Development of a microwave system for processing zirconia

The development of a 2.45GHz multimode oven is described. Difficulties were encountered in developing the temperature measurement and control system and the attainment of a uniform heating zone. On the strength of the development work, a number of recommendations to improve the microwave system were made. Suitability of the oven for processing of zirconia was investigated. Evaluation was carried out by a series of comparative experiments, with 3.0mol% Y-TZP, using conventional and hybrid microwave heating. It was demonstrated that the zirconia could be sintered, aged, and thermally etched with the microwave oven, and that binder burnout of the green compacts was successful. Interpretation of the experimental data, to determine whether the material properties were process or merely microstructure dependant, was unresolved due to the uncertainty of temperature measurements

Index to 1981 NASA Tech Briefs, volume 6, numbers 1-4

Short announcements of new technology derived from the R&D activities of NASA are presented. These briefs emphasize information considered likely to be transferrable across industrial, regional, or disciplinary lines and are issued to encourage commercial application. This index for 1981 Tech Briefs contains abstracts and four indexes: subject, personal author, originating center, and Tech Brief Number. The following areas are covered: electronic components and circuits, electronic systems, physical sciences, materials, life sciences, mechanics, machinery, fabrication technology, and mathematics and information sciences

The NASA SBIR product catalog

The purpose of this catalog is to assist small business firms in making the community aware of products emerging from their efforts in the Small Business Innovation Research (SBIR) program. It contains descriptions of some products that have advanced into Phase 3 and others that are identified as prospective products. Both lists of products in this catalog are based on information supplied by NASA SBIR contractors in responding to an invitation to be represented in this document. Generally, all products suggested by the small firms were included in order to meet the goals of information exchange for SBIR results. Of the 444 SBIR contractors NASA queried, 137 provided information on 219 products. The catalog presents the product information in the technology areas listed in the table of contents. Within each area, the products are listed in alphabetical order by product name and are given identifying numbers. Also included is an alphabetical listing of the companies that have products described. This listing cross-references the product list and provides information on the business activity of each firm. In addition, there are three indexes: one a list of firms by states, one that lists the products according to NASA Centers that managed the SBIR projects, and one that lists the products by the relevant Technical Topics utilized in NASA's annual program solicitation under which each SBIR project was selected

Microwave, spark plasma and conventional sintering to obtain controlled thermal expansion beta-eucryptite materials

Lithium aluminosilicate was fabricated by conventional and non-conventional sintering: microwave and spark plasma sintering, from 1200 to 1300 ºC. A considerable difference in densification, microstructure, coefficient of thermal expansion behavior and hardness and Young’s modulus was observed. Microwave technology made possible to obtain fully dense glass-free lithium aluminosilicate bulk material (>99%) with near-zero and controlled coefficient of thermal expansion and relatively high mechanical properties (7.1 GPa of hardness and 110 GPa of Young’s modulus) compared to the other two processes. It is believed that the heating mode and effective particle packing by microwave sintering are responsible to improve these properties.The authors would like to thank Dr. Emilio Rayon for performing the nanoindentation analysis in the Materials Technology institute (ITM) of the Polytechnic University of Valencia (UPV) and your financial support received of UPV under project SP20120621 and SP20120677 and Spanish government through the project (TEC2012-37532-C02-01) and cofunded by ERDF (European Regional Development Funds). A. Borrell acknowledges the Spanish Ministry of Science and Innovation for a Juan de la Cierva contract (JCI-2011-10498) and SCSIE of the University of Valencia.Benavente Martínez, R.; Salvador Moya, MD.; Borrell Tomás, MA.; García Moreno, O.; Peñaranda Foix, FL.; Catalá Civera, JM. (2015). Microwave, spark plasma and conventional sintering to obtain controlled thermal expansion beta-eucryptite materials. International Journal of Applied Ceramic Technology. 1-7. https://doi.org/10.1111/ijac.12285S17Bach, H. (Ed.). (1995). Low Thermal Expansion Glass Ceramics. Schott Series on Glass and Glass Ceramics. doi:10.1007/978-3-662-03083-7Roy, R., Agrawal, D. K., & McKinstry, H. A. (1989). Very Low Thermal Expansion Coefficient Materials. Annual Review of Materials Science, 19(1), 59-81. doi:10.1146/annurev.ms.19.080189.000423García-Moreno, O., Kriven, W. M., Moya, J. S., & Torrecillas, R. (2013). Alumina Region of the Lithium Aluminosilicate System: A New Window for Temperature Ultrastable Materials Design. Journal of the American Ceramic Society, 96(7), 2039-2041. doi:10.1111/jace.12428Chen, J.-C., Huang, G.-C., Hu, C., & Weng, J.-P. (2003). Synthesis of negative-thermal-expansion ZrW2O8 substrates. Scripta Materialia, 49(3), 261-266. doi:10.1016/s1359-6462(03)00213-6Abdel-Fattah, W. I., & Abdellah, R. (1997). Lithia porcelains as promising breeder candidates — I. Preparation and characterization of β-eucryptite and β-spodumene porcelain. Ceramics International, 23(6), 463-469. doi:10.1016/s0272-8842(96)00054-5Sheu, G.-J., Chen, J.-C., Shiu, J.-Y., & Hu, C. (2005). Synthesis of negative thermal expansion TiO2-doped LAS substrates. Scripta Materialia, 53(5), 577-580. doi:10.1016/j.scriptamat.2005.04.028Soares, V. O., Peitl, O., & Zanotto, E. D. (2013). New Sintered Li2O-Al2O3-SiO2Ultra-Low Expansion Glass-Ceramic. Journal of the American Ceramic Society, 96(4), 1143-1149. doi:10.1111/jace.12266Hu, A. M., Li, M., & Mao, D. L. (2008). Growth behavior, morphology and properties of lithium aluminosilicate glass ceramics with different amount of CaO, MgO and TiO2 additive. Ceramics International, 34(6), 1393-1397. doi:10.1016/j.ceramint.2007.03.032Ogiwara, T., Noda, Y., Shoji, K., & Kimura, O. (2011). Low-Temperature Sintering of High-Strength β-Eucryptite Ceramics with Low Thermal Expansion Using Li2O-GeO2 as a Sintering Additive. Journal of the American Ceramic Society, 94(5), 1427-1433. doi:10.1111/j.1551-2916.2010.04279.xAnselmi-Tamburini, U., Garay, J. E., & Munir, Z. A. (2006). Fast low-temperature consolidation of bulk nanometric ceramic materials. Scripta Materialia, 54(5), 823-828. doi:10.1016/j.scriptamat.2005.11.015Borrell, A., Salvador, M. D., Peñaranda-Foix, F. L., & Cátala-Civera, J. M. (2012). Microwave Sintering of Zirconia Materials: Mechanical and Microstructural Properties. International Journal of Applied Ceramic Technology, 10(2), 313-320. doi:10.1111/j.1744-7402.2011.02741.xYoshimura, M. (1998). Journal of Materials Science Letters, 17(16), 1389-1391. doi:10.1023/a:1026476430465Nishimura, T., Mitomo, M., Hirotsuru, H., & Kawahara, M. (1995). Fabrication of silicon nitride nano-ceramics by spark plasma sintering. Journal of Materials Science Letters, 14(15), 1046-1047. doi:10.1007/bf00258160Chaim, R. (2007). Densification mechanisms in spark plasma sintering of nanocrystalline ceramics. Materials Science and Engineering: A, 443(1-2), 25-32. doi:10.1016/j.msea.2006.07.092Chaim, R. (2006). Superfast densification of nanocrystalline oxide powders by spark plasma sintering. Journal of Materials Science, 41(23), 7862-7871. doi:10.1007/s10853-006-0605-7Borrell, A., Salvador, M. D., Rayón, E., & Peñaranda-Foix, F. L. (2012). Improvement of microstructural properties of 3Y-TZP materials by conventional and non-conventional sintering techniques. Ceramics International, 38(1), 39-43. doi:10.1016/j.ceramint.2011.06.035Benavente, R., Borrell, A., Salvador, M. D., Garcia-Moreno, O., Peñaranda-Foix, F. L., & Catala-Civera, J. M. (2014). Fabrication of near-zero thermal expansion of fully dense β-eucryptite ceramics by microwave sintering. Ceramics International, 40(1), 935-941. doi:10.1016/j.ceramint.2013.06.089Cheng, J., Agrawal, D., Zhang, Y., & Roy, R. (2002). Microwave sintering of transparent alumina. Materials Letters, 56(4), 587-592. doi:10.1016/s0167-577x(02)00557-8García-Moreno, O., Fernández, A., Khainakov, S., & Torrecillas, R. (2010). Negative thermal expansion of lithium aluminosilicate ceramics at cryogenic temperatures. Scripta Materialia, 63(2), 170-173. doi:10.1016/j.scriptamat.2010.03.047P. J. Plaza-Gonzalez A. J. Canos J. M. Catala-Civera J. D. Gutierrez-Cano Proceedings of the 13th International Conference on Microwave and RF Heating 447 450 2011Oliver, W. C., & Pharr, G. M. (1992). An improved technique for determining hardness and elastic modulus using load and displacement sensing indentation experiments. Journal of Materials Research, 7(6), 1564-1583. doi:10.1557/jmr.1992.1564Wang, S.-Y., Wang, W., Wang, W.-Z., & Du, Y.-W. (2002). Preparation and characterization of highly oriented NiO(200) films by a pulse ultrasonic spray pyrolysis method. Materials Science and Engineering: B, 90(1-2), 133-137. doi:10.1016/s0921-5107(01)00922-9Ghosh, S., Chokshi, A. H., Lee, P., & Raj, R. (2009). A Huge Effect of Weak dc Electrical Fields on Grain Growth in Zirconia. Journal of the American Ceramic Society, 92(8), 1856-1859. doi:10.1111/j.1551-2916.2009.03102.xCoble, R. L. (1961). Sintering Crystalline Solids. I. Intermediate and Final State Diffusion Models. Journal of Applied Physics, 32(5), 787-792. doi:10.1063/1.1736107Munir, Z. A., Quach, D. V., & Ohyanagi, M. (2010). Electric Current Activation of Sintering: A Review of the Pulsed Electric Current Sintering Process. Journal of the American Ceramic Society, 94(1), 1-19. doi:10.1111/j.1551-2916.2010.04210.xRybakov, K. I., Olevsky, E. A., & Krikun, E. V. (2013). Microwave Sintering: Fundamentals and Modeling. Journal of the American Ceramic Society, 96(4), 1003-1020. doi:10.1111/jace.12278Pelletant, A., Reveron, H., Chêvalier, J., Fantozzi, G., Blanchard, L., Guinot, F., & Falzon, F. (2012). Grain size dependence of pure β-eucryptite thermal expansion coefficient. Materials Letters, 66(1), 68-71. doi:10.1016/j.matlet.2011.07.107Bruno, G., Garlea, V. O., Muth, J., Efremov, A. M., Watkins, T. R., & Shyam, A. (2012). Microstrain temperature evolution in β-eucryptite ceramics: Measurement and model. Acta Materialia, 60(12), 4982-4996. doi:10.1016/j.actamat.2012.04.033Ramalingam, S., & Reimanis, I. E. (2012). Effect of Doping on the Thermal Expansion of β-Eucryptite Prepared by Sol-Gel Methods. Journal of the American Ceramic Society, 95(9), 2939-2943. doi:10.1111/j.1551-2916.2012.05338.xVaidhyanathan, B., Annapoorani, K., Binner, J., & Raghavendra, R. (2010). Microwave Sintering of Multilayer Integrated Passive Devices. Journal of the American Ceramic Society, 93(8), 2274-2280. doi:10.1111/j.1551-2916.2010.03740.

Microwave Sintering of zirconia materials: Mechanical and microstructural properties

Commercially, 3mol% Y2O3-stabilized tetragonal zirconia (7090nm) compacts were fabricated using a conventional and a nonconventional sintering technique; microwave heating in a resonant mono-mode cavity at 2.45GHz, at temperatures in the 11001400 degrees C range. A considerable difference in the densification behavior between conventional (CS) and microwave (MW) sintered materials was observed. The MW materials attain a full density of 99.9% of the theoretical density (t.d.) at 1400 degrees C/10min, whereas the CS reach only 98.0% t.d. at the same temperature and 1h of dwelling time. Therefore, the MW materials exhibit superior Vickers hardness values (16.0GPa) when compared with CS (13.4GPa).This work has been carried out under program to support research and development of the Polytechnic University of Valencia (U.P.V) under multidisciplinary projects, PAID-05-09 and PAID-05-10. A. Borrell acknowledges the Spanish Ministry of Science and Innovation for her FPI Ph.D. grant and the people from Institute Technological of Materials (ITM) of the U.P.V for helping us with the microwave experiments during a stay in 2010-2011. Felipe L. Penaranda-Foix thanks the Generalitat Valenciana for the grant in the frame of the Program BEST/2010 because some results of this paper have been possible with this help.Borrell Tomás, MA.; Salvador Moya, MD.; Penaranda-Foix, FL.; Catalá Civera, JM. (2012). Microwave Sintering of zirconia materials: Mechanical and microstructural properties. International Journal of Applied Ceramic Technology. 10(2):313-320. https://doi.org/10.1111/j.1744-7402.2011.02741.xS313320102Deville, S., Gremillard, L., Chevalier, J., & Fantozzi, G. (2005). A critical comparison of methods for the determination of the aging sensitivity in biomedical grade yttria-stabilized zirconia. Journal of Biomedical Materials Research Part B: Applied Biomaterials, 72B(2), 239-245. doi:10.1002/jbm.b.30123Binner, J., Annapoorani, K., Paul, A., Santacruz, I., & Vaidhyanathan, B. (2008). Dense nanostructured zirconia by two stage conventional/hybrid microwave sintering. Journal of the European Ceramic Society, 28(5), 973-977. doi:10.1016/j.jeurceramsoc.2007.09.002Anselmi-Tamburini, U., Garay, J. E., & Munir, Z. A. (2006). Fast low-temperature consolidation of bulk nanometric ceramic materials. Scripta Materialia, 54(5), 823-828. doi:10.1016/j.scriptamat.2005.11.015MENDELSON, M. I. (1969). Average Grain Size in Polycrystalline Ceramics. Journal of the American Ceramic Society, 52(8), 443-446. doi:10.1111/j.1151-2916.1969.tb11975.xChen, X. ., Khor, K. ., Chan, S. ., & Yu, L. . (2004). Overcoming the effect of contaminant in solid oxide fuel cell (SOFC) electrolyte: spark plasma sintering (SPS) of 0.5wt.% silica-doped yttria-stabilized zirconia (YSZ). Materials Science and Engineering: A, 374(1-2), 64-71. doi:10.1016/j.msea.2003.12.028Trunec, M., Maca, K., & Shen, Z. (2008). Warm pressing of zirconia nanoparticles by the spark plasma sintering technique. Scripta Materialia, 59(1), 23-26. doi:10.1016/j.scriptamat.2008.02.015Mazaheri, M., Hesabi, Z. R., Golestani-Fard, F., Mollazadeh, S., Jafari, S., & Sadrnezhaad, S. K. (2009). The Effect of Conformation Method and Sintering Technique on the Densification and Grain Growth of Nanocrystalline 8 mol% Yttria-Stabilized Zirconia. Journal of the American Ceramic Society, 92(5), 990-995. doi:10.1111/j.1551-2916.2009.02959.xGoldstein, A., Travitzky, N., Singurindy, A., & Kravchik, M. (1999). Direct microwave sintering of yttria-stabilized zirconia at 2·45GHz. Journal of the European Ceramic Society, 19(12), 2067-2072. doi:10.1016/s0955-2219(99)00020-5Upadhyaya, D. D., Ghosh, A., Gurumurthy, K. R., & Prasad, R. (2001). Microwave sintering of cubic zirconia. Ceramics International, 27(4), 415-418. doi:10.1016/s0272-8842(00)00096-1Mizuno, M., Obata, S., Takayama, S., Ito, S., Kato, N., Hirai, T., & Sato, M. (2004). Sintering of alumina by 2.45 GHz microwave heating. Journal of the European Ceramic Society, 24(2), 387-391. doi:10.1016/s0955-2219(03)00217-6Kuo, C.-T., Chen, C.-S., & Lin, I.-N. (2005). Microstructure and Nonlinear Properties of Microwave-Sintered ZnO-V2O5 Varistors: I, Effect of V2O5 Doping. Journal of the American Ceramic Society, 81(11), 2942-2948. doi:10.1111/j.1151-2916.1998.tb02717.xCong, L., Zheng, X., Hu, P., & Dan-feng Sun. (2007). Bi2O3Vaporization in Microwave-Sintered ZnO Varistors. Journal of the American Ceramic Society, 90(9), 2791-2794. doi:10.1111/j.1551-2916.2007.01848.xWang, J., Binner, J., Vaidhyanathan, B., Joomun, N., Kilner, J., Dimitrakis, G., & Cross, T. E. (2006). Evidence for the Microwave Effect During Hybrid Sintering. Journal of the American Ceramic Society, 89(6), 1977-1984. doi:10.1111/j.1551-2916.2006.00976.xMazaheri, M., Zahedi, A. M., & Hejazi, M. M. (2008). Processing of nanocrystalline 8mol% yttria-stabilized zirconia by conventional, microwave-assisted and two-step sintering. Materials Science and Engineering: A, 492(1-2), 261-267. doi:10.1016/j.msea.2008.03.023Ebadzadeh, T., & Valefi, M. (2008). Microwave-assisted sintering of zircon. Journal of Alloys and Compounds, 448(1-2), 246-249. doi:10.1016/j.jallcom.2007.02.032García-Gañán, C., Meléndez-Martínez, J. J., Gómez-García, D., & Domínguez-Rodríguez, A. (2006). Microwave sintering of nanocrystalline Ytzp (3 Mol%). Journal of Materials Science, 41(16), 5231-5234. doi:10.1007/s10853-006-0433-9Cheng, J., Agrawal, D., Zhang, Y., & Roy, R. (2002). Microwave sintering of transparent alumina. Materials Letters, 56(4), 587-592. doi:10.1016/s0167-577x(02)00557-8Nightingale, S. A., Dunne, D. P., & Worner, H. K. (1996). Sintering and grain growth of 3 mol% yttria zirconia in a microwave field. Journal of Materials Science, 31(19), 5039-5043. doi:10.1007/bf00355903Nightingale, S. A., Worner, H. K., & Dunne, D. P. (2005). Microstructural Development during the Microwave Sintering of Yttria-Zirconia Ceramics. Journal of the American Ceramic Society, 80(2), 394-400. doi:10.1111/j.1151-2916.1997.tb02843.xJanney, M. A., Calhoun, C. L., & Kimrey, H. D. (1992). Microwave Sintering of Solid Oxide Fuel Cell Materials: I, Zirconia-8 mol% Yttria. Journal of the American Ceramic Society, 75(2), 341-346. doi:10.1111/j.1151-2916.1992.tb08184.xANSTIS, G. R., CHANTIKUL, P., LAWN, B. R., & MARSHALL, D. B. (1981). A Critical Evaluation of Indentation Techniques for Measuring Fracture Toughness: I, Direct Crack Measurements. Journal of the American Ceramic Society, 64(9), 533-538. doi:10.1111/j.1151-2916.1981.tb10320.xNiihara, K., Morena, R., & Hasselman, D. P. H. (1982). Evaluation ofK Ic of brittle solids by the indentation method with low crack-to-indent ratios. Journal of Materials Science Letters, 1(1), 13-16. doi:10.1007/bf00724706Yucheng, W., & Zhengyi, F. (2002). Study of temperature field in spark plasma sintering. Materials Science and Engineering: B, 90(1-2), 34-37. doi:10.1016/s0921-5107(01)00780-2Acierno, D., Barba, A. A., & d’ Amore, M. (2003). Heat transfer phenomena during processing materials with microwave energy. Heat and Mass Transfer, 40(5), 413-420. doi:10.1007/s00231-003-0482-4Thostenson, E. T., & Chou, T.-W. (1999). Microwave processing: fundamentals and applications. Composites Part A: Applied Science and Manufacturing, 30(9), 1055-1071. doi:10.1016/s1359-835x(99)00020-2Matsui, K., Yoshida, H., & Ikuhara, Y. (2009). Isothermal Sintering Effects on Phase Separation and Grain Growth in Yttria-Stabilized Tetragonal Zirconia Polycrystal. Journal of the American Ceramic Society, 92(2), 467-475. doi:10.1111/j.1551-2916.2008.02861.xWilson, J., & Kunz, S. M. (1988). Microwave Sintering of Partially Stabilized Zirconia. Journal of the American Ceramic Society, 71(1), C-40-C-41. doi:10.1111/j.1151-2916.1988.tb05778.xUpadhyaya, D. D., Ghosh, A., Dey, G. K., Prasad, R., & Suri, A. K. (2001). Journal of Materials Science, 36(19), 4707-4710. doi:10.1023/a:1017966703650Winnubst, A. J. A., Keizer, K., & Burggraaf, A. J. (1983). Mechanical properties and fracture behaviour of ZrO2-Y2O3 ceramics. Journal of Materials Science, 18(7), 1958-1966. doi:10.1007/bf0055498

Microwave Processing Of Fiber Reinforced Composites (Optimization of Glass Reinforced Epoxy Curing Process)

Microwave curing of polymer matrix composites has proven to be an attractive substitute for conventional thermal curing. Industrial applications are currently developed including telecommunications, aerospace, food industry, enhancement concrete setting, composites manufacturing, and many others. Many universities and research centers around the globe are endeavoring to make use of this technology to the most. Common research objectives include homogeneity of the cure, the acceleration of cure kinetics, cure reaction mechanism, and enhancement of mechanical properties. In order to efficiently utilize this form of energy, precise control over power, temperature, and time were applied to achieve set goals: reduce cure time and thermal overshoots, assure complete cure, and maximize mechanical properties. This work discusses an optimization scenario to achieve these set goals by combining data from calorimetric analysis, insitu temperature and power monitoring, and energy conservation studies. An experimental setup is assembled consisting of laboratory equipped multi mode microwave applicator and programmable feedback controllers. For thermal curing, a typical electric furnace is used with three thermocouples measuring the cavity, mold, and sample temperatures. Test samples consisted of both neat blend of DGEBA resin together with samples of glass fiber reinforced epoxy. Prior to testing, the microwave cavity has been calibrated to approximate heat losses in the system and thus determine the expected data accuracy. Curing experiments for a specific temperature-time profile show that microwave applicator not only follows the set temperature but also eliminates thermal lag and temperature overshoot. While holdback technique could not deliver the required cure cycle, PID control strategy succeeded in homogenously curing successful epoxy and epoxy/fiberglass samples. Kinetic knowledge is enriched using DSC to determine expected curing times at different curing temperatures. Based on these data, a selected isothermal temperature of 100°C was used with variable dwell times between 13-30 minutes for microwave curing. Mechanical testing data shows that microwave cured samples have relatively exceeded the conventionally cured ones in both flexural strength and modulus. The DSC recommended time of cure 13 minutes, at 100 °C, is a good approximate which suggests similar curing mechanism of cure kinetics in both thermal and microwave· methods. High ramp rate, 200 °C/min could also be achieved without material degradation or temperature overshoot by carefully controlling power during the ramp stage. Effect of gelation time and vacuum degassing, being a major time saving area, were also tested. The gelation time has particularly enhanced the flexural modulus of the epoxy samples. In short, the use of efficient process controller resulted in superior mechanical properties at practically optimum time durations

Small business innovation research. Abstracts of completed 1987 phase 1 projects

Non-proprietary summaries of Phase 1 Small Business Innovation Research (SBIR) projects supported by NASA in the 1987 program year are given. Work in the areas of aeronautical propulsion, aerodynamics, acoustics, aircraft systems, materials and structures, teleoperators and robotics, computer sciences, information systems, spacecraft systems, spacecraft power supplies, spacecraft propulsion, bioastronautics, satellite communication, and space processing are covered

Research and technology highlights of the Lewis Research Center

Highlights of research accomplishments of the Lewis Research Center for fiscal year 1984 are presented. The report is divided into four major sections covering aeronautics, space communications, space technology, and materials and structures. Six articles on energy are included in the space technology section