Gotowa bibliografia na temat „Electroplating, 1909”

A real electroplating wastewater, containing 51,190 mg/L of free cyanide (CNf), 4899 mg/L of Ni and 1904 mg/L of Cu, was treated with calcium alginate hydrogel beads (CAB), pure or impregnated with biodegraded grape marc (EBGM) or activated carbon (EAC) in order to reduce the elevated load of toxic pollutants below the regulatory limits. It was evaluated the effect of increasing the amount of bioadsorbent as well as the influence of two successive adsorption cycles in the removal efficiency of pollutants. The most favourable sorption conditions onto CAB provided removal percentages of 85.02% for CNf and between 93.40–98.21% for heavy metals regarding the raw wastewater. The adsorption capacity of each pollutant onto CAB was considerably increased during the first 30 min of contact time, but after achieving the equilibrium, the following sorption capacities were obtained: 1177, 107.3, 39.5 and 1.52 mg/g for CNf, Ni, Cu and Zn, respectively. The kinetic adsorption of pollutants onto the CAB was adjusted to different kinetic models, observing that kinetic data agreed with the pseudo-second-order model. The information about intraparticle diffusion mechanisms in the bioadsorption process was also interpreted.

Modern electrochemistry is generally regarded as having its origins in the work of the Italian scientists Galvani (1737 – 1798) and Volta (1745 – 1827). Their discoveries led directly to the invention (1799) by Volta of the voltaic pile, a primitive form of what we now call a battery. This invention greatly facilitated electrical experimentation and quickly led to a host of other electrochemical discoveries such as the electrolysis of water (Nicholson and Carlisle in 1800, although it was first demonstrated in 1789 by Deiman and van Troostwijk using an electrostatic generator), isolation of elemental alkali and alkaline earth metals (Davy, 1807–1808) and electroplating (Brugnatelli, 1805). The work of Davy (1778 – 1829) and of Faraday (1791 – 1867) greatly advanced the understanding of electrochemistry and Faraday’s laws of electrolysis (1833) put the field on a quantitative basis. This was followed by a long succession of electrochemical discoveries that has continued to the present. Scientists such as Daniell (1790 – 1845), Grove (1811 – 1896), Leclanché (1839 – 1882) and Planté (1834 – 1889) made early improvements to batteries; of course, research and development of batteries remains an important area of electrochemistry. Historically, batteries were the primary source of electric current until practical electric dynamos became available in about 1870. Electroplating developed as a practical technology from about 1840, initially for electrodeposition of copper on printing plates. From 1893 to 1948, the international standard for electric current was based on electrodeposition of silver. Furthermore, an electrochemical cell invented by Weston (1850 – 1936) was adopted as the reference standard for voltage in 1903 and remained so until 1990 when it was replaced by a Josephson junction standard. The science of electrochemistry experienced rapid growth from the 19th century on, with major contributions from European scientists including Kohlrausch (1840 – 1910), Ostwald (1853 – 1932), Arrhenius (1859 – 1927), Tafel (1862 – 1918), Nernst (1864 – 1941), and Heyrovský (1890 – 1967), to mention but a few. In this talk, I will attempt to trace the evolution of electrochemistry and discuss some of the major landmarks and the European scientists who made important contributions. I will also comment on how equipment and methodology have changed over the last half-century.

Industrial improvements to silver plating through the work of electroplating firms such as Elkington, Mason and Co are an important part of our industrial heritage, bridging art, science and industry to form a significant portion of museum collections. However, the impact of this development of silverplating technology upon photography has not previously been explored. This article details the improvements that electroplated silver brought to the daguerreotype photographic process and to the manufacture of daguerreotype plates in Birmingham, offering a material reappraisal of the inventive qualities of the daguerreotype within a wider narrative of industrial manufacture. Chemists in 1840s Birmingham were developing photographic techniques and silverplating processes at the Birmingham Royal School of Medicine and Surgery, later Queens College on Paradise Street. These scientists – George Shaw (1818–1904) and John Percy (1817–1889) – had detailed, tactile knowledge of the convergent chemistry and processes in both arenas. Developments in the industrial manufacture of silverplate in 1840s Birmingham created significant improvements to the materials used in the daguerreotype photographic process, making photography more viable as a commercial venture. Shaw planned an early portrait studio and worked with early innovators in electroplating techniques the Marrian brothers (Francis (1802–1893) and Benjamin James Pratt Marrian (1811–1891)) using magneto-plate technology developed by another Birmingham industrial entrepreneur John Woolrich (c. 1791–1843). This potential studio did not emerge due to restrictive patenting and licensing restrictions around the practice of daguerreotype photography, yet extant daguerreotypes tell a story of improvements stemming from technical innovation. These daguerreotypes situate industrial Birmingham as a place of innovation and invention and place the daguerreotype photographic process within narratives of industrial improvements and radically inventive manufacturing practices. Key to the analysis presented here is the role of the recreation of historic techniques in historical research and the value of acquiring tactile knowledge of the behaviour of materials during the processes explored. Here practical experiments allowed the author to look beyond the surviving daguerreotypes via material knowledge to the circumstances and social environment of production. This approach revealed new knowledge which offers an alternative reading of the history of objects through their materials.

AbstractThe practical application of AZIBs is hindered by problems such as dendrites and hydrogen evolution reactions caused by the thermodynamic instability of Zinc (Zn) metal. Modification of the Zn surface through interface engineering can effectively solve the above problems. Here, sulfonate‐derivatized graphene–boronene nanosheets (G&B‐S) composite interfacial layer is prepared to modulate the Zn plating/stripping and mitigates the side reactions with electrolyte through a simple and green electroplating method. Thanks to the electronegativity of the sulfonate groups, the G&B‐S interface promotes a dendrite‐free deposition behavior through a fast desolvation process and a uniform interfacial electric field mitigating the tip effect. Theoretical calculations and QCM‐D experiments confirmed the fast dynamic mechanism and excellent mechanical properties of the G&B‐S interfacial layer. By coupling the dynamics‐mechanics action, the G&B‐S@Zn symmetric battery is cycled for a long‐term of 1900 h at a high current density of 5 mA cm−2, with a low overpotential of ≈30 mV. Furthermore, when coupled with the LMO cathode, the LMO//G&B‐S@Zn cell also exhibits excellent performance, indicating the durability of the G&B‐S@Zn anode. Accordingly, this novel multifunctional interfacial layer offers a promising approach to significantly enhance the electrochemical performance of AZIBs.

Abstract Narrow beamwidth is highly desirable for many micromechanical elements moving parallel to the substrate. A good example is the electrostatically driven flexure structure, whose driving voltage is determined by the width of the beam. This paper presents the process flow and the result of a high-aspect-ratio electroplating process using photoresist (PR) molds. Following a systematic optimization method, PR molds with aspect ratios up to 4.0 were fabricated with a beamwidth of only 2.1μm. Higher aspect ratios, up to 6.8, were achieved using PR double coating technique, with a beamwidth of 2.6μm. Using a Cr/Cu seed layer, nickel electroplating was successfully carried out to translate the PR molds into nickel micro-structures. We observed bend-down of the fully released nickel cantilevers that are over 8μm thick. Further investigation suggested a combined effect of residual stress gradient in the electroplated nickel layer and in-use stiction of the cantilever beams.

Chemical vapor deposition (CVD) is an old coating technology, but it was not successfully utilized to aluminize gas turbine hardware until recently (1989). In CVD aluminizing, the use of multiple, independently controlled, low temperature, external, metal halide generators combined with computer control of all process variables gives flexibility and consistent quality that is not possible with any other aluminizing process. It has been shown that harmful coating impurities (such as sulfur and boron etc.) can be transported to a coating from a high temperature aluminum source in the coating chamber during aluminizing. Representative processes include: pack cementation, above the pack, SNECMA, and high activity CVD. In contrast, it has also been demonstrated that CVD low activity aluminizing removes harmful impurities (S, P, B & W etc.) from the coating during deposition. Furthermore, clean, low activity coatings (simple aluminide MDC-210 or platinum modified MDC-150L) have been shown to exhibit superior oxidation resistance compared to similar coatings made by other aluminizing processes. A second significant source of impurities in platinum modified aluminide diffusion coatings is electroplating, that is, plating bath components (S, P, CI, K, Ca etc.) are codeposited with the platinum, and these impurities can have either a beneficial (K&Ca) or a detrimental (S,P&Cl) influence upon the oxidation resistance of the product coating. The results of investigations on the transport of impurities during aluminizing and electroplating, plus the influence of these impurities on oxidation resistance of the product coatings will be presented and discussed.

An anodically oxidized alumina film includes numerous cylindrical micropores oriented parallel to each other and located at a spacing much smaller than the wavelength of light. By electroplating metals into the pores, a lattice of metallic columns can be constructed in the film that works as a wire grid type polarizer. We have fabricated a nickel-implanted alumina film by using sulfuric acid and nickel sulfamate. The extinction ratio of the prepared sample was >30 dB at a wavelength of 1.3 μm. On the other hand, when the pores are filled with suitable dielectric materials, the film becomes birefringent and works as a retardation plate. Using a He-Ne laser (λ = 0.63 (μm), we examined the alumina film with water in its pores and found that the refractive index varies as much as 4 X 10−3 depending on the direction of polarization. We have also developed a theory to predict these optical properties from the analysis of the electromagnetic field around the columns.

Abstract This paper describes a novel technology for multiple wafer frontside to backside interconnects, which has been applied to a multifunctional interconnect layer for an integrated microphone for hearing aid applications. Besides the interconnect layer with relatively large through-holes the stack consists of the microphone itself and an integrated circuit chip for signal conditioning. The patterning of the metallization on the interconnect wafer has been done using electrodepositable photoresist as mold for electroplating of a variety of metals. For the interconnect metallization we use copper. The bonding pads on the microphone side of the interconnect layer have been provided with under bump metallizations (UBM) and solder bumps. The IC side features a top surface metallization (TSM) suitable for conductive adhesive bonding. The realized feedthrough wires show good electrical performance in terms of low series resistance (100 mΩ) and small parasitic capacitance (< 1 pF).

In a continuing effort to increase component lifespan and decrease overhaul cost, the US Navy has completed a 2nd phase of the Rainbow Rotor project. This project, initiated in the early 1990’s, consists of three LM2500 main propulsion engine, high pressure turbines (HPT) built up with refurbished blade pairs protected by various coatings. This turbine was operated for over 7,000 hours on a Cruiser-class ship where it was subjected to a typical operating profile. Six coatings were examined ranging from differing chemical compositions to application processes. The coating compositions were of four types, CoCrAlHf, PtAl, Physical Vapor Deposition (PVD) Zirconia thermal barrier coating (TBC) with a PtAl bond coat and a silicon aluminide type coating. The BC-22 (CoCrAlHf) overlay coatings were applied by either a plasma spray process or an electroplating process. The PtAl coatings, supplied by two vendors, and the TBC were applied by standard commercial processes. The goal behind this study is to find a coating that has the best balance between cost and performance. With the already realized cost savings in using refurbished components to overhaul the gas turbine engine, the emphasis is now placed on delaying the deterioration of the reprocessed blade pairs. The following discussion covers all aspects of this completed phase.