Failure modes chemical characterization

Raman spectra can be recorded in times as short as several nanoseconds using pulsed laser excitation/gated array detection techniques. This capability is important for the identification of transient species during fast chemical reactions or for characterizing structural failure modes in thin films exposed to heat or intense electromagnetic fields. An existing system... 

The bulk properties of the adhesive and its ability to effect the transfer of stress across the adhesive-adherend interface will strongly dictate the measured strength of the bond, often described in terms ofpractical adhesion. The durability of the bond will be governed by the physical and chemical nature of the interfacial region formed, aptly called the interphase. The failure of a bond is usually characterized as being adhesive in the case where the failure is between the adhesive and the substrate and cohesive where the failure is within the adhesive. Failure may also be mixed mode, and other subtleties of the failure mode should be noted during testing or in the field. If surface analysis will be carried out to determine details of failure, failed bonds should be closed until that analysis can be performed. 

A major objective of nucrostructural analyses on multiphase and other polymers is failure analysis, i.e. determination of the mode or cause of failure. Failure analysis generally involves characterization of a material which has failed, either in service, or in a physical test. Controls are not always available, and timing is often critical. In some cases, the types of analysis required may well be sinular to those described above phase contrast, SEM and TEM. Other nucrostructural techniques that are valuable in solving such materials problems are chemical contrast imaging and elemental x-ray mapping. 

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