Surface analysis of diffusion zones in multiple chemical vapor deposition coatings

In this investigation, a multilayer carbide coated cutting tool was examined. The cutting tool was produced through the sequential chemical vapor deposition (CVD) of TaC, TiC, Al2O3, and TiN layers over a WC/Co substrate. The purpose of this study was to characterize the interdiffusion of materials at each of the interfacial regions as a function of deposition conditions. To accomplish this, several surface analysis techniques were used including scanning Auger microscopy (SAM), scanning electron microscopy (SEM), and small spot x-ray photoelectron spectroscopy (XPS). The samples were prepared using a modified lapping technique. The lapping angle used was approx. 0.250, which yielded at least a 250 x expansion of the interfacial regions. This allowed interface characterization without instrumental resolution limitations. Scanning AES and small spot XPS were performed on interfaces to investigate interface chemistry and interdiffusion. Argon sputter depth profiling was also used to further characterize diffusion zone composition and dimension