Fractal and multifractal characteristics of CVD coatings deposited onto the nitride tool ceramics

Purpose: The goal of this work is the fractal and multifractal characteristics of the TiN+Al2O3 and Al2O3+TiN coatings obtained in the CVD process on the Si3N4 tool ceramics substrate. Design/methodology/approach: The investigations were carried out of the multi-edge inserts from the Si3N4 nitride tool ceramics uncoated and coated with the TiN+Al2O3 and Al2O3+TiN coatings deposited in the CVD process. Determining the fractal dimension and the multifractal analysis of the examined coatings were made basing on measurements obtained from the AFM microscope, using the projective covering method. Findings: Investigations carried out confirm that the fractal dimension and parameters describing the multifractal spectrum shape may be used for characterizing and comparing surfaces of coatings obtained in the CVD processes and of the substrate material from the Si3N4 nitride tool ceramics. Research limitations/implications: Investigation or relationship between parameters describing the multifractal spectrum and physical properties of the examined materials calls for further analyses. Originality/value: Employment of multifractal geometry in materials engineering provides the opportunity to work out more complete, also quantitative, characteristics of properties of the investigated objects. Multifractal analysis makes it possible to characterise in the quantitative way the extent of irregularities of the analysed surface.