Crystal Considerations Research Articles

Corrosion characteristics of microwave and furnace annealed electroless Ni-P-TiO2 coatings

The Co-deposition of TiO2 particles (anatase type) of 200–300 nm with Ni-P electroless coatings on low carbon steel. The coated specimen was annealed by microwave and common electric furnace. The effects of microwave and furnace annealing temperatures on these coatings were characterized via. XRD, SEM, EDAX, and the corrosion performance was characterized through electrochemical polarization technique. The corrosion medium used for this work was sodium chloride (NaCl) solution and which contains 3.5 wt-% in distilled water. The result showed that, the microwave annealing method was enhanced the corrosion performance of the coating by diffused TiO2 particle into the matrix and reduced the micro voids presented in the matrix. Further, the corrosion mechanisms of the non-treated and the annealed coated materials have been explained in the consideration of crystallization, transformation of phases, grain size, and micro strain.

Polymer crystallization in complex conditions. Towards more realistic modelling of industrial processes

Crystallization plays an important role in processing many industrial polymers. Crystallinity controls mechanical and sorptional properties of solid materials and strongly affects rheological properties of polymer melts and solutions. Therefore, realistic modeling of technological processes involving crystallizable polymers (melt spinning, film blowing, injection molding, etc.) requires that crystallization in the course of processing is taken into account. In contrast to idealized laboratory conditions usually applied in academic studies, crystallization in processing conditions covers wide range of rapidly changing temperatures and pressures. Simple models of non-isothermal, and stress-induced crystallization kinetics are discussed. Consideration of crystallization in the computer model of melt spinning reveals new effects, absent in earlier models, in which crystallization was ignored.

High Tc superconductivity and crystal structure of Pb Sr Y,Ca Cu O system

The search for high Tc superconductors in PbSrY,CaCuO system has been carried out based on crystal considerations as well as formal valency relationships. The four perovskite-like phases were detected in samples with different compositions. Superconducting resistive anomalies were detected in some samples at about 80 K, however it was not clear what phase was really superconducting one.

One- and Two-Dimensional Magnetic Systems

It is nearly a decade since the excellent collection of reprints and introductory chapters entitled Mathematical Physics in One Dimension was published (1), and in that time enthusiasm for the study of both oneand two-dimensional (hereafter 1-D and 2-D) systems has grown rapidly. But it is probably fair to say that a current book on this area, if it were to be a. representative survey (2), would no longer characterize the dominant direction as mathematical physics. Certainly the relative calculational simplicity of 1-D models continues to make them attractive for the analytical study of interesting physical phenomena, but in the last few years attention has tended to focus on the unique and fascinating properties of real materials exhibiting l-D and 2-D behavior. Not only has the list of such materials grown in recent years, but it has been recognized that subtle effects in 3-D crystals are trans­ formed into major features of the behavior of these lower dimensional systems. In this article we restrict ourselves to the consideration of crystals whose magnetic properties are dominantly one or two dimensional, i.e. where the magnetic moments are strongly coupled in linear chains or in planar sheets magnetically well isolated from one another. It is not our intent to give an exhaustive documentation of all the 1-D and 2-D materials and the related experimental and theoretical studies. Rather, we focus on a relatively few specific examples, try to point out the salient features of 1-D and 2-D in contrast to 3-D, and give a critical evaluation and discvssion of some of the experiments and theories. It is thus inevitable that some important papers will not be referenced here. We prefer, however, within the space limitations, to treat a

Considerations of Crystals which are “Antiferroelastic” as well as Paraelectric, Ferroelectric, or Antiferroelectric

In a recent paper, “ferroelasticity” has been defined on the analogy of “Ferroelectricity,” mechanical strain and stress in the former corresponding to electric polarization and field in the latter. Just as “antiferroelectricity” is associated with “ferroelectricity.” so is “antiferroelasticity” associated with “ferroelasticity.” It is considered that antiferroelastic crystals are possible. For the purpose of grasping them conceptually and knowing their characteristics and also for the purpose of understanding more deeply ferroelectricity and antiferroelectricity, this paper presents and thermodynamically investigates some model crystals are antiferroelastic as well as paraelectric, ferroelectric, or antiferroelectric.