Nanostructure Science and Technology - World Technology ...

More documents

Recommendations

Info

108 Carl Koch Other Ferromagnetic Nanocrystalline Materials Magnetic nanocomposite refrigerants, which have four times the magnetocaloric effects of the best low temperature magnetic refrigerant, were developed by NIST and described by R. Shull (1998, 43-58). The entropy change at a given (low) temperature for a system of magnetic spins is enhanced when the isolated spins are clustered. Shull et al. (1993) have shown that the nanocomposite Gd 3 Ga 5–x Fe x O 12 gives superior magnetocaloric effects, which increase with x up to x = 2.5 and can be extended to higher temperatures than conventional materials. Magnetostrictive materials such as Terfonol-D (Tb 0.3 Dy 0.7 Fe 2 ) have been of scientific and technological interest in recent years. It is suggested by G.C. Hadjipanayis (1998, 107-112) that nanostructured magnetostrictive materials can have improved properties, such as lower saturation fields, with reduced anisotropy and in multilayers with alternate layers of magnetostrictive and soft magnetic materials that are exchange-coupled. Hadjipanayis states that most of the research in this area is carried out in Japan and Europe. Opportunities and Challenges Nanocrystalline magnetic materials offer perhaps the nearest-term prospect of significant applications of bulk nanostructured materials. The remanence enhancement in two-phase hard/soft magnetic materials can result in excellent energy products—comparable to those from rapid solidification processing routes—in powder composites. The flexibility in manufacturing this allows should provide many possible permanent magnet applications. Nanocrystalline soft magnetic materials have the lowest energy losses of any material. While problems such as mechanical brittleness remain, these materials promise to replace existing transformer core materials for power applications. The U.S. research and industrial effort in these materials lags the efforts in Japan. OTHER BULK APPLICATIONS OF NANOSTRUCTURED MATERIALS Nanocrystalline Hydrogen Storage Materials R.B. Schwarz (1998, 93-95) has pointed out that nanostructured materials offer several potential advantages for hydrogen storage materials. Rapid kinetics of absorption/desorption can be aided by refining the microstructure
6. Bulk Behavior of Nanostructured Materials 109 to the nanoscale. For example, nanoscale inclusions of Mg 2 Ni in Mg catalyze the decomposition of the molecular hydrogen, increasing the hydrogen absorption/desorption kinetics. Another advantage of the nanoscale microstructure is that the alloy powder does not comminute on repeated charging/discharging with hydrogen. This is not strictly a bulk material, since powder agglomerates or green compacts can be used, thus obviating the need for compaction to theoretical density. Nanocrystalline Corrosion-Resistant Materials The limited work to date on corrosion resistance of nanocrystalline materials indicates that no generalizations can be made. Superior localized corrosion resistance in HCl was observed for nanocrystalline 304 stainless steel (Fe–18%Cr–8%Ni) prepared by sputter deposition (Inturi and Szklavska-Smialowska 1991 and 1992). This was attributed to the fine grain size and homogeneity of the nc material. However, the average dissolution rate of nc Ni was found to be higher than that for coarse-grained material (Rofagha et al. 1991). REFERENCES Alves, H., M. Ferreira, U. Koster, and B. Muller. 1996. Materials Science Forum 225–227: 769. Baibich, M..N., J.M. Broto, A. Fert, F. Nguyen Van Dau, F. Petroff, P. Etienne, G. Creuzet, A. Friederich, and J. Chazelas. 1998. Phys. Rev. Lett. 61:2472. Berkowitz, A.E., J.R. Mitchell, M.J. Carey, A.P. Young, S. Zhang, F.E. Spada, F.T. Parker, A. Hutten, and G. Thomas. 1992. Phys. Rev. Lett. 68:3745. Bohn, R., T. Haubold, R Birringer, and H. Gleiter. 1991. Scripta Metall. Mater. 25:811. Carsley, J.E., R. Shaik, W.W. Milligan, and E.C. Aifantis. 1997. In Chemistry and physics of nanostructures and related non-equilibrium materials. ed. E. Ma, B. Fultz, R. Shull, J. Morral, and P. Nash. Warrendale, PA: TMS. Cohen, J.B. 1992. Metall. Trans. A. 23A:2685. Darken, L.S. 1961. Trans. Am. Soc. Met. 54:599. Eastman, J.A., M. Choudry, M.N. Rittner, C.J. Youngdahl, M. Dollar, J.R. Weertman, R.J. DiMelfi, and L.J. Thompson. 1997. In Chemistry and physics of nanostructures, ed. Ma et al. El-Hilo, M., K. O’Grady, and R.W. Chantrell. 1994. J. Appl. Phys. 76:6811. Erb, U., G. Palumbo, R. Zugic, and K.T. Aust. 1996. In Processing and properties of nanocrystalline materials, ed. C. Suryanarayana, J. Singh, and F.H. Froes. Warrendale, PA: TMS. Gertsman, V.Y., M. Hoffman, H. Gleiter and R. Birringer. 1994. Acta Metall. Mater. 42:3539-3544. Gleiter, H. 1990. Progress in Materials Science 33:4. Guinier, A. 1938. Nature 142:569; Preston, G.D. 1938. Nature 142:570. Günther, B., A. Baalmann, and H. Weiss. 1990. Mater. Res. Soc. Symp. Proc. 195:611-615. Hadjipanayis, C.G. 1998. Nanostructured magnetic materials. In R&D Status and Trends, ed. Siegel et al.
Page 1 and 2:
National Science and Technology Cou
Page 3 and 4:
WTEC Panel on NANOSTRUCTURE SCIENCE
Page 5 and 6:
ABSTRACT This report reviews the st
Page 7 and 8:
Foreword Timely information on scie
Page 9 and 10:
Foreword iii collaboration and thus
Page 11 and 12:
Contents Foreword Table of Contents
Page 13 and 14:
List of Figures 1.1 Organization of
Page 15 and 16:
List of Figures ix 5.12 Granular GM
Page 17 and 18:
List of Tables ES.1 Technological I
Page 19 and 20:
Executive Summary Richard W. Siegel
Page 21 and 22:
Executive Summary xix past decade,
Page 23 and 24:
Executive Summary xxi TABLE ES.2. C
Page 25 and 26:
Executive Summary xxiii blocks, and
Page 27 and 28:
Chapter 1 Introduction and Overview
Page 29 and 30:
1. Introduction and Overview 3 •
Page 31 and 32:
1. Introduction and Overview 5 worl
Page 33 and 34:
1. Introduction and Overview 7 grow
Page 35 and 36:
1. Introduction and Overview 9 lead
Page 37 and 38:
1. Introduction and Overview 11 2.
Page 39 and 40:
1. Introduction and Overview 13 It
Page 41 and 42:
Chapter 2 Synthesis and Assembly Ev
Page 43 and 44:
2. Synthesis and Assembly 17 transi
Page 45 and 46:
2. Synthesis and Assembly 19 probe
Page 47 and 48:
2. Synthesis and Assembly 21 by adj
Page 49 and 50:
2. Synthesis and Assembly 23 blocks
Page 51 and 52:
2. Synthesis and Assembly 25 Self-A
Page 53 and 54:
2. Synthesis and Assembly 27 Figure
Page 55 and 56:
2. Synthesis and Assembly 29 us to
Page 57 and 58:
2. Synthesis and Assembly 31 Brotzm
Page 59 and 60:
2. Synthesis and Assembly 33 Siegel
Page 61 and 62:
Chapter 3 Dispersions and Coatings
Page 63 and 64:
3. Dispersions and Coatings 37 exis
Page 65 and 66:
3. Dispersions and Coatings 39 more
Page 67 and 68:
3. Dispersions and Coatings 41 into
Page 69 and 70:
3. Dispersions and Coatings 43 of N
Page 71 and 72:
3. Dispersions and Coatings 45 oppo
Page 73 and 74:
3. Dispersions and Coatings 47 Kanz
Page 75 and 76:
Chapter 4 High Surface Area Materia
Page 77 and 78:
4. High Surface Area Materials 51 w
Page 79 and 80:
4. High Surface Area Materials 53 F
Page 81 and 82:
4. High Surface Area Materials 55 T
Page 83 and 84: 4. High Surface Area Materials 57 s
Page 85 and 86: 4. High Surface Area Materials 59 T
Page 87 and 88: 4. High Surface Area Materials 61 F
Page 89 and 90: 4. High Surface Area Materials 63 m
Page 91 and 92: 4. High Surface Area Materials 65 I
Page 93 and 94: Chapter 5 Functional Nanoscale Devi
Page 95 and 96: 5. Functional Nanoscale Devices 69
Page 119 and 120: Chapter 6 Bulk Behavior of Nanostru
Page 121 and 122: 6. Bulk Behavior of Nanostructured
Page 133: 6. Bulk Behavior of Nanostructured
Page 139 and 140: Chapter 7 Biologically Related Aspe
Page 141 and 142: 7. Biologically Related Aspects of
Page 157 and 158: Chapter 8 Research Programs on Nano
Page 159 and 160: 8. Research Programs on Nanotechnol
Page 177 and 178: APPENDICES Appendix A. Biographies
Page 179 and 180: Appendix A. Biographies of Panelist
Page 185 and 186:
Appendix B. Site Reports—Europe S
Page 187 and 188:
Appendix B. Site Reports—Europe 1
Page 189 and 190:
Page 191 and 192:
Page 193 and 194:
Page 195 and 196:
Page 197 and 198:
Page 199 and 200:
Page 201 and 202:
Page 203 and 204:
Page 205 and 206:
Page 207 and 208:
Page 209 and 210:
Page 211 and 212:
Page 213 and 214:
Page 215 and 216:
Page 217 and 218:
Page 219 and 220:
Page 221 and 222:
Page 223 and 224:
Page 225 and 226:
Page 227 and 228:
Page 229 and 230:
Page 231 and 232:
Page 233 and 234:
Page 235 and 236:
Page 237 and 238:
Page 239 and 240:
Page 241 and 242:
Page 243 and 244:
Page 245 and 246:
Page 247 and 248:
Appendix C. European Roundtable Dis
Page 249 and 250:
Page 251 and 252:
Page 253 and 254:
Page 255 and 256:
Page 257 and 258:
Page 259 and 260:
Page 261 and 262:
Page 263 and 264:
Page 265 and 266:
Page 267 and 268:
Page 269 and 270:
Appendix D. Site Reports—Japan OV
Page 271 and 272:
Appendix D. Site Reports—Japan 24
Page 273 and 274:
Page 275 and 276:
Page 277 and 278:
Page 279 and 280:
Page 281 and 282:
Page 283 and 284:
Page 285 and 286:
Page 287 and 288:
Page 289 and 290:
Page 291 and 292:
Page 293 and 294:
Page 295 and 296:
Page 297 and 298:
Page 299 and 300:
Page 301 and 302:
Page 303 and 304:
Page 305 and 306:
Page 307 and 308:
Page 309 and 310:
Page 311 and 312:
Page 313 and 314:
Page 315 and 316:
Page 317 and 318:
Page 319 and 320:
Page 321 and 322:
Page 323 and 324:
Page 325 and 326:
Page 327 and 328:
Page 329 and 330:
Page 331 and 332:
Page 333 and 334:
Page 335 and 336:
Page 337 and 338:
Page 339 and 340:
Appendix E. Site Reports—Taiwan O
Page 341 and 342:
Appendix E. Site Reports—Taiwan 3
Page 343 and 344:
Page 345 and 346:
Page 347 and 348:
Page 349 and 350:
Page 351 and 352:
Page 353 and 354:
Appendix F. Glossary 2DEG A/D AAAR
Page 355 and 356:
Appendix F. Glossary 329 ESPRIT ESR
Page 357 and 358:
Appendix F. Glossary 331 MA MBE mCP
Page 359 and 360:
Appendix F. Glossary 333 PVDF QCA Q
Page 361 and 362:
Appendix F. Glossary 335 WTEC XAS X
show all

Nanostructure Science and Technology - World Technology ...

Create successful ePaper yourself

Delete template?

Save as template?