PubMed · 1300293
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R Feinman. 1992. Flexible ceramic bonding.. https://pubmed.ncbi.nlm.nih.gov/1300293/
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A site-specific technique for cross-section transmission electron microscopy specimen preparation of difficult materials is presented. A focused ion beam was used to slice an electron transparent membrane from a specific area of interest within a bulk sample. Micromanipulation lift-out procedures were then used to transport the electron-transparent specimen to a carbon-coated copper grid for subsequent TEM analysis. The FIB (focused ion beam) lift-out technique is a fast method for the preparation of site-specific TEM specimens. The versatility of this technique is demonstrated by presenting cross-sectioned TEM specimens from several types of materials systems, including a multi-layered integrated circuit on a Si substrate, a galvanized steel, a polycrystalline SiC ceramic fiber, and a ZnSe optical ceramic. These specimens have both complex surface geometry and interfaces with complex chemistry. FIB milling was performed sequentially through different layers of cross-sectioned materials so that preferential sputtering was not a factor in preparing TEM specimens. The FIB lift-out method for TEM analysis is a useful technique for the study of complex materials systems for TEM analysis.
When single crystals of two different materials are in contact at a sharp interface, the orientation relationship between them is said to be epitaxial and the configuration of the atoms at the two sides of the interface is such that the lattice mismatch between them is accommodated in the least energetic way. Among other factors, this depends on the bonding between the atoms on the two sides of the interface. In this paper, the relaxation of strain in thin films grown epitaxially on dissimilar substrates is first discussed theoretically for cases of small and large lattice mismatch. In a following section, two metal-ceramics heteroepitaxial systems are investigated in detail by various techniques of transmission electron microscopy. One case, vanadium on MgO, corresponds to a small-mismatched system and the interface changes from coherent to semicoherent above a critical thickness; this turns out to be much larger than the expected value. In the other case-vanadium on the basal and rhombohedral (R) planes of sapphire-the lattice mismatch is large and misfit dislocations exist from the very initial stages of deposition. It is argued that although misfit dislocations in small and large lattice-mismatched systems are geometrically similar, their physical nature is different.
Glass-reinforced HA composites were produced using phosphate-based glasses, and a structure refinement was carried out to determine the effect of the glass on the structure of the residual HA. Quantitative phase analysis showed that the glass causes some of the HA to decompose to beta-TCP and, at higher temperatures, to alpha-TCP. It also was indicated that when three phases were present, the formation of the alpha-TCP arose from decomposition of the beta-TCP and not from further decomposition of HA to alpha-TCP. The unit cell dimensions showed a decrease in the a axis and an increase in the c axis, giving an overall unit cell decrease in volume. There also was a significant effect based on the amount of glass added. The changes found in the composite containing the 4 wt% glass were attributed to the loss of carbonate and loss of hydroxyl. This was expected to cause shrinkage in the unit cell; however this was not seen, and therefore the major changes in the unit cell were attributed to the ions from the glass taking an interstitial role in the HA structure, thus not allowing the unit cell to shrink as much as expected.