Porosity evolution in SnO2 xerogels during sintering under isothermal conditions.

摘要: porosity and (ii) internal microporosity, respectively. The maximum of the peak increases with sintering time in all studied samples. At 300'C q value associated intensity remains constant. data analysis set scattering curves for increasing intervals at 300 C is agreement Cahn's theory spinodal decomposition. higher temperatures, 400— 600 C, structure function time, its position shifts continuously to lower values, integrated reciprocal space microporous Sn02 under isothermal treatment 600'C range exhibits dynamical scaling property. experimental results suggest that microporosity coarsening controlled by coagulation mechanism. I. INTRODUCTION kinetics aspect phase separation has received considerable attention during recent years' due relevance this phenomenon a wide materials including polymers, glasses, metallic alloys, ceramics. small-angle x-ray (SAXS) technique useful studying process. It allows, example, direct verification applicability decomposition statistical model. assumes boundary between phases diffuse, without sharp discontinuities. This based on Fick diffusion equation an additional term which accounts surface energy incipient interphases are formed first stages separation. linear equation, valid process, was solved isotropic systems Fourier transform method. result indicates S (q, t) also SAXS 1(q, (which proportional function) exhibit exponential growth: