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  for Metal Finishing since 1989
  

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"Matte" Silver Why?

"Matte" Silver called out in QQ-S-365 (Type I)with chromate (Grade A)was required for some small (hand held)manifolds used for low frequency (200 Mhz) operation. The plated finish called for Ag on Cu on Ni on Aluminum (about 1/2 mil for each Ag,Cu&Ni). My question is WHY "Matte" Silver? Could it be the that the conductivity, loss factor, co-deposition of sulfur type additives, or whatever? is better than "today's" Semi-Bright (Type II), or Bright silver deposits? Finally, is there a test to tell the difference between Matte, Semi-Bright and Bright?

Tom Andersen
- Balto., Maryland, USA
2000

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Sometimes, matte finish might be called out to be sure that pure silver is deposited. It may be ductility, stress, hardness, and conductivity (or some other property) that is best achieved with a silver deposited from a bath without brighteners. It also gives an indication of how clean the plating bath is running, since a matte finish is difficult to obtain from a contaminated bath.

  
Tom Pullizzi
Falls Township, Pennsylvania
2000