Net shape fabrication of magnesium aluminate (MgAl2O4) spinel (MAS) components like domes and radomes is of great importance because they are employed in certain important strategic applications. Environmentally and economically benign net-shape forming techniques such as aqueous gelcasting (GC) and hydrolysis induced aqueous gelcasting (GCHAS) cannot be employed to MAS powder as it reacts with water during processing and makes the process cumbersome. The processes reported in the literature to overcome this problem and for successful fabrication of net shape MAS components like thin wall radomes/crucibles following aqueous colloidal processing routes such as GC and GCHAS are reviewed in this paper. This article also reviews the effect of surface treatment of MAS powder against hydrolysis and of consolidation route on net shape forming capability and the sintering ability of MAS powder. Furthermore, various other net shaping techniques reported for MAS are also reviewed in this article.
PetersonRC, LagerGA, HittermanRL: ‘A time-of-flight neutron powder diffractionstudy of MgAl2O4 at temperatures up to 1273 K’, Am.Miner., 1991, 76, (9–10), 1455–1458.
3.
GreenKE, HastertJL, RoyDW: ‘Polycrystalline MgAl2O4spinel – a broad band optical material for offensive environments’, Proc.SPIE, 1989, 112, 14–74.
4.
SainzMA, MazzoniA, AgliettiE, CaballeroA: ‘Thermo-chemical formation and stabilityof spinel under strongly reducing conditions’, Proc.Conf. UNITECR’95, Kyoto, Japan, November 1995, Technical Associationof Refractories of Japan, 387–392.
5.
BeldingJH, LetzgusEA: ‘Process for producing magnesium aluminatespinel’, US Patent 3,950,504, 1976.
6.
LiJ.-G, IkegamiT, LeeJ.-H, MoriT: ‘Fabrication of translucent magnesiumaluminate spinel ceramics’, J. Am. Ceram. Soc., 2000, 83, (11), 2866–2868.
KumarP, SandhageKH: ‘Near net-shaped magnesium aluminatespinel by the oxidation of solid magnesium-bearing precursors’, TMSOutstanding Student Paper Contest Winner-1998, GraduateDivision, Department of Materials Science and Engineering, The Ohio StateUniversity, Columbus, OH, USA, 1998.
16.
ShimizuY, AraiH, SeiyamaT: ‘Theoretical studies on the impedance-humiditycharacteristics of ceramic humidity sensors’, Sens.Actuators, 1985, 7, 11–22.
GaneshI, BhattacharjeeS, SahaBP, JohnsonR, RajeshwariK, SenguptaR, RamanaraoMV, MahajanYR: ‘An efficient MgAl2O4spinel additive for improved slag erosion and penetration resistance of high-Al2O3and MgO–C refractories’, Ceram. Int., 2002, 28, 245–253.
19.
NakagawaZE, EnomotoN, YiIS, AsanoK: ‘Effect of corundum/periclase sizeson the expansion behavior during synthesis of spinel’, Proc.Conf. UNITECER’95, 1995, Tokyo, Japan, 379–386, Novemberand Technical Association of Refractories.
20.
GaneshI, TejaKA, ThiyagarajanN, JohnsonR, ReddyBM: ‘Formation and densification behaviorof magnesium aluminate spinel: the influence of CaO and moisture in the precursors’, J.Am. Ceram. Soc., 2005, 88, (10), 2752–2761.
21.
GaneshI, OlheroSM, RebeloAH, FerreiraJMF: ‘Formation and densification behaviourof MgAl2O4 spinel: the influence of processing parameters’, J.Am. Ceram. Soc., 2008, 91, (6), 1905–1911.
22.
EvansJRG: ‘Seventy ways to make ceramics’, J.Eur. Ceram. Soc., 2008, 28, 1421–1432.
23.
GermanRM: ‘R&D in support of powder injectionmolding: status and projections’, Int. J. PowderMetall., 2007, 43, (6), 47–57.
24.
GermanRM: ‘The scientific status of powder injectionmolding’, Int. J. Powder Metall., 2000, 36, (3), 31–36.
25.
GermanRM, CornwallRG: ‘Summary report on the worldwide marketand technology for injection molding of metals and ceramics’, Proc.1997 Int. Conf. on ‘Powder metallurgy and particulate materials’,Chicago, IL, USA, June–July 1997, MPIF, 1831–1844.
TayBY, EvansJRG, EdirisingheMJ: ‘Solid free form fabrication of ceramics’, Int.Mater. Rev., 2003, 48, (6), 341–370.
32.
CawleyJD: ‘Solid free form fabrication of ceramics’, Curr.Opin. Solid State Mater. Sci., 1999, 4, 483–489.
33.
SongJH, EdirisingheMJ, EvansJRG, TwizellEH: ‘Modelling the effect of gas transporton the formation of defects during thermolysis of powder mouldings’, J.Mater. Res., 1996, 11, (4), 830–840.
34.
‘SLSplastic prototypes for functional product testing’, DTMCorporation, Austin, TX, USA, 2001
35.
TolochkestoNK, MozzharovSE, SobolenkoNV, YadroitsevIA, GoryushkinVI, DubovetsVS: ‘Problems and prospects of selectivelayer-by-layer laser sintering of powders’, PowderMetall. Met. Ceram., 1995, 34, (3–4), 142–145.
36.
LiuZH, NolteJJ, PackardJI, HimasG, DoganF, LeuMC: ‘Selective laser sintering of high-densityalumina ceramic parts’, Proc. 35th Int. MATADORConf., Taipei, Taiwan, July 2007, National University of Taiwan, 351–354.
OlheroSM, GaneshI, TorresPMC, FerreiraJMF: ‘Surface passivation of MgAl2O4spinel powder by chemisorbing H3PO4 for an easy aqueousprocessing’, Langmuir,2008, 24, (17), 9525–9530.
56.
CullityBD: ‘Elements of XRD’, 2ndedn; 1978, Reading, MA, Addison-Wesley.
57.
GaneshI, BhattacharjeeS, SahaBP, JohnsonR, MahajanYR: ‘A new sintering aid for magnesium aluminatespinel’, Ceram. Int., 2001, 27, 773–779.
58.
GaneshI, SrinivasB, JohnsonR, SahaBP, MahajanYR: ‘Effect of fuel type on morphology andreactivity of combustion synthesized MgAl2O4 powders’, Br.Ceram. Trans., 2002, 101, (6), 247–254.
59.
GaneshI, SrinivasB, JohnsonR, RaoGVN, MahajanYR: ‘Effect of preparation method on sinterabilityand properties of nanocrystalline MgAl2O4 and ZrO2–MgAl2O4materials’, Br. Ceram. Trans., 2003, 102, (3), 119–128.
NyquistRA, KagelRO: ‘Handbook of infrared and Raman spectraof inorganic compounds and organic salts’, Vol.4, ‘Infrared spectra of inorganic compounds (3800–45 cm−1)’; 1996, London, Academic Press Limited.
62.
PhambuN: ‘Characterization of aluminum hydroxidethin film on metallic aluminum powder’, Mater.Lett., 2003, 57, (19), 2907–2913.
63.
ParmentierJ, Richard-PlouetM, VilminotS: ‘Influence of the sol–gel synthesison the formation of spinel MgAl2O4’, Mater.Res. Bull., 1998, 33, (12), 1717–1724.
64.
AdakAK, SahaSK, PramanikP: ‘Synthesis and characterization of MgAl2O4spinel by PVA evaporation technique’, J. Mater.Sci. Lett., 1997, 16, (3), 234–235.
65.
OliveiraM, OlheroSM, RochaJ, FerreiraJMF: ‘Controlling hydrolysis and dispersingAlN powder in aqueous media’, J. Colloid InterfaceSci., 2003, 261, 456–463.
66.
GaneshI, OlheroSM, FerreiraJMF: ‘A phosphoric acid treated AlN powderfor aqueous processing of net-shape dense AlN and β-SiAlONparts’, Adv. Appl. Ceram., 2009, 108, (2), 111–117.
67.
GaneshI: ‘Surface oxidation and dispersion behaviorof phenolic resin coated α-SiC powder in the aqueousmedium’, Adv. Appl. Ceram., 2008, 107, (4), 210–216.
68.
ParksGA: ‘The iso-electric points of solids oxides,solid hydroxides, and aqueous hydroxy complex systems’, Chem.Rev., 1965, 65, (2), 177–179.
69.
KrnelK, KosmacT: ‘Protection of AlN powder against hydrolysisusing aluminum dihydrogen phosphate’, J. Eur.Ceram. Soc., 2001, 21, 2075–2079.
70.
ParksGA, de BruynPL: ‘The zero point charge of oxides’, J.Phys. Chem., 1962, 66, 967–973.
