Optimizing the gel-casting parameters in synthesis of MgAl2O4 spinel

Abstract

In this paper MgAl 2 O 4 spinel powder with average particle size of 90 nm, purity of 99.99%, with stoichiometric ratio α-Al 2 O 3 and MgO and only 0.8 %wt. LiF add-on was solid-state synthesized at a temperature of 1300˚C and used in gel suspension with 83% solid load. Using the optimal value of ISOBAM (0.9 %wt.) as both dispersion and gelation factors led to a significant increase in the relative density of green body from 48.5% to 62.2%. Relative density increased after sintering at 1550˚C for 1h from 78% to 99.6% and pore size (40 nm) reduced to half the size of powder particles. Also, it resulted in appropriate pore distribution, because of the low number and value of the add-on in the gel system, and also optimization and preparation of nanopowders, as well as preparation and manufacture of suspension. XRD, BET, ICP, FESEM, FTIR analyses were done for synthesis and preparation of powder. Viscometery, Rheometery, Porosimetery, TG-DSC, Zeta potential, and sediment deposition analyses were done in order to optimize the parameters of the casting.

Aqueous alkaline suitable gel system and related mechanism for highly transparent La0.4Gd1.6Zr2O7 ceramic preparation

“…The two reactions corresponded to the endothermic peaks at 386.0 and 535.0 • C, and the oxidization of ISOBAM-104 was ascribed to the exothermic peaks at 377.3 and 519.0 • C. 41,42 The thermal processes of La(OH) 3 and ISOBAM-104/TAC overlapped in the range from 200 to 700 • C. As a result, the endothermic peaks of La(OH) 3 hydrolysis and the exothermic peaks of ISOBAM-104 oxidation were a high coincidence, and they were offsite to each other. It can explain that the red line of the DSC curve in Figure 11A was generally regarded as a relatively smooth exothermic process, and there is no prominent peak except two soft peaks at 325.5 and 361.9 • C. The overlap of F I G U R E 1 2 X-ray diffraction (XRD) patterns of the La 0.4 Gd 1.6 Zr 2 O 7 transparent ceramic thermal processes increased the possibility of the green bodies cracking during the debinding process.…”

Physical and Photocatalytic Properties of CeO2/ZnO/ZnAl2O4 Ternary Nanocomposite Prepared by Co-precipitation Method

“…Recently, AB 2 O 4 spinel oxides, in which A is a divalent metal ion and B is a trivalent metal ion, have gained attention from many research groups 4,[26][27][28][29][30][31] . This interest has led to their applications in water splitting, gas sensing, transparent conducting materials and photocatalysis.…”

Effect of Sodium Borate on the Preparation of TiN from Titanomagnetite Concentrates by Carbothermic Reduction–Magnetic Separation and Acid Leaching Process

“…However, no appropriate and economical method to process this slag is available to date because of the dispersed distribution of Ti in various fine-grained (<10 µm) mineral phases. Thus, this slag is treated as a solid waste and stored; this process not only wastes Ti resources, but also poses a threat to the environment [10]. Therefore, many studies have been devoted to develop a cleaner production process than before for comprehensively utilizing Fe, Ti, and V compounds of TMCs such as the direct reduction-smelting process [11], and the direct reduction-magnetic separation process [12].…”

“…The acid leaching process can be used to remove impurities from impure TiN given that TiN has excellent acid resistance. However, large amounts of MgAl 2 O 4 , which are difficult to dissolve in acid solution [10], are observed in the roasted product. Magnesium aluminate spinel is also concentrated in the impure TiN after magnetic separation and will thus hinder the purification of TiN by acid leaching.…”