Profile Measurement

Composition Profile Measurement. Results of Zieba et al. (1997) will be given as an example of the measurement of solute distribution in an alloy undergoing a phase transformation. They studied discontinuous precipitation in cobalt-tungsten alloys, in which a Co-32 wt% W alloy was aged in the temperature range 875 K to 1025 K, and high spatial resolution X-ray microanalysis of thin foils by STEM was used to measure the solute distribution near the reaction front. 

The cellular reaction product consisted of alternating plates of C03W lamellae in a solute-depleted Co matrix (eCo). Ffomogenized ingots were cut into slices 1 mm thick and then heat-treated. Spark erosion was used to trepan 3 mm diameter discs which were then jet electropolished to form thin foils for TEM examination in a Philips EM 430 STEM instrument operating at 300 kV in the nanoprobe mode with a probe size of 5 to 10 nm. 

Energy-dispersive X-ray analyses were carried out by using the ratio technique (equation 1) to relate compositions to the intensities of the CoKa and WL characteristic X-ray peaks. The value of the kw Co factor was experimentally determined using single-phase eCo samples. A series of EDX analyses was performed from the edge to the interior of the foil and the results plotted in the form of the relationship  

In order to explore the microchemical changes accompanying the growth process of the discontinuous precipitates high spatial resolution thin foil microprobe analyses were made by Zieba et al. (1997) across the moving cell boundary and across each set of several eCo and Co3W lamellae. 

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Once a flow profile has been established, samphng strategy can be considered. Since samphng collection can be simphfied and greatly reduced depending on flow characteristics, it is best to complete the flow-profile measurement before sampling or measuring pollutant concentrations. 

Figure 4.16. Free-surface velocity profiles measured on 1400° C molybdenum. The free-surface velocity profile is characterized by an 0.05 km/s amplitude elastic precursor, a plastic wave front, and a spall signal (characteristic dip) upon unloading. The dashed lines represent the expected free surface velocity based on impedance-match calculation [Duffy and Ahrens, unpublished].

The structure/property relationships in materials subjected to shock-wave deformation is physically very difficult to conduct and complex to interpret due to the dynamic nature of the shock process and the very short time of the test. Due to these imposed constraints, most real-time shock-process measurements are limited to studying the interactions of the transmitted waves arrival at the free surface. To augment these in situ wave-profile measurements, shock-recovery techniques were developed in the late 1950s to assess experimentally the residual effects of shock-wave compression on materials. The object of soft-recovery experiments is to examine the terminal structure/property relationships of a material that has been subjected to a known uniaxial shock history, then returned to an ambient pressure... 

Much of what we currently understand about the micromechanics of shock-induced plastic flow comes from macroscale measurement of wave profiles (sometimes) combined with pre- and post-shock microscopic investigation. This combination obviously results in nonuniqueness of interpretation. By this we mean that more than one micromechanical model can be consistent with all observations. In spite of these shortcomings, wave profile measurements can tell us much about the underlying micromechanics, and we describe here the relationship between the mesoscale and macroscale. 

A typical shock-compression wave-profile measurement consists of particle velocity as a function of time at some material point within or on the surface of the sample. These measurements are commonly made by means of laser interferometry as discussed in Chapter 3 of this book. A typical wave profile as a function of position in the sample is shown in Fig. 7.2. Each portion of the wave profile contains information about the microstructure in the form of the product of and v. The decaying elastic wave has been an important source of indirect information on micromechanics of shock-induced plastic deformation. Taylor [9] used measurements of the decaying elastic precursor to determine parameters for polycrystalline Armco iron. He showed that the rate of decay of the elastic precursor in Fig. 7.2 is given by (Appendix)... 

Sections of the borehole casing threatened by corrosion can be located with the help of the profile measurement technique described in Section 18.3.1. In general, the profile measurement cannot identify which factors are the main cause of corrosion danger. 

After measuring the zero profile, AU measurements are carried out with the injection of a cathodic protection current. In contrast to the zero profile measurements, the distance between the individual measurements is 25 to 50 m. Shorter distances between the measuring points are used only at depths where there are unusual AU profiles. Current should be injected at at least three different levels. The protection current density of about 12 mA m obtained from experience should be the basis for determining the maximum required protection current. As shown by the results in Fig. 18-3, the AU profiles are greater with increasing protection current. The action of local cells is suppressed when the AU values no longer decrease in the direction of the well head. This is the case in Fig. 18-3 with a protection current I = 4A. 

In the region of the double casing, part of the return current flows from the inner to the outer pipe, depending on the resistance of the pipe. This is shown by a sharp decrease in the AU values. The current that flows results from undefined electrical connections between the pipes. For this reason, evaluating the profile measurements in... 

The average protection current requirement can be conveniently determined for individual wells in an oilfield by measuring the Tafel potential. In contrast to profile measurements, internal measurements on the casing are not necessary. These measurements cannot be used to predict polarization behavior at greater depths. 

Figure 5 Comparison of spectral profiles measured from a specimen of NiO using EDS and EELS. Shown are the oxygen K- and nickel L-shell signals. Note the difference in the spectral shape and peak positions, as well as the energy resolution of the two spectroscopies.

In addition to comprehensive elemental coverj e, SNMS also provides for high-resolution depth profile measurements with the same quantitation capability... 

Every material sputters at a characteristic rate, which can lead to significant amb ity in the presentation of depth profile measurements by sputtering. Before an accurate profile can be provided, the relative sputtering rates of the components of a material must be independently known and included, even though the total depth of the profile is normally determined (e.g., by stylus profilometer). To first order, SNMS offers a solution to this amb ity, since a measure of the total number of atoms being sputtered from the surface is provided by summing all RSF- and... 

An imponant component of the complex metallizations for both semiconductor devices and magnetic media is the diffusion barrier, which is included to prevent interdiffiision between layers or diffusion from overlyii layers into the substrate. A good example is placement of a TiN barrier under an Al metallization. Figure 7a illustrates the results of an SNMSd high-resolution depth profile measurement of a TiN diffusion barrier inserted between the Al metallization and the Si substrate. The profile clearly exhibits an uneven distribution of Si in the Al metallization and has provided a clear, accurate measurement of the composition of the underlying TiN layer. Both measurements are difficult to accomplish by other means and dem-... 

Figure 3 Optical profiler measurements of a region on the unpolished back of a silicon wafer line scan (a) and 3D display (b) (Courtesy of WYCO Corp.).

As an example, consider again the back surface of the silicon wafer used in the mechanical profiler example. Eigure 4a, an SEM micrograph taken at 45° tilt, shows a surface covered with various sized square-shaped features that often overlap. This information cannot be discerned from the mechanical profiler trace, but can be obtained using a 3D optical profiler measurement. Eigures 4b and 4c are also... 

The similarity of velocity and of turbulence intensity is documented in Fig. 12.29. The figure shows a vertical dimensionless velocity profile and a turbulence intensity profile measured by isothermal model experiments at two different Reynolds numbers. It is obvious that the shown dimensionless profiles of both the velocity distribution and the turbulence intensity distribution are similar, which implies that the Reynolds number of 4700 is above the threshold Reynolds number for those two parameters at the given location. 

It should be observed that, in the most general case, interpretation of the mechanical responses requires time-resolved wave-profile measurements. As shown in Eqs. (2.2) and (2.3), direct evaluation of the response requires quantitative description of derivatives of kinetic and kinematic variables. 

When the pressures to induce shock-induced transformations are compared to those of static high pressure, the values are sufficiently close to indicate that they are the same events. In spite of this first-order agreement, differences between the values observed between static and shock compression are usually significant and reveal effects controlled by the physical and chemical nature of the imposed deformation. Improved time resolution of wave profile measurements has not led to more accurate shock values rather. 

Fig. 2.17. Fused quartz is known to have an anomalous softening with stress or pressure in both static and shock loading. The time-resolved wave profile measured with a VISAR system shows the typical low pressure ramp followed by a shock at higher pressure. The release to zero pressure is with a shock, in agreement with the shape of the pressure-volume curve (after Setchell [88S01]).

A number of thorough reviews on measurement techniques are listed in Table 3.1 each has a somewhat different thrust. The early review emphasizing wave profile measurement methods of Graham and Asay [78G01] has... 

Table 3.1. Reviews of wave profile measurement teehniques.

Table 3.3 summarizes the history of the development of wave-profile measurement devices as they have developed since the early period. The devices are categorized in terms of the kinetic or kinematic parameter actually measured. From the table it should be noted that the earliest devices provided measurements of displacement versus time in either a discrete or continuous mode. The data from such measurements require differentiation to relate them to shock-conservation relations, and, unless constant pressures or particle velocities are involved, considerable accuracy can be lost in data processing. 

Equation 11.12 does not fit velocity profiles measured in a turbulent boundary layer and an alternative approach must be used. In the simplified treatment of the flow conditions within the turbulent boundary layer the existence of the buffer layer, shown in Figure 11.1, is neglected and it is assumed that the boundary layer consists of a laminar sub-layer, in which momentum transfer is by molecular motion alone, outside which there is a turbulent region in which transfer is effected entirely by eddy motion (Figure 11.7). The approach is based on the assumption that the shear stress at a plane surface can be calculated from the simple power law developed by Blasius, already referred to in Chapter 3. 

Figure 4. Ozone profiles measured in 1987 over Halley Bay, Antarctica, by Farman (20).

Fig. 1—Profile measurement technique of Champper 2000+. A surface measurement is made with a linearly polarized laser beam that passes to translation stage which contains a penta-prism. The beam then passes through a Nomarski prism which shears the beam into two orthogonally polarized beam components. They recombine at the Nomarski prism. The polarization state of the recombined beam includes the phase information from the two reflected beams. The beam then passes to the nonpolarizing beam splitter which directs the beam to a polarizing beam splitter. This polarizing beam splitter splits the two reflected components to detectors A and B, respectively. The surface height difference at the two focal spots is directly related to the phase difference between the two reflected beams, and is proportional to the voltage difference between the two detectors. Each measurement point yields the local surface slope [7].

FIGURE 20.12 (a) Top part shows variations of elastic modulus profile measured in different locations of the polypropylene (PP)-ethylene-propylene-diene terpolymer (EPDM) blend. The locations are shown by white dots in the blend phase image placed at the bottom. Vertical white dashed lines show the components borders and the elastic modulus value for this location. Vertical black dotted lines indicate the locations where elastic modulus E gradually changes between PP (E ) and EPDM (E )- These values are indicated with black arrows on the E axis, (b) LvP curves for PP-matrix, EPDM-domains, and one of interface locations. The approach curves are seen as solid black lines and the retract curves as gray lines. 

Boyd, D.W., "Computerized Roughness/Profile Measurements Quantify Aspects of Appearance", 13th International Conference in Organic Coatings Science and Technology. Athens, Greece, July 7, 1987, p. 59-77. 

Temperature profile measurement in a flat, premixed fuel-rich pro-pene low-pressure flame by LIF, using seeded NO, and CRDS, using naturally present OH radicals. (Adapted from Figure 3 in Kohse-Hoinghaus, K. et al., Z. Phys. Chem., 219,583,2005.)... 

Comparison of the C2 radical mole fraction profile measured by LIF and CRDS in a flat, premixed fuel-rich propene flame at 50mbar. 

Fig. 1. TG spectra of carbon particulates with Fig. 2. TPR profiles measured for various Lao.gCso MnOj catalyst heating rate=l K/min. perovskite type oxides heating rate=10 K/min,...

Figure 5.4-34. Temperature profiles measured during heating and isothermal periods (reprinted with permission from Landau et al. (1994). Copyright (1994) American Chemical Society).

In the ASTER reactor deposition experiments were performed in order to compare with the 2D model results. Normalized deposition rates are plotted in Figure 22 as a function of radial position for data taken at 25 and 18 Pa. The deposition takes place on a square glass plate. For each pressure two profile measurements were performed, each profile perpendicular to the other (a and b in Fig. 22). A clear discrepancy is present. The use of the simplified deposition model is an explanation for this. Another recent 2D fluid model also shows discrepancies between the measured and calculated deposition rate [257], which are attributed to the relative simplicity of the deposition model. 

Figure 8. U concentration profiles measured using ICP-MS for bones from Boxgrove. These bones show characteristic leached profiles (compare with Fig. 5), and are rejected as unsuitable for dating. [Used by permission of Elsevier Science, from Pike et al. (2002), Geochim Cosmochim Acta, Vol. 66, Fig. 5f, p. 4280.]...

Figure 11. U concentration profile and profile measured using laser ablation ICP-MS across...

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