Coatings and Surface Treatments - Coating and Surface Treatment Options

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Extension Springs

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Torsion Springs

About Design Theory General Design Considerations Leg Configurations

REDUX™ Wave Springs

About Terminology General Design Considerations

Constant Force Springs

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Belleville Washers

About Stacking Formulas Additional Design Information

Material Selection Guide

Ferrous Metals Carbon Steel Alloy Steels Stainless Steels Precipitation-Hardening Stainless Steel Exotic Alloys Non-Ferrous Metals Spring Materials (Round Wire)

Coatings and Surface Treatments

About Electropolishing Tumbling Shot Peening Electroplating Electroless Plating Chemical Coatings Coating and Surface Treatment Options

Glossary of Terms

Coating and Surface Treatment Options

Process	Commercial Specifications	Classes Available	Finishes/Grades Available	Chromate Conversion Colors Available	Primary Purpose
Platings
Cadmium Plating	QQ-P-416 AMS-QQ-P-416	Class I - 0.0005" minimum thickness Class II - 0.0003" minimum thickness Class III - 0.0002" minimum thickness	Type I - As plated Type II - With chromate treatment Type III - With phosphate treatment	Colorless Irridescent Bronze Brown Olive Drab Yellow Forrest Green	Primarily used to protect steel and cast iron against corrosion.
Chrome Plating	QQ-C-320 AMS-QQ-C-320	Class I - Corrosion protective plating Class II - Engineering plating	Type I - Bright Finish Type II - Satin Finish	-	The metal so produced is extremely hard and corrosion resistant. The process is used for applications where excellent wear and/or corrosion resistance is required.
Copper Plating	MIL-C-14550B AMS 2418	Class 0 - 0.001" - 0.005" Thickness Class 1 - 0.001" minimum thickness Class 2 - 0.0005" minimum thickness Class 3 - 0.0002" minimum thickness Class 4 - 0.0001" minimum thickness	-	-	Good corrosion resistance and conductivity.
Gold Plating	MIL-G-45204C	Class 00 - 0.00002" minimum thickness Class 0 - 0.00003" minimum thickness Class 1 - 0.00005" minimum thickness Class 2 - 0.0001" minimum thickness Class 3 - 0.0002" minimum thickness Class 4 - 0.0003" minimum thickness Class 5 - 0.0005" minimum thickness Class 6 - 0.0015" minimum thickness	Type I - 99.7% gold minimum Type II - 99.0% gold minimum Grade A - 90 Knoop maximum Grade B - 91 - 129 Knoop Grade C - 130 - 200 Knoop Grade D - 201 Knoop and over	-	Good corrosion resistance and high tarnish resistance. Solderability and conductivity are excellent.
Nickel Plating	QQ-N-290 AMS-QQ-N-290	Class I - Corrosion protective plating Class II - Engineering plating	Class I - Grade A through G (0.0016" - 0.0002" Thickness)	-	Used extensively for decorative, engineering, and electroforming purposes.
Silver Plating	QQ-S-365D ASTM B700	Grade A - Chromate post-treatment Grade B - No supplementary treatment	Type I - Matte finish Type II - Semi-bright finish Type III - Bright finish	-	Good corrosion resistance and will tarnish easily. Solderability and conductivity are excellent.
Tin Plating	ASTM B545 MIL-T-10727C	Type I - Electroplated Type II - Hot dipped	-	-	Good corrosion resistance and excellent solderability.
Vacuum Cadmium	MIL-C-8837B AMS-C-8837	Class I - 0.0005" minimum thickness Class II - 0.0003" minimum thickness Class III - 0.0002" minimum thickness	Type I - As plated Type II - With chromate treatment Type III - With phosphate treatment	Colorless Irridescent Bronze Brown Olive Drab Yellow Forrest Green	Primarily used to provide corrosion resistance to parts free from hydrogen contamination and possible embrittlement.
Zinc Plating	ASTM B633	Service Condition 1 (Fe/Zn 5) - mild conditions, 5mm thickness Service Condition 2 (Fe/Zn 8) - moderate conditions, 8mm thickness Service Condition 3 (Fe/Zn 12) - severe conditions, 12mm thickness Service Condition 4 (Fe/Zn 25) - very severe conditions, 25mm thickness	Type I - As plated Type II - Colored chromate conversion coatings Type III - Colorless chromate conversion coatings Type IV - Phosphate conversion coating	Colorless Blue Olive Drab Yellow	Good corrosion resistance.
Chemical Conversion Coatings
Black Oxide	MIL-C-13924	Class 1 - Alkaline oxidizing process Class 2 - Alkaline chromate oxidizing Class 3 - Fused salt oxidizing process Class 4 - Alkaline oxidizing process	Supplementary oil treatment per MIL-C-16173	-	A uniform, mostly decorative black coating. Limited corrosion resistance.
Phosphate Coating (Light)	TT-C-490E	-	Type I - Zinc phosphate spray application Zinc phosphate immersion or dip application Type II - Aqueous iron phosphate Type III - Organic pretreatment coating (MIL-C-8514) Type IV - Discontinued Type V - Zinc phosphate	-	Type I - All-purpose pretreatment prior to painting Type II and IV - For parts to be formed after painting Type III - Size and shape preclude Type I, II, IV Type V - Zinc phosphate
Phosphate Coating (Heavy)	MIL-DTL-16232G	Class 1 (Type M/Z) - Supplementary preservative treatment or coating Class 2 (Type M) - Supplementary treatment with lubricating oil Class 2 (Type Z) - Supplementary treatment with preservative Class 3 (Type M/Z) - No supplementary treatment Class 4 (Type M/Z) - Chemically converted (may be dyed to color as specified)	Type M - Manganese Phosphate Base Type Z - Zinc Phosphate Base	-	Coating for medium and low alloy steels. Intended as a base for supplemental coatings which provide the major portion of corrosion resistance.
Electroless Plating
Electroless Nickel	MIL-C-26074F AMS 2404C AMS 2405B	Class 1 - As plated Class 2 - Heat treated	Grade A - 0.001" minimum thickness Grade B - 0.0005" minimum thickness Grade C - 0.0015" minimum thickness	-	Used to deposit nickel without the use of an electric current.
Lubrication
Solid Film Lubrication	MIL-L-46010	-	Color 1 - Natural product color Color 2 - Black	-	Used to reduce wear and prevent galling, corrosion, and seizure of metals.