Spark plasma sintering is a hot pressing technique where rapid heating by dc electric pulses is used simultaneously with applied pressure. Thus, spark plasma sintering is highly suitable for rapid densification of ceramic nanoparticles and preservation of the final nanostructure. A considerable portion of the shrinkage during densification of the green compact of nanoparticles in the first and intermediate stages of sintering occurs during heating by particle rearrangement by sliding and rotation. Further densification to the final stage of sintering takes place by either plastic yield or diffusional processes. Full densification in the final stage of sintering is associated with diffusional processes only. Nanoparticle sliding and rotation during heating may also lead to grain coalescence, with much faster kinetics than normal grain growth at higher temperatures. Based on existing models for particle rearrangement and sliding, the contributions of these processes in conjunction with nanoparticle properties and process parameters were highlighted.
GleiterH, WeissmullerJ, WollersheimO, WurschumR: ‘Nanocrystalline materials: a way to solids with tunable electronic structures and properties?’, Acta Mater., 2001, 49, (4), 737–745.
2.
DerletPM, MeyerR, LewisLJ, StuhrU, Van SwygenhovenH: ‘Low-frequency vibrational properties of nanocrystalline materials’, Phys. Rev. Lett., 2001, 87, (20), 205501.
3.
GrossingerR, SatoR, HolzerD, DahlgrenM: ‘Properties, benefits, and application of nanocrystalline structures in magnetic materials’, Adv. Eng. Mater., 2003, 5, (5), 285–290.
LiuL, LiY, WangFH: ‘Electrochemical corrosion behavior of nanocrystalline materials – a review’, J. Mater. Sci., 2010, 26, (1), 1–14.
6.
OrruR, LicheriR, LocciAM, CincottiA, CaoG: ‘Consolidation/synthesis of materials by electric current activated/assisted sintering’, Mater. Sci. Eng. R, 2009, R63, (4–6), 127–287.
7.
GarayJE: ‘Current-activated, pressure-assisted densification of materials’, Ann. Rev. Mater. Res., 2010, 40, 445–468.
8.
MunirZA, QuachDV, OhyanagiM: ‘Electric current activation of sintering: a review of the pulsed electric current sintering process’, J. Am. Ceram. Soc., 2011, 94, (1), 1–19.
9.
ChaimR, LevinM, ShlayerA, EstournésC: ‘Sintering and densification of nanocrystalline ceramic oxide powders: a review’, Adv. Appl. Ceram., 2008, 107, (3), 159–169.
10.
ChaimR, ShenZ, NygrenM: ‘Transparent nanocrystalline MgO by rapid and low-temperature spark plasma sintering’, J. Mater. Res., 2004, 19, (9), 2527–2531.
11.
AngererP, YuLG, KhorKA, KrumpelG: ‘Spark-plasma-sintering (SPS) of nanostructured and submicron titanium oxide powders’, Mater. Sci. Eng. A, 2004, A381, (1–2), 16–19.
12.
ZhouY, HiraoK, YamauchiY, KanzakiS: ‘Densification and grain growth in pulse electric current sintering of alumina’, J. Eur. Ceram. Soc., 2004, 24, (12), 3465–3470.
13.
ChaimR: ‘Densification mechanisms in spark plasma sintering of nanocrystalline ceramics’, Mater. Sci. Eng. A, 2007, A443, (1–2), 25–32.
ReedJS: ‘Principles of ceramics processing’, 2nd edn, 427; 1995, New York, Wiley.
16.
RingTA: ‘Fundamentals of ceramic powder processing and synthesis’, 656; 1996, San Diego, Academic Press.
17.
ValverdeJM, QuintanillaMAS, CastellanosA: ‘Jamming threshold of dry fine powders’, Phys. Rev. Lett., 2004, 92, (25), 258303.
18.
PotiguarFQ, MakseHA: ‘Effective temperature and jamming transition in dense, gently sheared granular assemblies’, Eur. Phys. J. E, 2006, 19E, (2), 171–183.
19.
MarderR, ChaimR, ChevallierG, EstournésC: ‘Effect of 1 wt% LiF additive on the densification of nanocrystalline Y2O3 ceramics by spark plasma sintering’, J. Eur. Ceram. Soc., 2011, 31, (6), 1057–1066.
20.
KuhnLT, McMeekingRM, LangFF: ‘A model for powder consolidation’, J. Am. Ceram. Soc., 1991, 74, (3), 682–685.
21.
WaltonK: ‘The oblique compression of two elastic spheres’, J. Mech. Phys. Solids, 1978, 26, (3), 139–150.
22.
KaratoS, WangZ, FujinoK: ‘High-temperature creep of yttrium–aluminum garnet single crystals’, J. Mater. Sci., 1994, 20, (24), 6458–6462.
23.
MezeixL, GreenDJ: ‘Comparison of the mechanical properties of single crystal and polycrystalline yttrium aluminum garnet’, Int. J. Appl. Ceram. Technol., 2006, 3, (2), 166–176.
24.
FeldmanR, ShimonyY, LebiushE, GolanY: ‘Effect of hot acid etching on the mechanical strength of ground YAG laser element’, J. Phys. Chem. Solids, 2008, 69, (4), 839–846.
25.
ChaimR, Marder-JaeckelR, ShenJZ: ‘Transparent YAG ceramics by surface softening of nanoparticles in spark plasma sintering’, Mater. Sci. Eng. A, 2006, A429, (1–2), 74–78.
26.
Tobi Even-TzurO, ChaimR: ‘Effect of green density and electric field direction on densification of YAG nano-powders by spark plasma sintering’, J. Mater. Sci., 2009, 44, (8), 2063–2068.
27.
FrageN, KalabukhovS, SverdlovN, EzerskyV, DarielMP: ‘Densification of transparent yttrium aluminum garnet (YAG) by SPS processing’, J. Eur. Ceram. Soc., 2010, 30, (16), 3331–3337.
28.
ChaimR, ShenZ: ‘Grain size control by pressure application regime during spark plasma sintering of Nd-YAG nanopowders’, J. Mater. Sci., 2008, 43, (14), 5023–5027.
29.
KenkreVM, EndicottMR, GlassSJ, HurdAJ: ‘A theoretical model for compaction of granular materials’, J. Am. Ceram. Soc., 1996, 79, (12), 3045–3054.
30.
ShenZ, JohnssonM, ZhaoZ, NygrenM: ‘Spark plasma sintering of alumina’, J. Am. Ceram. Soc., 2002, 85, (8), 1921–1927.
31.
ChaimR, ReshefR, LiuG, ShenZ: ‘Low-temperature spark plasma sintering of NiO nanoparticles’, Mater. Sci. Eng. A, 2011, A528, (6), 2936–2940.
32.
LiuJX, DeLoDP: ‘Particle rearrangement during powder compaction’, Metall. Mater. Trans. A, 2001, 32A, (12), 3117–3124.
33.
SchattW, FriedrichE: ‘Self-activation of sintering processes in one-component systems’, Powder Metall. Int., 1981, 13, (1), 15–20.
34.
SchattW, BoikoJuI, FriedrichE, ScheibeA: ‘Shrinkage by particle sliding in sintering powder compacts’, Powder Metall. Int., 1984, 16, (1), 9–11.
