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Technical Notes

Please include as many of below as possible when issuing a Purchase Order

  • FED-QQ-N-290C
  • Class of plating
  • Grade of Class 1 plating if applicable
  • Basis metal to be plated
  • Tensile strength or hardness of basis metal
  • Preplate stress relief to be performed by AOTCO (time and temp)
  • Underplating required of class 1 plating (if required)
  • Control record if required
  • Sampling plan
  • Number of samples for destructive testing
  • Unique features, geometry or processing present on parts that requires special attention by AOTCO
  • Hydrogen embrittlement relief to be performed by AOTCO (parameters or reference document)
  • If plating is subject to mild or moderate service conditions
  • Quantity of pieces to be plated

Class 1 plating (commonly referred to as decorative plating) shall be of the following grades, as specified

  • Grade A - 0.0016 inch thick (1600microinches)
  • Grade B - 0.0012 inch thick (1200microinches)
  • Grade C - 0.0010 inch thick (1000microinches)
  • Grade D - 0.0008 inch thick (800microinches)
  • Grade E - 0.0006 inch thick (600microinches)

  • Grade F - 0.0004 inch thick (400microinches)

  • Grade G - 0.0002 inch thick (200microinches)

Cu alloys must be between Grade A and Grade D.

Ferrous metals, Zn and Zn alloys must be between Grade A and Grade C.

Class 2 Nickel Plating Thickness shall be 2-3mils, if left unspecified by the customer.


Stress Relief Treatment

All steel parts having a hardness of 40 HRC and above and that are machined, ground, cold formed or cold straightened after heat treatment shall be cleaned to remove surface contamination and thermally stress relieved before plating. Temperatures to which parts are heated shall be such that stress relief is obtained while still maintaining hardness of parts. Unless otherwise specified, the following treatment temperatures and times shall be used:

For parts, excluding nitride parts, having a hardness of 55 HRC and above, and for carburized and induction hardened parts, stress relieve at 275 °F ± 25 (135 °C ± 14) for 5 to 10 hours.

For parts having a hardness less than 55 HRC, and for nitride parts, stress relieve at 375 °F ± 25 (191 °C ± 14) for a minimum of 4 hours.

For peened parts: If stress relief temperatures above 375 °F (191 °C) are elected, the stress relieve shall be performed prior to peening or AOTCO must be consulted and shall approve the stress relief temperature.

Embrittlement Relief - Steel parts plated to this specification MUST be subjected to a hydrogen embrittlement relief bake

Surface Finish – unless otherwise specified, either a fully bright, semi-bright, or dull shall be acceptable

Class 1 Plating

Used to protect iron, copper, or zinc alloys against corrosion attack in rural, industrial, or marine atmospheres depending upon the thickness of the nickel deposit. Also typically used as an undercoat for chromium or other precious metals. Class one is also used for decorative purposes.

Class 1 can be plated in the following forms:

  • Single layer coating in fully bright finish
  • Single layer coating in dull or semi-bright finish
  • Multilayer coating, either double or triple layer. Specific factors that need to be considered when plating a multilayer piece include sulfur content and thickness of each deposited layer.

Class 2 Plating

Used for wear resistance, abrasion resistance, and corrosion protection of parts. Heavy deposits of Class 2 Plating may be used for buildup of worn or undersized parts, salvage purposes, or protection against corrosive chemical environments.


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Services & Capabilities

Plating Substrates
Pre- & Post-Process Treatments
Dedicated Outsourced Finishing



Electroplating is a process by which one metal is deposited onto a base metal (substrate). These deposited metals offer a variety of benefits including thermal and electrical conductivity, corrosion resistance and more. AOTCO electroplates a wide variety of both standard and exotic metals.

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Sometimes called a “conversion coating” Anodizing is an electrolytic process in which an oxide (anodic) layer is chemically built on the surface of the substrate material, providing anti-corrosion and other benefits. AOTCO offers, Type I, Type 2, Type 3 and Titanium anodizing services.

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Passivation is a term for a variety if processes that make a metal (most commonly stainless steel) or other substance unreactive, or passive, by altering the surface layer or coating the surface with a thin inert layer. AOTCO performs both citric and black oxide passivation techniques to a range of specifications.

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Plating Substrates

Plating Substrates

AOTCO plates on a wide variety of Common, Exotic and Non-Metallic substrates, bringing exceptional expertise to magnesium, titanium, beryllium, BeCu, TeCu, tungsten and more. In some cases we pass as high as 450 degrees celsius, allowing for high temperature soldering, brazing, or post machining operations after plating.

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Pre- & Post-Process Treatments

Pre- & Post-Process Treatments

Pre-Process: In addition to offering both mechanical & chemical cleaning options, AOTCO specializes in creating solutions for complicated, difficult and tight-tolerance masking challenges. Post-Process: For clients with specialized needs AOTCO offers laser marking and engraving options, including color change caused by chemical or molecular changes, charring, foaming, melting, ablation, and more.

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Dedicated Outsourced Finishing

Dedicated Outsourced Finishing

Part of our cornerstone goal of building long-term, collaborative & solution-oriented partnerships, AOTCO will devote reserved physical and human resource capacity for our clients with long-term finishing and deadline requirements. For these partnerships our commitment is that AOTCO manages the process, while YOU control the results.

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