The effect of point defects (of different origin) of the crystal lattice on the creep of ceramic materials at high temperatures and small loads is considered. Experimental data are obtained on commercially pure vitrified ceramic samples whichmakes it possible to eliminate the effect of pores, glass-phase, etc. and to simulate the behavior of real materials. The basic mechanism of deformation in this conditions is diffusion. Deformation of pure materials of stoichiometric composition isdetermined by the processes of formation and motion of intrinsic thermal defects. As the content of impurity and nonstoichiometric defects increases above the certain level the deformation rate upon creep is limited with their mobility. Deformation ofreal materials from the standpoint of current theory of solids can be considered taking into account the effective characteristics of the material including empirical coefficients. Introduction of the point defects makes it possible to control thedeformation ability of the vitrified crystal ceramic materials or of the matrix of complex composition (having inclusion of pores, glass-phase, etc.).
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