Amorphous whisker

The modified diimide decomposition process uses gas mixtures of Si2Cl2, NH3, and H2. Amorphous whiskers are deposited on quartz or graphite substrates coated with a metal catalyst. The uniqueness of this method is the ability to form whiskers of a special shape, e.g., a coil. Whiskers with the best coil regularity have been obtained at 1200°C on a graphite substrate with Fe as the catalyst. All whiskers have a very smooth surface,... 

Each GaSb whisker is grown from a ball-shaped center and is capped by a spherule containing amorphous Ga as was shown by SAED (no... 

In general, in most CMCs, chemical reaction hardly occurs between fiber (or whisker) and matrix. However, an extremely thin amorphous film can be formed. 

MMMF are synthetics that have crystalline rather than amorphous structures. Not surprizingly, early examples are reminiscent of the naturally occurring fibers synthetic chrysotile (lander and Wuhrer, 1938) and needles of amphibolelike composition and crystal structure (Shell et al., 1958). However, the bulk of the crystalline synthetic fibers, both in use and under investigation, do not have mineral equivalents therefore, we chose to use the term whiskers to distinguish crystalline man-made inorganic fibers from their natural relatives. 

The most important application of boron is to make fibers or whiskers of single crystal or ceramic crystal. The addition of boron to metals, alloys, or other solids, imparts resistance to plastic flow, and thereby produces unusual strength in the material. Amorphous boron is used in rockets as an igniter, and in pyrotechnic flares to give green color. Many boron compounds, such as borax, boron hydrides, and boron hahdes, have important commercial applications (see individual compounds). 

The Ga Sb atomic ratio within each whisker equals almost 1 as was proven by EDX and EEL spectroscopy. The Sb distribution within the crystalhne needle is homogeneous whereas the (amorphous) tip contains Ga with an Sb concentration of about 1%. Carbon could not be detected by EELS within the GaSb whiskers, whereas O is present as a small surface layer due to surface ox-... 

Gas Phase Nucleation Amorphous Deposits Fine Grained Deposits Poiycrystais Dendrites Whiskers Piateiets Epitaxiai Growth... 

The model proposed assumes reversible formation of amorphous coke (Ccm) and simultaneous formation of whiskers (Ccw) on the catalytic surface. The amount of monolayer coke at infinite time (Cc ax) depends on the operating conditions (e.g. temperature) and is governed by values of the rate constant for... 

Elemental carbon is usually handled in three forms graphite, diamond, and amorphous carbon. Graphite and amorphous carbon have been extensively used in electrochemistry because of their high electrical conductivity, chemical stability, versatility, and low cost. For electrochemical applications, such materials can be manufactured in bars, powders, and fibers or can even form conducting composites when appropriate binders are used. A number of carbon-based materials, such as pyrolytic carbon, carbon blacks, activated carbons, graphite fibers, whiskers, glassy carbon, etc., have been used in electrochemistry for decades (Yoshimura and Chang, 1998). 

Many solid compounds are known to exist in different crystalline modifications such as amorphous, crystalline or glassy states affecting solubility, dissolution rate, stability and bioavailability. In order to improve the pharmaceutical potential, therefore, it is important to control the crystallization, the polymorphic transition, and whisker generation of solid drugs. ... 

It has already been well known for more than two decades that it is feasible to produce SiC powders and/or whiskers by pyrolyzing rice husk [178] under an inert atmosphere, since a considerable content of colloidal amorphous silica is incorporated in husks and straws of this vegetable. It means that nature by itself is supplying a similar intimate mixture of carbon-containing molecules (cellulose) and colloidal silica like those artificially made mixtures we discussed in the last section. Thus, also in this case, silicon carbide may be formed by a carbothermal reduction process. This process starts in the temperature range 1100-1400 °C ... 

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