Bronze Powder Research Articles

New Research on the Origin of Mosaic Gold

This article examines the origins of the golden pigment known as mosaic gold (SnS2), formed through the sublimation of tin with mercury, sulphur, and ammonium chloride. It explores the textual transmission of mosaic gold from the earliest known written testimonies, as well as the earliest material remnants of the pigment during the thirteenth and fourteenth centuries. Additionally, the study introduces and analyses two new recipes from an earlier date: one comes from the Greek treatise known as the Anonymous of Zuretti; and the other from the Latin alchemical work attributed to pseudo-Avicenna, De anima. The analysis of these new recipes allows for a better understanding of the origin of the pigment and its connection with the medieval alchemical tradition inherited from the Arabic world. Based on these testimonies, the study proposes a new hypothesis about the origin, development, and etymology of mosaic gold.

The extraordinary universe of Peter Apian: technical investigation of five copies of a 16th-century astronomical book

In 1540, in Ingolstadt, Germany, the influential astronomer and printer Peter Apian produced the Astronomicum Caesareum: a printed and hand-coloured astronomical book visualising the Ptolemaic universe through the use of diagrams and wheelcharts, worthy of his imperial patron, Charles V. About 130 copies have survived to this day, with varying degrees of paper quality and level of decoration, and only eleven volumes are considered deluxe copies. We thoroughly analysed one deluxe volume held at the Fitzwilliam Museum, Cambridge, and compared the results with four (one deluxe and three standard) other copies from institutions in the UK. A non-invasive analytical protocol was applied, including extensive microscopy, fibre-optic reflectance spectroscopy (FORS), X-ray spectroscopy (XRF), macroscale XRF (MA-XRF) and Raman spectroscopy. The most interesting pages were chosen based on art-historical evidence and the variety of the colour palette, including on volvelles (wheelcharts) and coats of arms. Following a systematic approach, we analysed the same pages in each volume, gathering information on the colour palette in all the volumes. The type of paper and the presence of watermarks were also documented. A wide range of materials was identified in the five copies, including red, purple and yellow organic dyes, lead white, verdigris, vermilion, azurite, indigo, smalt, and lead–tin yellow. Mosaic gold was used to embellish certain paint passages in the deluxe volumes and metals (gold and silver) were applied on some pages. The comprehensive findings were essential to identify specific traits related to Apian’s workshop, to differentiate deluxe from standard copies, to suggest an order of production of the copies, and to provide new information on this landmark book and more generally in an under-researched field of study.

Influence of the bronze powder filler on the adhesion of epoxy compound to aluminum bronze

Influence of the bronze powder filler on the adhesion of epoxy compound to aluminum bronze

SYNTHESIS OF COPOLYMERS FOR PROTECTIVE COATINGS

Copolymers were obtained in this work and the methodology for their synthesis was worked out. Various fillers were selected for the polymer coating. Resulting copolymers have good adhesion required for composite protective coatings. An experiment was conducted to determine the corrosion resistance of metals coated with copolymers when exposed to aggressive environments, as well as to determine the hardness and thickness of the polymer coatings obtained. It was found that the polymer coating filled with bronze powder, despite the small thickness of 43.4 μm, hasthe best adhesion and corrosion properties, as well as having the highest hardness values of 80.5 HB. Such physical and mechanical properties of polymer coatings allow them to be used as protective coatings for metal products working under the influence of aggressive media.

Feasibility Examination of the Field Multi-focal Metallography Method (FMM) for Characterisation of Metallic Marine Artefacts

Field multi-focal metallography (FMM) is a development of field metallographic replication (FMR). It is an innovative minimally destructive technique that facilitates high-resolution metallographic observations of metallic object surfaces, regardless of their orientation to the optical axis of the microscope. Several artefacts retrieved during underwater excavations (a bronze powder chamber, a stud-link anchor chain, a winch, a heart-shaped shackle, a deadeye strap with a futtock plate, and an iron stud-link chain controller) were examined. The FMM results were compared with conventional metallography, where the sampling process inflicts substantial damage to the item. This FMM trial produced results of comparable quality to conventional metallography for both the bronze and the ferrous objects. It revealed the microstructure of the archaeological objects with minimal damage. The FMM method was shown to be a suitable tool for the study of ancient metal objects retrieved from shipwrecks.

RbxCsyWO3 based superhydrophobic transparent thermal insulation film for energy saving

Superhydrophobic transparent insulation film has attracted more attentions in the field of energy-saving glass due to its excellent near-infrared (NIR) shielding property and good self-cleaning performance. In this study, Rb+, Cs+ co-doped tungsten bronze powders were synthesized through a solvothermal reaction, and the superhydrophobic transparent thermal insulation film was constructed on glass. Results show that the strategy of Rb+, Cs+ co-doping can improve the NIR shielding property by incorporating more alkali metal ions into the hexagonal channel and can increase the content of W5+. When n(Rb)/n(Cs)=2, the film exhibits the best NIR shielding performance, with a visible transmittance of 55.6% and an NIR shielding rate of 94.6%. The superhydrophobic tungsten bronze film was successfully prepared with a water contact angle of 163.3±4.1°. The film also exhibits good chemical stability and water impact resistance, with a visible light transmittance of 62.7%, and an NIR shielding rate of 92.9%. The maximum temperature difference in insulation between the uncoated glass and the glass coated with R2WO's PVA/PDMS/SiO2-2 film is 8.9℃ under the irradiation of a tungsten lamp. In conclusion, R2WO's PVA/PDMS/SiO2-2 film, which exhibits excellent heat insulation and good self-cleaning ability, holds great potential for application in the energy-saving glass industry.

Corrosion resistance of powder metallurgy fabricated Cu–10Sn/SiC/mica hybrid composite

Abstract For the first time, bronze/SiC/mica hybrid composite has been manufactured using powder metallurgy method. Mixture – process variable design has been applied to design of experiments and optimization of the composite composition, as well as the production process variables (compaction pressure and sintering temperature) to attain superior corrosion resistance. This involved mixing different compositions of bronze, SiC, and mica powders, which were subsequently subjected to varied pressures and temperatures during the pressing and sintering stages, all in accordance with the experimental design plan. The microstructure, chemical composition, and elemental distribution of the samples were examined using scanning electron microscope equipped by energy dispersive X-ray analyzer, and an optical microscope. In order to study the corrosion resistance, potentiodynamic polarization test and electrochemical impedance spectroscopy were performed in 3.5 wt.% NaCl solution. The results revealed that co-incorporation of SiC and mica particles in Cu–10Sn bronze matrix increases the corrosion resistance, with a synergistic effect between these particles. The result of optimization process showed that the highest corrosion resistance could be achieved for the composite with the composition of Cu–10Sn/9.85SiC/0.67mica. This outcome was subsequently validated through experimental procedures.

Boosted near-infrared shielding properties of cesium-tungsten bronze based on solid state reaction with optimized precursor

Cesium doped tungsten bronze (CWO) nanoparticles can selectively keep high transmittance in the visible while presenting significant shielding rate in the near-infrared region. How to further improve the optical properties of CWO based on solid state method is crucial to the industry production. Based on changing the particle size and morphology of WO3 precursors, cesium-tungsten bronze powders with different dispersivity and concentrations of Cs+ doping were successfully prepared by solid-phase method. The characterization analysis reveals that the precursors with appropriated surface area and morphology are significant to improve the dispersivity of CWO nanocrystal and increase the density of free carriers, thereby improving the small polariton absorption performance and the local surface plasmon resonance effect. The result provides an effective strategy to boost the optical property of CWO nanocrystal synthesized by optimizing the morphology and size of precursor, which is important to the industry production and practical applications in the field of energy-saving window films.

ПРИМЕНЕНИЕ ВТОРИЧНЫХ ПОРОШКОВЫХ МАТЕРИАЛОВ ДЛЯ ВОССТАНОВЛЕНИЯ БРОНЗОВЫХ ДЕТАЛЕЙ ГИДРОМАШИН

During the operation of agricultural machinery, machine parts and their connections lose their operability, which requires their replacement. The cost of restoration is 50-60 percent of the cost of a new part. The presence of non-ferrous metal and alloy parts in the equipment, and in particular bronze, makes the issue of restoration even more urgent due to the high cost of such parts. Methods using powder materials are particularly successful in restoring worn parts. It is characteristic that in order to reduce the cost of such technologies, it is possible to resort to recycling of metal waste and obtain powder by electroerosive dispersion without special economic costs. (Research purpose) The research purpose is studying the restoration of bronze parts of hydraulic machines with secondary powder materials and analyzing the tribotechnical indicators of the coatings obtained. (Materials and methods) The following equipment was used in the work: an Elitron-52B pulse generator, a scanning electron microscope, a spark plasma sintering unit, an electric spark alloying unit, an X-ray fluorescence spectrometer, a metallographic microscope, a tribometer, analytical scales, a drying cabinet, a set of sieves. (Results and discussion) Electrodes were made from bronze powder obtained by the method of electroerosive dispersion. Using electric spark alloying, samples with coatings from a standard and a new obtained electrode were created. The tribotechnical properties of these coatings were compared. Metallographic and chemical analyses were performed. (Conclusions) The coatings obtained with the new electrode showed the best tribotechnical characteristics in dry friction. At boundary friction, their performance was worse, which may be due to an incorrect choice of lubrication, modes of electric spark alloying and a violation of the technology for obtaining the electrode itself. In general, the use of secondary powder materials for the restoration of bronze parts is relevant.

Destruction mechanisms of epoxybased composite filled with metal powder under cavitation attack

The samples of epoxy compound with a powder filler and without it are tested on cavitation wear. The powder of aluminum bronze BrAZhNMts9–4–4–1 is used as a filler. The powder is obtained by filing the rod of the bronze. The composition of the epoxy compound is 100 parts of the resin K‑153 plus 12 parts of the hardener (polyethylene epolyamine). The distribution of the bronze particles in the epoxy compound follows the law close to the exponential one, the average particle size is equal to approximately 27 μm, and the volume fraction of the bronze powder in the compound is about 9,5 percent. The tests are conducted using the ultrasonic magnetostrictve vibrator UZDN‑2T in fresh water of room temperature, the frequency and amplitude of the vibrator horn end equal to 22 kHz and 28 µm respectively. The distance between the horn end and the sample surface is 0,5 mm. During the experiments the wear of the samples is evaluated by their weighting on analytical scales with step-type indication of 0,1 mg, measuring the surface roughness and the microhardness of the bronze particles in the composite is carried out as well. It has been shown that the addition of the bronze particles into the epoxy compound not only changes the kinetics of cavitation wear of the polymer but also decreases its cavitation resistance. The decrease in cavitation resistance caused by bronze particles addition is attributed to the fact, that the boundary between a metal particle and epoxy matrix is a «weak» spot, and the destruction of polymer begins from this boundary area under cavitation attack.

The Mechanical Properties of Thin-Walled Specimens Printed from a Bronze-Filled PLA-Based Composite Filament Using Fused Deposition Modelling.

This article focuses on the mechanical property analysis of important models omitted in many scientific papers (thin-walled specimens) printed from innovative material-such as PLA + bronze composite-using fused deposition modelling technology. It discusses the printing process, the measurement of the specimen geometry, the static tensile strength tests and the microscopic examinations conducted with a scanning electron microscope. The findings of this study could be used as an input to further research into the accuracy of filament deposition and the modification of base materials with bronze powder and for the optimization of the machine design, e.g., with the use of cell structures. The experimental results indicated that the thin-walled models fabricated using FDM showed substantial differences in tensile strength, depending on the specimen's thickness and the printing orientation. It was shown that it was not possible to test thin-walled models located on the building platform along the Z axis due to the lack of sufficient adhesion between the layers.

Investigation of Upgraded Technology for Plasma Spraying of Bronze Powder Using the Combined Process with Hydrocarbon Additions

The object of the research is thermal spray process for the formation of metal coating from bronze powder in plasma-fuel variant, using direct current (DC) electric arc plasma torch, on steel samples. The aim of the work was to investigate and develop the technology for plasma-fuel spraying of functional coatings (for wear-resistant and antimicrobial applications) on machine-building and medical purpose pieces with increased process capacity and moderate energy consumptions in a comparison with conventional thermal spray technologies with use of inert and oxygen-free gas media. During the study, using experimental and thermodynamic estimation methods, the thermal and chemical parameters of the process under the spraying conditions at ambient pressure were characterized, which made it possible to determine the area of preferred regimes of the developed technology. On the modernized testing unit for plasma spraying of metal powders with power of up to 40 kW, operating using a controlled combination of three types of gases – technical nitrogen and propane-butane (LPG) with compressed air, the measurement and optimization of the operating and constructive/assembling parameters of the system for aluminum bronze coating spraying were established. In this case, the experiments were carried out using the designed fuel intensifier, which is joined with the PP-25 arc plasma torch, as well as additional technological equipment (protective shroud). For samples of the resulting coatings with a thickness of 100 to 450 mm from the bronze material, testing of phase composition and some parameters of the resulting coatings on steel products was carried out. Operating capacity of the proposed process reaches 7–15 kg/h for bronze powder when using a moderate power of the torch – up to 35–40 kW and a limited flow rate of hydrocarbon gas (for example, LPG of the SPBT grade) – 0.1–0.35 kg/h. Analysis of the energy efficiency parameters of the developed technology, as well as its calculated technical characteristics, in a comparison with plasma and combined equipment of a similar purpose, showed that it has an advantage in terms of target indicators, in particular, in terms of energy consumption and total energy efficiency of the spraying unit, not less than 20–30 %. This makes it to proceed later to the stage of application of this technology into production based on a new process for the metal coating formation, in particular with antimicrobial properties, with improved energy efficiency of the process.

Sequential Solidification of Metal Powder by a Scanning Microwave Applicator.

This study examines the fundamental feasibility of sequential metal-powder solidification by localized microwave-heating (LMH) provided by a scanning, all-solid-state microwave applicator. This continuous process is considered for the additive manufacturing (AM) and 3D printing (3DP) applications of metal parts. In previous studies, we employed LMH for the incremental solidification of small batches of metal powder in a stepwise vertical manner. Here, we study a continuous lateral LMH process, layer by layer, in a fashion similar to laser scanning in powder beds, as performed in common laser-based AM systems. LMH solidification at scanning rates of ~1 mm3/s is obtained in bronze powder using ~0.25-kW microwave power. The effect is studied here by LMH scanning in one lateral dimension (~20-mm long) in layers, each of ~1-4 mm thickness and ~2-4 mm width (mechanically confined). Imperfect solid bars of ~20×4×5 mm3 are obtained with rough surfaces. Their joining in an L shape is also demonstrated. The experimental solidified products are tested, and their hardness and density properties are found to be comparable to laser-based AM products. The capabilities and limitations of the LMH scanning concept for metal-powder solidification are evaluated. The potential feasibility of a solid-state LMH-AM technology is discussed.

Production of electrodes by spark plasma sintering method of secondary powder materials

The article considers the practical possibility of manufacturing electrodes from secondary powder materials. Obtaining electrodes with desired properties suitable for electrospark alloying processes. Bronze powder obtained from waste metal scrap by electroerosive dispersion was used. The following equipment was also used: spark plasma sintering system SPS 10-3 from Thermal Technology, drying cabinet ShS-80-01 SPU, set of sieves according to GOST 2715—75, analytical balance Acculab ALC-210d4, XRD-6000 Shimadzu diffractometer, X-ray fluorescence spectrometer Niton XL3t 900 GOLDD+. Secondary bronze fine powder was subjected to pressure sintering in an SPS 10-3 spark plasma sintering system from Thermal Technology. The maximum temperature was 910 °C, pressure — 40 MPa. Materials before and after were examined for elemental composition. The resulting briquette was cut into electrodes, and test surfacing was carried out by the method of electrospark alloying. Using spark plasma sintering, it is possible to obtain electrodes from secondary bronze powder materials suitable for electrospark alloying processes.

Structure and Properties of Mechanically Synthesized Tin Bronze Powders and the Related Sintered Materials

Structure and Properties of Mechanically Synthesized Tin Bronze Powders and the Related Sintered Materials

Mechanical characteristics of laser-deposited sandwich structures and quasi-homogeneous alloys of Fe-Cu system

The laser metal deposition approach implements a unique opportunity for controlling the fabrication of functionally graded and sandwich structures from different metal powders for artificial physical properties management. In this study, the quasi-homogeneous alloys were fabricated by the simultaneous feed of bronze and steel powders from different feeders of the LMD installation and the gradient structures by alternating deposition of the materials. The resulting alloys consisted of 50 wt% − 50 wt% and 25 wt% − 75 wt% non-gradient bronze-steel parts and sandwich structures of alternating 250-μm-height steel and bronze layers. The alloy based on aluminum bronze demonstrated the highest ultimate tensile strength (838.6 MPa). Its yield stress amounted to 665 MPa, strain-to-fracture – 0.035, Poisson’s ratio – 0.23, and modulus of resilience – 1.03 MJ/m3. A digital image correlation approach was applied to study the character of major strain distribution in the fabricated specimens and localizations of strain concentrators and compare them with all specimens’ failure areas. Fractography analysis showed a predominantly brittle character of failure. Investigated materials are expected to be applied as interface regions of Fe-Cu system functionally graded structures.

Experimental investigation of WEDM process parameters on properties of bronze particles using the Taguchi method

Electrical discharge erosion in liquid media is a simple, effective technique to generate multi-scale metallic particles. An experimental investigation was conducted to determine the main machining parameters which contribute to particle size (PS) and size distribution (SD) in WEDM of bronze. Five factors, including three-level built-in processing patterns, wire speed and dielectric medium, are selected as control parameters using an orthogonal array L16(45) Taguchi method, PS and SD of produced powders are the measure of quality. The goal is to obtain micron-scale spherical metal powder with uniform particle size. Results show that cutting-section pattern is the most significant factor, and the electrolyte is the least. The PS and SD performance of the optimized powders is significantly improved by using Taguchi method. Spherical bronze powder with particle size of d10 11.05 μm, d50 31.13 μm and d90 67.48 μm are prepared using the optimized WEDM process parameter, which is A3–B4–C3–D1–E1 including dielectric medium water, cutting class 4, cutting division 3, cutting Sect. 1 and wire speed 200 μm/s. The research confirms that WEDM can be used to produce micron-scale metallic powders, providing cheap and high-quality metallic powders for the metal additive manufacturing industry.

Metallurgical analysis of a bronze powder chamber retrieved from an underwater excavation in Akko (Israel): an application of novel minimally destructive field multi-focal metallography

Metallurgical analysis of a bronze powder chamber retrieved from an underwater excavation in Akko (Israel): an application of novel minimally destructive field multi-focal metallography

Microstructure and properties of cold sprayed aluminum bronze coating on MBLS10A-200 magnesium-lithium alloy

Aluminum bronze coatings were prepared on MBLS10A-200 magnesium-lithium alloy substrate by cold spraying technology to improve the surface properties of Mg–Li alloys. The microstructure, phase composition, microhardness, tribological properties and corrosion resistance of the coatings were systematically analyzed. The results show that aluminum bronze coatings are mainly composed of α phase. β phase in the original aluminum bronze powder disappeared in the coating due to the eutectoid transition of β→α + γ2 during the cold spraying. Compared with the Mg–Li alloy substrate, the aluminum bronze coating exhibits the higher microhardness (222.88 HV0.3) and wear resistance (friction coefficients, wear track widths and wear mass losses are 0.37, 0.79 mm and 2.47 mg, respectively). The dominant wear mechanism of the coatings was abrasive wear. In the electrochemical test, the corrosion current density of the aluminum bronze coating (3.07 × 10−5 A/cm2) was an order of magnitude lower than that of Mg–Li alloy substrate (6.15 × 10−4 A/cm2), indicating that the coating had superior corrosion resistance. The above analysis confirms that preparing a cold sprayed aluminum bronze coating has outstanding tribological and corrosion resistance properties.

Evaluation of Sulfides as Solid Lubricant: Lubricity of Compounded Sulfides

Sulfide was used as solid lubricant, and MoS2 was popular. It was used industry as powder shape. Sulfur as oil additive; ZDDP, MoTDC were also well known. These composites make tribofilm which prevent seizure, scoring and some tribological troubles. In this paper, sulfides were synthesized by powder metallurgy technics. In addition, these sulfides were mixed with bronze powders and sintered as cylindrical specimen. As a result of the friction test in the lubricated condition, tribofilm were covered with specimen surface. By XPS observation, sulfides and oxides were detected on the specimen surface. In the test, additive was not contained in the lubricant because PAO as base oil was adapted. However, sulfide in the specimen affect the making the tribofilm, especially when bornite (Cu5FeS4) was used.