Yazar "Mandal, Hasan" için Makale Koleksiyonu listeleme
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a-SiAION ceramics densified with mixed oxide sintering additives
Mandal, Hasan; Oberacker, R. (2000)Densification and stabilization of ?-sialon ceramics were investigated by using oxides of large cations (Sr2+, La3+, Ce3+, Nd3+) and their equi-molar mixtures with CaO or Yb2O3. All multi-cation and single cation (only ... -
alpha ->beta sialon transformation in calcium-containing alpha-SiAlON ceramics
Mandal, Hasan; Thompson, D. P. (Elsevier Sci LTD, 1999)Recent studies on rare earth densified a-sialon ceramics have shown that the resulting alpha-sialon product, present either as a single phase or in conjunction with beta-sialon, is unstable when heat treated at lower ... -
The driving force for ??ß transformation in rare earth ? sialon ceramics
Mandal, Hasan; Thompson, D. P. (1997)In-situ ??ß sialon transformation in rare earth sialon systems, which occurs when dense ?- and ?/ß-sialon samples are heat-treated at temperatures in the range 1300-1600°C was first observed five years ago, and has generated ... -
The effect of heat-treatment on the performance of sub-micron SiCp-reinforced alpha-beta sialon composites .1. Preparation of agglomerate-free starting powders
Liu, Q; Gao, L; Yan, DS; Mandal, Hasan; Thompson, DP (Elsevier Sci LTD, 1997)In order to prepare good-quality, dense, SiCp-reinforced alpha-beta sialon composites by hot-pressing, a technique was developed to prevent agglomeration of the SiC grains during powder processing. For this purpose, the ... -
The effect of heat-treatment on the performance of sub-micron SiCp-reinforced alpha-beta sialon composites .2. Heat-treatment studies
Liu, Q; Gao, L; Yan, DS; Mandal, Hasan; Thompson, DP (Elsevier Sci LTD, 1997)The effects of heat-treatment on alpha --> beta sialon transformation in dense, agglomerate-free Ln-sialon/SiCp(Ln=Nd,Yb) composites are reported. The stability of the alpha-sialon phase is not only dependent on the ... -
The effect of heat-treatment on the performance of sub-micron SiCp-reinforced alpha-beta sialon composites .3. Mechanical properties
Liu, Q; Gao, L; Yan, DS; Mandal, Hasan; Thompson, DP (Elsevier Sci LTD, 1997)Agglomerate-free SiCp-reinforced Ln-sialon (Ln=Nd and Yb) composites were fabricated by hot-pressing and by pressureless sintering to evaluate the improvement in microstructure and mechanical properties that could be ... -
The effect of heat-treatment on the performance of submicron SiCp-reinforced ?-ß sialon composites: III. Mechanical properties
Liu, Q.; Gao, L.; Yan, D. S.; Mandal, Hasan; Thompson, D. P. (Elsevier BV, 1997)Agglomerate-free SiCp-reinforced Ln-sialon (Ln=Nd and Yb) composites were fabricated by hot-pressing and by pressureless sintering to evaluate the improvement in microstructure and mechanical properties that could be ... -
The effect of processing conditions, amount of additives and composition on the microstructures and mechanical properties of alpha-SiAlON ceramics
Kurama, Semra; Herrmann, M; Mandal, Hasan (Elsevier Sci LTD, 2002)A series of samples with yttrium alpha -SiAlON compositions and different amounts of additive has been fabricated from alpha -Si3N4, AIN, Al2O3 and Y2O3 starting powders, using gas pressure sintering and three different ... -
Effect of starting composition, type of rare earth sintering additive and amount of liquid phase on ? ? ß sialon transformation
Camuşcu, N.; Thompson, D. P.; Mandal, Hasan (1997)Five different ?-ß sialon and ?-sialon compositions have been prepared using different rare earth oxide additives namely, neodymium, samarium, dysprosium and ytterbium. Post-sintering heat treatments have been carried out ... -
Effect of starting composition, type of rare earth sintering additive and amount of liquid phase on alpha reversible arrow beta sialon transformation
Camuşcu, N.; Thompson, DP; Mandal, Hasan (Elsevier Sci LTD, 1997)Five different alpha-beta sialon and alpha-sialon compositions have been prepared using different rare earth oxide additives namely, neodymium, samarium, dysprosium and ytterbium., Post-sintering heat treatments have been ... -
Effect of starting Si3N4 powder type and sintering conditions on grain morphology of alpha-SiAlON ceramics
Kuşhan, Seniz Reyhan; Mandal, Hasan (Maney Publishing, 2002)Nitrogen rich multication alpha-SiAlON ceramics doped with Y-Ce have been densified by gas pressure sintering using alpha-Si3N4 or mixed beta/alpha-Si3N4 starting powder. The effects of alpha-SiAlON nucleation and growth ... -
Hard and tough ?-SiAION ceramics
Mandal, Hasan; Hofmann, J. Michael (2000)Yb, Nd/Ca and Ce/Ca containing a-sialon starting compositions have been densified by either pressureless sintering or capsul free sinter/HIP'ing using "conventional" ?-Si3N4 powder. X-ray diffraction studies of both ... -
Investigation of the phase composition and stability of the alpha-SiAlONs by the Rietveld method
Herrmann, M; Kurama, S; Mandal, Hasan (Elsevier Sci LTD, 2002)Different compositions of Y- and Nd-alpha-SiAlONs were sintered at 1825 degreesC and analysed by the XRD method. The Rietveld technique was used for characterisation of the diffraction pattern and the x value of alpha-SiAlON, ... -
Luminescence properties of terbium-, cerium-, or europium-doped alpha-sialon materials
van Krevel, JWH; van Rutten, JWT; Mandal, Hasan; Hintzen, HT; Metselaar, R (Academic Press Inc Elsevier Science, 2002)… -
New developments in ? -SiAlON ceramics
Mandal, Hasan (1999)Two different ?-sialon compositions have been densified by either pressureless sintering or capsul-free sinter HIPing using either single cation namely strontium, lanthanum, cerium, neodymium or their equimolar mixtures ... -
New heat treatment methods for glass removal from silicon nitride and sialon ceramics
Mandal, Hasan; Thompson, D. P. (Kluwer Academic Publ, 2000)Sialon ceramics were discovered simultaneously (but independently) in late 1971 at Newcastle University and also at the Toyota Research Laboratories in Japan. During the 30 years since their original discovery, the Newcastle ... -
Novel developments in a-SiAION ceramics
Mandal, Hasan; Hofmann, J. Michael (2000)Densification and stabilization of ct-sialon ceramics have been investigated by using oxides of large cations (Sr2+, La3+, Ce3+, Nd3+) and their equimolar mixtures with calcium or ytterbium as a principal cation. All ... -
Optimization and improvement of sialon ceramics with new heat treatment techniques
Mandal, Hasan; Thompson, D. P. (1997)Sialons are of interest for use as engineering materials for high temperature (>1000°C) applications becuase they retain good mechanical properties at these temperatures, whereas competing metallic materials are weak and ... -
Preparation of Ce and Nd beta-sialon ceramics by alpha ->beta sialon transformation
Thompson, DP; Mandal, Hasan (Inst Materials, 1997)It has previously been accepted that lanthanum and cerium do not form alpha-sialon structures because their ions are too large to enter the interstices in the structure. Recent work on heat treatment of rare earth densified ... -
Preparation of multiple-cation ?-SiAlON ceramics containing lanthanum
Mandal, Hasan; Hofmann, J. Michael (1999)Until recently, it was accepted that Ce 3+ cations, with an ionic radius (r) of 1.03 Å, were too large to form an ?-SiAlON structure. However, more-recent studies have shown that cerium cations can be incorporated into ...