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MIL-G-45204
Specifications

Technical Notes

With MIL-G-45204, there are several properties that are associated with the part finish

  1. Type – Percentage of gold in the deposit
    1. Type I – 99.7% gold
    2. Type II – 99.0% gold
    3. Type III – 99.9% gold
  2. Hardness Grades – Deposited gold’s resistance to a localized deformation force
    Grade A (90 Knoop) Grade B (91-129 Knoop)
    Grade C (130-200 Knoop) Grade D (201+ Knoop)
  3. Relationship between Type and Hardness:
    Since more impurity results in higher hardness values, the following are acceptable combinations per MIL-G-45204:
    1. Type I (99.7% gold) can be Hardness Grade A (90 Knoop), B (91-129 Knoop), or C (130-200 Knoop)
    2. Type II (99% gold) can be Hardness Grade B (91-129 Knoop), C (130-200), or D (201+ Knoop)
    3. Type III (99.9% gold) can ONLY be Hardness Grade A (90 Knoop)
  4. Gold Class – MINIMUM gold thickness required
    NOTE: Any Gold Class is acceptable and must be specified by the customer.
    1. Class 00 – 20 microinches
    2. Class 0 - 30 microinches
    3. Class 1 - 50 microinches
    4. Class 2 - 100 microinches
    5. Class 3 - 200 microinches
    6. Class 4 - 300 microinches
    7. Class 5 - 500 microinches
    8. Class 6 - 1500 microinches

Example: How to interpret the blueprint note “Type I, Grade A, Class 3”

99.7% gold, 90 Knoop Hardness, 200 microinch thick gold deposit

Strikes and Underplating

Silver or copper plus silver may not be used as an underplate. When gold is applied to a copper rich surface such as brass, copper, bronze, or beryllium copper, an anti-diffusion underplate such as nickel shall be applied.

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Electroplating

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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Anodizing

Anodizing

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

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

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-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

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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