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Abstract: Zirconium titanate based ceramics are commonly used as dielectrics in microwave devices. The basic compound, ZrTiO4, has long been known to have a low temperature coefficient of the dielectric permittivity, while the compound Zr0.8Sn0.2TiO4 has optimal properties at microwave frequencies (ɛ r ∼38, T cc =0ppm°C−1 and tan δ ≈1×10−4). Thin films of these materials appear as very promising dielectric layers for the integration in MIM and MIS structures. In this work we describe the pulsed laser deposition of zirconium titanate based materials on Pt/TiO2/SiO2/(100)Si substrates. The influence of the different processing parameters on film orientation, microstructure and chemical composition is discussed. Surface roughness, chemical composition and microstructural features of the films were optimised to achieve the most suitable dielectric properties. A laser fluence J ≈4.5J/cm2, a substrate temperature T s ≈550–600°C and 5×10−2 mbar of oxygen atmosphere are required to achieve highly oriented and crystalline films. The departure from these optima deposition conditions causes variations on the film composition, microstructure and residual strains. The permittivity of the films is affected by the presence of foreign crystalline phases. Crystalline and single phase thin films having a dense columnar structure is a fundamental requirement to achieve low loss dielectric films. [Copyright &y& Elsevier]

Abstract: Smart (Nano) materials with biosensing functions posses enormous potential in the development of new generation stable biosensors, chemical sensors, and actuators. Recently, there is a considerable interest in using TiO2 nanostructured materials as a film-forming material since they have high surface area, optical transparency, high bio-compatibility, and relatively good conductivity. In this work, TiO2 oxides were used as nanoporous electrodes to study the electron transfer mechanisms of H2O2, and many interesting biological molecules, as 3,4-dihydroxyphenylacetic acid (DOPAC), ascorbic acid, guanine, l-tyrosine, acetaminophen, and β-NADH, in order to assemble a new generation of chemical sensors and biosensors. A kinetic study was also reported in this paper, which demonstrated high performances towards electrocatalytic processes, obtained at nanostructured TiO2-modified electrodes. [Copyright &y& Elsevier]

The bulk and surface chemical composition of Renaissance coins minted at Gubbio (Central Italy) from 1508 to 1516 and from 1521 to 1538 by Francesco Maria della Rovere is investigated by means of the combined use of different analytical techniques such as scanning electron microscopy (SEM), energy dispersive spectrometry (EDS), and optical microscopy (OM). The aim of the work is to determine the bulk chemical composition of these commonly used coins at Gubbio, to ascertain their surface nature and if they were coated by a thin film of silver or other white metals similar to silver. The results indicate that the coins were produced by coating a copper core with a thin film of silver and antimony, and also with lead whose thickness is of a few microns which is now scarcely present because the original silvered surface was almost entirely removed by degradation phenomena. Furthermore, the SEM+EDS results show that the surface content of silver and antimony cannot be attributed to long-term selective corrosion phenomena leaving the coin slightly silver or antimony enriched. Therefore, the presence of silver or apparently silver-like metals i. e. antimony and lead, could be considered as a deliberate surface finishing of the coins obtained via inverse segregation or intentional selective corrosion based on pickling solutions or a combination of them. From a historical point of view the presence of a Ag or Sb film on the surface of the coins discloses the occurrence of a period of economic difficulties. [ABSTRACT FROM AUTHOR]

Conservation of historical buildings is an important issue and the environmental conditions seriously affect the monument's stones. The protection of cultural heritage buildings and monuments by surface treatment with polymers is a common practice due to their ability to form a protective layer on the monument's surface as well as to control the transport of different fluids from the surface to the monument's interior. In this work, three different substrates were used: Carrara marble, Botticino limestone, and Angera stone. A commercially available Si-based resin (AlphaSI30) was used as protective agent to improve the hydrophobicity features of the different tested materials. The surface properties of the coating and the relative interaction with the adopted stones were studied using different techniques such as contact angle measurements, electron microscope coupled with an energy dispersive spectrometer, X-ray photoelectron spectroscopy, atomic force microscopy, and attenuated total reflection infrared spectroscopy. [ABSTRACT FROM AUTHOR]

This work belongs to the framework of the national research project 'COMAS' (Planned COnservation, ' in situ', of underwater archaeological artifacts), funded by the Italian Ministry of Education, Universities and Research (MIUR), concerning the submarine archaeological area of Baia (Naples, Italy). The site includes remains of the ancient cities of Baiae and Portus Iulius, which, since the 4th century AD, started to be submerged because of the bradyseism phenomenon. The work aims to the characterization of four different types of stone materials collected from the site, specifically marbles, limestones, ignimbrites, and bricks, in order to investigate their state of conservation. In particular, specimens were sampled from some masonry structures and pavement slabs ( opus sectile) in a specific area of the submerged site, called ' Villa a Protiro'. In order to characterize archaeological samples from a mineralogical-petrographic point of view, polarized optical microscopy and X-ray diffraction analyses were carried out, while to assess their conservation state, the surface colonization by biodeteriogen agents and their interaction with the substrate were studied through observations under a stereomicroscope, scanning electron microscopy and Fourier transform infrared spectroscopy. Marble and limestone samples revealed an intense bioerosion phenomena, attributable to epilithic and endolithic forms, particularly boring sponges. On the contrary, ignimbrites suffer a lower degree of biological colonization related to the activity of other species, such as serpulids and bryozoans. In bricks, biocolonisation is correlated to the type of temper used in the artifact, the quartz pastes having a greater susceptibility to biological attack than the volcanic ones. [ABSTRACT FROM AUTHOR]

Dissemination of Della Robbia glazed terracotta in the Marche (Italy) region started from the third decade of the 16th century. Numerous altarpieces, some of which no longer exist, document this artistic production. The protagonists of this diffusion phase were two of Andrea Della Robbia’s sons, Marco (Fra Mattia) and Francesco (Fra Ambrogio). This paper shows the results of the scientific investigations carried out on constitutive materials of different altarpieces located in South Marche belonging to the Fra Mattia’s production: the Coronation of Virgin between Saints Rocco, Sebastian, Peter martyr and Antonio abbot, dated back to 1527–1530, located in the collegiate church of S. Maria Assunta in Montecassiano; the Annunciation, dated back to 1520, placed in the church of S. Maria del Soccorso in Arcevia; the fragmentary Crowned Madonna and saints altarpiece, probably realized after 1531, today preserved in Civic Museum of Ripatransone. The first altarpiece was made in Montecassiano using two different assembling or production techniques: the external part of the lunette and the pillar strips are made of glazed polychrome terracotta, while the altar step and the internal part are an interesting and uncommon example of polychrome painted terracotta. The provenance of the glazed Arcevia altarpiece is not clear yet: some historians hypothesize a local manufacture of Fra Mattia and some others a Roman or Florentine production. The remaining parts of Ripatransone altarpiece are partially glazed and partially not coated perhaps because they were unfinished and not yet painted. Clay body samples collected from the above mentioned altarpieces were investigated using different analytical techniques (OM, XRD, XRF, PIXE) to point out differences in chemical and mineralogical composition and to determine if the altarpieces were made by using local raw clay materials or other clays from Tuscany or Campania as in the Della Robbia previous production. A comparison has also been made with literature data on the Della Robbia terracotta masterpieces. From the chemical point of view, the clay bodies show a good compositional homogeneity and result calcium and iron-rich according with the raw local materials. The presence of gehlenite, pyroxenes, and hematite and the incomplete decomposition of clay minerals indicate that firing for all different terracotta parts occurred in a thermal range between 800 and 950 °C, mostly in oxidizing conditions. [ABSTRACT FROM AUTHOR]

Abstract: The properties of diamond-like carbon (DLC) are strongly affected by the amount of carbon atoms bonded in sp 2 and sp 3 electronic hybridizations. Also the amount of incorporated hydrogen and oxygen plays an important role in the final properties of DLC films. Usually, the structure and chemical composition of thin DLC films can be changed by varying the deposition parameters. Therefore, the influence of PECVD process parameters on the properties of DLC films, grown on Si substrates, was investigated in this work. Thin DLC films were deposited in a CH4/H2 plasma by using Ar as a gas carrier. Different ratios of gas flows were used as a variable parameter of the PECVD process. The effect of cathodic ion bombardment was also investigated. The chemical composition of DLC specimens was studied by X-ray photoelectron spectroscopy (XPS). The ratio of carbon in sp 2 and sp 3 hybridizations was determined by analyzing the first derivative of Auger C KLL spectra. These results were also confirmed by the measurements of electrical resistivity. The changes of surface morphology and microadhesion were analyzed by Atomic Force Microscopy (AFM). [Copyright &y& Elsevier]

Abstract: In this study, diamond-like carbon (DLC) films modified with titanium were deposited by plasma decomposition of metallorganic precursor, titanium isopropoxide in CH4/H2/Ar gas atmosphere. The obtained films were composed of amorphous titanium oxide and nanocrystalline titanium carbide, embedded in an amorphous hydrogenated (a-C:H) matrix. The TiC/TiO2 ratio in the DLC matrix was found to be dependent on the deposition parameters. The dependence of the films chemical composition on gas mixture and substrate temperature was investigated by X-ray photoelectron spectroscopy, whereas the crystallinity of TiC nanoparticles and their dimension were evaluated by X-ray diffraction. The size of TiC crystallites varied from 10 to 35nm, depending on the process parameters. The intrinsic hardness of 10–13GPa, elastic modulus of 170–200GPa and hardness-to-modulus ratio of obtained coatings were measured by the nanoindentation technique. Obtained results demonstrated a correlation of mechanical properties with the chemical composition and the ratio of amorphous/crystalline phases in the films. In particular, the formation of nanocrystalline TiC with atomic concentration not exceeding 10% and with grain size between 10nm and 15nm resulted in significantly enhanced mechanical properties of composite material in comparison with ordinary DLC films. [Copyright &y& Elsevier]

The paper presents a comprehensive physico-chemical investigation on a series of Hispano-Moresque objects produced in the eastern Spain workshops between the XIV and XVIII centuries and fragments from XII century, in order to compare them with the Italian Renaissance majolica production. The techniques used are mainly non-destructive (ion beam analyses and X-ray diffraction), sometimes complemented by SEM observation and microanalysis, and electrothermal atomic emission spectrometry. Such methods allow a full description of the terra cotta, of the glaze and of the different surface layers which constitute the lustre decoration indicating individual elemental composition and thickness of each layer containing or not metallic nanoparticles. Principal results show the following: i) a constant source of supply for the eastern Spain terra cotta; ii) a significant change in the composition of the Spanish glazes around the XVII century, with the disappearance of the opacifying tin oxide addition; iii) significant evolutions in the structure and composition of the lustre layers, in particular related to the presence or not of a metal-free surface glaze film and its thickness; iv) interesting analogies and differences with the Italian majolica; v) confirmation of the change in the quality of blue pigment during XVI century, already evidenced by the authors in previous publications. A discussion about the transmission of the lustre technique between eastern Spain and Italy at the Renaissance period is proposed. [ABSTRACT FROM AUTHOR]

Abstract: Gold nanowires were prepared by electroless deposition within the pores of polycarbonate particle track-etched membranes (PTM). Glucose oxidase was deposited onto the nanowires using self-assembling monolayer as anchor layers for the enzyme molecules. AFM characterization was performed before and after the immobilization of the enzyme. Finally cyclic voltammetry was performed for different enzymes to test the applicability of gold nanowires as biosensors. The AFM measurements proved the immobilization of the enzyme while the electrochemical characterization showed that the presence of nanowired substrates greatly enhances the electrical response of the biosensor. [Copyright &y& Elsevier]

Abstract: The recent restriction in the use of chromium VI gave a new impulse in the field of anti-corrosion treatment for an alternative solution. A promising route seems to be the deposition of a thin ceramic layer on the metallic surface. In this study, four zirconia primers have been deposited on 1050 aluminium sheets by sol–gel process. Sol preparation was obtained starting from two different precursors and two curing temperatures were tested. Surface microstructure and chemical composition were determined by AFM and XPS for all samples. Electrochemical Noise Analysis (ENA) was used in Harrison''s solution to evaluate the corrosion resistant features of the samples. Tests have been also performed on samples protected by polyester topcoat deposited on the aforesaid primers. AFM analysis revealed that, for all the samples, covering and structure of the coating were uniform. XPS depth profiling allowed concluding that film thickness was in the range from 18 to 30 nm and that chemical composition was constant through primer thickness. Corrosion tests demonstrated that zirconia primers showed good performances in terms of corrosion resistance, comparable to chromate and fluotitanate layers industrially prepared. Topcoated samples gave an optimal corrosion resistance. [Copyright &y& Elsevier]

Abstract: The functionalisation of solid electrodes with thin films of biocompatible materials revealed very attractive for the development of biosensors on miniaturized platforms, since this configuration could provide a rapid translation of the biological processes occurring on the surface to electronic outputs. In this study, the realization of functionalised TiO2 thin films on Si substrates for the immobilization of several enzymes and biological molecules is reported. Deposition parameters were found to affect the chemical and microstructural features of the films, which influenced the protein immobilization. Glucose oxidase and horseradish peroxidase immobilized onto TiO2-based nanostructured surfaces exhibited a pair of well-defined and quasi-reversible voltammetric peaks. The electron exchange between the enzyme and the electrodes was greatly enhanced in the TiO2 nanostructured environment. The electrocatalytic activity of HRP and GOD embedded in TiO2 electrodes toward H2O2 and glucose, respectively, may have a potential perspective in the fabrication of third-generation biosensors based on direct electrochemistry of enzymes. [Copyright &y& Elsevier]

Luminescence measurements have been performed on several Italian Renaissance ceramic shards produced in central Italy, as well as on some others from Hispano–Moresque and Fatimid periods. The aim of this study was the characterisation of the raw materials used to manufacture lustre decorated majolica. At first, the thermoluminescence (TL) dating of all ceramic bodies was performed, because the shards lacked sure chronological attribution, having been provided by private collectors, or found during emergency restoration works or archaeological surveys. To characterise the defects and the recombination centers of the different components of the ceramics (ceramic body, glaze, glaze, and lustre), radioluminescence (RL) measurements have been performed on samples representative of each historical period. The dating results are reported, as well as the preliminary RL results. [ABSTRACT FROM AUTHOR]

Abstract: Diamond-like carbon (DLC) films have been largely studied for their excellent mechanical properties and their high potential in many industrial applications. Although DLC films have poorer physical properties than diamond films, their lower thermal stability and high internal residual stress can be avoided with the incorporation of other elements, such as silicon, nitrogen and some metals. Nanostructured DLC coatings are usually deposited by a combined plasma assisted PVD/CVD technique and sputtering system. We have prepared Ti-containing DLC films deposited by plasma decomposition of CH4/H2/Ar gas mixture with titanium isopropoxide (Ti[OCH2CH3]4), as a metal precursor. The deposited films were found to be composed of amorphous titanium oxide and nanocrystalline titanium carbide, embedded in an amorphous hydrogenated (a-C:H) matrix (DLC). The TiC/TiO2 ratio in the DLC matrix was dependent on the process parameters. The films'' composition was monitored as a function of gaseous fluxes. The structural and chemical–physical characterization has been performed by means of XRD and XPS techniques. [Copyright &y& Elsevier]