Person: Astilleros García-Monge, José Manuel
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First Name
José Manuel
Last Name
Astilleros García-Monge
Affiliation
Universidad Complutense de Madrid
Faculty / Institute
Ciencias Geológicas
Department
Mineralogía y Petrología
Area
Cristalografía y Mineralogía
Identifiers
20 results
Search Results
Now showing 1 - 10 of 20
Item Estudio de la influencia del carbonato en el crecimiento de la barita a nanoescala.(Macla, 2004) Sánchez Pastor, Nuria; Pina Martínez, Carlos Manuel; Astilleros García-Monge, José Manuel; Fernández Díaz, María LourdesItem The growth mechanisms of solid solutions crystallising from aqueous solutions(Chemical geology, 2004) Pina Martínez, Carlos Manuel; Putnis, Andrew; Astilleros García-Monge, José ManuelIn this paper, we present a generalisation of the classical growth rate equations to the case of crystallisation in solid solution–aqueous solution (SS-AS) systems. In these new equations, basic growth parameters, interfacial free energy and supersaturation are functions of the solid composition. Therefore, each equation describes, for a given aqueous solution, a growth rate distribution as a function of the solid composition. Different crystal growth models such as two-dimensional nucleation or spiral growth mechanisms provide different growth rate distributions. We have studied the general behaviour of growth rate equations in solid solution–aqueous solution (SS-AS) systems. Finally, we have applied the generalised growth rate equations to the BaxSr1xSO4–H2O SS-AS system. It allowed us to determine relationships between growth mechanisms and solid composition in such a model system. The result of our calculations were discussed and compared with previous experimental work on the BaxSr1xSO4–H2O SS-AS system.Item Crecimiento epitaxial de celestina sobre la superficie (001) de la barita(Macla, 2004) Sánchez Pastor, Nuria; Pina Martínez, Carlos Manuel; Astilleros García-Monge, José Manuel; Fernández Díaz, María LourdesItem Comment: supersaturation in binary solid solution-aqueous solution systems (Comment on “Crystallization kinetics in binary solid solution – aqueous solution systems” by Alexander G. Shtukenberg, Yurii O. Punin and Pavel Azimov, American Journal of Science, v. 306, p. 553–574.)(American Journal of Science, 2007) Prieto Rubio, Manuel; Astilleros García-Monge, José Manuel; Pina Martínez, Carlos Manuel; Fernández Díaz, María Lourdes; Putnis, AndrewItem Estudio mediante AFM de la influencia del Mn sobre el crecimiento de la calcita(Cuadernos do Laboratorio Xeolóxico de Laxe, 2000) Astilleros García-Monge, José Manuel; Pina Martínez, Carlos Manuel; Fernández Díaz, María Lourdes; Putnis, A.Item Metastable phenomena on calcite {1014} surfaces growing from Sr2+–Ca2+–CO3 2- aqueous solutions(Chemical geology, 2003) Astilleros García-Monge, José Manuel; Pina Martínez, Carlos Manuel; Fernández Díaz, María Lourdes; Putnis, AndrewIn situ atomic force microscopy (AFM) experiments, scanning electron microscopy (SEM) imaging and composition analysis, and X-ray diffraction have provided information about the growth, dissolution and transformation processes promoted by Sr2 + –Ca2 + –CO3 2 aqueous solutions in contact with calcite {101¯4} surfaces. Experiments have shown a wide variety of surface phenomena, such as the influence of the Sr-bearing newly-formed surface on the subsequent growth (template effect), the growth and subsequent dissolution of surfaces and the nucleation of secondary three-dimensional nuclei on calcite surfaces. These phenomena reveal the metastability of the crystallisation system and are a consequence of the interplay between thermodynamics (the relative stability of the two calcite and aragonite structure solid solutions that can be formed), supersaturation of the aqueous solution with respect to the two possible solid solutions, and the crystallographic control of the surfaces on cation incorporation.Item Molecular-scale surface processes during the growth of calcite in the presence of manganese(Geochimica et cosmochimica acta, 2002) Astilleros García-Monge, José Manuel; Pina Martínez, Carlos Manuel; Fernández Díaz, María Lourdes; Putnis, AndrewAbstract—This paper deals with the growth behaviour of the Mn-Ca-CO3-H2O solid solution-aqueous solution system on calcite {1014} surfaces. This system represents a model example, which allows us to study the effect of a number of controlling factors on the crystallisation: (1) the supersaturation function, (x), and nucleation rate function, J(x), for the Mn-Ca-CO3-H2O system, (2) the relationship of such functions to the molecular scale growth mechanisms operating on growing surfaces, and (3) the surface structure of the calcite {1014} faces. In situ atomic force microscopy (AFM) growth experiments revealed a wide variety of surface phenomena, such as the transition between growth mechanisms, anisotropic changes in the step rates, and the influence of the Mn-bearing newly formed surface on subsequent growth (step stoppage followed by the formation of two-dimensional nuclei and the reproduction of the original calcite {1014} surface microtopography). These phenomena result from the interplay between the controlling parameters and are explained in those terms.Item Malachite Crystallisation in a Diffusing-Reacting System(Crystal Research and Technology, 1998) Astilleros García-Monge, José Manuel; Pina Martínez, Carlos Manuel; Fernández Díaz, María Lourdes; López Andrés, SolThe crystallisation of malachite has been studied in a system involving the counter diffusion of Cu2+ and CO3 through a silica gel column at 25 ºC. In such a system supersaturation is a function of time and position along gel column. Under these conditions kinetic variables are required in order to justify nucleation behaviour. Supersaturation rate has revealed as the most important parameter controlling nucleation features (waiting time, position of the precipitate, and metastability levels). The results presented here confirm the general nucleation behaviour reported by Prieto et al., (1989, 1991, 1994) for other carbonates. On the other hand, supersaturation changes during crystallisation process control the morphological evolution of malachite crystals.Item Nanoscale phenomena during the growth of solid solutions on calcite {101¯4} surfaces(Chemical geology, 2006) Astilleros García-Monge, José Manuel; Pina Martínez, Carlos Manuel; Fernández Díaz, María Lourdes; Prieto Rubio, Manuel; Putnis, AndrewThis work deals with the growth behaviour of calcite {101¯4} surfaces in contact with multicomponent aqueous solutions containing divalent cations (Ba2+, Sr2+, Mn2+, Cd2+, or Mg2+). The result is the formation of solid solutions, with calcite or aragonite as one of the end-members. In situ atomic force microscopy has revealed a wide variety of surface phenomena occurring during the formation of these solid solutions. Among them are: (1) the thickening of growth steps and the subsequent dissolution of surfaces followed by the nucleation of secondary three-dimensional nuclei on calcite surfaces, (2) the transition between growth mechanisms, (3) the formation of an epitaxial layer that armours the substrate from further dissolution and (4) the inhibitory effect of the newly formed surface on the subsequent growth (template effect). The two last phenomena can considerably limit coprecipitation as an effective mechanism for divalent metal uptake. All the phenomena described are a consequence of the interplay between thermodynamics, supersaturation of the aqueous solution with respect to the possible solid solutions and the crystallographic control of the surfaces on the cation incorporation, and indicates that there are many differences between the crystal growth of solid solutions and phases with fixed composition.Item Nucleation of solid solutions crystallizing from aqueous solutions(Philosophical transactions - Royal Society. Mathematical, physical and engineering science, 2003) Putnis, Andrew; Pina Martínez, Carlos Manuel; Astilleros García-Monge, José Manuel; Fernández Díaz, María Lourdes; Prieto Rubio, ManuelThe study of nucleation and growth mechanisms of salts from aqueous solutions, as a function of supersaturation, is described using both macroscopic and microscopic experiments. In situ observations in a fluid cell in an atomic force microscope (AFM) reveal phenomena not accounted for in standard crystal-growth theories, specifically on the role of the crystal structure of the substrate in controlling spiral growth and two-dimensional nucleation. As a model example, the crystallization of two isostructural salts, BaSO4 and SrSO4, is described. The growth of solid-solution crystals is considerably more complex. The supersaturation of a given aqueous solution relative to a solid solution is different with respect to each solid composition, and it leads to the possibility that different compositions can simultaneously grow by different mechanisms on the same crystal face. Oscillatory compositional zoning is another consequence of the interplay between the thermodynamics and the kinetics of nucleation. The factors which control nucleation and growth of the solid solution (Ba,Sr)SO4 from an aqueous solution are described. The predictions made from the theory are compared with direct observations of crystal growth in an AFM.