Fluorescent (FL) encrypting nanostructures, such as quantum dots, carbon dots, organic dyes, lanthanide nanocrystals, DNA, and more, are effective tools for advanced applications in high-resolution hidden imaging. These applications include tracking, labeling, security printing, and anti-counterfeiting drug technology. In this work, what we believe to be a new FL encoding nanostructures has been proposed, which consists of recently discovered nanometer-scale peptide dots. When refolded into a beta-sheet peptide secondary structure, these biocompatible nanoparticles exhibit a strong and tunable FL effect. The biophotonic FL covers the entire visible spectrum, making the peptide dots next-generation nanoscale light sources with a quantum yield of 30%. Our studies demonstrate that these FL bio-nanodots also exhibit a significant irreversible photo-bleaching effect associated with the light-induced destruction of noncovalent intermolecular hydrogen bonds of the peptide dots' highly stable beta-sheet secondary structure. We present what we believe is a new approach for achieving high-resolution long-term optical memory by tailoring various hidden images in the developed thin polyvinyl alcohol (PVA) polymer films with an embedded dense array of FL peptide nanodots. The technology enables recording photo-bleached patterns, barcodes, and high-resolution images.

Five copper ingots from the National Archaeological Museum of Aquileia (NAMA nos. 2, 3, 4, 7, 8) and four copper ingots from the National Archaeological Museum of the Sea (NAMS nos. 1, 2, 3, 4), retrieved from a sea environment, were the subject of the current study. The aim of this research is to apply a metallurgical approach in order to add further information about these objects, including their composition, microstructure, manufacturing process, and if possible, their origin. Samples were examined by a variety of testing methods, including visual testing, XRF analysis, metallographic examination, digital 3D multi-focal light microscope observation, SEM-EDS analysis, and lead isotope measurements (LIA). Cast defects were observed on both sides of the NAMA and NAMS ingots. Metallographic examination of the ingots from both collections revealed a dendritic microstructure typical to as-cast products. All ingots have a slight step on one side, probably resulting from plastic deformation, perhaps developed as a result of lifting them with a wrecking bar tool. Both the NAMA and NAMS ingots were made of copper with a small percentage of lead, yet their general composition was different. The better preservation of the NAMS ingots may probably result from the 0.1-0.5 wt% zinc content according to the XRF results. The inclusions observed in the NAMA ingots included Cu, Pb, O, Cl, As, Sb and Sn, while the inclusions observed in the NAMS ingots included Cu, Pb, O, Cl, Fe and a high content of sulphur (up to 21.9 wt% S). Based on their dissimilar bulk composition, the NAMA and NAMS ingots were most likely manu-factured in different workshops and from dissimilar ore sources. The lead isotope ratios measured on the NAMS no. 1 sample are compatible with Iberian deposits of the Ossa Morena zone, and they are consistent with the published data available on coeval wrecked ingots from the Western Mediterranean.

Thirteen Late Roman copper alloy coins with a dark concretion layer from the Early Islamic period Ma‘agan Mikhael B shipwreck were chosen to undergo an experimental chemical cleaning and polishing procedure for removing the concretion while limiting the damage to the surviving metal. These coins, and two more without concretion discovered on the beach nearby, were then subjected to a series of non-destructive analyses–visual testing, XRF, multi-focal light microscopy, and Raman spectroscopy–to determine their state of preservation, identify their corrosion products, and acquire information regarding their core material. An additional coin was examined by destructive metallographic light microscopy and SEM-EDS analyses to gain further information concerning the concretion cover. Preservation varied: For some chemically cleaned coins, a shiny orange-coloured metallic surface was exposed, while others were poorly preserved. Moreover, evidence of the stamping process was also observed. The results show that the suggested chemical cleaning treatment could be useful for processing other copper alloy objects retrieved from underwater environments; we propose a 12-step methodology to this effect.

Light‐delivering optical fibers are widely used for biomedical imaging, theranostics and surgery, and optogenetics. In this work, a new generation of bioinspired optical fibers is proposed. Developed amyloidogenic peptide fibrillary structures with tailored β‐sheet conformation exhibit unique optical properties of full overlapping of broadband visible fluorescence (FL) and optical absorption spectra. This study reports on unexpected lossless propagation of the FL light along 100 µm length β‐sheet microfibers. It is shown that the found FL long‐distance lossless radiative energy transport occurs due to highly effective FL photon recycling phenomenon supported by FL zero Stokes shift and high quantum yield. This new non‐Beer–Lambert FL lossless propagation mechanism is observed in very thin ≈1 µm diameter fibers, providing a single/few‐mode waveguiding regime. The developed model and computer simulations, based on the finite difference time domain method, are consistent with the experimental results. Fabricated peptide FL fiber probes permit delivering intensity‐modulated FL signal with selected wavelength over the whole visible spectrum in wide modulation frequencies range.

Additive manufacturing (AM) revolutionary technologies open new opportunities and challenges. They allow low-cost manufacturing of parts with complex geometries and short time-to-market of products that can be exclusively customized. Additive manufactured parts often need post-printing surface modification. This study aims to review novel environmental-friendly surface finishing process of 3D-printed AlSi10Mg parts by electroless deposition of gold, silver, and gold–silver alloy (e.g., electrum) and to propose a full process methodology suitable for effective metallization. This deposition technique is simple and low cost method, allowing the metallization of both conductive and insulating materials. The AlSi10Mg parts were produced by the additive manufacturing laser powder bed fusion (AM-LPBF) process. Gold, silver, and their alloys were chosen as coatings due to their esthetic appearance, good corrosion resistance, and excellent electrical and thermal conductivity. The metals were deposited on 3D-printed disk-shaped specimens at 80 and 90 °C using a dedicated surface activation method where special functionalization of the printed AlSi10Mg was performed to assure a uniform catalytic surface yielding a good adhesion of the deposited metal to the substrate. Various methods were used to examine the coating quality, including light microscopy, optical profilometry, XRD, X-ray fluorescence, SEM–energy-dispersive spectroscopy (EDS), focused ion beam (FIB)-SEM, and XPS analyses. The results indicate that the developed coatings yield satisfactory quality, and the suggested surface finishing process can be used for many AM products and applications.

Fragments of decorated floor tiles were retrieved from the Akko Tower shipwreck, Israel. Most tiles were made of bright brown fired clay with a white glaze decorated with colored stenciled motifs (Type A); and others consisted of a red-brown fired clay body, coated with a brown pigment covered with transparent brown glaze (Type B). This study aimed to characterize the two tile types; to reveal information concerning the manufacturing process; and to determine the origin of their raw material. A multidisciplinary approach was used, including light microscopy, SEM-EDS, electron probe microanalysis with wavelength-dispersive X-ray spectroscopy (EPMA-WDS), XRD, Raman spectroscopy, and time-of-flight secondary ion mass spectrometry (TOF-SIMS) analyses. The characterization of both tile types demonstrated the use of different raw materials. The Type A tiles were covered with tin-opacified majolica glaze and colored with various mixtures of pigments. The blue color was due to pigment rich in cobalt; the yellow color was due to Naples yellow and lead-tin yellow I minerals; and the green, orange, and brown colors were all prepared by mixing the Naples yellow pigment with different minerals. These majolica glaze tiles were probably manufactured in Sicily. The brown coating of the Type B tiles was due to pigment rich in lead and iron minerals. These tiles were produced with different manufacturing processes, and apparently made in France.

The current research presents a novel methodology for surface finishing of printed AlSi10Mg parts by electroless deposited gold–silver (electrum) alloys. The parts were printed by additive manufacturing laser powder-bed fusion (AM-LPBF). The electrum was chosen due to its appearance and good electrical and thermal properties and was deposited on disk-shaped specimens at 80 and 90 °C. The coating quality and appearance were studied by different methods for various deposition times and film thicknesses. The results indicate that Au–Ag coatings of AM-LPBF AlSi10Mg yield satisfactory results. The XRD analysis revealed that the coatings were composed of Au–Ag crystalline phases and beneath them, a quasi-amorphous or mixed quasi-amorphous and nanocrystalline Ni–P interlayer. The mechanism of electrum formation was studied based on the XPS analysis results as a function of the temperature and concentration. At 80 °C, the Ag was dominant at the beginning of the deposition process, while at 90 °C the Au was first detected on the interface. This result was explained by the electrochemical properties of alloying metals and the binding energies required to form metal–Ni and Au–Ag bonding. The results indicate that the electrum coatings are satisfactory, and the developed surface finishing process could be used for many applications.

Laser powder-bed fusion (LPBF) method is one of the most important additive manufacturing (AM) technologies. AM-LPBF parts frequently need post-printing coatings for electrical and thermal conductivity enhancement, or matching decoration considerations. The current study presents a methodology for surface finishing of AM-LPBF AlSi10Mg artifacts coated with electroless gold. For this purpose, gold was deposited on AM-LPBF AlSi10Mg disk-shaped specimens and coins, resulting in an appearance similar to the original objects. The gold coating was characterized as a function of deposition time and gold film thickness. Mass and dimension measurements, optical profilometry, light microscopy observation, XRD analysis and a FIB-SEM technique were applied to characterize the coated samples. The roughness of the plated specimens was slightly reduced as the thickness of the gold film was increased. AM-LPBF AlSi10Mg disk-shaped specimens were coated successfully for the first time by electroless gold plating technique. The developed surface finish technique can be used for various applications, including 3D-printed replicas of ancient prestige artifacts and coins for museum exhibitions.

Fused Deposition Modeling is one of the most common Additive Manufacturing methods for polymers. For some applications, parts manufactured by this method need post-printing surface coating. The present research aims at examining the surface finishing properties of Fused Deposition Modeling Acrylonitrile Butadiene Styrene parts coated for the first time with laboratory-developed electroless gold. Such coating can be applied for electrical purposes and as a decorative cover for 3D-printed prototypes, as well as on top of printed replicas of archaeological artifacts. Gold was deposited by electroless plating on top printed disk-shaped specimens, making them look like an ancient artifact. The electroless gold film was studied by various methods, including dimensions and mass measurements, qualitative pilling test, multifocal light microscopy, optical profilometer and X-ray diffraction analysis. The gold layer thickness was studied as a function of deposition time. The laboratory-developed electroless gold coating was deposited from a cyanide free bath and was compared to a commercial one deposited from a cyanide bath. The results displayed high-quality gold, and a satisfactory appearance. The roughness of the laboratory gold plated samples was somewhat reduced as the thickness of the gold film was increased, and the surface appearance was improved correspondingly. The developed gold coating can be adapted for various applications, including 3D printed artifacts for museum exhibitions.

Additive manufactured selective laser melting (AM-SLM) parts often need post-printing coatings. The current research presents a method for surface finishing of AM-SLM AlSi10Mg parts coated by electroless silver plating. Such coating can be applied as a decorative film on printed replicas of antique artifacts. For this purpose, silver was deposited for the first time on AlSi10Mg printed disk-shaped specimens and coins, making their appearance close to the original artifact. The silver was plated with and without adhesion-promoting silane self-assembled monolayers. Dimensions and mass measurements, pilling test, light microscopy, optical profilometer, SEM–EDS examination, XRD analysis, and FIB-SEM technique were applied to characterize the coated samples. The results displayed good silver quality with a satisfactory appearance. The roughness of the plated samples was slightly reduced as the thickness of the silver layer was increased. The developed coating can be adapted for different applications, including printed replicas of coins in museum exhibitions.

After three excavation seasons the Ma‘agan Mikhael B shipwreck has revealed, among other objects, seven coins. The coins were found covered with a black concretion layer, which was carefully removed from five of them. Metallurgical methods were used in order to reveal the composition, microstructure, and manufacturing process of the coins and to determine their date and the origin of the raw material. The coins were made of cast copper-lead alloy and were heated before being stamped. Based on the portrait of the House of Constantine I found on coins 120.1 and 120.2, and the figure on coin 120.5, combined with the composition of the coins, they were dated to the fourth century AD, when high concentrations of lead were added to alloys, most probably due to economic constraints. The study of the coins does not identify the ship’s origin or her ports-of-call, since coins were essentially mobile.

The Akko Tower Wreck is ently the remains of a 25-m-long merchant brig, dated to the first half of the nineteenth century. During the 2015 underwater excavation, a piece of brass sheet was retrieved from the shipwreck and its surface and bulk were examined by metallurgical analyses. The examinations revealed a unique example of almost two hundred years? natural etching, which took place in the sea underwater environment. The surface of the sheet was covered with different copper and zinc oxides, which were identified by XRD analysis. Observation of the naturally etched surface with multi-focal light microscopy and SEM-EDS analysis indicated a microstructure of annealed ?-brass, similar to that of its bulk. S-OES chemical analysis of the bulk revealed a composition of 65.0 wt% Cu, 34.4 wt% Zn and 0.6 wt% Pb. Based on the thickness of the sheet and its good state of preservation, it is suggested that it was used as sheathing to protect the hull against marine organisms, and to improve the sailing qualities of the ship. The results provide further information about the Akko Tower shipwreck; and expand our knowledge regarding the corrosion processes and preservation of brass during a long burial period in marine environments.

Unique combination of rhenium (Re) mechanical and physical properties makes it very attractive material for variety of applications. Pure Re does not have a ductile-to-brittle transition temperature. Compared to other refractory metals, Re has the greatest tensile strength and excellent creep resistance over a wide range of temperatures (up to ~2000 °C). Moreover, Re does not form stable carbides. Thus, it is potentially attractive coating on different carbon materials. Re-based alloy coatings have been produced so far mainly by chemical vapor deposition (CVD) and electroplating. Electroless deposition is relatively simple and low cost method for thin metallic and metal alloy films preparation on conductive and nonconductive surfaces. The ability of electroless plating to coat the inside of holes and recesses without using external current source or vacuum technology equipment makes it an ideal coating technology for many uses. In this study, high Re content (more than 65 at.%) Re-Co coatings were prepared by electroless deposition on a functionalized SiO 2 substrate and their morphology, composition, structure and properties were studied. The obtained films were characterized by HRSEM, AFM, XPS, XRD and EBSD methods. It was shown that as deposited films are amorphous with average microhardness of 620 HV that is higher than known in literature for binary Co-Re alloys. Crystalline hcp structure of Re-Co coating was detected only after annealing at 550 o C for 1 h in vacuum. Thin coatings (250-500 nm) have demonstrated good corrosion protection of copper in salt medium reducing corrosion current at list by one order of magnitude. The annealed deposits have shown improved mechanical and electrical properties. Such films exhibit ferromagnetism and could be applied in mobile magnetic components where soft-magnetic response combined with mechanical stability is required (MEMS devices).

Seven coins, covered with black concretion coating, found in the Byzantine-period Ma'agan Mikhael B shipwreck, were examined in this study. Metallurgical methods comprising visual testing, XRF, multi-focal light microscopy, SEM-EDS analysis and Raman spectroscopy, were used to determine the corrosion products and microstructure of the coins. The analysis results show that the coins were made of copper-lead alloy with a heterogeneous microstructure of bright and dark metal areas. The external surfaces of the coins were mostly composed of oxides and corrosion product compounds rich in Cu, Pb and Sn, while the external dark concretion coating was rich in Si, S, Ca and C compounds. Gradual variation of the composition and structure of the oxides and concretion coating layers was observed.

We report on the study of novel polymeric electrodes made by the selective, electroless plating, of Copper (Cu) films on gold (Au) nanostructure-modified polypyrrole (Ppy). The main aim of the work is to define the effect of Au nanoparticle seed preparation method on its catalytic properties for Cu electroless deposition. The Au nanostructures were produced by two different techniques, namely, cluster beam deposition from a magnetron sputtering/gas condensation source (with precise size and composition control) and electrochemical deposition. To carry out the research, polypyrrole films were first synthesized by electro-polymerization on Au (200nm)/SiO2/Si substrates, followed by modification of the polymer surface by either electroplating of Au nanoparticles or Au923 clusters deposition from a magnetron cluster source. The gold nanoparticle modified electrodes were subjected to copper electroless deposition for different time intervals. The morphology, growth and nucleation kinetics of the resulting copper film were studied by environmental scanning electron microscopy-Energy dispersive X-ray spectroscopy (ESEM-EDS), atomic force microscopy (AFM) and X-ray fluorescence (XRF). Although both nanoparticle type showed similar incubation time, a faster catalytic response, once deposition had been initiated, was observed when the polypyrrole film was modified with Au923 clusters. The incubation time was independent of cluster size and type. This could be explained by a simple model assuming that the incubation time depends on similar parameters for both nanoparticle types, such as metal-metal (Au-Cu) binding energy, crystallographic misfit (Au- Cu) and lateral growth of the copper film. Further discussion is presented in this paper in attempt to explain the different growth rate of Cu film catalysed by the Au923 clusters and electroplated Au nanoparticles.

The Akko Tower Wreck is the remains of a 25-m-long merchant brig, dated to the first half of the 19th century. A well preserved piece of brass sheathing was found in the shipwreck, retrieved and examined by non-destructive and destructive metallurgical methods, including visual testing, XRF, OES, light microscopy, SEM-EDS examination, microindentation hardness measurements and lead isotope analysis. The results demonstrate that the sheet is made of α-brass, containing about 34 wt% Zn. Its thickness (average 0.85 mm) and microstructure indicate that it was produced as rolled sheet, annealed during its manufacturing process. Its composition and manufacturing process indicate that it was produced during the first half of the 19th century, thus supporting the dating of the ship. The lead isotope analysis suggests that the raw material most probably originated in Great Britain, similarly to brass nails retrieved from the ship. This is an example of the exploitation of the corrosion resistance of α-brass sheet for use as sheathing to protect a ship against Teredo navalis and to improve its sailing qualities by its anti-fouling properties.

Iron artefacts corrode severely in a marine environment, and require further conservation after retrieval. This research proposes a novel conservation method, based on a bi-layered concept: a thin silane self-assembled monolayer serving as nano-scale barrier, covered by a thicker waxlayer, which is applied by dipping the object into a suitable solution. An accelerated corrosion test was performed, using modem cast iron and steel samples, and repeated on archaeological wrought iron artefacts retrieved from shipwrecks. This protection, which can be easily applied, was found to improve the corrosion resistance of the artefacts.

Rhenium (Re) is a promising refractory metal that has unique combination of properties. Compared to other refractory metals, Re has the greatest tensile strength and excellent creep resistance over a wide range of temperatures (up to ~2000°C). Pure Re does not have a ductile-to-brittle transition temperature. Moreover, unlike other refractory metals, Re does not form stable carbides. Thus, it is potentially attractive coating on different carbon material. Electroless plating is relatively simple method for generating thin metallic and metal alloy films on conductive and nonconductive surfaces. The ability of electroless plating to coat the inside of holes and recesses without using external current source or vacuum technology equipment makes it an ideal coating technology for many applications. In this study, high Re content (more than 65 at.%) Re-Co coatings were prepared by electroless deposition. The pH dependence of process kinetics, film microstructure and composition was studied. The obtained films were characterized by HRSEM, AFM, XPS and XRD methods. It was shown that as deposited films have amorphous structures with microhardness value of 600 - 620 HV. Crystalline hcp structure of Re-Co coating was detected only after annealing at 550 oC. Thin coatings (250-500 nm) have demonstrated good corrosion protection of copper in salt medium reducing corrosion current at list by one order of magnitude. The annealed deposits have shown improved mechanical and electrical properties. Such films exhibit ferromagnetism and could be applied in mobile magnetic components where soft-magnetic response combined with mechanical stability is required (MEMS devices).

The Ma'agan Mikhael ship, dated to 400 BC, was built 'shell-first', with the planks first connected edge-to-edge by mortise-and-tenon joints, and then, the frames were fastened to the pre-existing shell by double-clenched copper nails. The construction of a sailing replica began in 2014. The aims of the project are to increase knowledge of ancient ship construction, and to test her sailing capabilities. The shipwrights of the replica reproduced the original components to the closest possible degree of material, shape, and methods. One of the most intriguing elements is the copper nails. The aim of this study was to investigate the replica nails by comparing them with the original shipwreck nails. One example of each nail was tested by archeometallurgical methods. It was demonstrated that the nails of the replica and the original nails of the Ma'agan Mikhael ship were similar, thus providing additional information on the manufacturing technique of the nails and their application in the hull.

A flintlock musket and a brass case with two nails attached, were retrieved from the Akko 1 shipwreck, dated to the early 19th century, and studied using metallurgical analysis. Both artefacts were covered with encrustation and concretion. The iron musket barrel and the iron nails did not survive; only corrosion products and oxides were left of them. The brass case, the brass musket ramrod pipe, and the wood texture were well preserved. In both artefacts the iron was sacrificed to protect the brass. This information may assist in future conservation of similar objects. (C) 2016 Elsevier Ltd. All rights reserved.