| PROCESS |
MIL.SPEC |
THICKNESS |
COMMENTS |
| BLACK CHROME |
MIL-C-14538 |
|
|
|
|
As specified on drawing |
Color is a dull gray, approachingblack. |
| The Black Chrome surface may be waxed or oiled to darken the surface. |
|
|
It shall approximate color plate 37038of Fed Std No. 595 |
| BLACK OXIDE COATING |
MIL-C-13924 |
|
|
| A uniform black coating for ferrousmetals. Mostly a decorative coating. Only very limited corrosion protectionunder mild corrosion conditions. |
|
No dimensional range |
For moving parts which cannot toleratethe dimensional change of a more corrosion resistant finish. For decorativeapplications and can be used to decrease light reflection. |
|
Class 1 |
|
Alkaline oxdizing. For wrought iron,cast and malleable irons, plain carbon and low alloy steels. |
| Black oxide coatings should normallybe given a supplemental treatment (i.e. oil displacement per MIL-C-16173Grade 3 or protection treatments of MIL-C-16173). |
Class 3 |
|
Fused salt oxidizing. For corrosionresistant steel alloys which are tempered at 900°F (482°C) or higher. |
|
Class 4 |
|
Alkaline oxidizing. For 300 seriescorrosion resistant steel alloys only. |
| CADMIUM |
QQ-P-416 |
|
|
| Bright silvery white.Supplementary treatment for Type II can be golden, irdescent, amber, black,olive drab. Corrosion resistance is very good, especially with Type IIfinish. Type II shall show no surface corrosion products after 96 hours(5%) salt spray exposure. Partrs with hardness greater than 40-Rc shallbe stressed relieved before cleaning and plating. Parts subject to flexure(springs, etc.) over Rc-40 hardness, shall be given a 375° +- 25°Fpost bake. |
Type I |
|
No Supplementary treatment |
| Type II |
|
Supplementary chromate treatment |
| Type III |
|
Supplementary phosphate treatment |
| Salt-Spray Test |
|
|
|
| Type II Class 1 Test Periodfor White Corrosion Products (Hours) 96 Hours |
Class 1 |
0005 min |
Type II best for corrosion resistance |
| Class 2 |
0003 min |
Type III is used as apaint base. Excellent for plating stainless steels that are to be usedin conjuction with aluminium to prevent galvanic corrosion |
| Class 3 |
0002 min |
| CHEMICAL FILMS |
MIL-C-5541 |
|
|
| Materials qualified producecoatings that range in color from clear to iridescent yellow or brown.Inspection difficulties may arise with clear coatings because visual inspectiondoes not reveal the presence of a coating. |
Class 1A |
|
Class 1A chemical conversion coatingsare intended to provide corrosion prevention when left unpainted as wellas to improve adhesionof paint finish systems on aluminum and aluminumalloys. May be used on tanks, tubings, and components structures wherepaint finishes are mot required for the exterior surfaces but are requiredfor the interior surfaces. |
| Class 3 |
|
Class 3 chemical conversion coatingsare intended for use as corrosion preventative film for electrical andelectronic applications where lower resistant contacts, releative Class1A coatings, and anodic coatings wil MIL-A-, are required. Th eprimarydifference bewteen a Class 1A and Class 3 coating is thickness |
| CHEMICAL FINISH: BLACK |
MIL-C-495 |
|
|
| A uniform black corrosion retardantfor copper. Coating has no abrasion resistance. |
|
|
|
| CHROME |
QQ-C-320 |
|
|
| Excellent hardness (Rc68-74), wear resistant and erosion resistance. Has low coefficient of friction,and is resistant to heat. In addition to above properties, can be renderedporous for lubrication purposes |
Type I |
|
Bright. |
| Type II |
|
Satin. |
| Class 1 |
00001 min on all visible surfaces |
Corrosion protection plating |
| Class 2 |
As specified on drawing. If thicknessnot specified, min thickness shall be 002 |
Engineering plating |
| Post bake at A89° for 3 hoursor as specified |
Class 2a |
|
Plated to Specified dimensions orprocesssed to Specified dimensions after plating |
| Shot peening and post baking not required |
Class 2b |
|
Parts below Rockwell C40 and subjectto static loads or designed for limited life under dynamic loads |
| Shot peen per MIL-S-13165 or MIL-R-8141 |
Class 2c |
|
Parts below Rockwell C40 and subjectto unlimited life under dynamic loads |
| Post bake at 375° +- 25° for3 hours |
Class 2d |
|
Parts have hardness of Rockwell C40or above and subject to static loads or designed for limited life underdynamic loads. |
| Shot peen before plating. Post bakeat 375° +- 25° for 3 hours |
Class 2e |
|
Parts have hardness of Rockwell C40or above and designed for unlimited life under dynamic loads. |
| CHROMICANODIZE |
MIL-A-8625 |
|
|
| Color will cary from light gray todark gray depending on alloy. Not as readily died as sulfuric anodize. |
Type 1A |
.00002″ – .00007″ |
Conventional coating produced fromchromic acid bath. Unless otherwise specified, coating wil be sealed. Metalsalt sealants should not be used on items that will be painted. |
| New salt spray requirements is 336hours (5% solution per method B-117 of ASTM) |
Type 1B Class 1 |
|
Low voltage chromimic acid anodizing20V Non-dyed (Natural including dichromate seatings). |
| Minimum weight for Type I coatings:Class 1 200 Miligrams sq ft. Class 2 600 Milligrams sq ft. Because of thinesswill scratch easily. Can be used for inspection of aluminum forgings orcastings by noting evidence of chromic acid bleed out from taps, cracks,seams, etc. |
Class 2 |
|
Dyed Shall not be applied to alumiumalloys with over 5.0% copper, 7% silicon or total alloying constitutionover 7.5%. When Copper content is less than 4.6% and for all suitable castingsalloys be sure alumium is tempered (such as -T4 or -T6). |
| COPPER |
MIL-C-14550 |
|
|
| Copper in color and matteto a very shiny finish. Good corrosion resitance when used as undercoat.A number of copper processes are available, each designed for a specificpurpose. Brightness (to eliminate the need for buffing); High speed (forelectroforming); fine grain (to prevent casehardening); etc. |
|
Unless otherwise specified |
|
| Class 0 |
.001 – .005″ |
For heat treatment stop-off |
| Class 1 |
.001″ |
For carburizingand decarburizing shield, also plated through printed circuit boards |
| Class 2 |
| Class 3 |
.0005″ |
|
| Class 4 |
.0002″ .0001″ |
|
| ELECTROLESS NICKEL |
MIL-C-26074 |
|
|
| Similar to stainless steelin color. Plates uniformly in recesses and cavities (does not build upon edges) Corrosion resistance is good for coating over .001″ thickness.Electroless nickel is used extensively in salvage of mis-machines parts.Also, for inside dimensions and irregular shapes (where assembly tolerancesneed uniformily provided by ‘electroless” process). |
|
Unless otherwise specified |
|
| Class 1 |
Fe and Al alloys willbe grade A |
As coated |
| Class 2 |
Steel and other base metals heat treatableto improve hardness |
| Class 3 |
Cu,Ni, Co alloys will be Grade B |
Aluminum and other base metals notheat treatable |
| Class 4 |
|
Aluminum alloy , heattreatable, processd to improve adheasion of the nickel deposit |
| Class A |
.0015″ min |
| Class B |
.0005″ min |
| GOLD |
MIL-G-45204 |
|
|
| Yellow to orange colordepending on proprietary process used. Will range from mattle to brightfinish depending on basis metal. Good corrosion resistance, and has hightarnish resistance. Provides a low contact resistance, and is a good conductor.Has excellent solderability |
|
Unless otherwise specified |
|
| Type I |
|
99.7% gpld min |
| Type II |
|
99.0% gold min |
| Type III |
|
99.9% gold min |
| Class 00 |
.00002″ min |
Grade A 90 Knoop max |
| Class 0 |
.00003″ min |
Grade B 91-129 Knoop |
| Class 1 |
.00005″ min |
Grade C 130-200 Knoop |
| Class 2 |
.00010″ min |
Grade D 201 Knoop and over |
| Class 3 |
.00020″ min |
|
| Class 4 |
.00030″ min |
Type I (Grade A, B, or C) |
| Class 5 |
.00050″ min |
Type II (Grade B, C, or D) |
| Class 6 |
.00150″ min |
Type III (Grade A only) |
| HAE |
MIL-M-45202 |
|
|
| A corrosion, heat, andabrasion-resistant coating for magnesium. Suitable for use on all formsand alloys of magnesium. The color of HAE shall be lustreless brown andwithin range from number3010to 3035 of specification TT-C-595. The coatingshall be able to withstand a 20% alt spray exposure of 196 hours. |
Type 1 |
Increase per side |
Light coating |
| Class A |
.0001″ – .0002″ |
Tan coating |
| Grade 1 |
Without post treatment |
| Grade 2 |
With Bifluoride-didriomate treatment |
| Class C |
.0001″ – .0005″ |
Light green coating |
| Type II |
Heavy coating |
| Class A |
.0013″ – .0017″ |
Hard brown coating |
| Grade 1 |
|
Without post treatment |
| Grade 3 |
|
With bifluoride-dichromate seal |
| Grade 4 |
|
With bifluoride-dichromate seal andmoist heat aging |
| Grade 5 |
|
Double application of Grade 4 posttreatment |
| Class D |
.0009″ – .0016″ |
Dark green coating * |
| HARD ANODIZE |
MIL-A-8625 |
|
|
| Color will vary from lighttan to black depending on alloy and thickness. Can be dyed in darker colorsdepending on thickness. Coating PENETRATES base metal as mush as buildsup on the surface. The term THICKNESS includes both buildup and the penetration.provides very hard ceramic type coating. Abrasion resistance will varywith alloy and thickness of coating goo dielectric properties. Corrosionresistance is good, but recommend seal hard anodize in 5% dichromate solutionwhere increased corrosion abrasion resistance is required. Where extremeabrasion resistance is required do not seal as some softening is encountered. |
Type III |
As specified on drawing. If not specifiednormal thickness shall be 0.002″ |
Most aluminum alloys depending onprocess used. Where maximium serviceability or special properties are required,consult metal finisher for best alloy choice. Thick coatings (over .004″)will tend to break down sharp edges. Typical applications, hydraulic cylinders,wear surfaces, actualic cylinders, wear surfaces, actuating cama, etc.Can be used instead of conventional anodixe for corrosion resistance andmay be more economical in conjuction with other hard anodized areas. |
| Class 1 |
|
Non-dyed |
| Class 2 |
|
Dyed |
| LUBRICANT, SOLID FILM |
MIL-L-8937 |
|
|
| Used to prevent gallingand seizure of metals. Lubricant covered by this specification is intendedfor use on aluminum, copper, steel and stainless steel, titanium, and chromiumand nickel bearing surfaces. Useful where conventional lubricants are difficultto apply or retain or where other lubricants may be easily contameasilycontaminated. cured lubricant film is highly resistant to conventionalfluid lubricants. |
|
Unless otherwise specified |
For sliding motion applicationssuch as plain and spherical bearingsm flap tracks, hinges, threads, camsurfaces, etc. Do not use on materials adversely affected by exposure totemperatures of 300 F for 1 hour – on bearings containing rolling elements- or where tehre is potential contact with liquid oxygen |
| .0002″ – .0005″ |
| NICKEL |
QQ-N-290 |
|
|
| There is a nickel finishfor almost any need. Nickel can be deposited soft or hard – dul or bright,depending on processed used and conditions employed in plating. Thus hardnesscan range from 15-500 Vickers. Can be similar to stainless steel in color,or can be a dull gray or light gray (almost white) color. Corosion resistanceis a function of thickness. Has a low coeffecient of thermal expansion- is magnetic. All steel parts having a hardness of Rc-40 or greater requirea post bake at 375° +- 25°F for 3 hours. |
|
Total thickness of copper and nickel |
NOTE: All steel partshaving a tensile strength of 220,000 or greater shal not be nickel platedwithout specific approval of procuring agency. For Corrosion protection |
| Class 1 |
|
| Grade A |
.0016″ |
| Grade B |
.0012″ |
| Grade C |
.0010″ |
| Grade D |
.0008″ |
| Grade E |
.0006″ |
| Grade F |
.0004″ |
| Grade G |
.0002″ |
| Class 2 |
|
For engineering applications |
| PASSIVATE |
MIL-S-5002 |
|
|
| A process designed toremove foreign metals from the surface of stainless and corrosion resistantsteels and to promote natural tendency to surface to oxide. Does not changethe apperance of the base metal. Process purifies surface and thereforeimproves corrosion resistance. |
Type I |
No dimensional change |
Low temperature |
| Type II |
Medium temperature |
| Type III |
High temperature |
| Type IV |
For steels containing large amounts(0.15 percent) of surfur or selenium. |
| Type V |
Anodic – For high carbon martensitic(440) steels |
| Type VI |
Low temperature (optional) |
| PHOSPHATE COATING: HEAVY |
DOD-P-16232 |
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|
|
|
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Heavy coating for corrosionand wear resist. |
| A coating for medium andlow alloy steels. Gray to brack in color. Type M is more resistant thanType Z to alkaline enviroments. Type M can be used up to 250 F. Providesmoderate corrosion resistant and prevents wear. |
Type M |
.0002″ – .0004″ |
Manganese phoshate base coating (min16g/m2 or 11g/m2 when specified)+D134 |
| Class 1 |
Supplementary preservative treatmentorcoating, as specified. |
| Class 2 |
Supplementary treatment with lubricatingoil conforming to MIL-L-3150 |
| Class 3 |
No supplementary treatment |
| Class 4 |
Chemically converted (may be dyedto color as specified). With no supplementary coating or supplementarycoating as specified. |
| Type Z can be used uptp 200 Fto prevent galling in extrusion and depp drawing. Class 2 is goodfor corrosion resistance. |
Type Z |
.0002″ – .0006″ |
Zinc phosphate base coating (min 11g/m2) |
| Class 1 |
Supplementary preservative treatmentor coating, as specified |
| Class 2 |
Supplementary treatment with preservativeconforming to MIL-C-16173, Grade 1 or MIL-L-3150 as alternate for verysmall parts). |
| Class 3 |
No supplementary treatment |
| Class 4 |
Chemically converted (may be dyedto color as specified). With no supplementary coating or supplementarycoating as specified. |
| SILVER |
QQ-S-365 |
|
|
| White matte to very brightin apperance. Good corrosion resisatnce, depending on base metal. Willtarnish easily. Hardeness caries from about 90 Brinnell to about 135 Brinnelldepending on process and plating conditions. Solderability is excellent,but decreases with age. Best electrical conductor. Has excellent lubricityand smear characteristics for anti-galling uses on static seals, bushings,etc. |
|
.0005″ min unless otherwise specified |
|
| Type I |
|
Matte |
| Type II |
|
Semi-bright |
| Type III |
|
Bright |
| Grade A |
|
Chromate post-treatment to improvetarnish resistance |
| Grade B |
|
No chromate treatment |
| SULFAMATE NICKEL |
MIL-P-27418 |
|
|
| The plating conformingto this specification is intended to facillitate the formation of a sealbetween two metallic surfaces. PLATING HARDNESS not to exceed 150 Knoophardness (500gm. Load) after annealling. |
|
Unless otherwise specified |
|
|
.0020″ |
|
|
“+-” “.0003” |
The nickel plating shall have columnarcrystalline structure before anneating. |
| SULFURIC ANODIZE |
MIL-A-8625 |
|
|
| Color will vary with alloy.Aluminum with low alloying elements will show practically no color change.Best coating on aluminium for dyeing. Can be dyed practically any coloror shade (Black, blu, red, etc.) |
Type II |
.00020″ – .0010″ |
All aluminium alloys, but do not usewhere solutions will entrap. |
|
FED-STD No 595 may be used as a guidefor specifying color (approximate comparison only) |
| Salt Spray requirementis 336 hours (5% solution per method ASTM-B-117) |
Class 1 |
|
Non-dyed |
| Class 2 |
|
dyed |
| Minium weight for Type II coatings:Class 1: 600 Milligrams sq-ft. Class 2: 2500 Milligrams sq-ft. |
|
|
NOTE: For wrought 2000 series andcastings with 1% or greater copper min cfg. Wf. Shall be 1400 milligramssq-ft. |
| TIN |
MIL-T-10727 |
|
|
| Color is gray-white ina plated condition. Had very high luster in fused conditions. Soft, butis very ductile. Corrosion resistance is good. (Coated items should meet24 hour 5% salt spray requirements.) Salderability is excellent. Tin isnot good for low temperature applications 9changes structure and losesadhesion when exposed to temperature below 40 C). |
|
As specified on drawing. Thicknessguide not part of Spec. |
Electrodeposited. Use ASTM-B 545 |
| Type I |
|
Standard specification |
| Type II |
|
Hot dipped |
| If a bright finish isdesired to be used in lieu of fused tin, specify Bright Tin plate. Thicknessness can exceed that of fused tin and deposit shows excellent corrosionresistance and solderability. |
|
.0001″ – .00025″ |
Flash for soldering |
| .0002″ – .0004″ |
To prevent galling and seizing |
| .0003″ min |
Where corrosion resistance is important |
| .0002′ – .0006″ |
To preventformation of case duringnitriding |
| ZINC |
ASTMB633-85 |
|
|
| Either a bright or dullfinish is acceptable. Bright Zinc plating closely resembles bright chromium.However, bright zinc does not have the permanence of surface appearance.Zinc coated steel will not rust even when exposed by scratches becauseof the galvanic protection of the zinc. On weathering, zinc turns to adrab color. Zinc should be deposited directly on the base metal (Nickelis permissible undercoat if base metal is a corrosion resisting steel).Parts having a hardness greater that Rc-40 must be given a heat treatmentprior to plating. Springs having a hardness over Rc-40 must be given anafter plating baking of 375° +- 25°F for 3 hours. |
Fe/Zn25 SC4 |
.0010″ |
The primary use of chromatefinishes on zinc is to retard or prevent formation of white corrosion productson zinc surfaces |
| Fe/Zn13 SC3 |
.00050″ |
| Fe/Zn8 SC2 |
.00030″ |
The primary purpose ofphospate coating on zinc is to provide a paint base |
| Fe/Zn5 SC1 |
.00020″ |
| Type I |
|
Without supplementary treatments |
| Type II |
|
With supplementary chromate treatment |
| Type III |
|
With supplementary colorless chromatetreatment |
| Type IV |
|
With phosphate conversion treatment |
|
|
Corrosion resistance requirementsType II 96 Hours Type III 12 Hours |
| ZINC NICKEL |
AMS-2417 BAC-5637 |
|
|
| Dull matte gray or greenirridescent. Type II acid or alkaline process. Excellent alternative forcadmium plate requirements. Meets and exceeds 96 hours salt spray test. |
|
.0005″ min |
No supplementary treatmentor supplementary chromate treatment. |
|
.0003″ min |
|
.0002″ min |
