Advanced Materials & Processes

FEB 2015

Covers developments in engineering materials selection, processing, fabrication, testing/characterization, materials engineering trends, and emerging technologies, industrial and consumer applications, as well as business and management trends

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BRIEFS Perpetuus carbon Group, UK, a producer of purified and functionalized graphene, received independent verification of its graphene production. An independent work-study using a measurement study compliant with BS 3138:1992, concluded that the annual theoretical capacity, running 30 kg batches of raw graphite, is 140 tons per year from a single reactor. Graphene has incredible intrinsic properties, showing great potential for industrial and commercial applications across a wide range of industries. Courtesy of Haydale Ltd. CoRn HuSkS ConvERtEd to SIlICon CaRBIdE Scientists at the U.S. Naval Re- search Laboratory (NRL), Washington, are exploring ways to convert agricul- tural waste into high-value silicon car- bide that can be used for a variety of electronic and structural applications. Agricultural waste products have signifi- cantly high silica content in a molecular state, similar to hydrocarbons. Armed with that knowledge, Syed B. Qadri and his team discovered that these agricul- tural waste products can be econom- ically transformed into silicon carbide (SiC) consisting of nanostructures and nanorods in various polytypes. The team accomplished this by pyrolysis of the agricultural waste to produce the crystalline phases of sili- con carbide, a highly stable compound, in various shapes of nanocrystals, na- norods, and nanowires. By selectively heating and cooling the agricultural waste products, they were able to sys- tematically investigate the role of tem- perature rise and cooling rates. They observed that this heating and cooling process directly impacts the extended defect formation mechanisms that help in modifying the optical, electrical, and structural properties of these nanoparti- cles. nEw undERStandIng oF nanoCRyStalS Nanocrystals exhibit unprecedent- ed properties that intrigue scientists and engineers. To apply these materials in emerging nanotechnologies, scien- tists need to better understand their structure, corresponding functions, and how they pack together. Collaboration between Cornell High Energy Synchro- tron Source (CHESS), Ithaca, N.Y., and materials scientists has yielded great- er understanding of what particular nanocrystals look like individually and how they fit together as they form larg- er structures called supercrystals. This discovery could lead to effective bot- tom-up engineering of new materials for applications ranging from solar cells to electronic components. The team used innovative x-ray crystallography methods at the B1 CHESS beamline led by Zhongwu Wang. Data was simultaneously collected on the ordering and orientation of lead sulfide nanocrystals and supercrys- tals using both wide-angle (WAXS) and small-angle (SAXS) x-ray scattering, which are typically done one at a time. The new method provides insights into the unexpected complexity of the ar- rangement of nanocrystals within the supercrystal. The discovery could result in new methods for growing supercrys- tals and how to optimize their proper- ties. nanotECHnology for u.s. naval Research laboratory scientists, the conversion of rice husks to high value sic nanowires may provide new materials for electronic and structural applications. norThwesTern UniversiTy, evA nsTon, ill., pRofessoR mARk heRsAm won A "genius g RAnt" fRom the mAcARthuR foundAtion foR his investigAtions into how the tiniest mAteRiAls cAn impRove electRonics, medicAl devices, And RenewAble eneRgy. heRsAm is using g RA phene to fA shion novel devices th At c R eAte new possibilities in suppoRt of the office of nAvAl ReseARch plAn to enhAnce the nAvy's AsymmetRic c A pA bilities Ac R oss the physic A l domA in, cybe RspAce, A nd electRomAgnetic spectRum. A D V A N C E D M A T E R I A L S & P R O C E S S E S | F E B R U A R Y 2 0 1 5 1 6

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