Processes of microporosity formation at initial stage phase transition
Abstract:
Computer experiments of ions implantation can be applied to assess the porosity in objects of cultural heritage. The pores appear under action natural and antropogenic factors of enviroment, the estimation can be made thanks to existance parametres of similarity and processes periodicity accounting. The interaction of inert gas flux of 5-10 keV ions energy with lattice of solid are discussed. Formation of porous and stressed structures in the sample as a result of phase transition at the duration of the process is about 10-100 msec. The initial (non-equilibrium) stage of the phase transition is considered as the superposition of two random processes: Clustering of gas monomers and their Brownian motion in crystal lattice of sample consisting of several layers.At phase transition the clustering of nuclei appears in result of the inert gas implantation into lattice in form of gaseous bubbles (blisters). Kinetic equations for function the distribution of gas bubbles in the layers of SiC and Mo by sizes and coordinates in lattice , are replaced by equivalent stochastic differential equations Ito in the sence of Stratonovich. The stochastic dynamical variables of clusters in phase spaces of sizes and of their coordinates are used in calculations the porosity and local stress, which structures depend on potentials of elastic indirect interaction each with other and with borders of layers.
