Roughness increases significantly after finishing procedures. The aim of this study was to assess by the atomic force microscope~AFM! the effect of finishing instruments on the surface roughness of composite resins. A nanofiller composite resin~Filtek Supreme, 3M-F! and a microhybrid composite resin~Point 4, Kerr-P! were selected. The finishing procedures were done with a 30-blade carbide bur~C! and a 30-mm finishing diamond bur~D!. Standardized specimens were produced and divided into six experimental groups n ϭ 4! according to~1! composite resin,~2! absence of finishing~Mylar matrix-M!, and~3! finishing instrument~FM, PM, FC, FD, PC, PD!. The mean surface roughness was evaluated by AFM in the contact mode. FM and PM groups were assessed statistically by the Student's T test, and FC, FD, PC, PD groups were submitted to variance analysis~ANOVA!, both at 5% significance. The mean surface roughness values, in nanometers, were FM, 23.63~b!; FC, 283.88~c!; FD, 510.55~d!; PM, 12.52~a!; PC, 343.98~c!; PD, 531.64~d!. Microhybrid composite displayed less roughness than nanofiller composite in the absence of finishing procedures. The 30-blade carbide bur produced less roughness compared to the extra fine diamond bur.

Dynamic vulcanization is a mixing process employed in the melt state of elastomers with thermoplastics. This process may result in the formation of thermoplastic vulcanized (TPV) materials with improved properties such as mechanical strength, Young's modulus, hardness, and abrasion fatigue. In this study, a vulcanized thermoplastic was obtained by the dynamic vulcanization of poly(vinyl chloride)/acrylonitrile butadiene rubber (PVC/NBR) blends using a curative system based on sulfur (S)/tetramethylthiuram disulfide (TMTD) and mercaptobenzothiazyl disulfide (MBTS). The formation of crosslinks was characterized by differential scanning calorimetry (DSC) and Fourier transform infrared (FTIR) spectroscopy. The mechanical properties were analyzed by tensile tests and the phase morphology was investigated using atomic force microscopy (AFM) operating in the tapping mode-AFM. The phase images of the dynamically vulcanized blends showed an elongated morphology, which can be associated to the formation of crosslinks that give the material its excellent mechanical properties.

Duplex stainless steels are austenitic-ferritic alloys used in many applications, thanks to their excellent mechanical properties and high corrosion resistance. In this work, chemical analyses, x-ray diffraction, and magnetic force microscopy (MFM) were employed to characterize the solution annealed and aged duplex stainless steel. The samples exhibited no changes in lattice parameters and the MFM technique proved successful in clearly imaging the magnetic domain structure of the ferrite phase.

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