A batch of bimetal foil/epoxy laminates was rejected because of poor peel strength. The laminates were manufactured by sintering a nickel/phosphorus powder layer to a copper foil, cleaning, then chromate conversion coating the nickel-phosphorus surface, and laminating the nickel-phosphorus side of the clad bimetal onto an epoxy film, so that the end product contained nickel-phosphorus sandwiched between copper and epoxy, with a chromate conversion layer on the epoxy side of the nickel-phosphorus. Peel testing showed abnormally low adhesion strength for the bad batch of peel test samples. Comparison with normal-strength samples using XPS indicated an 8.8% Na concentration on the surface of the bad sample; the good example contained less than 1% Na on the surface. After 15 min of argon ion etching, depth profiling showed high concentrations of sodium were still evident, indicating that the sodium was present before the chromate conversion treatment was performed. A review of the manufacturing procedures showed that sodium hydroxide was used as a cleaning agent before the chromate conversion coating. Failure cause was that apparently the sodium hydroxide had not been properly removed during water rinsing. Thus, recommendation was to modify that stage in the processing.

This article reviews the abrasive and adhesive wear failure of several types of reinforced polymers, including particulate-reinforced polymers, short-fiber reinforced polymers (SFRP), continuous unidirectional fiber reinforced polymers (FRP), particulate-filled composites, mixed composites (SFRP and particulate-filled), unidirectional FRP composites, and fabric reinforced composites. Friction and wear performance of the composites, correlation of performance with various materials properties, and studies on wear-of failure mechanisms by scanning electron microscopy are discussed for each of these types.

A laminated-paper microwave food tray collapsed with hot food in it. Microscopic examination of the failed tray revealed no structural or material defects. Five additional trays of like construction were also tested to determine the conditions necessary to simulate the permanent deflection of the tray handles that had occurred in the failed tray. Full distortion of the handles was obtained experimentally only by dropping a full hot tray on its end onto the floor. The test results indicated that the tray had slipped from the hand of the user.