New Plating System for the Circle Pattern Circuit Shells

The compositive plating technique is first applied to the circle pattern circuit. The new plating system consists of dark nickel, Ni-Al₂O₃ compositive plating and acid pulse gold plating. After application of the new plating system, the break tendency of the external leads of the shells can be decreased remarkably. On the basis of intermediate experiments for batch process, the technological factors suitable for practical process are found out. A new experimental method for evaluation of the corrosion resistance of external leads of the shells is first established by authors.