Sintering behavior of magnesium aluminate spinel MgAl 2 O 4 synthesized by different methods

International audienceThis paper is focusing basically on the ceramic technology, of which several methods for the synthesis of MgAl 2 O 4 have been investigated. The synthesis conditions regarding the powders cleanliness, microstructure, and sintering parameters of MgAl 2 O 4 were studied. MgAl 2 O 4 powder was synthesized via conventional solid-state route using different milling process vertical attrition milling, WAB as a high-energy horizontal attrition milling, and Pulverisette as a planetary ball miller, and via solution combustion route using Urea, Glycine, and a mixture of Urea/Glycine. Urea and Glycine was used as fuel. The white powders were obtained for all solid-state routes and for Urea-combustion technique. The black and gray powders were obtained in the case of combustion technique, respectively, using a fuel of Glycine and Glycine/Urea mixture. The obtained powders and pellets were characterized by XRD, SEM, and Dilatometry. The results show that, among all the solid-state route processes, wet attrition milling gives the better and clean spinel phase. The WAB milling and Pulverisette miller introduce a contamination by some yttria-stabilized zirconia balls in the corresponding powder. Furthermore, the flash combustion technique permit to have nanoparticles with a dense spinel phase of MgAl 2 O 4 and with lower sintering temperature in less time and with no calcination step. © 2019 The American Ceramic Societ

Sintering behavior of magnesium aluminate spinel MgAl 2 O 4 synthesized by different methods

International audienceThis paper is focusing basically on the ceramic technology, of which several methods for the synthesis of MgAl 2 O 4 have been investigated. The synthesis conditions regarding the powders cleanliness, microstructure, and sintering parameters of MgAl 2 O 4 were studied. MgAl 2 O 4 powder was synthesized via conventional solid-state route using different milling process vertical attrition milling, WAB as a high-energy horizontal attrition milling, and Pulverisette as a planetary ball miller, and via solution combustion route using Urea, Glycine, and a mixture of Urea/Glycine. Urea and Glycine was used as fuel. The white powders were obtained for all solid-state routes and for Urea-combustion technique. The black and gray powders were obtained in the case of combustion technique, respectively, using a fuel of Glycine and Glycine/Urea mixture. The obtained powders and pellets were characterized by XRD, SEM, and Dilatometry. The results show that, among all the solid-state route processes, wet attrition milling gives the better and clean spinel phase. The WAB milling and Pulverisette miller introduce a contamination by some yttria-stabilized zirconia balls in the corresponding powder. Furthermore, the flash combustion technique permit to have nanoparticles with a dense spinel phase of MgAl 2 O 4 and with lower sintering temperature in less time and with no calcination step. © 2019 The American Ceramic Societ

‘Effect of Single Walled Carbon Nanotubes in the Nanocomposites (Mo2C)1_x–(TiC)x (2≤x≤4)//1wt% SWCNTs during Field Activated Sintering Technique (SPS): Physical, Mechanical Properties and Sintering Process’

International audienc

Study on the Synthesis and Structural Characterization of the Cermets TiC/Fe by Self-Propagating-High-Temperature and by Thermal Explosion

International audienceA study of the TiC/Fe cermets produced by self-propagating high-temperature synthesis and by thermal explosion with various quantities of added iron was performed. It was established that both experimental and calculated adiabatic temperature of combustion and the propagation velocity of the reaction front decrease with the addition of iron in the reactants. The addition of iron was optimized at 30 wt % to ensure the stability of the propagation. The products were characterized by X-ray diffraction (XRD); the reaction seems to start at the surface of the solid titanium particle and to proceed by solid-state diffusion of iron and carbon to form TiFe and TiC/Fe cermets composite. The evolutions of the phases, size, and density of TiC grains during both kinetics reactions were highlighted by X-rays diffraction, optical and scanning electronic microscopy equipped with microindentation and energy-dispersive X-ray spectroscopy, respectively

Study of the Nanocomposite Mo2C(1-x)-TiC(x)-SWCNTs by Field Actived Sparck Plasma Sintering Process’

International audienc

‘Study of the High Performance Ceramic-Matrix Composites (CMC’s) byCombustion in the TiO2-Al-C System’

International audienc

Nanocomposite Beta Nb50Ti based SWCNTs by FAST-SPS-FCT

International audienceThe synthesis of β-type phase NbxTi (x= 50 at%) / SWCNTs (Single Walled Carbon Nanotubes) intermetallic matrix nanocomposite by mechanical alloying to ensure the effective distribution of (SWCNTs) within the matrix. It has been stated by several researchers that during ball-milling of NbxTi (x =50 at%) powder mixtures, Nb-Ti intermetallic compound formation occurs either gradually along milling time of mechanical allowing (MA), or suddenly through amechanically self-propagating reaction (MSPR), which occurs after a ignition time of MA. For this purpose, 0.4and 0.8 at% of SWNTs was added to the powder mixture after the completion of reactionbetween Nb and Ti. The obtained powders Nb50Ti intermetallic compound mixed with SWCNTs powder and then was also ball-milled. Bulk samples were compacted and then sintered by (FAST-SPS-FCT) method (Field Assisted Sintering Technics-Sparck Plasma Sintering- Furnace, Advanced Ceramics for High-Temperature) at the temperature range (1273-1473 °K) with some time that retained the integrity of SWNTs in the intermetallic matrix.Structural and mechanical and vibronic changes of the nanocomposites were investigated by X-ray diffractometery (XRD). Field emission scanning electron microscopy (FESEM) micrographs showed that the offered MA approach caused the SWNTs to be uniformly embedded in the in situ synthesized NbTi intermetallic matrix. Meanwhile better distribution of SWCNTs resulted in higher density of FAST-SPS-FCT bulk nanocomposite as well higher hardness up to 2.75GPa compared to 2.4 of Nb50Ti intermetallic alloy obtained after MA time. The total porosity, compressive strength, and compressive elastic modulus of the FAST-SPS-FCT manufactured material were determined as 7%, 600 MPa, and 120 MPa, respectively. The alloy’s and its intermetallic nanocomposite have Young’s elastic modulus is comparable to that of healthy cancellous bone which makes it applicable in the biomedical field. The in vitro biocomptability will be performed in the near future. The comparable results for the FAST-SPS-FCT nanocomposites were 3%, 650 MPa, and 130 MPa. The alloy’s elastic modulus is comparable to that of healthy cancellous bone. This difference in mechanical properties results from different porosity and phase composition of the bot β-phase NbxTi (x= 50 at%) and NbxTi (x= 50 at%)/SWCNTs intermetallic matrix nanocomposite. More other nanotechnologies applications of the nanocomposite will be focused in the study of the superconducting type I for the ITER Poloidal Field Coils by measuring of Jc (T, B) characteristics