Metal Finishes

Use either trivalent Cr    chrome formulations requiring top coating with organic coverings or NON-CHROME coatings based on fluoride salts.

 

RoHS & WEEE Compliant Chem-film

1A, 3

Traditional Hex (Cr    ) chrome based coatings ) from Mil-DTL-5541 specifications.

 

  • Class 1A,-thicker coating, less electrical conductive coatings

 

  • Class 3 -thinner coating, more electrical conductive coatings 

Regular Anodize

Hard Anodize with or without PFTE Coatings

Grown under ambient bath temperatures (68-72 F), regular anodize and has a much thinner coating thickness typically in the range of .0002”-.0004” thick depending on Al alloy composition.  This coating is excellent for applications requiring mild wear and abrasion resistance (30-32 Rc), same minimum corrosion resistance (336 hours) as HARD anodize and can be dyed various colors.  In electrical applications, its lower dielectric strength approaches that of 10,000 V before breakdown. 

 

PFTE and other lubricative organic coatings can be applied to the porous anodic surface further enhancing the bulk mechanical properties of the coated part.

 

Dyed colors over a regular anodize surface are very cosmetically appealing and stay true to their colors as the regular anodic coating formed is light or similar in appearance to that of unanodized aluminum.

Grown under thermally constrained bath temperatures (28-32 F) and has a typical coating thickness of .001”-.003” thick depending on Al alloy composition.  This coating is excellent for applications requiring extreme wear and abrasion resistance (58-60 Rc) surfaces that have exceptional corrosion resistance (> 1000 salt spray) and can be dyed various colors.  Unfortuntely the colors tend to be much DARKER than regular anodize colors due to the thicker coating that create a dark background prior to dyeing (e.g. Sky blue (regular) vs Navy Blue (hard) for same dyed color). In electrical applications, hard anodize coatings have a dielectric strength approaching that of 30,000 V before breakdown.

 

PFTE and other lubricative organic coatings can be applied to the porous anodic surface which further enhances the surface mechanical properties of the coated part.

Anodize is a electrolytic process done most commonly in either Sulfuric or Chromic (being phased out due to environmental concerns) acid whereby the surface of the electrically conducting base metal ALUMINUM (Al) is converted to a non-conductingdielectric porous metal oxide ALUMINA (Al  O  (S,Cr)) coated surface.  This porous coating can then be dyed a variety of colors, and the new surface coating has added value to the bulk metal mechanical properties by making in harder, and more corrosion resistant when compared to the base metal. The difference between HARD and REGULAR anodize mainly deals with how thick the oxide coating is formed during processing. 

Chem-film is a chromate conversion coating whereby the aluminum surface comes in contact with chromic acid forms chrom-alumino compounds that re-deposit back onto the aluminum surface with large, adherent grain structure forming an excellent protective layer thick (.00005” or less) that acts as an excellent paint base, or a stand-alone corrosion resistant layer able to withstand 168 hours of salt spray testing.

 

In response to increasing environmental and human health concerns about the toxicity and carcinogenic aspects of hexavalent chrome, (Cr   ), the market place responded with governmental legislation stemming from European RoHS and WEES restrictions with the development of trivalent Cr    chrome or other fluoride based (non-chrome) conversions coating

 

Hard Anodize with PFTE Coating

Hard Anodize without PFTE Coating

Black Anodize

Stop off lacquer and pull plugs

Gold Chem-film

x     y

+3

+6

 

+3

+6

 

Provides a finish on the customer's part that has a "super corrosion resistant," chromium enriched passive surface with an oxide surface layer that is ~3x the thickness of the naturally formed layer produced by passivation alone. Electropolishing is certifed in accordance to ASTM-B-912 and other internal SPS standards.

 

Benefits of an Electropolished Surface Include:

  • Ultra cleanliness leaving a smooth, "pit-free" surface

  • Cosmetic Appeal

  • A thickened chromium oxide layer for enhanced passivity

  • Reduced mechanical stresses in upper metallic surface layers that are areas for subsequent corrosion pit formation

  • ~3x the thickness

  • Super corrosion resistant

Passivation is a chemical treatment using either Nitric or Citric acid formulations that remove any "embedded" iron fines or particles placed on the surface by the fabrication process. Unless removed by passivation, these particles disrupt the continuity of naturally occurring oxide formed on the surface of stainless steel and other refractory alloys (Ti, Nb, Zr).  After passivation, the oxide surface layer can reform as a continuous layer based upon the metals's surface roughness and irregularities.

 

All parts are passivated prior to leaving our facility and are certified to various industry standards: ASTM-A-380, ASTM-A-976, AMS QQ-P-35C, MiL-STD-5002, AMS 2700B. 

Passivation

Electropolishing

(10-15 Ra) 

                 (Mil-C-26074, ASTM B 733, AMS 2404, 2405)

 

  • Bright to satin luster

  • Corrosion resistant coatings

  • Enhanced hardness to base metal with potential for heat treating to higher R   values

  • Able to plate uniformly and in blind holes

  • Low, Mid Phos Magnetic; High Phos – NON Magnetic

Electrolytic

Electroless

Nickel Plating is a process by which metallic nickel is plated onto the metal surface.  The driving force for the migration of nickel metal ions from the plating solution to the parts can either be by electrical DC current (Electrolytic) or by autocatalytic chemical energy (Electroless) from bath constituents.  In either case, the nickel metal imparts a bright luster, decorative finish, increase hardness to the base metal and enhance corrosion resistance.  The nickel coating can be magnetic, however, high phosphorous coatings are NOT magnetic. Nickel Plating can be combined with other metal finishes on the same part.

                                                (QQ-N-290)

 

  • Bright to satin luster

  • Corrosion resistant coatings

  • Able to plate thicker coatings (0.005”) for salvage work

  • Can be barrel plated for fastener industry

  • Hardness “as plated” - not heat treatable like electroless coatings

  • Magnetic coating

Gold Chem-film

Electroless Nickel

c

 

1721 Ives Ave, Oxnard, CA 93033

(805) 385-3330

© Alliance Finishing & Manufacturing 2020. All rights reserved. Made in California.