William L. Baun

Infrared absorption study of metal oxides in the low frequency region (700-240 cm−1)

Abstract The characteristic frequencies of oxides of 52 metals have been studied in the region 700-240 cm−1. Data for oxides of metals of different valence states and the frequencies of polymorphic forms of several oxides are presented. A particle size of 10 μ or smaller was found to give the best representative spectrum.

Band Structure and the Titanium LII, III X‐Ray Emission and Absorption Spectra from Pure Metal, Oxides, Nitride, Carbide, and Boride

The titanium LII, III x‐ray emission and absorption spectra (λ∼27.5 A) from pure metal, oxides, nitride, carbide, and boride have been investigated using a plane‐crystal vacuum spectrometer with electron‐beam excitation and flow‐proportional counter detection. Emission spectra were studied over a wide range of accelerating voltages and takeoff angles, showing that satellite emission and self‐absorption effects can significantly distort the band shapes and energy positions of intensity maxima. A replica of the LII, III absorption spectrum can be constructed solely from emission spectra affiicted with widely different amounts of self‐absorption. The LII, III emission spectra from the oxides, nitride, and carbide exhibit an important crossover transition from the 2p level of the anion to the LII and LIII levels of titanium. Results indicate formation of a 3d band in titanium compounds which is only partially filled, giving rise to metallic conduction. X‐ray data is compared to density of states calculations ...

Diagram and Nondiagram Lines in K Spectra of Aluminum and Oxygen from Metallic and Anodized Aluminum

Wavelength and intensities are reported for the Al K series using primary excitation. Included in the tabulation are the diagram lines α1α2 and β1, and the nondiagram lines α′, α3, α4, α5, α6, β′, β″, and β″′. Spectra are shown and line positions and intensities are detailed using both aluminum metal and aluminum oxide as the target materials. Significant differences are seen between metal and oxide spectra, especially in wavelength and shape of the Kβ1 band, and large changes are noted in the intensity of some satellite lines. The oxygen K band at 23.60 A from an anodized film is shown. The band is only slightly asymmetrical and no satellites are detected on the band contour. The application of x‐ray spectroscopy to the study of elements in anodic oxide pores is discussed with reference to quantitative changes and coordination determination.

Diagram and non-diagram lines in K spectra of nagnesium and oxygen from metallic and anodized magnesium

Abstract Data for diagram (α 1 , α 2 and β) and non-diagram (α′, α 3 , α 4 , α 5 , α 6 ) lines of the Mg K series are given and discussed. Significant differences in wavelength, intensity, and line shape are seen between Mg metal and MgO. Large differences in intensity are seen particularly for the satellite lines α 3 and α 4 . In the metal the α 4 /α 3 ratio is 0·60 while in the oxide it is 0·98. Satellite lines are very strong in the Mg K spectrum. For instance, α 3 as in the metal is over 10 percent of the parent α 1 α 2 doublet. The largest wavelength shift is seen in the weak diagram line K β which increases 0·0468 A in going from the metal to the oxide. The oxygen K α line at 23·59 A from MgO is shown, discussed and compared to earlier work.

Self‐Absorption Effects in the Soft X‐Ray Mα and Mβ Emission Spectra of the Rare Earth Elements

The Mα and Mβ emission spectra and the MIV and MV absorption spectra have been studied for the rare earth elements. It is conclusively shown that the complicated multiplet structure observed in the emission spectra is not real emission structure but is, instead, produced by sample self‐absorption. This is demonstrated by observing the emission spectra over wide variations in take‐off angle and bombarding‐electron energies and finally by comparing the detailed structure of both the emission and absorption spectra. The MIV and MV absorption structure completely overlaps the Mα and Mβ emission lines which are each found to have but one intensity maximum when obtained under conditions of minimum self‐absorption. Some of these spectra have never been shown previously, while others have been studied in detail by several investigators. Points of agreement and disagreement with previous work are mentioned and the wavelengths of the emission lines and absorption edges are listed for all of the lanthanides. It is c...

Phase Transformation at High Temperatures in Hafnia and Zirconia

Phase transformation curves for HfO2 and ZrO2 have been made. Transformation hysteresis is discussed. The transformation of monoclinic to tetragonal as temperature increases occurs over the range 1000� to 1200�C in ZrO2, and 1500� to 1600�C in HfO2. With decreasing temperature the transition back to monoclinic occurs from 970� to 750�C in ZrO2 and 1550� to 1450�C in HfO2. These transformations have been visually observed in ZrO2, but not in HfO2.

K X-Ray emission spectra from silicon and silicon compounds

Abstract Wavelength and intensities are reported for the Si K series from silicon metal using primary excitation. Included in the tabulation are the diagram lines α 1,2 and β and the non-diagram or satellite lines α′, α 3 , α 4 , α 5 , α 6 , β″ and β‴. The strongest Si K lines (α 1,2 , α 3 , α 4 , β′ and β) are listed for SiO 2 and changes in intensity, wavelength and band shape are discussed. Features of spectra from silicon compounds are shown and compared to results obtained on Al K spectra from aluminum compounds.

Applications of surface analysis techniques to studies of adhesion

Abstract The question is often asked: “Which is the best surface chemistry tool for research on adhesive bonding?” This question is difficult to answer because it depends on the aspect of adhesion which is being studied. Often a combination of instruments must be used to take advantage of the strong points of each. In metal-to-metal bonding there are many facets of adhesive/adherend interaction. Elemental characterization of adherends, especially when composition with depth is desired, is often best accomplished with Auger electron spectroscopy (AES). When information of chemical bonding is required, X-ray photoelectron spectroscopy (XPS) is the choice of most workers. Extremely thin layers of material (when first layer surface sensitivity is needed) requires ion scattering spectrometry (ISS). The high sensitivity of secondary ion mass spectrometry (SIMS) to many elements important in adhesive bonding makes this technique useful, especially coupled with other methods, such as ISS and AES. Modern surface analysis along with scanning electron microscopy (SEM) provides information on failure surfaces to allow unequivocal determination of the mode of failure. Although original surfaces and failure surfaces following testing are relatively routinely analyzed, the characterization of the intact bond is not so easy. The interphase region between adherend and adhesive is smaller than the probe, exhibits charging and is unstable. Although no one technique adequately characterizes the bond interphase region, the SEM, the AES microprobe, and special techniques using transmission electron microscopy (TEM), may be used to gain some information about the bond. The more fundamental study of the interaction of polymers and polymer precursors with metal and alloys is carried out by surface energetics measurements, infrared and Raman spectroscopy, XPS and electron tunneling spectroscopy.

Effect of Alloying on the Aluminum K and Iron L X‐Ray Emission Spectra in the Aluminum‐Iron Binary System

The aluminum K and iron L emission bands and the aluminum Kα3 and Kα4 satellite lines from a series of aluminum‐iron binary alloys have been studied using 6‐kV electron excitation and a flat crystal x‐ray vacuum spectrometer equipped with a flow proportional counter. It is found that the AlK band energy position and the AlKα4/Kα3 intensity ratio are both linearly dependent on alloy composition. As the aluminum concentration is lowered, the AlK band intensity maximum shifts to lowery energy and the band becomes more symmetrical in shape. In general, these results are very similar to those obtained previously from the aluminum‐nickel system. The FeLIII band undergoes very little change in shape but shifts to higher energy as the aluminum‐to‐iron ratio is increased. The spectral changes are interpreted as indicating that the predominately metallic bond in the pure metals acquires a certain amount of covalent‐like character in the alloys with the aluminum atoms behaving as electron donors.

Effect of Chemical Combination on the Soft X‐Ray K Emission Spectrum of Boron

Major changes due to chemical combination are observed in the soft x‐ray K emission spectrum of boron. The largest changes occur between elemental boron (B), boron nitride (BN), and boron oxide (B2O3). Spectra obtained from these compounds using a stearate crystal are compared with results of previous workers from a ruled grating. Points of agreement and differences are noted. The spectra were obtained from a flat‐crystal vacuum spectrometer using a flow‐proportional counter and electron excitation.