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Non-Galvanic Corrosive Plating on Non-Conductive Material for Electromagnetic Interference Shielding

IP.com Disclosure Number: IPCOM000114306D
Original Publication Date: 1994-Dec-01
Included in the Prior Art Database: 2005-Mar-28
Document File: 2 page(s) / 41K

Publishing Venue

IBM

Related People

Higuchi, K: AUTHOR [+2]

Abstract

Disclosed is a plating system which has Zinc or Zinc alloy layer as top layer on non-conductive substrate. The plating system provides electro-conductive film for Electromagnetic Interference (EMI) shielding without galvanic corrosion when used in contact with Magnesium or Magnesium alloy.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 74% of the total text.

Non-Galvanic Corrosive Plating on Non-Conductive Material for Electromagnetic
Interference Shielding

      Disclosed is a plating system which has Zinc or Zinc alloy
layer as top layer on non-conductive substrate.  The plating system
provides electro-conductive film for Electromagnetic Interference
(EMI) shielding without galvanic corrosion when used in contact with
Magnesium or Magnesium alloy.

      In case that product housing require EMI shielding, the housing
should be electro-conductive and every parts should be connected
electrically each other to secure shielding effect.  To provide
electro-conductivity, parts made of non-conductive material such as
plastics and ceramics are metallized popularly.  However, the popular
metallizing such as Nickel over Copper plating or Aluminum vapor
deposition cause galvanic corrosion when used in contact with
Magnesium parts because of too large potential difference.  The
potential difference between Zinc and Magnesium is not enough to
cause galvanic corrosion in normal office environment.  Then, in
application used in contact with Magnesium, by applying Zinc
metallizing process plastics can be used as a part of EMI shielding.
Following is one of possible application.  The product housing
consists of Magnesium diecast parts and plastic injection molded
parts.  All the parts are designed to be assembled keeping electrical
contact between adjacent part.   The plastic parts are Copper plated
at first step by catalyzed...