| PROCESS |
MIL.SPEC |
THICKNESS |
COMMENTS |
| BLACK
CHROME |
MIL-C-14538 |
. |
. |
| |
|
As specified on drawing |
Color is a dull gray, approaching
black. |
| The Black Chrome surface may be waxed
ot oiled to darken the surface. |
|
|
It shall approximate color plate 37038
of Fed Std No. 595 |
| BLACK
OXIDE COATING |
MIL-C-13924 |
. |
. |
| A uniform black coating for ferrous
metals. Mostly a decorative coating. Only very limited corrosion protection
under mild corrosion conditions. |
|
No dimensional range |
For moving parts which cannot tolerate
the dimensional change of a more corrosion resistant finish. For decorative
applications 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 normally
be given a supplemental treatment (i.e. oil displacement per MIL-C-16173
Grade 3 or protection treatments of MIL-C-16173). |
Class 3 |
|
Fused salt oxidizing. For corrosion
resistant steel alloys which are tempered at 900°F (482°C) or higher. |
| |
Class 4 |
|
Alkaline oxidizing. For 300 series
corrosion 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 II
finish. Type II shall show no surface corrosion products after 96 hours
(5%) salt spray exposure. Partrs with hardness greater than 40-Rc shall
be stressed relieved before cleaning and plating. Parts subject to flexure
(springs, etc.) over Rc-40 hardness, shall be given a 375° +- 25°F
post bake. |
Type I |
|
No Supplementary treatment |
| Type II |
|
Supplementary chromate treatment |
| Type III |
|
Supplementary phosphate treatment |
| Salt-Spray Test |
|
|
|
| Type II Class 1 Test Period
for 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 a
paint base. Excellent for plating stainless steels that are to be used
in conjuction with aluminium to prevent galvanic corrosion |
| Class 3 |
0002 min |
| CHEMICAL
FILMS |
MIL-C-5541 |
. |
. |
| Materials qualified produce
coatings that range in color from clear to iridescent yellow or brown.
Inspection difficulties may arise with clear coatings because visual inspection
does not reveal the presence of a coating. |
Class 1A |
|
Class 1A chemical conversion coatings
are intended to provide corrosion prevention when left unpainted as well
as to improve adhesionof paint finish systems on aluminum and aluminum
alloys. May be used on tanks, tubings, and components structures where
paint finishes are mot required for the exterior surfaces but are required
for the interior surfaces. |
| Class 3 |
|
Class 3 chemical conversion coatings
are intended for use as corrosion preventative film for electrical and
electronic applications where lower resistant contacts, releative Class
1A coatings, and anodic coatings wil MIL-A-, are required. Th eprimary
difference bewteen a Class 1A and Class 3 coating is thickness |
| CHEMICAL
FINISH; BLACK |
MIL-C-495 |
. |
. |
| A uniform black corrosion retardant
for copper. Coating has no abrasion resistance. |
|
|
|
| CHROME |
QQ-C-320 |
. |
. |
| Excellent hardness (Rc
68-74), wear resistant and erosion resistance. Has low coefficient of friction,
and is resistant to heat. In addition to above properties, can be rendered
porous 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 thickness
not specified, min thickness shall be 002 |
Engineering plating |
| Post bake at A89° for 3 hours
or as specified |
Class 2a |
|
Plated to Specified dimensions or
processsed to Specified dimensions after plating |
| Shot peening and post baking not required |
Class 2b |
|
Parts below Rockwell C40 and subject
to 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 subject
to unlimited life under dynamic loads |
| Post bake at 375° +- 25° for
3 hours |
Class 2d |
|
Parts have hardness of Rockwell C40
or above and subject to static loads or designed for limited life under
dynamic loads. |
| Shot peen before plating. Post bake
at 375° +- 25° for 3 hours |
Class 2e |
|
Parts have hardness of Rockwell C40
or above and designed for unlimited life under dynamic loads. |
| CHROMIC
ANODIZE |
MIL-A-8625 |
. |
. |
| Color will cary from light gray to
dark gray depending on alloy. Not as readily died as sulfuric anodize. |
Type 1A |
.00002" - .00007" |
Conventional coating produced from
chromic acid bath. Unless otherwise specified, coating wil be sealed. Metal
salt sealants should not be used on items that will be painted. |
| New salt spray requirements is 336
hours (5% solution per method B-117 of ASTM) |
Type 1B Class 1 |
|
Low voltage chromimic acid anodizing
20V 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 thiness
will scratch easily. Can be used for inspection of aluminum forgings or
castings by noting evidence of chromic acid bleed out from taps, cracks,
seams, etc. |
Class 2 |
|
Dyed Shall not be applied to alumium
alloys with over 5.0% copper, 7% silicon or total alloying constitution
over 7.5%. When Copper content is less than 4.6% and for all suitable castings
alloys be sure alumium is tempered (such as -T4 or -T6). |
| COPPER |
MIL-C-14550 |
. |
. |
| Copper in color and matte
to a very shiny finish. Good corrosion resitance when used as undercoat.
A number of copper processes are available, each designed for a specific
purpose. Brightness (to eliminate the need for buffing); High speed (for
electroforming); fine grain (to prevent casehardening); etc. |
|
Unless otherwise specified |
|
| Class 0 |
.001 - .005" |
For heat treatment stop-off |
| Class 1 |
.001" |
For carburizing
and 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 steel
in color. Plates uniformly in recesses and cavities (does not build up
on 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 tolerances
need uniformily provided by 'electroless" process). |
|
Unless otherwise specified |
|
| Class 1 |
Fe and Al alloys will
be grade A |
As coated |
| Class 2 |
Steel and other base metals heat treatable
to improve hardness |
| Class 3 |
Cu,Ni, Co alloys will be Grade B |
Aluminum and other base metals not
heat treatable |
| Class 4 |
|
Aluminum alloy , heat
treatable, processd to improve adheasion of the nickel deposit |
| Class A |
.0015" min |
| Class B |
.0005" min |
| GOLD |
MIL-G-45204 |
. |
. |
| Yellow to orange color
depending on proprietary process used. Will range from mattle to bright
finish depending on basis metal. Good corrosion resistance, and has high
tarnish 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, and
abrasion-resistant coating for magnesium. Suitable for use on all forms
and alloys of magnesium. The color of HAE shall be lustreless brown and
within range from number3010to 3035 of specification TT-C-595. The coating
shall 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 and
moist heat aging |
| Grade 5 |
|
Double application of Grade 4 post
treatment |
| Class D |
.0009" - .0016" |
Dark green coating * |
| HARD
ANODIZE |
MIL-A-8625 |
. |
. |
| Color will vary from light
tan to black depending on alloy and thickness. Can be dyed in darker colors
depending on thickness. Coating PENETRATES base metal as mush as builds
up on the surface. The term THICKNESS includes both buildup and the penetration.
provides very hard ceramic type coating. Abrasion resistance will vary
with alloy and thickness of coating goo dielectric properties. Corrosion
resistance is good, but recommend seal hard anodize in 5% dichromate solution
where increased corrosion abrasion resistance is required. Where extreme
abrasion resistance is required do not seal as some softening is encountered. |
Type III |
As specified on drawing. If not specified
normal thickness shall be 0.002" |
Most aluminum alloys depending on
process 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 and
may 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 galling
and seizure of metals. Lubricant covered by this specification is intended
for use on aluminum, copper, steel and stainless steel, titanium, and chromium
and nickel bearing surfaces. Useful where conventional lubricants are difficult
to apply or retain or where other lubricants may be easily contameasily
contaminated. cured lubricant film is highly resistant to conventional
fluid lubricants. |
|
Unless otherwise specified |
For sliding motion applications
such as plain and spherical bearingsm flap tracks, hinges, threads, cam
surfaces, etc. Do not use on materials adversely affected by exposure to
temperatures 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 finish
for almost any need. Nickel can be deposited soft or hard - dul or bright,
depending on processed used and conditions employed in plating. Thus hardness
can 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 resistance
is a function of thickness. Has a low coeffecient of thermal expansion
- is magnetic. All steel parts having a hardness of Rc-40 or greater require
a post bake at 375° +- 25°F for 3 hours. |
|
Total thickness of copper and nickel |
NOTE: All steel parts
having a tensile strength of 220,000 or greater shal not be nickel plated
without 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 to
remove foreign metals from the surface of stainless and corrosion resistant
steels and to promote natural tendency to surface to oxide. Does not change
the apperance of the base metal. Process purifies surface and therefore
improves 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 |
. |
. |
| |
|
|
Heavy coating for corrosion
and wear resist. |
| A coating for medium and
low alloy steels. Gray to brack in color. Type M is more resistant than
Type Z to alkaline enviroments. Type M can be used up to 250 F. Provides
moderate corrosion resistant and prevents wear. |
Type M |
.0002" - .0004" |
Manganese phoshate base coating (min
16g/m2 or 11g/m2 when specified)+D134 |
| Class 1 |
Supplementary preservative treatmentor
coating, as specified. |
| Class 2 |
Supplementary treatment with lubricating
oil conforming to MIL-L-3150 |
| Class 3 |
No supplementary treatment |
| Class 4 |
Chemically converted (may be dyed
to color as specified). With no supplementary coating or supplementary
coating as specified. |
| Type Z can be used up
tp 200 Fto prevent galling in extrusion and depp drawing. Class 2 is good
for corrosion resistance. |
Type Z |
.0002" - .0006" |
Zinc phosphate base coating (min 11g/m2) |
| Class 1 |
Supplementary preservative treatment
or coating, as specified |
| Class 2 |
Supplementary treatment with preservative
conforming to MIL-C-16173, Grade 1 or MIL-L-3150 as alternate for very
small parts). |
| Class 3 |
No supplementary treatment |
| Class 4 |
Chemically converted (may be dyed
to color as specified). With no supplementary coating or supplementary
coating as specified. |
| SILVER |
QQ-S-365 |
. |
. |
| White matte to very bright
in apperance. Good corrosion resisatnce, depending on base metal. Will
tarnish easily. Hardeness caries from about 90 Brinnell to about 135 Brinnell
depending on process and plating conditions. Solderability is excellent,
but decreases with age. Best electrical conductor. Has excellent lubricity
and 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 improve
tarnish resistance |
| Grade B |
|
No chromate treatment |
| SULFAMATE
NICKEL |
MIL-P-27418 |
. |
. |
| The plating conforming
to this specification is intended to facillitate the formation of a seal
between two metallic surfaces. PLATING HARDNESS not to exceed 150 Knoop
hardness (500gm. Load) after annealling. |
|
Unless otherwise specified |
|
| |
.0020" |
|
| |
"+-" ".0003" |
The nickel plating shall have columnar
crystalline 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 color
or shade (Black, blu, red, etc.) |
Type II |
.00020" - .0010" |
All aluminium alloys, but do not use
where solutions will entrap. |
| |
FED-STD No 595 may be used as a guide
for specifying color (approximate comparison only) |
| Salt Spray requirement
is 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 and
castings with 1% or greater copper min cfg. Wf. Shall be 1400 milligrams
sq-ft. |
| TIN |
MIL-T-10727 |
. |
|
| Color is gray-white in
a plated condition. Had very high luster in fused conditions. Soft, but
is very ductile. Corrosion resistance is good. (Coated items should meet
24 hour 5% salt spray requirements.) Salderability is excellent. Tin is
not good for low temperature applications 9changes structure and loses
adhesion when exposed to temperature below 40 C). |
|
As specified on drawing. Thickness
guide not part of Spec. |
Electrodeposited. Use ASTM-B 545 |
| Type I |
|
Standard specification |
| Type II |
|
Hot dipped |
| If a bright finish is
desired to be used in lieu of fused tin, specify Bright Tin plate. Thickness
ness can exceed that of fused tin and deposit shows excellent corrosion
resistance 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 during
nitriding |
| ZINC |
ASTMB633-85 |
. |
. |
| Either a bright or dull
finish 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 because
of the galvanic protection of the zinc. On weathering, zinc turns to a
drab color. Zinc should be deposited directly on the base metal (Nickel
is permissible undercoat if base metal is a corrosion resisting steel).
Parts having a hardness greater that Rc-40 must be given a heat treatment
prior to plating. Springs having a hardness over Rc-40 must be given an
after plating baking of 375° +- 25°F for 3 hours. |
Fe/Zn25 SC4 |
.0010" |
The primary use of chromate
finishes on zinc is to retard or prevent formation of white corrosion products
on zinc surfaces |
| Fe/Zn13 SC3 |
.00050" |
| Fe/Zn8 SC2 |
.00030" |
The primary purpose of
phospate 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 chromate
treatment |
| Type IV |
|
With phosphate conversion treatment |
| |
|
Corrosion resistance requirements
Type II 96 Hours Type III 12 Hours |
| ZINC
NICKEL |
AMS-2417 BAC-5637 |
. |
. |
| Dull matte gray or green
irridescent. Type II acid or alkaline process. Excellent alternative for
cadmium plate requirements. Meets and exceeds 96 hours salt spray test. |
|
.0005" min |
No supplementary treatment
or supplementary chromate treatment. |
| |
.0003" min |
| |
.0002" min |