Chem Film & Alodine Conversion Coating Services for Aluminum Components
MIL applies Type I (hexavalent) and Type II (non-hexavalent) chromate conversion coatings to deliver corrosion protection, conductivity, and superior paint/coating adhesion for aluminum parts used in aerospace, defense, medical, and industrial applications.
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High-Performance Chromate Conversion Coatings for Aluminum
Conversion coating—commonly referred to as Chem Film or Alodine—is a thin, electrically conductive, corrosion-resistant treatment applied to aluminum surfaces. Unlike anodizing, which builds an oxide layer, Chem Film chemically modifies the surface without adding measurable thickness, making it ideal for tight-tolerance, precision-machined components.
MIL processes both Type I (hex chrome) and Type II (RoHS-compliant) conversion coatings in accordance with MIL-DTL-5541 and major OEM/prime specifications.
Conversion Coating Highlights
- Corrosion protection without dimensional change
- Excellent base for paint, primer, dry film lubricant & masking adhesion
- Available as Class 1A (maximum corrosion resistance)
- Available as Class 3 (provides electrical conductivity)
- Type I hex-chrome & Type II environmentally friendly chemistries
- Distinctive finish colors for inspection and identification
- Ideal for tight-tolerance aerospace components
How the Chem Film / Alodine Process Works
Step 1 — Cleaning & Surface Activation
Parts undergo solvent cleaning, alkaline cleaning, or deoxidizing to remove:
- Oils and machining residue
- Oxides & surface contamination
- Embedded foreign materials
A clean, uniform surface is critical for consistent conversion coating.
Step 2 — Immersion or Spray Application
Parts are immersed or sprayed with the appropriate Chem Film / Alodine chemistry, which reacts with the aluminum surface to create a corrosion-resistant, conductive (Class 3), or non-conductive (Class 1A) finish.
Coloration may range from:
- Gold
- Green
- Brown
- Clear (Type II options)
Step 3 — Rinsing & Chemical Stabilization
Excess chemistry is removed while preserving the uniform conversion layer.
This step ensures:
- Consistent electrical performance
- Even adhesion properties
- No buildup on tight features
Step 4 — Drying & Final Inspection
MIL verifies:
- Visual appearance & uniformity
- Adhesion and coverage
- Electrical conductivity (for Class 3)
- Corrosion resistance expectations
Full traceability is provided for all aerospace and defense components.
Why Work With MIL for Conversion Coating?
Expertise in MIL-DTL-5541 Type I & II Processing
MIL interprets and applies complex coating specifications with accuracy, ensuring full compliance and reliable performance.
Zero-Dimensional-Change Surface Treatment
Perfect for precision parts where even microinches of thickness would affect fit or function.
Ideal Pre-Treatment for Multi-Step Finishing
Chem Film is frequently used before:
- Prime & paint
- Dry / solid film lubricant
- Masking-dependent anodizing
- Coating systems requiring enhanced adhesion
MIL performs all these services under one roof for controlled workflow.
Trusted for High-Stakes Aerospace Hardware
With thousands of prime approvals and Nadcap accreditation, MIL is a preferred processor for spec-driven aluminum components.
Applications & Industries Served
Component Types
- Electrical housings & enclosures
- Aerospace brackets, frames & machined structures
- Hydraulic and mechanical assemblies
- Precision aluminum hardware
- Masking-prepped parts for anodizing or painting
Industries
- Aerospace & defense
- Space systems
- Medical devices
- Industrial equipment
- Electronics & communication hardware
- R&D and prototyping
Frequently Asked Questions About Conversion Coating
- Type I uses traditional hexavalent chromium and provides a recognizable gold/green finish.
- Type II is non-hex chrome, more environmentally friendly, and usually clear.
Both offer corrosion protection; Type I often provides enhanced durability for aerospace.
- Class 1A: Maximum corrosion resistance.
- Class 3: Provides electrical conductivity (used for bonding, grounding, and electronic components).
No. Conversion coating produces no measurable buildup, making it ideal for tight-tolerance components.
They serve different purposes:
- Chem Film: thin, conductive, corrosion resistance, great pre-treatment
- Anodizing: thicker, harder, wear-resistant, dyeable
Yes—Type II options (trivalent or chrome-free) meet RoHS requirements.
Yes—this is one of its most common uses. It significantly improves adhesion and durability.
Get Started Today
Fast, accurate estimates for Chem Film / Alodine conversion coating and multi-process finishing.
Need help selecting the correct Type (I/II) or Class (1A/3)? Our engineering team will guide you.
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