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→Destructive Testing
Destructive tests can be performed on a sampling basis in rather simple ways:
*De-brazing<br />The contact tip is being removed by slow heating and simultaneous applicationof force perpendicular to the contact surface area. Visual inspection of theseparated components reveals the non-wetted defect areas as discolorationfrom either flux remnants or oxidation of the carrier material.<br />
*Milling Sample<br />The contact tip is milled off in layers to a depth that makes the joint area visiblefor optical evaluation.<br />
*Saw-Cutting<br />A crossing pattern is cut with a fine saw into the contact tip. Areas that are notbonded fall off in pieces.<br />
*Metallographic Micro-section<br />In a metallographic micro-section perpendicular to the contact surface wettingdefects can also be made visible ''(Fig. 3.14)'' which however are only indicativeof the brazing temperature and brazing time.<br />
Fig. 3.14:
Ag/CdO tip on Cu carrier.
*Shear test<br />The contact tip is sheared off from the carrier with the required shear force beinga measure for the bond quality. This method is especially suitable for hard andbrittle contact tip materials such as for example tungsten.<br />
===Non-Destructive Test Methods===
