Papers by Author: Daniela Carbone

Abstract: Composite coatings based on PEEK and Lignin were obtained by EPD. The addition of Lignin had some beneficial effects, the most relevant being an increased coating adhesion on conductive substrates. Before using in EPD suspensions, Lignin was functionalised by a carbonyl group. This functionalisation produced chemical interactions between PEEK powder and Lignin, and, as a consequence, better results in terms of both EPD efficiency and adhesion coating. Moreover, the addition of Lignin increased the hydrophobicity of PEEK coatings when they were thermally treated at temperature lower than the melting point of PEEK.

Abstract: The combination of nanoparticles and conducting polymers, known as hybrid conducting nanocomposites, is a new emerging field. The combination of conductive polymers, such as polyaniline (PANI), with conductive carbon nanotubes (CNTs) has already shown some synergistic properties. As a consequence, they have a variety of applications, such as sensors, actuators, touch screens, etc.. Usually PANI and CNTs are combined by using electrochemical synthesis starting with the monomer aniline. In this work PANI-CNTs nanocomposite films were obtained by using different combinations of two methods, Electrochemical Deposition (ELD) and Electrophoretic Deposition (EPD). The samples prepared by using these combined methods were compared with the material prepared by the usual electrochemical synthesis. Therefore, all the films so prepared were characterised and their electrochemical properties were investigated, particularly for evaluating their use as supercapacitor components.

Abstract: Poly(etherether-ketone)-alumina coating were deposited by EPD. In order to densify the coatings, conventional thermal treatments were performed at a temperature equal or higher than the melting point of the polymer. The samples treated at the lower temperature showed an increase in the quality of crystallinity of the polymer. As an alternative method, an excimer laser was used to treat the surface of the composite coatings. The laser beam irradiation did not induce any modification in the crystalline structure of the polymer and at the same time did not produce strong degradation of the polymer molecule, also when the laser beam fluence was higher than the ablation limit. The most relevant modification induced by both the treatments was a change in the morphology and the porosity.

Abstract: Poly(etherether-ketone) (PEEK) suspensions in ethanol and isopropanol containing also α-alumina and hydroxyapatite powders were studied. An innovative method was used in the study of the quality of suspensions. We studied suspensions by means of zeta potential and grain-size measurements. The comparison amongst the different suspensions was carried out by using statistical and chemometric tools, especially by the use of an explorative test based on the Principal Component Analysis (PCA). The chemometric analysis was performed by involving different combinations of each type of powder and each type of solvent.

Abstract: Multi-walled carbon nanotubes (CNTs) were deposited by electrophoretic deposition on stainless steel substrates forming homogeneous porous CNT deposits. These CNT structures were then coated with a thin layer of Ni by electrodeposition. SEM and TEM observations confirmed that the Ni layer covered uniformly the CNT surfaces. This Ni coating treatment could facilitate the dispersion of CNTs in metal matrix composites leading to improved mechanical and thermal properties.

Abstract: In order to obtain wear resistant coating as well as thermal barrier on metallic substrates by EPD, the conventional high temperature treatments are inapplicable; so we used an alternative method to densify and make the electrophoretic deposit more adherent. In this work we described a novel method to obtain EPD deposits with good density and adherence to stainless steel substrate. At first, we achieved stabilized alumina and alumina-zirconia based suspensions; to improve the adhesion of ceramic coating on metal, some stainless steel substrates were sandblasted, others were coated with titanium bond layers. Then the substrates were coated by EPD; finally, we used the electron beam to treat the ceramic coating-metallic substrate system on the surface; in this way we obtained adherent and dense EPD coatings. In order to evaluate the quality and the microstructure of the coating sintering, the samples were observed by scanning and transmission electron microscopy; pull tests showed the adhesion of treated EPD coating was about one hundred times higher than that of deposited EPD coating.