X-ray diffraction and SEM/EDX studies on technological evolution of the oxide-fluoride ceramic flux for submerged arc-surfacing

Abstract

The ceramic flux for submerged arc-surfacing with main component composition MgO (10.0 wt. %)-Al2O3 (25.0 wt. %)-SiO2 (40.0 wt. %)-CaF2 (25.0 wt. %) was prepared in a disk dryer-granulator using a sodium/potassium silicate solution as a binder. X-ray powder diffraction (XRPD) collected at r.t. identified α- phase of quartz, Al2O3, MgO and CaF2 of the initial components in the samples taken after granulation and subsequent annealing at 600 °C. In contrast to the low temperature annealing, anorthite (CaAl2Si2O8) is the main phase in the composition of the samples remelted at 1500 °C and quenched subsequently. Chemical analysis performed by means of scanning electron microscopy with energy-dispersive X-ray spectroscopy analysis (SEM/EDX) detects that the grains of the remelted samples possess the same Ca : Al : Si elemental ratio as anorthite. High temperature X-ray diffraction (HTXRD) was used to examine structural transformation in the solid at 600 °C < T < 1200 °C and stages of thermal evolution of ceramic flux were determined. The ceramic flux melts completely at the temperature above 1350 °C. The intensity pattern of the flux melt was obtained by X-ray diffraction of scattered X-rays at 1450 °C. After calculating the structure factor (SF), the radial distribution function (RDF) was evaluated and used to calculate the structural basicity of the flux melt

Investigation of the structure of CaO-Al2O3-SiO2 melts as a basis for the development of new agglomerated welding fluxes and industrial refractories

“…The crucible was installed in the hot stage of the hightemperature diffractometer specially designed for studies on liquid melts [7][8]. Such set-ups, originally developed in Russia and Japan, are described in detail elsewhere [1,9]. Fig.…”

“…Therefore, the development of new ceramic fluxes and improvement of existing ones is an actual task of modern material science. The X-ray diffraction and SEM/EDX (Scanning Electron Microscopy with Energy Dispersive X-Ray Analysis) studies of a model ceramic flux of the composition MgO (10% wt) -Al 2 O 3 (25 5 wt) -SiO 2 (40% wt) -CaF 2 (25% wt) [1], which are successfully used for welding and surfacing of various steels, have shown that after annealing at 1500 o C a complex oxide compound The CaO-Al 2 O 3 -SiO 2 oxide system is one of the most important slag compositions. Such slag is used in blast-furnace cast process as welding fluxes, etc.…”

“…The experimental IC's(1) for sample 1 at 1673 K (a) and sample 3 at 1913 К (b), the reflexes (2) of crystalline mullite are shown inFig. b, calculated IC (2)assuming the blurred mullite crystal cell is shown inFig.…”

X-ray diffraction study of structure of CaO-Al2O3-SiO2 ternary compounds in molten and crystalline states

“…For example, slags based on these systems are applied in blast furnace production. Many welding fluxes and fluxes for surfacing are also known [1]. Gehlenite, anorthite, mullite, sillimanite, and other synthetic compounds of the CAS system have been used at ZAO "Technohim" (Zaporizhia, Ukraine).…”

“…Normalized background of anorthite sample in liquid and solid states at different temperatures. There are two curves at RT: before(1) and after remelting(2) …”