Kinetics of Formation and Crystal Structure Determination of Sr4Al6O12SO4

Abstract

The sulphoaluminate of strontium, Sr 4 Al 6 O 12 SO 4 , was synthesized by solid state reaction from mixture of SrCO 3 , Al 2 O 3 and SrSO 4 (3:3:1 molar ratio) as pellets. The kinetics of formation has been studied in the range of temperature between 850°C and 1100°C using quantitative X-ray powder diffraction data (XRD) analysis. Likewise, at room temperature, the crystal structure was determined from conventional X-ray powder diffraction data using direct methods and it was refined by the Rietveld method. The kinetics mechanisms that showed the best fit, were identified as geometrical contraction at grain boundary (R 1.1 ) and nucleation and growing by energy law (P 1.1 ). The activation energy values obtained were 145.47KJmol -1 (R 1.1 ) and 151.35KJmol -1 (P 1.1 ), respectively. The resulting crystal structure was orthorhombic type (a: 13.32802Å, b: 13.34430Å and c: 9.38704Å). The observed adjustment parameters were R B : 0.0985, R wp : 0.137, R p : 0.0925 and Chi 2 : 1.94.

Chemical Interaction between the Sr4Al6O12SO4 Ceramic Substrate and Al–Si Alloys

“…It can be seen in the X-ray diffraction pattern that only intensities corresponding to the strontium compound Sr4Al6O12SO4 are recorded throughout the entire length of the analyzed samples. This means that the synthesis process used and reported in the literature was effective [23]. Table 1 shows the results of the spark chemical analysis of the composition of the aluminum alloy used in the static immersion and wettability tests.…”

“…It can be seen in the X-ray diffraction pattern that only intensities corresponding to the strontium compound Sr 4 Al 6 O 12 SO 4 are recorded throughout the entire length of the analyzed samples. This means that the synthesis process used and reported in the literature was effective [23].…”

“…The sample showed good corrosion resistance by presenting BaAl 2 Si 2 O 8 grains in the interfacial zone [22]. On the other hand, Rodríguez et al, in preliminary studies, stated that the strontium compound Sr 4 Al 6 O 12 SO 4 presents good resistance to corrosion by Al-Si and Al-Mg alloys at 900 • C for 24 h, where the samples did not suffer penetration by the liquid metal [23].…”

Upscaling of W zeolite direct synthesis from coal fly ash and its water adsorption capacity

“…The content of mineralogical phases present in the FA amorphization products was obtained following a methodology reported previously in the literature . The FA alkaline amorphization products were analysed by XRD and the crystalline phases were identified by JCPDS data bases.…”