flow reality: Confirm posted flow covers alkaline clean, mechanical blast, dip-spin or rack-spray basecoat, controlled cure, and sealer cure as published by the licensor. Ask to see real oven profiles and witness how parts are oriented and spun.
• Hydrogen risk controls: Verify the process is non-electrolytic and that the supplier understands hydrogen embrittlement qualification methods used in the industry for zinc flake systems IBECA research report.
• Test capability: Check in-house or partner lab methods for ASTM D1186 thickness, ASTM B571 or D3359 adhesion, and ISO 9227 or ASTM B117 salt spray. For fasteners, confirm ISO 16047 friction testing practice and fixtures Wurth surface protection overview.
• Compliance files: Review chromium(VI)-free documentation and REACH and RoHS evidence.
• Quality system readiness: Ask for PPAP or FAI experience and how traceability is maintained from incoming parts to packed lots. If you prefer one accountable partner from metal forming to Dacromet-compatible finishing and assembly, consider a qualified example such as Shaoyi, which supports IATF 16949 programs and rapid prototyping.

Documentation you should always receive

• Certificate of conformance citing ASTM F1136 and the exact coating grade or stack, including topcoat.
• DFT map and gauge log per ASTM D1186 showing measurement points and results.
• Salt spray report per ISO 9227 or ASTM B117, with photos and hours to red rust as defined in the spec.
• Adhesion results per ASTM B571 or D3359, plus any paintability notes if you overcoat parts.
• Friction data for threaded fasteners per ISO 16047 concepts, including mating hardware and lube condition.
• Batch traceability: slurry lot, filtration changes, application parameters, oven profile, and inspection records.
• Environmental compliance letters covering chromium(VI), REACH, and RoHS.

With a clear RFQ and audit plan, you will be ready to move into pilot runs and torque-tension verification before launch.

From spec to scale for dacromet coated bolts and screws

Ready to turn your print into parts that assemble right the first time? Here is how to bridge intent and execution so your coating, friction targets, and fit all land together in production.

Turning specifications into reliable supply

Dacromet shines when you need thin, uniform protection and controlled friction on threaded hardware. For fasteners, lock in a defined friction window and the topcoat that delivers it. Licensor zinc flake systems can tune coefficient of friction across steel, aluminum, and e-coat bearing surfaces, and many OEMs include multi-tightening checks in their specs NOF METAL COATINGS friction guidance. Tie your drawing to the test method too. ISO 16047 concepts relate torque and clamp load and explain how a K factor captures friction and geometry in the simple T = K × D × F relationship, which is why torque–tension correlation on your hardware is essential Peak Innovations Engineering on ISO 16047.

Still weighing dacromet coating vs hot dip galvanizing in certain joints? Decide based on thread fit and friction control needs first, then confirm the corrosion strategy fits the operating environment from your earlier comparison.

Pilot builds that de-risk launches

Before volume release, run a controlled pilot so you can measure, adjust, and freeze parameters:

• Verify the friction window on representative joints using your specified hardware stack and tightening strategy per ISO 16047 concepts.
• Confirm dry film thickness at thread roots, bearing faces, and edges, then link readings to cure and application settings.
• Run multi-tightening when applicable to your spec and record behavior with and without topcoat.
• Validate rack or basket setups so drainage and coverage stay consistent across part families of dacromet coated bolts and dacromet coated screws.
• Lock packaging, handling, and storage conditions so surface condition and friction remain stable up to assembly.

Where to go for integrated manufacturing support

Prefer one accountable path from metal forming to surface treatment and assembly? Many manufacturing groups coordinate internal fabrication with licensed partners for finishing operations, including Dacromet coating, to deliver ready-to-use kits and assemblies example of integrated coordination. If you want a single point of contact for machining or stamping, Dacromet-ready prep, finishing coordination, and PPAP support, consider an IATF 16949 capable partner such as Shaoyi as one credible option among qualified suppliers.

• Engineers: Specify coating family and topcoat, name the friction window and ISO 16047 test conditions, set the DFT band, and note critical no-coat areas.
• Buyers: Require licensor authorization, documented oven profiles, friction test capability, and lot-level traceability in the RFQ and PO.
• Quality: Pilot through PPAP, capture torque–tension plots, attach licensor data sheets to the control plan, and freeze the process recipe before SOP.

Follow this path and your specification becomes a stable, scalable process that delivers repeatable assembly torque, proven corrosion performance, and clean, on-time launches.

Dacromet coating FAQs for automotive parts

1. Is Dacromet better than galvanized?

It depends on the use case. Dacromet is a thin, non-electrolytic zinc flake finish that preserves thread fit and helps manage friction on fasteners, while reducing hydrogen embrittlement risk on high-strength bolts. Hot-dip galvanized is thicker and very rugged for large outdoor parts, but that build can affect fine threads. Choose by thread tolerance, friction control needs, environment, and test requirements.

2. How thick is the coating on Dacromet?

Dacromet is engineered as a thin, uniform film typically in the single-digit micron range. The exact dry film thickness is set by licensor specifications and controlled by process parameters like slurry viscosity, spin speed, drainage, and cure. Keeping to the specified band protects threads and supports consistent torque-tension behavior.

3. What is the best coating to prevent corrosion?

There is no one best coating. For fasteners that need thin, uniform protection and controlled friction, Dacromet is a strong option. For heavy outdoor structures where maximum build is acceptable, hot-dip galvanized is common. For cosmetic and cost-driven needs, zinc plating is used with suitable post-treatments, and stainless hardware avoids coatings entirely. Match the coating to environment, thread fit, friction targets, and your specified test methods.

4. Is Dacromet RoHS compliant or banned?

Dacromet is a coating technology, not a single formula. Compliance depends on the chemistry. Modern zinc flake systems are designed to be chromium(VI)-free to align with RoHS and REACH. Always request supplier declarations and keep them in your control plan. If you are sourcing regionally, confirm local requirements whether you search for dacromet coating canada or dacromet coating australia.

5. How do I source a qualified Dacromet coater?

Specify the coating family and licensor authorization, define the dry film thickness band, and require test capability for DFT, adhesion, salt spray, and fastener friction. Ask for PPAP or FAI readiness, traceability, and an IATF 16949 quality system. Build a regional list using terms like dacromet coating canada or dacromet coating australia. For integrated manufacturing and PPAP support, a partner such as Shaoyi can coordinate metal forming with Dacromet-ready finishing and assembly at https://www.shao-yi.com/service.