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UHTCs: Ultra-High Temperature for Extreme Environment Applications by E. Wuchina, E. Opila, M. Opeka, W. Fahrenholtz, and I. Talmy

.That’s not just hot SiO(g) instead of a protective SiO2 layer) 3000°C..– it’s EXTREMELY can occur at very high temperatures hot. It is above the melting or (> 1350°C, depending on PO2) and decomposition temperatures for most reduced system . In addition, of the materials known to man. But decomposition of already-formed SiO2, in the world of extreme environment or the interface reaction between SiC , it is just a baseline. The list and SiO2 results in SiO(g) formation at of materials with melting temperatures high temperatures and reduced above 3000°C is limited to perhaps 15 environments. Other materials, such as elements or compounds (Table I). That TiB2, TiC, NbB2, NbC, while having high is a pretty small palette of materials to melting temperatures, form with draw from for an or designer. low melting points (TiO2 – Tm = 1840°C and Nb2O5 – Tm = 1485°C). has Table I. Materials with melting temperatures the highest melting temperature of any above 3000°C. known, but starts to burn TaB Re thet 800°C. While it is a most widely 2 used material in high-temperature W HfC BN applications, it must be protected by HfB HfN ZrC coatings for long-term use. 2 What we are left with are the borides, TaC ZrB2 TiC , and of the Group IV & V elements, as well as based on TaN NbC ThO 2 these compounds. While these materials of interest have been known since the Since the late 1960s, the world 1930s, it wasn’t until the seminal works of high-temperature materials has sponsored by the U.S. Air Force6 as focused primarily on SiC and Si N 3 4 well as the work of Samsonov7 in the as the materials of choice. Entire 1960s that the class of UHTC materials industries have developed to produce became more widely known. As the ball bearings, armor, , and even ZrB and HfB -based UHTCs are the turbine . But recently, there has 2 2 most widely studied of these materials been a revival of sorts in materials due to their good oxidation resistance originally studied in the 1960s for Fig. 1. Conceptualized drawings of hypersonic from room temperature to over 2000°C, potential aerospace applications, driven 1 2 and as potential applications we will start by discussing them. by “the need for speed”—with new for UHTC leading edge and nozzle components. propulsion and hypersonics concepts as shown in Fig. 1. Current increasing Borides interest in hypersonic and , , fabric- weapons points to the need for new ability, and cost are also important It is well known that Zr and Hf are ultra-high-temperature materials for factors in determining the optimal very chemically similar elements, with wing leading edges and nosetips, as material for a given application. their primary differences being density well as propulsion system components. For the purposes of this paper, we and nuclear capture cross section, so it is There are more than 300 materials will simply define UHTC materials by not surprising that the borides of these with melting temperatures over their usefulness in a real structural elements are also very similar. Both exist 2000°C, including the aforementioned (load-) application where the in hexagonal structures of the very high temperatures are generated SiC, (Hf, Nb, AlB2 prototype, with layers of B Ir, Re, Ta, W), oxides (HfO , ZrO , rapidly by burning fuels or in 2D graphite-like rings, alternating 2 2 with the atmosphere (not steady state). UO2, ThO2), a variety of transition with Zr or Hf layers in a hexagonally carbides, nitrides, and borides This will quickly eliminate most of close-packed array. Because of the very as well as other compounds. For real the materials mentioned above. While high strengths of the B-B rings and M-B engineering applications, though, oxides are reasonable to consider for bonds, these materials have very high melting temperature is only one of use in oxidizing environments, poor and temperature stability. many of properties used in the materials thermal shock resistance due to high While most extrinsic properties such as selection process.3 As most and thermal expansion and low thermal strength are dependent on processing hypersonic leading edge applications conductivity eliminates them from and , the intrinsic will involve exposure to oxidizing further discussion. The based thermal conductivities of the diborides fuels or aeroheating, all nonoxide refractory compounds (SiC, Si3N4, are very high, approaching at materials will undergo oxidation to MoSi2, etc.) possess excellent oxidation room temperature, with little dropoff resistance up to 1700°C due to the form some combination of , liquid, up to 2500°C. This makes ZrB2 and HfB2 or gaseous reaction product. It is the formation of a layer of SiO2 that very appealing for applications where oxidation behavior that is a second inhibits to the parent thermal response is an important 4 primary property associated with the material. This is the primary reason for issue. A good example of this is rocket materials selection process. Strength the popularity of these materials for a motor nozzles. In these applications, the (room temperature and at application wide variety of applications. However, temperature rise on the inside surface temperature), thermal conductivity, active oxidation (the direct formation of can approach 2000°C in less than 0.15

30 The Electrochemical Society Interface • Winter 2007 Fig. 2. Finite element modeling results showing the peak tensile stresses generated in rocket motor nozzles during the early stages of firing.8 seconds, while the outer wall is still at processing and microstructure (as well Cougherty, et al.,9 in the 1960s as a room temperature. This ∆T generates a as test methods used to measure the grain refiner to improve its strength. compressive stress on the inside (hot) property). It is not surprising, then, More recent second phase additions surface, while the outside (cool) surface that the strength values reported in the include carbides and . While carries a tensile stress. Depending literature have a wide range. Because these additions also influence the on the thickness of the nozzle, the ZrB2 and HfB2 are hexagonal , the strength of the diboride , the thermal conductivity and strength will properties exhibit anisotropic behavior primary interest of research on ZrB2 determine the success or failure of the within individual crystals. However, and HfB2 has primarily focused on part. A finite element model of thick the bulk data reported are traditionally improving their oxidation resistance. and thin-walled cross-section (Fig. 2) gathered from polycrystalline ceramics, The presence of a silica-forming shows the highest tensile loads in red.8 and therefore do not show anisotropic species in the diborides greatly With higher thermal conductivity, the behavior. As is common in ceramic increased their oxidation resistance borides can more readily transmit the systems, the strength of the diborides due to the in-situ formation of a heat through the part and equilibrate is generally shown to increase with borosilicate glass on the surface of the temperature within the cross- decreasing according to the the material, which impeded oxygen section, thereby reducing the thermal Hall-Petch relationship. The influence diffusion to the parent material. It was stress. of second-phase additions has also been found that an optimal composition of As mentioned previously, the reported. Silicon was originally ZrB2 plus 20 to 30 vol% SiC, produced is dependent on incorporated into HfB2 and ZrB2 by the highest oxidation resistance up to 2000°C.10,11 Pure diborides form liquid B2O3 during oxidation that can be protective up to around 1200°C, but the B2O3 evaporates at higher temperatures and no longer provides a diffusion barrier. The addition of the SiO2- forming species helps increase the oxidation resistance by “tieing- up” the boria by the formation of a borosilicate glass that can be stable up to at least 1600°C. A cross-section of a ZrB2-SiC material oxidized at 1627°C for ten 10-minute cycles in air is shown in Fig. 3.12 Efforts to model this oxidation behavior and the complex porous ZrO2-glass scale are Fig. 3. Scanning micrograph and composition profile of a cross session of ZrB2-SiC material after ten 10-minute being undertaken cycles at 1627°C in air.12 by a variety of

The Electrochemical Society Interface • Winter 2007 31 Wuchina, et al. (continued from previous page)

14 Fig. 4. Scanning electron micrographs of top surface of ZrB2-SiC modified with TaB2 oxidized at 1300°C in air. researchers13 and will hopefully lead during oxidation to further been in the form of -processed to further improvements in oxidation reduce the oxygen diffusion rates materials. Most boride have resistance. Hypersonic aerosurfaces will through the glass. An example of the been synthesized by reduction, chemical need to have lifetimes on the order immiscible glass microstructure and or reactive processes. Carbothermal of hundreds to thousands of hours a thermogravimetric oxidation curve reduction of ZrO2 + B2O3 is the most to become cost-effective on reusable showing the improvement of oxidation commercially viable process to produce structures. One avenue to further resistance is presented in Fig. 4. ZrB2, but often leaves B2O3 and carbide increase the oxidation resistance has Processing—While there has been a impurities. Other economically feasible been reported by Talmy and Zaykoski.14 small amount of work describing the processes for powder production16 This involves the addition of transition- chemical vapor deposition of boride include self-propagating high- metal elements in the form of borides or coatings,15 the vast majority of research temperature synthesis17 from the pure silicides to produce complex immiscible on dense bulk boride materials has elements. The highly exothermic nature

Hf Ta

Fig. 5. The phase equilibrium diagrams for the Hf-C24 and Ta-C25 systems.

32 The Electrochemical Society Interface • Winter 2007 be covalent.21 These highly covalent main rate controlling mechanism for bonds not only affect the melting the growth. While others27 have temperature, but contribute to the high also found evidence of oxycarbide at of these materials as this interface (Fig. 6) after arcjet testing well. However, the precise nature of at higher temperatures (> 2200°C) in bonding in these compounds is not reduced pressure environments (using well understood, as discussed in these NASA Ames AHF arc-jet facility), both recent reviews.22,23 Shimada28 and Wuchina27 noted the As shown in Fig. 5, the phase diagrams presence of carbon (both graphitic for Hf-C24 and Ta-C25 show a wide and amorphous) at the interface after homogeneity region for the stability of furnace oxidation at lower temperatures the monocarbides. While the chemical (800-1500°C). The effect of pressure formula is generally written as MeC, on oxidation of the carbides has not MeCx is more appropriate, where x is been well studied, but the oxidation of the C/Me ratio. The properties of the carbon and HfC is controlled by the PO2 materials across this stability range will at the interface, with the reaction: Fig. 6. SEM of HfC/HfO2 interface showing evidence of oxycarbide interphase. (Arrow obviously be a function of the interaction indicates interphase layer.) between the and vacancies HfC + O2 → HfO2 + C (1) in the lattice. This interaction increases of these reactions makes them difficult the Peierls stress (the force needed describing the oxidation reaction at low to control, but can result in highly to move a disclocation through the PO2, while at higher oxygen pressures, defective, very small crystals that have lattice) and also changes the bonding the C would oxidize as well, leaving been linked to improved sinterability. character (reduced contribution of C HfO2 and CO2 as the reaction products. Densification of these materials atoms to cohesion by reducing the The effect of carbide stoichiometry has traditionally involved uniaxially number of Me-C bonds that need to has also been studied. In furnace testing hot-pressing in graphite molds at be broken during motion (below 1600°C), HfC.67 had a thinner temperatures above 1800°C. However, as well as reducing the strength of the oxide scale than HfC.98, as shown in Fig. recent work18 on the use of spark- Me-Me bond by increasing vacancy 7. The oxide on the subcarbide was also concentration) that will decrease the denser, with less and cracking, to minimize grain growth 21 during hot pressing has drawn interest, Peierls stress. than on the higher carbide. The main and the reports of pressureless A number of studies on the oxidation difference between HfC and TaC is by groups in Italy and the U.S.19,20 behavior of HfC over a wide range the melting temperature of the oxide could lead to a wider use of borides in of temperatures have shown excellent formed. While HfO2 is itself a high- engineering applications by lowering oxidation behavior at temperatures temperature ceramic, with a melting processing temperatures and increasing above 1800°C, when the oxide formed temperature of 2758°C, Ta2O5 has a the size and shape of articles that can can densify. At temperatures below much lower melting point of 1872°C. be produced commercially. 1500°C, the oxide grains formed are This difference is a major component not able to sinter, causing them to in the materials selection process. spontaneously spall off the parent For high-temperature applications in Carbides

The transition-metal carbides have also been considered as UHTC materials of interest due to their extremely high melting points—exceeding those of the aforementioned refractory borides. The monocarbides of Ta and Hf are of particular interest because they possess the highest melting temperatures of any compounds (3980 and 3928°C, respectively), as well as very high hardness and elastic modulus. Many of the monocarbides exist in the NaCl-type face-centered cubic . The carbides are not as commonly studied as the borides due to the low-temperature “pesting” that occurs during oxidation, which will be described later. However, for applications where there is a rapid Fig. 7. Photographs of HfC.67 and HfC.98 after furnace oxidation at 1500°C for 15 minutes in air. rise to temperatures above 2000°C, the carbides have become of considerable carbide, a process known as pesting. oxidizing environments, such as engine interest. At low temperatures, the HfO2 forms propulsion or hypersonic leading edges, Many transition-metal carbides have a porous scale (due to the evolution where a shape-stable, non-eroding potentially tailorable thermomechanical of CO2 during the oxidation), and the oxide is needed, TaC is not likely to and thermophysical properties due to a oxidation kinetics are linear. At higher be used because the oxide formed will wide phase stability field that allows a temperatures, the kinetics can be readily slough off, especially in high- large number of vacancies to exist in parabolic due to the slower diffusion of shear flight environments, as shown the crystal lattice. The extremely high oxygen through a dense scale. Bargeron26 in Fig. 8. HfC is a much better choice melting temperatures of TaC and HfC studied the oxidation behavior of HfC due to the HfO2 stability. However, are due to their interatomic bonding, films, and described the presence of an when PO2 is considerably lower, it is which while most researchers agree is oxycarbide interlayer between the HfO2 possible that the oxide will not form on a of metallic, covalent, and outer later and the parent carbide. He TaC, whereas HfO2 will form on HfC at ionic—the strongest component in the concluded that the diffusion of oxygen even very low oxygen pressures. Under monocarbides has been determined to through that the oxycarbide was the these conditions, TaC would be a better

The Electrochemical Society Interface • Winter 2007 33 Wuchina, et al. (continued from previous page) structural material. Agte29 reported a maximum in the melting temperature in TaC-HfC solid solutions, but more recent studies in this system have indicated that the melting temperatures fall within the melting temperatures of the pure components.30 Processing—As with the diborides, monocarbides powders are commercially produced by either carbothermal reduction (sometimes with CaCO3) or direct reaction (SHS synthesis).31,32 Densification is typically done by hot pressing, but plasma spraying and hot isostatic processing (HIP) have also Fig. 8. Optical micrographs of HfC and TaC after 3 minute exposure in NASA-Ames arcjet facility been employed. Plasma spraying has (T > 2000°C) showing presence of dense, adherent HfO2 scale on HfC and evidence of residual molten the advantage of producing near net- Ta2O5 on TaC.

barrier in magnetic recording devices. In the world of structural ceramics, these materials offer a wide range of thermal and mechanical properties that are of use to a systems designer. As structural ceramics, the UHTC nitrides (ZrN, HfN, and TaN) are less well known than the diborides or monocarbides, but they do offer some advantageous properties. Like the monocarbides, HfN (and ZrN) can exist over a range of stoichiometries, as shown in Fig. 9. With a melting temperature of 3387°C, it certainly qualifies as a UHTC material. That temperature was measured in an atmospheric pressure environment: at an overpressure of at 60 atmospheres, the melting point increases to 3800°C!33 For long temperature applications at high temperatures, the loss of N from the lattice is thought to be a considerable problem to overcome. It is interesting to note that small N additions to the αHf with N additions lattice dramatically raise the melting temperature—from 1743°C for the pure metal to 2910 for 30%N. The thermomechanical properties of αHf have been described in the literature.34 For the HfN phase, Fig. 9. The phase equilibrium diagram for the Hf-N system.36 the thermal expansion and strength and modulus are all very close to that measured for HfC, while the thermal shape articles, but stoichiometry tends to be difficult to control due to loss of C at extremely high-temperatures in the plasma, while the HIP process is used when control of carbon content is of high importance. The metallic encapsulation necessary to densify the carbides from the powders is an effective diffusion barrier to the carbonizing atmosphere in the HIP vessel from the heating elements. Nitrides

Transition metal nitrides are of critical importance in the microelectronics as a diffusion barrier between Cu interconnects and the SiO2 insulation Fig. 10. Post-test photographs showing evidence of porous, adherent scale on HfN and dense oxide layer, as well as an interlayer/diffusion .95 that formed on HfN.75. The buildup of N2 behind the oxide burst during testing.

34 The Electrochemical Society Interface • Winter 2007 conductivity is slightly higher.35 TaN is 3. M. Opeka, I. Talmy, and J. Zaykoski, 24. E. Rudy and S. Windisch, AFML-TR- considerably less stable than HfN, with J. Mat. Sci., 39, 5887 (2004). 65-2, Part I, Vol. IV, 1965. decomposition temperatures below 4. B. Deal, and A. Grove, J. App. Phys., 25. E. Rudy and D. Harmon, ARML-TR- 2700°C at atmospheric pressure. 36, 3770 (1965). 65-2, Part I. Vol. V, 1965. Oxidation testing of HfN was carried 5. N. Jacobson, J. Am. Ceram. Soc., 76, 5 26. C. Bargeron, R. Benson, R. Newman, out in a similar method as described for (1993). A. Jette, and T. Phillips, Johns Hopkins the HfC materials. While HfN.92 did not 6. E. Rudy, AFML-TR-65-2, 1969. APL Technical Digest, 14 (1993). have as significant of a pesting problem 7. G. Samsonov and I. Vinitskii, 27. E. Wuchina and M. Opeka, in High as HfC.98 did, the scale formed was Handbook of Refractory Compounds, Temperature and Materials not protective and showed evidence English Translation, IFI/Plenum, : Per Kofstad Memorial of porosity and cracking. In higher- New York (1980). Symposium, M. McNallan, E. Opila, temperature arcjet testing, however, 8. J. Pluscauskis, M. Dion, and T. Maruyama, and T. Narita, the HfN.75 did show a very different K. Buesking, 32nd Conference Editors, PV 99-38, p. 477, The response in forming an oxide scale. on Composites, Materials, and Electrochemical Society Proceedings While the oxygen diffusion inward / N2 Structures, Daytona Beach, FL, Series, Pennington, NJ (2000). evolution and NOx species formation January 2008 (in preparation). 28. S. Shimada and F. Yunazar, J. Am. / outward diffusion are not well- 9. E. Clougherty, R. Pober, and L. Ceram. Soc., 83, 721 (2000). understood, the gas pressures at the Kaufman, Trans. Met. Soc. AIME, 242, 29. C. Agte and H. Alterthum, Z. techn. interface must be significantly lower as 1077 (1968). Physik, 11, 182 (1930). the oxide that formed during testing 10. W. Tripp and H. Graham, J. 30. E. Rudy, AFML-TR-65-2, Part II, Vol. formed a dense, adherent scale—so Electrochem. Soc., 118, 1195 (1971). I, 1965. much so that subsequent oxidation 11. J. Berkowitz, J. Electrochem. Soc., 113, 31. J. Puszynski, in Carbide, , caused the formation of a gas bubble 908 (1968). and Boride Materials Synthesis and behind the oxide scale, resulting in 12. S. Levine, E. Opila, M. Halbig, J. Processing, A. Weimer, Editor, a “blowout” of the oxide towards the Kiser, M. Singh, and J. Salem, J. Euro. Chapman & Hall, London (1997). end of the 3 minute test, as shown in Ceram. Soc., 22, 2757 (2002). 32. D. Butts, Personal , Fig. 10. 13. A. Bongiorno, C. Forst, R. Kalia, J. Li, 2006. J. Marschsall, A. Nakano, M. Opeka, 33. R. Eron’yan, Avarbe and T. Danisina, Summary I. Talmy, P. Vashita, and S. Yip, MRS Teplofiz. Vys. Temp., 14, 398 (1976): Bulletin, 31, 410 (2006). High Temp. (English Transl.), 14, 359 Ultra-High Temperature Ceramics 14. I. Talmy, J. Zaykoski, M. Opeka, (1976). are a family of compounds that display and S. Dallek, in High Temperature 34. E. Wuchina, M. Opeka, F. Guitierrez- a unique set of properties, including Corrosion and Materials Chemistry Mora, R. Koritala, K. Goretta, and extremely high melting temperatures III, M. McNallan and E. Opila, J. Routbort, J. Euro. Ceram. Soc, 22, (> 3000°C), high hardness, and good Editors, PV 2001-12, p. 144, The 2571 (2002). chemical stability and strength at high Electrochemical Society Proceedings 35. E. Wuchina, M. Opeka, S. Causey, temperatures. Structural materials for Series, Pennington, NJ (2001). K. Buesking, J. Spain, A. Cull, J. use in high-temperature oxidizing 15. E. Wuchina, M. Opeka, J. Brown, D. Routbort, and F. Guitierrez-Mora, J. environments are presently limited Joslyn, and K. More, in CVD XIII, T. Mat. Sci., 39, 5939 (2004). mostly to SiC, Si3N4, oxide ceramics, Besmann, M. Allendorf, M. Robinson 36. H. Okamoto, Bull. Phase and composites of these materials. and R. Ulrich, Editors, PV 96-5, p. Diagrams, 11, 146 (1990). The maximum-use temperatures of 750, The Electrochemical Society silicon-based ceramics are limited to Proceedings Series, Pennington, NJ approximately 1700°C due to the onset (1996). About the Authors of active oxidation (lower temperatures 16. R. Thomson, in The and in water vapor environments. The Chemistry of Carbides, Nitrides, and Eric Wuchina is a materials research development of structural materials for Borides, R. Freer, Editor, p. 113, Kluwer engineer at the Naval Surface Warfare use in oxidizing and rapid heating Academic Publishers, Dordrecht Center, Carderock Division in West environments at temperatures above (1990). Bethesda, MD. He received his BS in 1988 1700°C is therefore of great engineering 17. Z. Munir and N. Sata, Int. J. of and PhD in 1995, both from Virginia importance. UHTC materials are Self-Propagating High-Temperature Tech. His research interests include typically considered to be the carbides, Synthesis, 1, 355 (1992). chemical vapor deposition, ultra-high nitrides, and borides of the transition 18. U. Anselmi-Tamburini, Y. Kodera, temperature ceramics processing and metals, but the Group IV-V compounds M. Gasch, C. Unuvar, Z. Munir, M. characterization, , (Ti, Zr, Hf, Ta) are generally considered Ohyanagi, and S. Johnson, J. Mat. and oxidation behavior of non-oxide to be the main focus of research due Sci., 41, 3097 (2006). ceramics in extreme environments. to the superior melting temperatures 19. A. Chamberlain, W. Fahrenholtz, He currently serves as the chair of and formation of stable high-melting and G. Hilmas, J. Am. Ceram. Soc., the ECS High Temperature Materials temperature oxides. The combination 89, 450 (2006). Division and is the organizer of the ECS of properties make these materials 20. D. Sciti, S. Guicciardi, and A. Bellosi, symposium High-Temperature Corrosion potential candidates for a variety of high- J. Am. Ceram. Soc., 89, 2320 (2006). and Materials Chemistry VII and Ultra- temperature structural applications, 21. R. Davis, in Advances in Ceramics, Vol. High Temperature Ceramics: Materials for including , hypersonic vehicles, 23: Nonstoichiometric Compounds, C. Extreme Environment Applications, both plasma arc electrodes, cutting tools, Catlow and W. Mackrodt, Editors, p. to be held in 2008. He may be reached furnace elements, and high temperature 529, The American Ceramic Society at [email protected]. shielding. (1987). 22. V. A. Gubanov, A. L. Ivanovsky, Elizabeth Opila is a materials research References and V. P. Zhukov, engineer at the NASA Glenn Research of Refractory Carbides and Nitrides, Center in Cleveland, Ohio. She received Cambridge University Press, 1. D. Glass, Private communication, her BS in at the Cambridge (1994). University of Illinois in 1981, her MS 2006 23. S. T. Oyama, The Chemistry of 2. DARPA HyFly website, http://www. in at the University Transition Metal Carbides and of California, Berkeley in 1983, and darpa.mil/tto/Programs/hyfly.htm. Nitrides, Chapman and Hall, London (1996). The Electrochemical Society Interface • Winter 2007 35 Wuchina, et al. (continued from previous page) her PhD in materials science at the Massachusetts Institute of in 1991. Her research interests include the and kinetics of high temperature materials oxidation and corrosion reactions. She may be reached at [email protected].

Mark Opeka is a research materials engineer for the Naval Surface Warfare Center, Carderock Division, in West Bethesda, MD. He earned his BS and MS in , and his PhD in materials science, all from the University of Maryland. His PhD included significant studies at Ohio State University in metallurgical thermodynamics and oxidation kinetics. He has been employed by the Navy for 30 years and has conducted research and development on high temperature materials, including refractory metals, , ceramics and ceramic composites, carbon-carbon composites, and carbon-phenolic composites. He has authored or co-authored 30 publications on materials selection for high temperature systems and oxidation properties of high temperature materials. He may be reached at mark.opeka@ navy.mil.

Bill Fahrenholtz is an associate professor of ceramic engineering at the University of Missouri-Rolla. He teaches undergraduate and graduate courses on thermodynamics as well as a required sophomore level laboratory on traditional ceramics. His research focuses on the processing and characterization of ceramics and ceramic-metal composites. He has current projects related to ultra- high temperature ceramics as well as the use of cerium oxide coatings for the corrosion protection of high strength aluminum alloys. He has published over 50 papers on his research. He may be reached at [email protected]. Looking for Inna Talmy is the senior research ECS takes an active ceramist and group leader of the Ceramic Science and Technology Group interest in the affairs at NSWCCD. She received both her Student News of its Student MS (1957) and PhD (1965) degrees in ceramic science and engineering from Members, and is the Mendeleev Institute of Chemical Technology in Moscow, Russia. Send all correspondence to: always interested in Previously, she worked in the ceramic hearing from you departments of Institutes of Chemical 65 South Main Street Technology in Moscow and Prague, Pennington, NJ 08534-2839, USA about your interests, Czechoslovakia. Her primary research Tel: 609.737.1902 activities, and efforts are in the field of structural Fax: 609.737.2743 non-oxide ceramics, cermets, E-mail: [email protected] accomplishments. ceramics, superconductors, and ceramic- matrix composites. Inna directed the development of celsian and phosphate ceramics as candidates for next w w w . electrochem.org generation tactical missile radomes. Her work has resulted in over 80 publications and 21 patents. She may be reached at [email protected].

36 The Electrochemical Society Interface • Winter 2007