In the microcrystalline regime, the electrical (impedance/dielectric) behavior of grain boundarycontrolled electroceramics is well described by the “brick-layer model” (BLM). In the nanocrystalline regime, however, grain boundary layers can represent a significant volume fraction of the overall microstructure. Simple boundary-layer models no longer adequately describe the electrical properties ...

Sintering of powders is a common means of producing bulk materials when melt casting is impossible or does not achieve a desired microstructure, and has long been pursued for nanocrystalline materials in particular. Acceleration of sintering is desirable to lower processing temperatures and times, and thus to limit undesirable microstructure evolution. Here we show that markedly enhanced sinter...

Amorphous and nanocrystalline carbon films possess special chemical and physical properties such as high chemical inertness, diamond-like properties, and favorable tribological proprieties. The materials usually consist of graphite and diamond microstructures and thus possess properties that lie between the two. Amorphous and nanocrystalline carbon films can exist in different kinds of matrices...

An interesting change of scale sequence occurred during oxidation of nanocrystalline surface layer by means of a surface mechanical attrition treatment. The three-layer oxide structure from the surface towards the matrix is Fe3O4, spinel FeCr2O4 and corundum (Fe,Cr)2O3, which is different from the typical two-layer scale consisted of an Fe3O4 outer layer and an FeCr2O4 inner layer in convention...

Nanocrystalline materials, with a grain size of typically < 100 nm, are a new class of materials with properties vastly different from and often superior to those of the conventional coarse-grained materials. These materials can be synthesized by a number of different techniques and the grain size, morphology, and composition can be controlled by controlling the process parameters. In compariso...

Nanocrystalline NaNO3 enclathrated microporous material with intermediate structure (INT) between the well known zeolites sodalite (SOD) and cancrinite (CAN) can be prepared from aluminosilicate gels under addition of high amounts of NaOH and NaNO3 using low temperature conditions (333 K) within reaction periods of 1 96 h. The nanocrystalline products were characterized by X-ray powder diffract...

Nanocrystalline silver dressings are widely known to be potent antimicrobial and anti-inflammatory agents and have long been used to treat topical wounds. Gold is known to be a strong anti-inflammatory agent and has been used in the treatment of rheumatoid arthritis for >70 years. The purpose of this work was to study the effect of incorporating gold into nanocrystalline silver dressings from a...

Direct electrode/neuron interfacing is a key challenge to achieve high resolution of neuronal stimulation required for visual prostheses. Neuronal interfacing on biomaterials commonly requires the presence of glial cells and/or protein coating. Nanocrystalline diamond is a highly mechanically stable biomaterial with a remarkably large potential window for the electrical stimulation of tissues. ...

As commercially manufactured nanomaterials become more commonplace, they have the potential to enter ecological and biological environments during their lifecycle of production, distribution, use or disposal. Despite rapid advances in the production and application of nanomaterials, little is known about how they may interact with the environment or affect human health. This research investigat...

While there have been numerous studies to determine osteoblast (bone forming cell) functions on nanocrystalline compared to micron crystalline ceramics, there have been few studies which have examined osteoclast activity (including tartrate-resistant acid phosphatase, formation of resorption pits, size of resorption pits, and receptor activator of nuclear factor κB [RANK]). This is despite the ...