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Prohibited Materials

Parts Selection Table of Contents

• Capacitors
• Circuit Protection Devices
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• Connectors
• Filters
• Inductors
• Microcircuits NEW!
  • Monolithics
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• Resistors
• Semiconductors (Summary)
  • Diodes
  • Transistors
• Thermistors
• Wire and Cable

Zinc Plating Prohibition

There are several reasons for prohibiting the use of Zinc plating in space flight electronic systems.

• Zinc is known to sublimate in a vacuum environment (especially at elevated temperatures). The sublimation products are conductive and can result in short circuits.
• Zinc is subject to the spontaneous growth of Zinc whiskers. Zinc whiskers (like tin whiskers) grow spontaneously and are capable of causing electrical failures ranging from parametric deviations to sustained plasma arcing that can result in catastrophic short circuits. See prohibition against pure tin plating for additional insight regarding the risks of metal whiskers

Zinc (galvanized) plating is occasionally used on mechanical hardware such as fasteners for its corrosion resistant properties. By using alternative plating materials most NASA applications can avoid the risks associated with the use of Zinc plating while still achieving suitable corrosion resistance. Consult your materials or parts specialists for suggested alternatives to Zinc plating.