Bronze Casting Staining Defect Failure Analysis

Since 1983 Touchsone Research Laboratory has provided fast, accurate and affordable failure analysis to a wide range of industries – from underground mines to advanced spacecraft.

Engine Bearing Failure

The quality of ornamental bronze is usually judged by its surfaces. They should be clear of defects and the details should be clear and properly formed.

A bronze foundry was experiencing a recurring problem of veined staining on the surface of their ornamental bronze castings. This led the company to ask Touchstone to institute an investigation of the cause.

Samples were examined via SEM (scanning electron microscopy) equipped with an energy dispersive X-ray microanalysis system.

It was found that shrinkage in heavier sections allowed lead to migrate to the cavity and to form a galvanic cell, which was activated when moisture was present. The galvanic action of the lead/copper cell produced copper oxide surface stains.

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