GMW14711

Description / Abstract: Introduction

Note: Nothing in this standard supercedes applicable laws and regulations.

Note: In the event of conflict between the English and domestic language, the English language shall take precedence.

Purpose.

Determination of the specific volume resistance of elastomers, plastics, and adhesives.

Applicability.

Elastomers, plastics, and adhesives in contact with light metals.

Remarks.

If body panels, made of light metals (e.g., aluminum, magnesium) or are zinc-plated, can be in contact with precious metals or solid bodies conducting electrons (e.g., graphite) and are in the presence of electrolytes, note this may lead to the preferential corrosion of the light metals.

To avoid the contact corrosion, elastomers, plastics, and adhesives shall have a sufficiently high insulation resistance. The same applies if such materials are in contact with painted light metal surfaces as the insulating paint layer may not offer sufficient protection against contact corrosion, because of faults or damages in the part. The insulation resistance depends both on the specific volume resistance and on the specific surface resistance of the test piece.

The determination of the specific volume resistance is performed to check the uniformity of the insulating material. The specific volume resistance is considerably affected by temperature and moisture.