You are browsing the archives of 2012 May.

Credit: ACS_Live.

Given that in the last few days there have been high-profile stories about tuna being caught in the Pacific with trace (but, apparently, not unsafe) amounts of cesium from the Fukushima incident, I thought it might be timely to highlight some interesting work by an ACerS member regarding materials that could aid in the removal of some nasty contaminants in food and water supplies.

I am speaking of the work of Oklahoma State University chemistry professor Allen Apblett, whose research has been paying off in developing radiation-snaring materials. Apblett’s efforts were featured a few months ago at the annual meeting of the American Chemical Society, where the above video was taped.

In brief, Apblett has developed special ceramic pellets composed of alumina coated with nanoparticles of metal oxides designed to absorb, for example, cesium, by swapping it with a calcium ion. They could be used to decontaminate milk, baby formula and other drinks following a radioactive disaster such as Fukushima.

His work originated when he was working on a successful project to develop materials to remove uranium from water supplies. He explains that in the course of that work, he and his colleagues discovered another material that could selectively remove actinides and other toxic elements, such as lead and arsenic.

He suggest that the pellets be put in a porous capsule that then could be used by food manufacturers to process large batches of liquids such as apple juice or brown rice syrup contaminated with radioactive or non-radioactive toxic substances. (The capsule, of course, would eventually be removed before final processing, and the materials could be sent to a special recycling facility.)

Apblett says in the ACS presentation that he estimates such a capsule could remove all the radioactive strontium from a container of milk within 12 hours without changing the taste of the milk. He points out that tests have been conducted to make sure the pellets, themselves, don’t somehow contaminate the milk.

Apblett told the university’s newspaper, the O’Collegian, that he came across this discovery during routine testing in the laboratory to observe how calcium interfered with the process of uranium. What Apblett discovered was not what he was expecting.

“We found that not only did calcium not interfere, but it actually made the reaction go faster,” Apblett says in the story.

Apblett is working to commercialize some of the potential applications for the pellets. An OSU news release describes the creation of a business called Associated Material Processing, “the first company to enter the commercialization process through the early seed investor fund provided by Cowboy Technologies, LLC at Oklahoma State University.” The school credits Apblett with providing the technology for AMP, specifically “a system for arsenic byproduct removal from water and was targeted by Cowboy Technologies for use in the semi-conductor industry.”

Share

AGC’s new chemically strengthened Leoflex glass coming June 1. Credit: AGC.

Here is what we are hearing:

Khosla joins Bill Gates & Total to back Liquid Metal Battery

(GigaOm) Liquid Metal Battery, a startup developing a battery for the power grid that already counted Bill Gates and oil giant Total as an investor, has now brought on another high profile backer: Khosla Ventures. The startup, which is the brainchild of MIT Professor Donald Sadoway and is based in Cambridge, plans to announce on Thursday that it has raised a Series B round of $15 million led by Khosla Ventures. Liquid Metal Battery is developing a battery for the power grid using molten salt sandwiched between two layers of liquid metal. The battery is still at least two years from commercialization, and the team has built a 16-inch prototype, though they might later scale that up to 36 inches. The company is betting that a battery based on liquid metal electrodes will be stable, scalable, and low cost enough that it could revolutionize grid storage.

Siam Cement Group receives Gold LEED rating

Testament to its leadership in sustainability and environment-friendly business operations, the
ASEAN conglomerate Siam Cement Group, has received a gold rating in Leadership in Energy and Environmental Design for Existing Building: Operations & Maintenance for its corporate headquarters. Moreover, highlighting its continued commitment to forwarding green operations in the Philippines with its subsidiary, Mariwasa Siam Ceramics, the Conglomerate has increased its stake in MSC from 46% to 83c. The conglomerate’s headquarters was recently renovated to be more energy-efficient and environment friendly. For their efforts, SCG won the Thai Energy Award in the retrofitted building category, and was also the first runner-up in the same category at the Asean Best Practice for Energy Efficient Building Awards in 2011.

Doulton brings over 185 years of ceramic filtration technology to filtersfast.com

Filtersfast.com, an authoritative resource for consumers regarding the importance of changing residential and commercial air filters and water filters, is a supplier of Doulton eco-friendly, reusable cartridge filters. Providing safe, healthy, great-tasting drinking water wherever and whenever you need it is the basic principle behind Doulton products. Fairey Industrial Ceramics Ltd. is the sole manufacturer of the world famous range of Doulton ceramic drinking water filters. Millions of Doulton ceramic filter candles are produced annually, which sells to 140 countries worldwide. Their global success is due to the versatility of the products by producing clean, healthy, great tasting water, at anytime and anywhere. Installing a home filtration system offers a greener and cost effective solution to having good quality drinking water. Bottled water is expensive to buy and produces a lot of plastic waste that is not an eco-friendly alternative. Whether a filter unit is needed underneath the kitchen sink, on the countertop, mounted on a wall or in the back of a water cooler, Doulton provides drinking water solutions for practically every situation.

Washington Mills expands aluminum oxide recycling services

Washington Mills has expanded its aluminum oxide recycling services for spent aluminum oxide blasting grit. Improvements have been made that allow Washington Mills to recycle higher volumes of dust and finer spent aluminum oxide blasting grit and powder than ever before. The previous system limited the amount of very fine material that could be recycled, but new developments have eliminated the grit size restrictions. Washington Mills recycles spent aluminum oxide blasting grain in a completely closed loop recycling system by utilizing its unique furnace technology. It recycles 100 percent of the material in a totally closed loop process that leaves no waste. Washington Mills offers companies holding spent blasting grain an environmentally friendly and cost effective way of getting rid of 100 percent of their spent grit that avoids landfill costs.

Morgan Technical Ceramics celebrates 50th anniversary of Auburn manufacturing site

Morgan Technical Ceramics proudly announced the 50th anniversary of its Auburn, Calif., site, which has grown from its humble beginnings in a garage to become a key supplier of engineered structural ceramic components used in the medical instrument, analytical equipment, power generation and aerospace markets. MTC Auburn is renowned for its ability to work with customers to develop and produce technically challenging parts, and for its outstanding customer service. Operations began in 1962 as R&W products, founded by Will Rogers and Bob Wire in a garage in Redwood City, California. Growing rapidly, the firm moved to the foothills of the Sierras in 1978, becoming the first high-technology company in Auburn. It was later purchased by Carpenter Technology, a US-based specialty alloy company. In 2008, the company was acquired by the Morgan Crucible Company Plc. and became a part of its Morgan Technical Ceramics business. The Auburn site has continued to expand its production of custom-made, high-precision ceramic components. The vertically integrated Auburn facility provides complete solutions to its customers, beginning with green machining and firing materials in-house and carrying the process through to the finished product, which could be a metalized product or a brazed assembly.

Gas hydrates research and characterization using calorimetry

Gas hydrates are an important, and growing area of research for widely different applications from flow assurance - especially when considering deep off shore exploration—methane recovery from large hydrate deposits and of course for storage and transportation of gases by creation of the such hydrates. Traditional techniques are severely restricted by sample nature, in particular the presence of particles or fines and calorimetry is becoming an ever more important technique. Calorimetry has been used on hydrates for a while, however with the development of a range of Calvet sensors Setaram has enabled the simulation of pressures up to 1000 bar, the use of truly representative samples and in some cases a bench top system that can be used in the field. Setaram presents a new free of charge applications summary, detailing important experimental parameters and some of the experiments produced in the field today.

AGC unveils Leoflex, a chemically strengthened specialty glass for versatile applications

Asahi Glass Co. announced it is releaseing Leoflex, a newly-developed chemically strengthened glass, on June 1. Leoflex is stronger than conventional soda-lime glass and is resistant to cracking, even with its reduced thickness, which will enable us to significantly reduce the weight of glass. With Leoflex, AGC will respond to the need for more lightweight glass of all sizes in a wide range of applications such as solar panels, building materials, and lighting. AGC has been supplying soda-lime glass in various markets such as construction, automobile, solar power generation. AGC will capitalize on its understanding of the needs and technical expertise in these markets and promote the use of the Leoflex specialty glass that enables weight reduction across a wide range of applications, such as solar panels, building materials, and lighting.

Take the guess work out of film testing!

Brookfield Engineering Laboratories offers the TA-FSF Film Support Fixture for their CT3 Texture Tester. The Film Support Fixture is designed to test the rupture strength, resilience and relaxation properties of thin films and other similar products. Brookfield’s TexturePro CT software, when used with the CT3 Tester, enables the operator to automate test procedures and generate valuable data for analyzing the strength of film products. CT3 Tester is the best value in a stand-alone instrument for physical testing. It combines simplicity of operation with expanded test-method capability and operates in both compression and tension modes. A wide variety of standard probes, (cones, cylinders, blades, balls, punches) and fixtures (extrusion cell, shear cell, grips, etc.) are available for a multitude of applications.

New white paper: Quantifying the impact of humidity on powder properties

New experimental data from Freeman Technology demonstrate how dynamic, shear and bulk powder testing can be applied to quantify the impact of humidity on powder behaviour, supporting the need to develop effective strategies for moisture control and process optimization. “Quantifying the impact of humidity on powder properties,” by Brian Armstrong (Powder Technologist) and Jamie Clayton (Operations Manager), Freeman Technology, is now available for download at the company website. Of the many factors that influence powder behaviour, moisture, or humidity, is perhaps one of the most instantly recognised and potentially one of the most problematic. Adding even small amounts of water to a powder can transform its properties. The challenge for formulators and process engineers is to understand the extent to which a powder will take up moisture and, more importantly, how this will affect the powder and its performance. The new white paper explores the impact of humidity through the application of dynamic, shear and bulk property testing using Freeman Technology’s FT4 Powder Rheometer. Together these techniques reliably quantify how powder behaviour changes as a result of moisture uptake, providing the comprehensive insight needed to develop effective strategies for moisture control and process optimization.

Share

BCC Research predicts strong growth for smart-glass products over the next five years. Credit: BCC Research.

Apparently some business researchers believe the demand for smart-glass products in the construction industry is poised to soar. Undoubtedly, smart glass—think photochromic and electrochromic glass, windows and curtain walls—has a big future because of potential energy savings and also because they open up huge opportunities for innovative interior designs that are based on walls that can instantly transition from opaque to clear.

I, however, have no particular insights and am agnostic about how quickly demand will climb. Nevertheless, the staff at BCC Research have strong opinions and they say in a new report that the global market for smart glass-based products will grow at a compound annual growth rate (CAGR) of 21.6 percent from 2011 to 2016, reaching global revenues of nearly $4.2 billion in 2016. That’s a helluva good growth rate (compare this to the 10 percent growth rate BCC recently predicted for sol-gel product markets).

Interestingly, they say the market has been expanding at a pretty healthy clip the last few years, having increased from $883.1 million in 2009, then to $1.2 billion in 2010 and nearly $1.6 billion in 2011. Of that, BCC says the construction segment reached $92.7 million in 2010 and $113.3 million in 2011. This segment is expected to reach $224.3 million by 2016, a CAGR of 14.6%.

What I found to be unexpected is that BCC says the smart glass market in commercial buildings only reached $69.8 million in 2010 and $79.7 million in 2011 (with a projection of reaching $129.5 million by 2016, a CAGR of 10.6 percent). As the chart above indicates, the largest demand has been, and will continue to be, in the transportation and aerospace sectors. I know that smart glass is being used in auto and truck mirrors, and in special displays in aircraft, but perhaps I am missing some other major applications in those sectors.

BCC’s report contains eight sections: history; technical overview; global market analysis (by product type, application and region); overviews of the transportation and aerospace, construction and electronics markets; global industry structure; and finally an analysis of US patents (by region, country, assignee, patent category, application and smart glass type).

For more about smart glass applications, here are a couple of overview videos, the first covering use in the automotive and aerospace industries and the second in construction and interior design

Share

SEM photograph of hexagonal ferrite crystals. 30000 X magnification, scale bar = 1 microns (0.0001 cm). Credit: Robert C. Pullar.

Hexagonal ferrite ceramics have well known abilities and properties, and are used in everything from fridge magnets to high-tech applications. Now, scientists have discovered room-temperature multiferroic hexaferrites, a development that extends the capabilities of these materials tremendously.

Hexagonal ferrites, also known as hexaferrites, are magnetic iron oxides with a hexagonal structure. They are formed by iron, oxygen and one or more other elements, which could be barium, strontium, cobalt, or a combination of these.

The development of hexagonal ferrites started in the 1950s, when scientists studied and tried to reproduce the structure of magnetoplumbite, a natural magnetic mineral. In the synthetic hexagonal ferrites, lead is replaced by barium or strontium, the simplest example being BaFe₁₂O₁₉.

Hexagonal ferrites are the most common magnetic materials used today, covering about 90% of the market - and it’s a big market: in 2012, it was worth almost $4 billion. Over 300,000 tons of the most common hexagonal ferrite, BaFe₁₂O₁₉, are produced every year, which corresponds to 50 grams for every person on earth.

The wide spread use of ferrite magnets is due to their lower cost compared to other magnets, such as metallic alloys, the best of which are based on the expensive rare earth metal neodymium.

Hexagonal ferrites are currently employed in many different sectors: permanent magnets, such as fridge magnets (both the magnet which keeps the door shut, and the one you stick on the outside), electric motors (there are about 100 different ferrite-based motors in every car) and loudspeakers.

Another important use is data storage. Many computer hard disks and tapes are made of hexagonal ferrites, some having very impressive storage capacity. In 2011, for example, Fujifilm produced a barium hexaferrite-based tape with a memory of 5 terabytes, so large that one tape could store the equivalent of eight million books.

Other uses include microwave devices, wireless communications and stealth and RAM (radar absorbing material) technology.

Although these current applications are very important, the search is on to improve the properties of these materials and to find innovative applications. Recently there has been increasing interest in hexaferrite nanofibers, and fiber alignment effects on magnetic properties. Nanotechnology and composites are also growing areas of research.

SrCoZnFe16O27 (W hexaferrite) crystal unit cell. Green = strontium; red = iron, cobalt or zinc; brown & pink = oxygen atoms. Credit: Robert C. Pullar.

In the last year, there has been a sudden growth of interest in hexagonal ferrites because of their room temperature multiferroic properties. Multiferroics are materials that can be both ferromagnetic and ferroelectric; moreover, the magnetic properties can affect the electric ones, and vice versa, a process known as coupling. There are very few single-phase materials that show multiferroic behavior at room temperature. Instead, they usually need cooling to cryogenic temperatures to exhibit these properties. However, the hexaferrite Sr₃Co₂Fe₂₄O₄₁ was found in 2010 to be a room-temperature multiferroic, and several other hexagonal ferrites have also been recently reported as room-temperature multiferroics.

Last year there were a record number of papers published on hexaferrites. The use of hexaferrites in multiferroic applications has immense potential, and could be used for various technologies, such as highly sensitive magnetic field sensors (used in biomedicine), a new generation of smart stealth technology (used in military and defense), improved data storage solutions for IT and computing, and field-responsive smart filters and switches for wireless communications. Furthermore, hexaferrites are already major global commercial products, cheaply produced in great quantities, and no special processing is required to make them. Therefore, their production for multiferroic applications is definitely feasible.

For more information on these materials, see a new in-depth review in Progress in Materials Science, which continues to looks at the past, present and future of these important ceramic materials.

(Robert C. Pullar is a member of the Department of Materials and Ceramic Engineering, University of Aveiro, Aveiro 3810-193, Portugal)

Share

For many high-temperature applications, ceramics are indispensable. No other engineering materials offer such high stiffness, strength, hardness and durability in the same package. The major difficulty in applying ceramic materials is their relatively low fracture toughness. Ceramic materials are generally vulnerable to tensile stresses and impact loading. Cracks propagate with high speed, which leads to sudden failure of ceramic components.

The use of segmented, rather than monolithic, structures is an appropriate way to cope with this low fracture toughness. Cracks that do occur remain confined within a single segment. The segments can be held together by a binder phase, keys, and connectors or by virtue of special geometry and arrangement of the segments.

A group of researchers from the University of Bremen, Germany, the German Aerospace Center and the Monash University in Clayton, Australia, studied the force-fit connection of discrete ceramic components by means of geometrically interlocking surfaces. These surfaces possess a concavo-convex topology permitting assembly of structures in which each individual element is kinematically locked by its neighbors.

The researchers produced the elements by freeze gelation of ceramic slurries, which enable a near net shape and a low shrinkage. The freeze gelation process involves rapid freezing of colloidal dispersed slurries containing ceramic particles and subsequent drying and sintering. This method is cost-effective and offers many possibilities to control the production of ceramic parts.

For comparison, the group tested solid plates of the same ceramic material in the same loading mode. During loading, the planar surfaces within the interlocked structure lose contact to their neighbors. But the concavo-convex surfaces remain in contact. Cracks are localized within individual blocks. As no binder phase connects the constituent blocks, the weakest link principle does not fully apply to an interlocked structure. Thus, these structures allow for large deformations and are tolerant to missing or destroyed elements.

However, the solid plate could not withstand deformation beyond the point of maximum load, the segmented ones were able to maintain their structural integrity and stay deformable well beyond the point of maximum load. The assemblies of interlocked ceramic elements can withstand flexural deflections up to a ten-fold of those the solid plate from the same material can sustain.

A paper on this work, “Mechanical properties of topologically interlocked structures with elements produced by freeze gelation of ceramic slurries,” appears in Advanced Engineering Materials (doi:10.1002/adem.201100244)

(Martin Grolms writes for MaterialsViews.com)

Share