Metal protection by anticorrosion papers in humid tropical climate

Results of 3-year full-scale field climatic tests on application of five types of inhibiting papers for anticorrosion protection of ferrous and nonferrous metals during storage in a humid tropical climate have been carried out by the Joint Russian and Vietnamese Tropical Research and Technology Center and presented here. It has been shown that the inhibiting paper IPCAS-118 can be recommended for anticorrosion protection of equipment made of steel, copper, and aluminum during 3-year storage in sheds in humid tropical climate conditions     

Dissolution of bioactive glasses: The effects of crystallinity coupled with stress

Fixing the chemical composition of bioactive ceramic glass does not dictate biological response. Processing history can alter the microstructure, phase composition, degree of crystallinity, and residual stress—all of which can contribute to mechanical performance and bioactive response. This paper discusses effects of thermal and mechanical processing performed on bioactive glass 45S5 with regard to the micro-structural changes that occur during in vitro immersion, and how such changes can be related to bioactivity with respect to implant materials. The underlying theme is the relationship between mechanical properties, stress, microstructure, and bioactivity, and how to achieve optimization.     

Anode effect elimination by subsonic and sonic vibrations

The only method so far used industrially to produce primary aluminum is the combination of the Bayer process with the Hall-Héroult process. The production process of aluminum which was patented by Charles Martin Hall and Paul Louis Toussaint Héroult in 1886, has long been important in our daily lives and that importance is likely to increase year by year. In this study, different subsonic and sonic vibrations, which were obtained from a 0.30 kW, 1,400 rpm three-phase motor, also a 0.55 kW, 2,800 rpm three-phase motor and 0.75 kW frequency converter, were applied to a laboratory-type aluminum electrolysis cell and the possibility of eliminating the anode effect was investigated.     

Bulk metallic glasses for biomedical applications

The selection criteria for biomaterials include the material’s properties and biocompatibility, and the ability to fabricate the desired shapes. Bulk metallic glasses (BMGs) are relative newcomers in the field of biomaterials but they exhibit an excellent combination of properties and processing capabilities desired for versatile implant applications. To further evaluate the suitability of BMGs for biomedical applications, we analyzed the biological responses they elicited in vitro and in vivo. The BMGs promoted cell adhesion and growth in vitro and induced improved foreign body responses in vivo suggesting their potential use as biomaterials. Because of the BMGs’ flexible chemistry, atomic structure, and surface topography, they offer a unique opportunity to fabricate complex implants and devices with a desirable biological response from a material with superior properties over currently used metallic biomaterials.     

Grain boundary complexions in ceramics and metals: An overview

The concepts of grain boundary phase transitions and complexions offer clues to resolve old problems such as abnormal grain growth and solid-state activated sintering as well as new opportunities for mechanism-informed materials design.     

The electrochemical recovery of metallic palladium from spent electroless plating solution

Semiconductor bond pads are sometimes coated with palladium for good electrical properties and wire adhesion. The palladium is deposited by immersing the wafers in an electroless plating solution. When the plating solution is depleted and no longer achieves the desired results it is treated as waste. This work investigates the recovery of the remaining palladium in the waste solution by means of electrochemical deposition onto a high surface area cathode. Experiments show that the remaining palladium can be recovered economically and efficiently. This makes the process environmentally friendly and cost effective.     

The nature and impacts of fines in smelter-grade alumina

Fines in smelter-grade aluminas are recognized as a significant process problem in aluminum smelting. However, understanding the nature of this fine material and how it impacts the reduction process are less clearly understood. The combination of new analytical methods such as variable pressure scanning electron microscopy and very high field solid state nuclear magnetic resonance provide new insights into the phases present and their spatial distribution within aluminas, and suggest how such fine materials are generated, particularly during calcination in the alumina refinery.     

Winning the global race for solar silicon

While there are numerous contestants in the race to produce low-cost solar silicon, the chemistries involved can be grouped into three categories: new Siemens-like processes, new approaches to reduction of silica, and upgrades of metallurgical-grade silicon. This review is focused on the thermo-chemistries being employed in the last two categories, with emphasis on removal of boron and phosphorous, as these elements are the two most difficult to remove from silicon by unidirectional solidification.