Chemical Conversion Coating
Precision Cerakote ceramic coatings for aerospace, defense, and industrial components.
How Chemical Conversion Coating Protects Your Aluminum
Chemical conversion coating is a controlled chemical reaction that forms a protective chromate or chromate-free oxide layer at under 1 micron thickness. Parts move through alkaline cleaning, acid deoxidizing, and MIL-DTL-5541 conversion solution immersion at 70-90 F for 2-5 minutes. Multi-stage deionized water rinses between each step prevent cross-contamination and ensure uniform coating formation.
Precision Chemistry, Not Approximation
Many shops treat conversion coating as a commodity dip-and-rinse process with loose controls. ColoradoKote monitors solution concentration daily through titration, maintains temperature within 5 F of specification, and documents immersion times for every batch. Rinse water conductivity is verified below 10 microsiemens per centimeter. The result is 168+ hours of salt spray resistance (ASTM B117) for Type I Class 1A.
Aerospace-Grade Documentation
Every conversion coating job follows AS9100 protocols. Solution concentration, temperature logs, immersion times, and visual inspection results are recorded and traceable to each lot. Type II processing is documented against MIL-DTL-5541 and MIL-DTL-81706 requirements, with REACH and RoHS compliance verified. You receive a Certificate of Conformance that includes all process parameters your quality team and auditors require.
What Conversion Coating Delivers for Your Parts
Aluminum components face corrosion, adhesion failure, and compliance gaps without proper surface treatment. Conversion coating addresses all three.
MIL-DTL-5541 Type I and II Protection
Type I Class 1A delivers 168+ hours of salt spray resistance per ASTM B117, creating a barrier against moisture, salt spray, and galvanic contact. Type II chromate-free formulation meets MIL-DTL-81706 environmental requirements while maintaining corrosion protection. Both specifications form oxide layers at 0.00001-0.00004 inches that protect aluminum alloys including 2024, 6061, and 7075.
Zero Dimensional Impact with Enhanced Bonding
Coating thickness under 1 micron means zero dimensional change to machined parts. The conversion coating creates a chemically reactive surface that bonds with Cerakote at the molecular level, preventing adhesion failure on bare aluminum. Thread fits, bearing surfaces, and mating components remain unaffected.
AS9100 Full Traceability for Every Lot
Solution concentration, temperature logs, immersion times, and visual inspection results are recorded and traceable to each lot number. Type II documentation includes MIL-DTL-5541 and MIL-DTL-81706 conformance with REACH and RoHS compliance verified. Your Certificate of Conformance contains all process parameters and coating weight measurements at 40-100 mg per square foot.
Technical Specifications for MIL-DTL-5541 Chemical Conversion Coating
| Specification | Value | Test Method |
|---|---|---|
| Corrosion Resistance (Type I, Class 1A) | 168-240+ hours | ASTM B117 |
| Corrosion Resistance (Type II, Class 1A) | 96-168+ hours | ASTM B117 |
| Coating Thickness | 0.00001-0.00004 inches (<1 micron) | Not applicable (chemical conversion) |
| Coating Weight (Class 1A) | 215-600 mg/ft² | ASTM B137 |
| Coating Adhesion (with topcoat) | 5B rating (no delamination) | ASTM D3359 |
| Appearance (Type I) | Gold/tan/bronze iridescent | Visual Inspection |
| Appearance (Type II) | Clear to slight iridescence | Visual Inspection |
| Dimensional Impact | None (sub-micron thickness) | Per MIL-DTL-5541 |
| Environmental Compliance (Type II) | REACH and RoHS compliant | Per MIL-DTL-81706 |
| Applicable Alloys | 2024, 6061, 7075, 5052, cast aluminum | Per MIL-DTL-5541 |
| Service Life Extension (with Cerakote) | 10-15+ years vs. 5-8 years standalone | Field performance data |
Applicable Specifications: MIL-DTL-5541F Type I | MIL-DTL-5541F Type II | MIL-DTL-81706 | AS9100 | ISO 9001 | ITAR
Industries That Require Chemical Conversion Coating
Ceramic coating protects components across demanding industries. From aircraft engines to military hardware, our process delivers the durability these applications demand.
Aerospace parts
Engine components, landing gear, fasteners, and structural elements face extreme conditions. Ceramic coating extends service life and ensures reliability at altitude.
Aerospace parts
Engine components, landing gear, fasteners, and structural elements face extreme conditions. Ceramic coating extends service life and ensures reliability at altitude.
Aerospace parts
Engine components, landing gear, fasteners, and structural elements face extreme conditions. Ceramic coating extends service life and ensures reliability at altitude.
Aerospace parts
Engine components, landing gear, fasteners, and structural elements face extreme conditions. Ceramic coating extends service life and ensures reliability at altitude.
Where ceramic coating delivers real value
Engine components, landing gear, and fasteners face conditions that demand absolute reliability. Ceramic coating extends service life and ensures performance at altitude and beyond.
Alkaline cleaning removes contaminants from bare aluminum
Parts arrive from sandblasting with fresh aluminum surface exposed. Processing begins within hours to prevent re-oxidation. Ultrasonic degreasing removes residual blast media and handling oils. An alkaline bath at 120-140 F strips surface oxides over 3-5 minutes. Two-stage deionized water rinsing ensures no cleaning chemistry carries forward.
Acid deoxidizer prepares a uniform surface for coating
A mild acid solution removes the natural aluminum oxide layer that would prevent uniform conversion coating formation. Immersion lasts 1-2 minutes at room temperature. This step creates a microscopically roughened surface that accepts the conversion coating chemistry evenly. Three-stage deionized water rinsing follows. Insufficient deoxidizing is the most common cause of poor conversion coating, and ColoradoKote does not cut this step short.
Surface is cleaned and made ready for coating
Degreasing, cleaning, and light abrasion remove contaminants and create the ideal surface for adhesion. This step determines coating quality.
MIL-DTL-5541 solution converts the aluminum surface
Parts immerse in Type I or Type II conversion coating solution at 70-90 F for 2-5 minutes. The solution reacts chemically with the aluminum, forming a protective chromate or chromate-free oxide layer at under 1 micron thickness. For Type I, uniform gold or tan color confirms complete conversion. For Type II, slight iridescence indicates proper formation. Visual inspection verifies full coverage with no bare spots.
Ceramic coating is applied in controlled layers
We apply the coating using precision equipment, monitoring thickness and coverage. Each layer cures before the next is applied, building a durable finish.
Multi-stage rinsing removes residual chemistry
Three-stage cascade rinsing with deionized water removes all residual conversion coating solution. Final rinse conductivity is verified below 10 microsiemens per centimeter. Forced-air drying at 140-160 F prevents water spotting on the freshly converted surface. This precision rinsing step prevents staining and ensures a clean substrate ready for topcoat or standalone use.
Coating hardens and bonds to the substrate
The coating cures under controlled temperature and humidity. We don't rush this phase. Full cure strength takes time, and we give it that time.
Visual verification and documentation for every lot
Inspectors verify complete, uniform coverage across all surfaces. Type I parts must show consistent gold or tan iridescence. Type II parts are checked for even formation without bare aluminum. Solution concentration, temperature logs, and immersion times are compiled into a Certificate of Conformance. Parts destined for Cerakote topcoat transfer within 24-48 hours under contamination-free handling.
Every part is measured and tested before shipment
We measure coating thickness, check for defects, and verify specifications. Documentation is prepared for your records. Only parts that pass leave our facility.
Frequently Asked Questions
Find answers about our coating processes and technical capabilities
Standalone ultrasonic cleaning turnaround is typically 3-5 business days from receipt of parts. Cycle time per batch is 10-30 minutes depending on contamination severity, but turnaround includes intake, pre-assessment, cleaning, verification, and documentation. For parts proceeding to coating, cleaning is integrated into the coating schedule and does not add separate lead time. Contact us at 970.541.7331 for current scheduling availability.
We use a multi-method verification approach. Water-break testing confirms DI water sheets uniformly across surfaces with zero beading, verifying the absence of oils and films. White-glove inspection checks for particulate transfer. For critical aerospace applications, dyne pen testing measures surface energy against your specified threshold. Rinse water conductivity is verified below 10 microsiemens per centimeter. Parts that fail any verification step are re-cleaned before release.
Yes. While ultrasonic cleaning is frequently performed as surface preparation before coating application, we also provide it as a standalone precision cleaning service. Standalone cleaning orders receive the same AS9100 process controls, documentation, and verification as cleaning performed before coating. Parts are returned clean with a Certificate of Conformance documenting all cleaning parameters and verification results.
Ultrasonic cavitation removes machining fluids, cutting oils, coolant residue, fingerprint oils, mold release agents, flux residue, carbon deposits, embedded particulates, and additive manufacturing support material. The cavitation action reaches contaminants in blind holes, internal passages, threads, and lattice structures that manual cleaning and spray methods cannot access. Solution chemistry is selected based on the specific contamination type and substrate material.
No. Ultrasonic cavitation is a non-contact cleaning method that does not mechanically abrade or distort parts. Cleaning solution chemistry is matched to the substrate material to prevent chemical attack. Alkaline solutions are used for aluminum, neutral formulations prevent hydrogen embrittlement on titanium, and polymer-safe solutions protect additive manufacturing parts. We have cleaned parts with wall thicknesses under 0.5mm without damage or dimensional change.
Start Your Chemical Conversion Project
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