High Entropy Alloys for Medical Applications

A wide variety of metallic biomaterials have been developed so far, including various types of alloys. However, there is a strong need in the medical field for new solutions in what concerns metallic biomaterials with superior biocompatibility and mechanical properties in order to meet future requirements, including the recently developed high entropy alloys (HEAs). This chapter presents some characteristics of high entropy biocompatible metallic alloys produced in an electric-arc remelting furnace in argon inert atmosphere. The effects of the chemical elements used, the microstructural features, and some mechanical characteristics, both in the cast state or after some heat treatments, are highlighted

Development of New Advanced Ti-Mo Alloys for Medical Applications

The use of titanium and titanium-based alloys with applications in implantology and dentistry has made remarkable progress in the promotion of new technologies and new materials that have been developed in recent years. This is justified thanks to their excellent mechanical, physical, and biological performance. Today’s generation promotes new titanium alloys, with nontoxic elements and long-term performance and without rejection of the human body. This book chapter describes new original compositions of Ti-based alloys for medical applications, with improved properties compared to existing classical alloys (C.p. Ti, Ti6Al4V, CoCrMo, etc.). The addition of nontoxic elements such as Mo, Si, Zr, and Ta brings benefits as reduced modulus of elasticity, increased corrosion resistance, and improved biocompatibility

A Typical Surface Formations Found on the Corrosion Layer of Iron Artefacts

The paper presents the experimental results obtained by applying non-invasive methods (OM, SEM-EDX, XRF) on two iron artefacts from the IInd and the IIIrd centuries A.D. (discovered in the incineration graves from Gabăra-Moldoveni and Văleni-Boteşti, Neamt County), for determining the surface and the internal microstructures (cross-section), corrosion products distribution and some atypical formations resulted from the incineration processes. The results allow the rendering evident of some attributes used in authentication, the determination of the conservation state and the establishing of the proper procedures for the active conservation and the restoration of the artefacts

Ceramic Nanofiltration Membrane Fouling: Application of Mathematical Modelling to the Use of Excitation Emission Matrix Spectroscopy

This paper presents a mathematical modeling for a series of experiments in which humic acid (AH) and calcium chloride (CaCl2) were used, in order to visualize the amount of contaminant before and after the nanofiltration (NF) process, using Excitation Emission Matrix Spectroscopy (EEMS). It allows to a better understanding of membrane fouling. The membrane used for these experiments was a NF ceramic membrane made of titanium dioxide (TiO2). For the experimental determinations, a constant amount of 10 mg/L HA and different amounts of CaCl2, respectively 1, 2, 3 and 4 mmol/L were used, considering the working methodology presented in this article. The presence of the amount of contaminant in water was determined using the EEMS method using the FP-8300 Spectrophotometer, after which a spectral analysis was performed. TableCurve 3D software was used to make the mathematical models in order to ensure that the equations obtained had the same shape. The values of the correlation coefficients, corresponding to the generated equations, have values ranging from 0.91 to 0.93. In order to verify the mathematical models thus obtained, graphs of the difference between the surface obtained with the help of the mathematical models and the surface obtained by means of real data were drawn. In conclusion, it turns out that, the largest difference was obtained in the case of samples taken from the feed, with a maximum difference of 31 fluorescence intensity arbitrary units (a.u.), and for the samples taken from the permeate the deference is 14 fluorescence intensity a.u

Study on the Specific Effects of Corrosion Processes on Ancient Bronze Artefacts

The paper presents the cases of the corrosion processes which take place on starting from the usage period when the primary patina is being formed and when the secondary patina starts, than continuing with the archaeological site where the contamination patina is obtained under the influence of the pedological processes. The paper is a review from the specialised literature and from the contributions of the authors. There has been used the direct analysis with optical instruments, electron microscopy and EDX

Um estudo comparativo interdisciplinar das técnicas e materiais de douramento em dois conjuntos de talha dourada barrocos portugueses

The gilded polychrome carved wood in Portugal, (talha dourada) gained its most rich expression during the Baroque epoch with the development of production techniques and the use of of gold leaf. The present paper proposes a complementary and comparative study of two important complexes of talha: one from St. Alberto’s church, integrating the visiting circuit of the Museu Nacional de Arte Antiga (Lisbon), and the other from church of Vale de Figueira (Santarém district). Both complexes house talha dourada’s decoration from the 18th century, that were studied through an inter-disciplinary approach, in which analytical data (optical microscopy, fluorescent stain, XRF, SEM-EDX, micro-computerized tomography, FTIR, Matrix-Assisted Laser Desorption/Ionisation-Time of Flight Mass Spectrometry) complement historical data.El arte de la talla dorada en Portugal ganó su más rica expresión durante el período barroco a través del desarrollo de técnicas de producción y el uso de pan de oro. Este trabajo propone un estudio complementario y comparativo de dos grandes complejos de talla, el de la Iglesia de San Alberto, integra el circuito de visita del Museu Nacional de Arte Antiga en Lisboa, y el de la Iglesia de Vale Figueira, en Santarém. Los dos complejos albergan retablos dorados del siglo XVIII, que han sido estudiados a través de una metodología interdisciplinar, en la que los datos analíticos (microscopia óptica, tinción fluorescente, fluorescencia de rayos X, SEM-EDX, micro-tomografía computerizada, FTIR, MALDI-TOF-MS) complementan los datos históricos.A arte da talha dourada em Portugal ganhou a sua mais rica expressão durante a época barroca devido ao desenvolvimento das técnicas de produção e ao uso do ouro em folha. O presente trabalho propõe um estudo complementar e comparativo de dois complexos importantes da talha respectivamente em Lisboa, na Igreja de São Alberto, integrada no circuito de visitas do Museu Nacional de Arte Antiga, e no distrito de Santarém, na Igreja de Vale de Figueira. Os dois complexos albergam decoração em talha dourada do século XVIII, estudados através de uma abordagem inter-disciplinar, em que os dados analíticos (microscopia óptica, teste de coloração fluorescente, FRX, MEV-EDX, microtomografia computadorizada, FTIR, Matrix-Assisted Laser Desorption/Ionisation-Time of Flight Mass Spectrometry) complementam os dados históricos

Obtaining and Characterisation of Thermoresistive Pigments

The paper describes the obtaining and chemical and physico-structural characterisation of a green thermoresistive pigment. The pigment is made of ZnO dopped with Sb, Bi, Cr, Co and Fe oxides and it is used at mosaics and stained glass. The procedure is based on a sequential coprecipitation “layer on layer” process in aqueous solution, followed by drying and calcinations at controlled temperature conditions, then grinding in a colloidal mill and mixed with glass powder forming the “frit pigment”. This by vitrification and frosting colours superficial the glass. The powder was analysed by SEM-EDX and DSC

Studies Regarding Nickel Electrodeposition from Watts Bath with Addition of Polyvinylpyrrolidone and Sodium Saccharine

This paper is based on some studies about the influence of polyvinylpyrrolidone (PVP) and sodium saccharine as far as concern their influence on the nickel electroplating processes from Watts bath. PVP is a wetting agent which improves the quality of deposited layers. Sodium saccharine is a leveling agent which improves adherence and brightness of the deposited layers. PVP actions through the inhibition of adsorption of (NiOH)+ species on the cathode surface. Sodium saccharine controls crystals growth on the electro-crystallization process. Our results are able to promote using of these additives for future commercial applications. SEM-EDX techniques and optical microscopy were used with the aim to emphasize the uniformity, the continuality and the micro-structural granularity of the electrodeposited layers,, correlated with chemical composition and metallic brightness, through absorption spectroscopy

The Conservability of Old Wood at the Contact with Metallic Structural Components from Artifacts

The paper presents the impact of metallic pieces being in contact with wood, as structural elements, used in obtaining artifacts. The paper studies, based on old samples, the reciprocal effect obtained at the wood-metal interface, the diffusion and segregation area of metallic cations in wood and the protective role of some wood volatile components on metal

Influence of Substrate Temperature on the Properties of Ga Doped ZnO thin Films

Transparent conductive oxides, including single layer and multilayer structures, have been investigated in the last years, for transparent or semitransparent conducting electrode applications in optoelectronic devices and transparent electronics. Owing to their properties such as: high transmission in the visible region (>80%) and high electrical conductivity, they been used in applications like LEDs, laser diodes, solar cell, flat panel displays, thin films transistors etc Some alternative TCO materials including ZnO doped with III rd group elements (In, Al, Ga); TiO 2 doped with Ce, Nb, Fe; SnO 2 doped with F etc., have been investigated in the last years In order to use Ga doped ZnO thin films for different application it is very important to obtain layers with reproducible properties. Because the deposition parameters of each deposition technique can be varied, the properties of obtained thin films may differ significantly. Despite the progress made in the field, the researchers are still doing studies to establish the most convenient deposition parameters for processing Ga doped ZnO thin films with excellent optical and electrical properties. A large number of techniques were used in order to obtain ZnO:Ga thin films including pulsed laser deposition, reactive plasma deposition, RF Magnetron Sputtering, The aim of this paper is reporting some results regarding the influence of substrate temperature on the physical properties of ZnO:Ga thin films prepared by RF magnetron sputtering being analysed by XRD, SEM, Profilometry and two point method for electric properties. Experimental part Materials and methods The obtaining of thin films Ga doped ZnO thin films were deposited on glass substrates by RF Magnetron Sputtering using a 98 wt. % ZnO doped with 2 wt. % Ga 2 O 3 ceramic target of 40 mm diameter, keeping RF power constant at 50W. The substrate temperature was of 300K (sample 1), 423K (sample 2) and 523K (sample 3) respectively. The distance between target and substrate was maintained at 55 mm. For the thin film deposition, the work pressure was maintained at 1.4 mTorr in argon atmosphere. The deposition parameters are presented in table 1. Analysis methods and techniques Structural analyses of the studied films were carried out using a DRON 2 diffractometer with CuK α radiation (λ = 1.5418 A) as an X -ray source at 20 kV and 40 mA, in the 2θ =20-70° range. The films morphology was investigated by using scanning electron microscopy (SEM Tescan VEGA II LSH). The thickness of investigated films, measured using a DEKTAK profilometer, was found to be around of 150 nm. The electrical properties of studied samples were measured in a two points configuration, by using a sensitive Keithley model 6517 multimeter. For gas sensing measurements, the thin films were placed in a glass enclosure capable of controlling the different gas concentrations and working temperature. The resistance was measured in the presence of the tested gas. The gas sensing properties were investigated at various operating temperatures from 373K to 750K. As test gases were use