Quantitative Description of Overlaps on Sialon Ceramics Fractures by the Multifractal Method

2013

Polym Eng Sci

Self Cite

Purpose: The aim of this work was to estimate the multifractal spectra of 3D surface roughness for unworn hydrogel contact lenses (CL), obtained with atomic force microscopy (AFM) analysis. Materials and methods: Contact lenses made from vifilcon A (Focus® Monthly Toric Visitint® model, CIBA Vision Corp.) were investigated. CL surface roughness was studied by AFM in tapping‐mode™, in an aqueous environment, on square areas ranging from 1 to 4 μm2. A detailed methodology for CL surface multifractal characterization, which may be applied for AFM data, was presented. Results: The CL surface roughness revealed multifractal geometry at various magnifications. The generalized dimension Dq and the singularity spectrum f(α) provided quantitative values that characterize the local scale properties of CL surface geometry at nanometer scale. Conclusions: Multifractal analysis provides different yet complementary information to that offered by traditional surface statistical parameters. POLYM. ENG. SCI., 54:1066–1080, 2014. © 2013 Society of Plastics Engineers

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Multifractal characterization of unworn hydrogel contact lens surfaces

Ţălu

2013

Polym Eng Sci

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“…The occurrence of secondary cracks and overlaps was only sporadically observed. More details of material, testing, pictures of fracture surfaces and definition of overlaps are presented in [8].…”

Section: Characterization Of the Research Materialsmentioning

confidence: 99%

Fracture Surface Development Coefficient and Sialon Ceramics’ Bending Strength

Roskosz

Cybo

et al. 2009

KEM

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Resistance to brittle cracking is one of the most important functional properties of sialon ceramics. Evaluation of the resistance requires an analysis of decohesion processes occuring in the material. Aiming at a comprehensive description of the morphology of typically brittle fractures, a quantitative characterization was made using different methods and techniques, regarding the surface of fractures formed in a three-point bending test. By using the parameter Sdr, determined via the surface stereometry method, the fracture surface development coefficient, RS, typical for fractography, was calculated. Analysis of the research results indicates a proportional relation between parameter RS and the sialon ceramics’ bending strength.

“…Multifractal analysis has clearly an advantage compared with standard statistical approaches because its parameters are independent over a range of scales as well as that no assumption is required about the data following any specific distribution. Also, it gives information about both local and global properties of the analyzed datasets [22].…”

Section: Multifractal Analysis Of the 3-d Surface Texturementioning

confidence: 99%

“…The multifractal spectrum can be calculated explicitly through several methods [22][23][24][25][26].…”

Section: Multifractal Analysis Of the 3-d Surface Texturementioning

confidence: 99%

Multifractal characteristics of titanium nitride thin films

Ţălu

Materials Science-Poland

Valedbagi

et al. 2015

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The study presents a multi-scale microstructural characterization of three-dimensional (3-D) micro-textured surface of titanium nitride (TiN) thin films prepared by reactive DC magnetron sputtering in correlation with substrate temperature variation. Topographical characterization of the surfaces, obtained by atomic force microscopy (AFM) analysis, was realized by an innovative multifractal method which may be applied for AFM data. The surface micromorphology demonstrates that the multifractal geometry of TiN thin films can be characterized at nanometer scale by the generalized dimensions D q and the singularity spectrum f(α). Furthermore, to improve the 3-D surface characterization according with ISO 25178-2:2012, the most relevant 3-D surface roughness parameters were calculated. To quantify the 3-D nanostructure surface of TiN thin films a multifractal approach was developed and validated, which can be used for the characterization of topographical changes due to the substrate temperature variation.