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[References: 23 tit.]

The structure and mechanical properties of magnetron-sputtered Ti–Al–Ta–N and Ti–Al–Ta–Si–N coatings were studied using x-ray diffraction, scanning electron microscopy, transmission electron microscopy, and nanoindentation. The chemical compositions of the coatings were Ti0.41Al0.49Ta0.10N and Ti0.36Al0.44Ta0.10Si0.10N. The x-ray diffraction investigation has revealed that both coatings had the B1-type FCC crystal structure. The microscopic studies showed that alloying of the Ti–Al–Ta–N coating with Si resulted in modification of their microstructure from pronounced columnar structure to predominantly fine-grain structure. The incorporation of Si was found to substantially enhance the hardness of the Ti–Al–Ta–Si– N coating compared with the Ti–Al–Ta–N one with simultaneous improvement of toughness.