MIL-DTL-81706
Chemical Conversion Materials for Coating Aluminum and Aluminum Alloys
Covers qualified chemical conversion materials used to form coatings on aluminum and aluminum alloys.
What MIL-DTL-81706 specifies
MIL-DTL-81706 is a material qualification specification, not the usual finished-part callout. It classifies products by chemistry, performance class, supplied form, and application method. Type I contains hexavalent chromium and Type II contains none; Class 1A provides maximum corrosion protection and Class 3 provides low electrical resistance. Forms I through VI describe concentrate, powder, ready-to-use, thixotropic, and applicator-device packaging. Methods A through D are spray, brush or wipe, immersion, and applicator device. Approved products are listed in the qualified products database. Finished aluminum parts are normally called out to MIL-DTL-5541, with the processor using a MIL-DTL-81706-qualified material.
MIL-DTL-81706 types and classes
Every designation the document defines, with the thickness it requires and the tests it imposes.
| Designation | Meaning | Requirement / test |
|---|---|---|
Type I | Chemical conversion material containing hexavalent chromium. | Qualification includes coating performance for the approved class and application method. |
Type II | Chemical conversion material containing no hexavalent chromium. | Qualification includes coating performance for the approved class and application method. |
Class 1A | Material qualified to form coatings for maximum corrosion protection, painted or unpainted. | Corrosion resistance and wet-tape adhesion as applicable. |
Class 3 | Material qualified to form coatings with corrosion protection and low electrical resistance. | Corrosion resistance and electrical contact resistance. |
Forms I–VI | I concentrated liquid; II powder; III premixed touch-up liquid; IV premixed thixotropic liquid; V premeasured thixotropic powder; VI premixed liquid in a self-contained applicator. | Form-specific storage stability, preparation, application, and qualification tests. |
Methods A–D | A spray; B brush-on or wipe-on; C immersion; D applicator pen or presaturated applicator device. | Product qualification is limited to its approved application method. |
Tests and the drawing call-out
Tests the document imposes
- Coating corrosion resistance by ASTM B117 exposure
- Wet-tape adhesion of the applied paint system
- Class 3 electrical contact resistance
- Material storage stability
- Qualification by type, class, form, and method
How to cite it
Drawing call-out
USE CHEMICAL CONVERSION MATERIAL QUALIFIED TO MIL-DTL-81706 TYPE <I|II>, CLASS <1A|3>, FORM <I–VI>, METHOD <A–D>Angle brackets mark the choices the drawing must make; every finish page shows a completed example.
Finishes specified to MIL-DTL-81706
Also referenced by: Chemical Conversion Coating.
MIL-DTL-81706 — frequently asked
What is the difference between MIL-DTL-81706 and MIL-DTL-5541?
MIL-DTL-81706 qualifies the chemical material. MIL-DTL-5541 controls the conversion coating applied to the finished aluminum part.
What do Forms I through VI mean?
They identify how the product is supplied, from concentrated liquid and powder through ready-to-use thixotropic or applicator products. Form does not state corrosion class.
What are Methods A through D?
Method A is spray, B is brush or wipe, C is immersion, and D is an applicator pen or presaturated device. A product must be qualified for the method used.
MIL-DTL-81706 is a work of the US Government and not subject to copyright. The authoritative copy is the DLA ASSIST database; check it for amendments issued after this page was updated. Official source ↗