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Carbon-coated sand improves purification of drinking water

Where’s the octopus?

Yacht designers turn to Zircotec’s ceramic technology for durability & performance gains

Poneman to lead interagency delegation to Brasília to launch the US–Brazil strategic energy dialogue

Eye-pleasing energy reshapes power designs

‘Hybrid’ solar system proves cheaper than photovoltaics

Japanese rare earth consumers set up shop in China

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Chemically bonded phosphate ceramic coating on a metal substrate (black region) (50x original magnification). Credit: EonCoat

Corrosion is expensive. The cost of corrosion to industrialized nations is about 3 percent of GDP. In the United States that adds up to $2-4 trillion per decade, which equates to rebuilding Hurricane Katrina-scale infrastructure three or four times.

A recent online article published by Environmental Protection reports on a new protective coating based on chemically bonded phosphate ceramics. CBPCs are a class of materials that were developed originally at Argonne National Lab (pdf) and Battelle (pdf) to stabilize mercury-containing DOE wastes. A Raleigh-Durham Research Triangle company, EonCoat, has picked up the technology and developed it into a corrosion resistant coating.

The DOE reports linked above describe the CBPC acid-base synthesis reaction between magnesium oxide and a mono-potassium phosphate solution (KH₂PO₄). The chemical reaction yields MgKPO₄-6H₂O, a hard, dense material.

The EonCoat product is applied as a two-component system that is sprayed simultaneously in a 1:1 ratio using standard plural spray equipment. The components react with the substrate in a mildly exothermic reaction, which “creates an alloyed metal surface rather than a layer that sits on top of the substrate,” the EP story says, and that “makes it virtually impossible for corrosion promoters like oxygen and humidity to get behind the coating…”

The coatings have the additional advantage of being able to accommodate flexure up to 19 percent. According to the company website, “fibers and fillers with an acicular structure…create toughness and additional ductility (flexibility).” Most ceramics cannot accommodate such additives because they burn during firing, however the heat released by the CBPC synthesis reaction raises the temperature by only 7-40 °C, which is survivable by a wide range of additive materials.

EonCoat has found that the chemical reaction works best when the steel surface is slightly oxidized, so surface preparation is modest. A commercial blast (NACE 3) or high pressure water blast (NACE 5) is enough.

Coatings for corrosion protection are 3-9 mils thick and cost about $1.50 per square foot. The coatings also can be applied for chemical resistance (6-20 mils) or severe abrasion resistance (5 mils to 0.25 in.) with commensurate costs.

The National Academy of Engineering released a report last fall titled “Research Opportunities in Corrosion Science and Engineering,” that summarized the corrosion problem and identified grand challenges for corrosion research and opportunities for basic and applied research in corrosion. After a rigorous discovery process, four research “grand challenges” were identified. Paraphrasing, they are

1. Development of cost-effective, environmentally friendly corrosion-resistant materials and coatings;
2. Modeling to predict corrosion degradation in service environments;
3. Accelerated corrosion testing correlated to long-term behavior in service environments; and
4. Accurate forecasting of remaining service time, i.e., corrosion prognosis.

Bottom line, there is big money to be made in meeting the NAE’s first challenge to develop corrosion-resistant materials and coatings.

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A roll of ZircoFlex.

Via Gizmag, news came out about the UK-based company Zircotec that developed what it claims to be the first-ever flexible ceramic heat-shield material, opening the door for ceramic materials to be used in a far wider range of automotive, aerospace and industrial applications.

ZircoFlex used under the hood.

The application of ceramic coatings to metallic and composite components traditionally uses plasma spraying. This results in coatings that are applied to the material surface in a lightweight layer and can reduce surface temperatures by up to 33 percent, but the process entails treating parts directly using  a plasma torch whose jet reaches temperatures in the 14,000ºK range.

After more than five years of research, Zircotec says it has developed a new plasma-spray process in which the ceramic material is sprayed on the surface of aluminum foil. While the platelets are close-packed to provide comprehensive heat protection, this structure allows the foil to be bent and manipulated to suit different shapes. It can even be folded tightly through 180 degrees without damaging the thermal barrier.

The product, dubbed ZircoFlex, will allow ceramic coatings to be installed in-line to parts and assemblies during manufacture, even in high volume applications, without disrupting production flow. And the advantages aren’t limited to production lines. The company says parts can now be upgraded without needing to dismantle or decommission equipment.

Zircotec expects early applications for ZircoFlex to come from the automotive industry, where the foil can be used to protect sensitive components from heat, and the motorsport sector. It is suitable for applications with temperatures up to 500ºC.

The material is 0.25 mm thick, weighs 460g/m², comes on a roll, and can be cut and installed by hand or machine.

Zircotec says it also researching a range of alternative substrates.

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Global Industry Analysts has a new report on the high-performance ceramic coatings market. Revenues in North America are projected to reach $1.8 billion by the year 2012, driven by advantages such as high resistance against corrosion and chemicals, high reflectivity, preventing diffusion of hydrogen and electrical resistance. The report - High Performance Ceramic Coatings - A North American Market Report - contains a review of market trends, drivers, product profile, players, competition, recent developments, mergers, acquisitions and other strategic industry activities.

GIA says there is a heightened interest in these coatings. Their use spans the automotive, medicine, defense, aerospace, fiber-optic communications and environmental protection sectors. Besides these applications, the ceramic coatings field is presently exploring the possibility of extending the scope and functionality to other varied applications. Increasing applications of advanced ceramics for a variety of uses is likely to drive the ceramics market and maintain the growth of the market.

GIA takes note of several high-performance ceramic coatings companies, including Accuwright Industries Inc., American Roller Company, APS Materials Inc., Aremco Products Inc., Cetek Ltd., Cincinnati Thermal Spray Inc., Flame Spray Coating Company Inc., Honeywell International Inc., Heany Industries Inc., High Performance Coatings Inc., Materials and Electrochemical Research Corp., Praxair Surface Technologies Inc., Precision Coating Inc. and Sermatech International Inc.

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Wishbones, part of a F1 car's suspension, treated with ceramic composite coating are featured in the Fast Forward show. Credit: Science Museum.

London’s Science Museum has a great new exhibit – Fast Forward: 20 ways F1 is changing our world. The “F1″ reference is, of course, to auto racing, which has always been a testing ground of sorts for cutting edge materials and applications.

The show has lots of examples of how F1 carbon composites are being incorporated into everything from thin, light weight furniture designs to portable infant incubators.

Of particular interest to ceramists are displays showing high performance ceramic brakes and piezoelectric sensors that recently made their way onto top-shelf racing bicycles, and ceramic coatings that originally served to protect F1 drivetrain and electrical equipment form intense exhaust heating will be used in 2009 in the retail auto industry for similar purposes.

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