Electrical Contacts, 2nd Edition

2

Introduction to Contact Tarnishing and Corrosion

Paul G. Slade

How dull is it to pause, to make an end,   To rust unburnished not to shine in use!

Ulysses, Alfred Tennyson

CONTENTS

2.1    Introduction

2.2    Corrosion Rates

2.3    Corrosive Gases

2.4    Types of Corrosion

2.4.1    Dry Corrosion

2.4.2    Galvanic Corrosion

2.4.3    Pore Corrosion

2.4.4    Creep Corrosion

2.4.5    Metallic Electromigration

2.4.6    Stress Corrosion Cracking

2.4.7    Contacts under Mineral Oil

2.5    Gas Concentrations in the Atmosphere

2.6    Measurements

2.6.1    Weight Gain Measurement

2.6.2    Visual Inspection

2.6.3    Cathodic Reduction

2.6.4    Scanning Electron Microscopy with Energy-Dispersive X-Ray Spectroscopy (SEM/EDAX)

2.6.5    X-Ray Photoelectron ...