Scanning diamond

Hardness. The Knoop indentation hardness of vitreous sihca is in the range of 473—593 kg/mm and the diamond pyramidal (Vickers) hardness is in the range of 600—750 kg/mm (1 4). The Vickers hardness for fused quartz decreases with increasing temperature but suddenly decreases at approximately 70°C. In addition, a small positive discontinuity occurs at 570°C, which may result from a memory of quartz stmcture (165). A maximum at 570°C is attributed to the presence of small amounts of quartz microcrystals (166). Scanning electron microscopic (sem) examination of the indentation area indicates that deformation is mainly from material compaction. There is htfle evidence of shear flow (167). 

Fig. 14. A scanning electron micrograph of a diamond coating on a siUcon nitride cutting tool (b) at higher magnification, the octahedral growth of...

The diffraction pattern obtained in the detector plane when the beam scan in a STEM instrument is stopped at a chosen point of the image comes from the illuminated area of the specimen which may be as small as 3X in diameter. In order to form a probe of this diameter it is necessary to illuminate the specimen with a convergent beam. The pattern obtained is then a convergent beam electron diffraction (CBED) pattern in which the central spot and all diffraction spots from a thin crystal are large discs rather than sharp maxima. Such patterns can normally be interpreted only by comparison with patterns calculated for particular postulated distributions of atoms. This has been attempted, as yet, for only a few cases such as on the diffraction study of the planar, nitrogen-rich defects in diamonds (21). 

Figure 4.7. Boron scanned ion beam mass spectrometry (SIMS) image of a B-doped diamond specimen. The image is 430 pm in width, and the variation of B intensity from one grain to another is approximately a factor of 8. (Reproduced by permission of Professor J. W. Steeds.)...

FTIR Microspectroscopy.3 A microscope accessory coupled to a liquid-nitrogen-cooled mercury-cadmium-telluride (MCT) detector can be used to obtain an IR spectrum. This is possible in both the transmission and reflectance modes. Several beads are spread on an IR-transparent window (NaCl, KBr, diamond) and possibly flattened via a hand-press or a compression cell. The IR beam is focused on a single bead using the view mode of the microscope. The blank area surrounding the bead is isolated using an adjustable aperture, and a spectrum is recorded using 32 scans (<1 min). A nearby blank area of the same size on the IR transparent window is recorded as the background. 

A.H. Deutchman and R.J. Partyka (Beam Alloy Corporation observe, "Characterization and classification of thin diamond films depend both on advanced surface-analysis techniques capable of analyzing elemental composition and microstructure (morphology and crystallinity), and on measurement of macroscopic mechanical, electrical, optical and thermal properties. Because diamond films are very thin (I to 2 micrometers or less) and grain and crystal sizes are very small, scanning electron microscopy... 

Melt calibration standards (from step 1) in a water bath if necessary. Using a disposable pipet, place each standard on the ATR horizontal surface making sure that the surface of the ZnSe or diamond crytal is completely covered, collect a 128-scan single-beam FTIR spectrum (Fig. D1.7.1B) at 4 cm"1 resolution, and save it. Repeat step 5 after each measurement. 

Figure 10.1 Scanning electron microscope image of a roughly 10 /rm thick CVD diamond film exposing its (001) facets at the top. The image was kindly provided by X. Jiang [414].

Some important functional groups and their region of absorbance are highlighted. Cheddar cheese was scanned by pressing 0.5 g of cheese on a diamond attenuated total reflectance (ATR) crystal. Extracts was scanned by drying 10 pi of the extract on a zinc selenide ATR crystal. 

Fig. 11.1. Topographical AFM image of boron-doped polycrystalline diamond grown for 8h. Scan size was 10 pm x 10 pm.

Recently, Colley et al. [104] studied the distribution of electrochemical activity in microarray electrodes. The array contained 50-pm diameter boron-doped regions spaced 250 pm apart in an intrinsic diamond disk. Reaction rate imaging was done in the substrate generation/tip collection mode. The electroactive boron doped regions were biased at a suitable potential to reduce the mediator, [Ru(NH3)6]3+, and the product of the reduction reaction was collected at the tip. Two-dimensional scans over different regions (Fig. 21) revealed wide variations in local electroactivity. 

Fig. 4.12 (a) and (b) Scanning electron micrographs of a Cr composite deposited from a type II Cr/ChCl liquid containing 5 wt.% diamond powder. 

---