| PROCESS | METAL | APPLICABLE SPECIFICATION | NORMAL COATINGS THICKNESS & COLOR OR APPEARANCE | REMARKS |
| ANODIZE - CHROMIC ACID | ALUMINUM | MIL-A-8625 / AMS-A-8625
TYPE I - Conventional TYPE IB - Low Voltage
CLASS 1 - Non Dyed
CLASS 2 - Dyed | .00002-.0003 Clear to dark gray depending on alloy | Not to be applied to alloys with copper content in excess of 5.0% or silicon in excess 7.0% and when total alloying elements exceed 7.5%. Non-conductive, good paint base, poor abrasion resistance, not good for dyes except black. Should be used for close tolerance parts. |
| ANODIZE - SULFURIC ACID | ALUMINUM | MIL-A-8625 / AMS-A-8625
TYPE II
CLASS 1 - Non Dyed
CLASS 2 - Dyed | .00007-.001 Clear All colors | Not to be applied to assemblies or parts with joints or recesses which might entrap solution. Good electrical barrier and paint base. May be dyed in all colors. Dichromate seal, when specified, will impart yellow color. Produces excellent decorative finishes when the part is either polished, brushed, or bright dipped prior to anodizing. Good corrosion and abrasion resistance. |
| ANODIZE - HARD | ALUMINUM | MIL-A-8625 / AMS-A-8625
TYPE III
CLASS 1 - Non Dyed
CLASS 2 - Dyed | Unless otherwise specified, .0016/.0024 will be applied. Color will vary with alloy and thickness | Dense hard wear resistant coating. Coatings are approximately 50% penetration and 50% buildup. Excellent dielectric and heat absorption properties. May be considered for minor salvage applications. Sealing greatly increases corrosion resistance, but slightly reduces wearing qualities. Teflon sealing may be substituted to increase lubricity. |
| BAKING | ALL | In accordance with applicable plating specification | No dimensional change Slight staining may result | Used for stress relief or hydrogen embrittlement before and/or after processing; for improving the adhesion of plating the base metal; or increasing the hardness of plating. All ovens are certified. |
| BLASTING (includes glass bead and Aluminum oxide) | ALL | As required by applicable process specification | May remove metal Dull to semi-bright | For removing scale and rust, etc., and blending imperfections. The amount of metal removed will depend on media selected. May be used for decorative and optical finishes. Provides uniform matte finish before decorative processing. |
| CADMIUM | ALL | +QQ-P-416 s/s AMS-QQ-P-416 TYPE I | CLASS 1 - .0005 Min.
CLASS 2 - .0003 Min.
CLASS 3 - .0002 Min.
TYPE I - Clear
TYPE II - Gold, | Most commonly used plating. High density of plate affords excellent corrosion resistance. TYPE I coating is very susceptible to stains and fingerprints. TYPE II coating is excellent for resistance to moisture and humidity, and a paint base. Chromate colors besides gold are clear. Stress relief is required on metal with a hardness of Rockwell C34 or above and hydrogen embrittlement relief is required after plating on metal with a hardness of Rockwell C36 or above. |
| CHROMIUM | ALL | +QQ-C-320 s/s AMS-QQ-C-320
CLASS 1 - Corrosion protective (decorative)
TYPE II - Satin
*CLASS 2 - Engineering (hard) | CLASS 1 - .00001-.00005 (plus under plate)
*CLASS 2 - .002 unless otherwise specified
Dull to bright | TYPE II satin coating is put on the base metal that is either blasted, grained or brushed. Hard chrome is plated directly on the base metal. Parts requiring heavy metal deposits should be overplanted and ground to the final finished dimension. |
| COPPER | ALL | +MIL-C-14550(s/sAMS-2418) CLASS 0 - .001-.005 CLASS 1 - .001 min. CLASS 2 - .0005 min. CLASS 3 - .0002 min. CLASS 4 - .0001 min. AMS-2418 TYPE 1 - Energy. Plating Thickness = .0005-.0007 TYPE 2 - Plating for masking Thickness = .002 nominal | | Stop off for heat treat (CLASS 0) and carburizing (CLASS 1). Undercoat for other plated metals to improve adhesion, corrosion resistance, and to increase electrical conductivity (CLASS 2). Under tin plating to prevent base metal migration into the tin (prevents poisoning solder ability) (CLASS 3 and CLASS 4). |
| DOW #7 (Dichromate Treatment) | MAGNESIUM | AMS-M-3171 TYPE III
ASTM D1732 CLASS 1, TYPE III | No dimensional change Brassy to dark brown | Good paint base. Best corrosion protection of the chemical coatings on magnesium. May be applied to all alloys except EK30A, EK41A, EK33A, HK31A, M1A, HM31A, HM21A, and LA141A. |
| ELECTROLESS NICKEL | ALL | AMS-C-26074
CLASS 1 - As plated, no subsequent heat treatment
CLASS 2 - Heat treated to obtain required hardness
CLASS 3 - On aluminum alloys, nonheat-treatable, & beryllium alloys, processed to verify nickel adhesion
CLASS 4 - On aluminum alloys, heat-treatable, processed to verify nickel adhesion AMS 2404 = Thks. as specified |
GRADE A = .0010 min.
GRADE B = .0005 min.
GRADE C = .0015 min.
| 100% uniformity of plating thickness on all accessible internal and external areas. Exceptionally good for salvage purposes. Good corrosion, oxidation, and wear resistance. Facilitates soldering on aluminum and brazing on stainless steel. CLASS 1 and CLASS 2 coated steel parts, Rockwell C40 or above, are baked for hydrogen embrittlement relief. CLASS 2 coated parts are additionally heated to 500 degrees F. or more, to harden the nickel deposit to 800 Knoop or better. CLASS 3 and 4 coated parts shall be baked for 1-1 1/2 hours at 375 degrees or 250 degrees F. |
| MAGNETIC PARTICLE INSPECTION | STEEL AND MAGNETIC MATERIAL | ASTM E 1444 | No dimensional change No appearance change | This inspection method is used for detecting cracks, seams, laps, inclusions, welding flaws, and discontinuities on the surfaces of ferromagnetic materials. |
| NICKEL (Electrodeposited) | ALL | +QQ-N-290s/sAMS-QQ-N-290
CLASS 1 - Corrosion protective
CLASS 2 - Engineering (Also see SULFAMATE NICKEL) | CLASS 1
GRADE A - .0016 min.
GRADE B - .0012 min.
GRADE C - .0010 min.
GRADE D - .0008 min.
GRADE E - .0006 min.
GRADE F - .0004 min.
GRADE G - .0002 min.
CLASS 2 - as specified | There is a nickel finish for almost any need. Nickel can be deposited in soft or hard form, dull to bright finish. Corrosion resistance is related to the thickness applied. Low thermal expansion. Slightly magnetic. CLASS 2 plating will be .002 to .003 thick unless otherwise specified, but may be controlled to fit any engineering application. CLASS 1 coatings that include copper undercoat are used for decorative chromium systems. Embrittlement relief is required on all metals with hardness above Rockwell C40. |
| Nital Etch/ Temper Inspection | Steel | HP30-4 MIL-STD-867 | 0.00005-0.0002t. | The temper etch process shall be used after final grinding or machining operations but prior to any processing, which may interfere with this inspection, such as plating or shot peening. Parts finished to close tolerances shall be dimensionally inspected after etch inspection as the etch process may remove from 0.0013 to 0.0051 millimeters (0.00005 to 0.0002 inch) of material from the surface of the part. |
| PENETRANT INSPECTION | ALL | ASTM E 1417 TYPE I - Fluorescent dye
TYPE II - Visible dye METHOD A - Water-washable METHOD B - Post emulsifiable (lipophilic) METHOD C - Solvent removable METHOD D - Post emulsifiable (hydrophilic) | Prepenetrant etch of .0002 - .0004 metal removal on all alloys when approved by consumer | As required, to protect them from metal removal, prior to the etching operation. |
| PHOSPHATE (Heavy) | IRON AND STEEL | +DOD-P-16232 s/s MIL-DTL-16232 TYPE M - Manganese base TYPE Z - Zinc base
CLASS 1 - With preservative treatment when specified
CLASS 2 - MIL-PRF-16173Gr.3 preservative treatment
CLASS 3 - No preservative treatment
*CLASS 4 - Chemically converted | .0002-.0006 avg. thickness, however coating is measured by weight Gray to Black
Type M-16g/m2
Type Z-11g/m2 | Abrasive blasting is the required pretreatment, unless otherwise specified by customer or drawing. Used for corrosion protection of ferrous metals. Also used to prevent galling in cold extrusion and deep-drawing applications. Not recommended if the coating is expected to come in contact with alkaline materials or to be exposed to temperatures above 200 degrees F.
CLASS 2 and CLASS 4 coatings extend the corrosion protection of the phosphate. MIL-PRF-3150 oil may be used as an alternative for very small parts under Type M CLASS 2. Provides an improved break-in coating. |
| PHOSPHATE (Light) | IRON AND STEEL | TT-C-490 Zinc base TYPE 1 TYPE V | Minor dimensional change
TYPE 1 300-500 mg/sq ft coating weight
TYPE V 500-1100 mg/sq ft coating weight Gray | Used for pretreatment of base metal for organic coatings such as primer, enamel, lacquer, etc. Improves corrosion resistance of the base metal, and promotes better adhesion between the base metal and the organic coating. Also, used for post treatment of both cadmium and zinc plating. |
| PICKLING | ALL | In accordance with applicable plating specifications | Removes metal Cleaner and brighter surface | Generally used as a cleaner to remove corrosion, rust and scale from heat treating or welding. The hazards involved in this process should be investigated before using. |
| SILVER | ALL | AMS 2410, AMS 2411 & AMS 2412 QQ-S-365s/s ASTM B 700
TYPE I - Matte
TYPE II - Semi bright
*TYPE III - Bright G
GRADE B - Without supplementary tarnish-resistant treatment
ASTM B 700
TYPE I - III - Purity GRADE A - Matte GRADE D - Semi bright
*GRADE B + C - Bright
CLASS N - no tarnish resistant
CLASS S - with tarnish resistant | .0005 unless otherwise specified. Suggested are .0003 for soldering parts: .0005 for corrosion protection of nonferrous basis metals. See REMARKS | Excellent conductivity. Application of light water dip lacquer or tarnish-resistant treatment per GRADE A does not impair solderability. Greatly increases conductivity of lesser metals. Ferrous basis surfaces require an undercoat of .0005 comprised of copper or nickel or any combination. Nickel undercoat is advantageous when corrosion protection is important. |
| SOLID FILM LUBRICANT | ALL | AS-5272 TYPE I, TYPE II
MIL-PRF-46010 TYPE III
MIL-L-23398
MIL-L-45983
MIL-L-81329
MIL-L-85614 | .0003-.0005 Dull gray to black | Pretreatment compatible with the base material is normally necessary (i.e.; anodize, chemical film, blasting and phosphate etc.) Low co-efficient of friction reduces wear, prevents galling and seizing. Excellent fluid and corrosion resistance when used in conjunction with pretreatment. |
| SULFAMATE NICKEL | ALL | +QQ-N-290s/sAMS-QQ-290
CLASS 2 | .002-.003 or as specified Semi-bright | Low stressed nickel deposit. Used for wear and abrasion resistance. Also, for heavy buildups on worn parts and for salvage purposes. |
| TESTING (for lot acceptance) | ALL PLATED AND UNPLATED | ASTM B 117 - Salt Spray MIL-STD-753 *METHOD 100 - Humidity METHOD 101 - Water immersion METHOD 102 - Copper sulfate Also applicable process specifications | No dimensional change Salt spray is considered a "destructive" test. | These tests are designed to verify the integrity of various metals and metal surface finishes. The salt spray method is used extensively for testing of anodize, chemical films, and plated metal coatings. The salt spray, humidity, water immersion, and copper sulfate methods are used to check on the passivity of stainless steel after the passivation process. |
