Phase segregation in binary SiO_2/TiO_2 and SiO_2/Fe_2O_3 nanoparticle aerosols formed in a premixed flame

Binary SiO_2/TiO_2 and SiO_2/Fe_2O_3 nanoparticle (diameter < 100 nm) aerosols of varying mole ratios of Ti or Fe to Si were generated in a premixed Bunsen-type aerosol flame reactor. The distribution of species within the particles was investigated using transmission electron microscopy, electron energy loss spectrometry, x-ray diffraction, and Fourier transform infrared spectroscopy. Phase segregation was observed to varying degrees in qualitative agreement with segregation expected from binary phase diagrams for the bulk systems. Differences between the SiO_2/TiO_2 and SiO_2/Fe_2O_3 systems can be explained by considering the variation in the thermodynamically stable liquid-phase solubility and differences in the ability of iron and titanium ions to substitute for silicon ions in the network structure.

[1]  S. Friedlander,et al.  Characteristics of SiO2/TiO2 nanocomposite particles formed in a premixed flat flame , 1998 .

[2]  P. McMillan,et al.  Silicon and Oxygen Self-Diffusivities in Silicate Liquids Measured to 15 Gigapascals and 2800 Kelvin , 1997 .

[3]  P. Biswas,et al.  In situ characterization of vapor phase growth of iron oxide-silica nanocomposites: Part I. 2-D planar laser-induced fluorescence and Mie imaging , 1996 .

[4]  K. Gonsalves,et al.  Nanotechnology: Molecularly Designed Materials , 1996 .

[5]  S. Pratsinis,et al.  Dopants in Flame Synthesis of Titania , 1995 .

[6]  Eric B. Steel,et al.  Formation of superparamagnetic nanocomposites from vapor phase condensation in a flame , 1995 .

[7]  Wu,et al.  Linear rate law for the decay of the excess surface area of a coalescing solid particle. , 1994, Physical review. B, Condensed matter.

[8]  J. Ottino.  Mixing in the process industries Edited By N. Harnby, M. F. Edwards, and A. W. Nienow, 2nd ed., 1992, Butterworth‐Hinemann, Oxford, 414 pp , 1993 .

[9]  Sotiris E. Pratsinis,et al.  Formation of agglomerate particles by coagulation and sintering—Part II. The evolution of the morphology of aerosol-made titania, silica and silica-doped titania powders , 1993 .

[10]  J. Katz,et al.  Formation of mixed oxide powders in flames: Part I. TiO_2−SiO_2 , 1992 .

[11]  W. Koch,et al.  The effect of particle coalescence on the surface area of a coagulating aerosol , 1990 .

[12]  M. Leslie,et al.  Lattice dynamics of zeolitic silica polymorphs , 1990 .

[13]  A. Sarofim,et al.  Factors determining the primary particle size of flame-generated inorganic aerosols , 1989 .

[14]  Constantine M. Megaridis,et al.  Morphology of flame-generated soot as determined by thermophoretic sampling , 1987 .

[15]  N. Shimizu,et al.  Diffusivity of oxygen in jadeite and diopside melts at high pressures , 1984 .

[16]  W. White,et al.  The oxide handbook , 1983 .

[17]  R. Greegor,et al.  Investigation of TiO2SiO2 glasses by X-ray absorption spectroscopy , 1983 .

[18]  Herbert Herman,et al.  Treatise on Materials Science and Technology , 1979 .

[19]  Richard C. Flagan,et al.  Design and evaluation of new low-pressure impactor. I , 1978 .

[20]  G. D. Ulrich,et al.  III. Coalescence as a Rate-Controlling Process , 1977 .

[21]  E. A. Porai-Koshits.  The structure of glass , 1977 .

[22]  P. C. Schultz.  Binary Titania‐Silica Glasses Containing 10 to 20 Wt% TiO2 , 1976 .

[23]  G. H. Stewart.  Science of ceramics , 1963 .

[24]  A. Muan,et al.  Phase Equilibria in the System CaO‐Iron Oxide‐SiO2, in Air , 1959 .

[25]  C. Brown,et al.  The Infrared Spectra of Some Ti-O-Si, Ti-O-Ti and Si-O-Si Compounds , 1957 .

[26]  A. G. Pincus,et al.  ATOMIC CONSIDERATION OF IMMISCIBILITY IN GLASS SYSTEMS , 1940 .

[27]  S. Friedlander,et al.  Production of nanometer-sized metal oxide particles by gas phase reaction in a free jet. I : Experimental system and results , 1997 .

[28]  S. Friedlander,et al.  Production of Nanometer-Sized Metal Oxide Particles by Gas Phase Reaction in a Free Jet. II: Particle Size and Neck Formation—Comparison with Theory , 1997 .

[29]  S. Friedlander,et al.  Controlled Synthesis of Nanosized Particles by Aerosol Processes , 1993 .

[30]  J. P. Eberhart,et al.  Structural and chemical analysis of materials , 1991 .

[31]  D. Hanna.  Optical Fibers: Materials and Fabrication , 1988 .

[32]  M. F. Edwards,et al.  Mixing in the process industries , 1985 .

[33]  W. D. Kingery,et al.  Introduction to Ceramics , 1976 .

[34]  L. D. Pye,et al.  Introduction to Glass Science , 1972 .