Analyses of the surface parameters in polycrystalline diamonds

There is a progressing interests for polycrystalline diamonds and they have been more extensively used recently. This area has been intensively researched due to the outstanding potential of this material, and this necessitated presenting some of the latest application related to engineering in this paper. A better insight of polycrystalline diamonds properties can be achieved by intensively researching the surface structure. Samples of nanocrystalline diamonds grown by the chemical vapor deposition method are analyzed and accordingly, the focus of the research was the surface parameters and their structure. It is observed that waviness and texture are unique for any direction, their values are almost the same for the chosen directions and they vary approximately from -0.2 nm to 0.4 nm. Analyses of the parameters allowed a more detailed insight into the morphology of the surfaces of polycrystalline films

The structure analysis methods for synthetized diamonds consolidation and fractals characterization

Synthetized diamonds have application in many areas, especially for electronic devices and components or mechanisms in watches, and medicine where they can be used for surgery knifes. Considering that for small grains is commonly known that atomic structure of grain size has strong impact on structural characteristics of synthetized diamonds, research of fractal nature of microstructure of diamond films can have very important role in optimization of properties of these films. Regarding these processes, it was applied several characterization methods like SEM, EDS. These data were prepared and used as a source for fractal analysis application. Fractal theory can help in explanation of systems in which, at first sight, roles chaos. For that reason, fractal analysis can be applied on surface topology of synthesized diamonds and during the process of characterization of grains morphology. Thin films of diamonds, which are examined, are formed in chemical vapor deposition or CVD process. Aldo in some implementations is desirable to reduce the grain size, it can bring to the reducing the hardness of ultra-nanocrystalline or UNCD thin films. Because of that, it is very important to find the optimum between smooth surfaces from one side and hardness from the other side in order to create contact which is resistant to wear. Diameter of grain and their fractal geometry are very important microstructural characteristics. which have strong influence on all physical and chemical characteristics. In this paper, the goal is development of more accurate models which describe transportation and mechanical properties of polycrystalline diamonds

The synthesized diamonds microstructure consolidation review

Excellent mechanical, optical and thermal properties of diamonds are the advantages for which they are used in many areas and thus in the industrial as well. Considering that natural diamonds are rare and expensive, in order to overcome that, production of synthesized diamonds is a good solution. Hence, investigation of alternative producing methods led to discovery of commercially available chemical vapor deposition – CVD method. Using this method led to creation of microcrystalline diamond (MCD) with grain size larger than 100 nm. Because of some disadvantages of this synthesized diamond, new nanocrystalline (NCD) and ultra-nanocrystalline (UNCD) diamond materials were developed, with average size of grains ranging 5-100 nm and 3-5 nm, respectively. Reactor geometry, filament setup and gas phase conditions are also very important parameters for diamonds growth on silicon wafers, in addition to the mixture composition and pressure of applied gases. The goal of the paper is to present the relation of microstructure and diverse consolidation methods

Electrical conductivity and fractal nature analysis synthesized diamonds phenomena

Chemical Vapor Deposition – CVD can be used for creation of synthesized diamonds. The result of the process is the microstructure which is composed of numerous small grains. Such structure can be applied in various areas, like medicine, electronics, micromechanical systems, microelectromechanical systems – MEMS and many others. For these and many other applications, one of the most important feature is the electrical conductivity. Although the natural diamond is an excellent insulator, synthesized diamonds show different behavior. The exploring of this feature is a complex area with a strong convolution between grain size and sp2 bond ing effect. The optimization of the synthesized diamond properties requires the revealing of the size and the shape of the created crystallites. Due to the size of grains being significantly reduced, the fractal theory can help in analysis of the grain morphology and especially of electrical conductivity

The synthesized diamonds thermal conductivity and fractal nature

It is well known that diamonds are almost the best thermal conductors. This property as well as other convenient features, leaded to intensive research of synthesized diamonds production. Also, the investigation of the most valuable characteristics is the aim of permanently exploring. The thermal conductivity of synthesized diamonds research is very important, and because of that, the knowledge of the thermal conductivity properties is a basic point for completely understanding the synthesized diamonds phenomena. The experimental procedure confirmed interesting results regarding thermal conductivity. Investigation of the influence of different inputs on the synthesized diamonds process is of high importance. Due to the fact that the dimensions of the grain size have an impact on thermal conductivity, and that they are very small in deposited films of synthesized diamonds, the investigation of their fractal nature could lead to the further explanation of phenomena. The goal of this paper is basic analysis of what is the influence on thermal conductivity in the light of fractal nature materials properties

The consolidation process and microstructure analysis of synthesized diamonds within fractal nature analysis

The development of new technologies is very often based on improvement of novel materials and the features of the existing ones as well as their application. Considering that the synthetic diamonds are one of the most appealing areas of modern materials science and its modern applications, the research in this area is becoming more intensive. Therefore, in this paper, an overview of the basic properties of natural and synthesized diamonds is firstly presented followed by the method of forming and parameters that affect the final properties of polycrystalline diamonds. The first method which was used for obtaining synthesized diamonds was HPHT (high pressure high temperature) method, by which were produced diamonds very similar to the natural ones. However, CVD (chemical vapor deposition) method for obtaining polycrystalline diamond films was more promising. By applying this method microcrystalline diamond (MCD) with grain size larger than 100 nm were created. Considering that there were some disadvantages of MCD, new nanocrystalline (NCD) and ultra-nanocrystalline (UNCD) diamond materials were developed, which average size of grains were 5-100 nm as well as 3-5 nm. Depending on the consolidation process (composition and pressure of applied gases, filament setup and reactor geometry) the properties of polycrystalline diamonds can vary. Detailed analysis of these materials nature can be additionally obtained by application of the fractal analysis which is presented in this paper

Ram pressure stripping of disc galaxies orbiting in clusters. I. Mass and radius of the remaining gas disc

We present the first 3D hydrodynamical simulations of ram pressure stripping of a disc galaxy orbiting in a galaxy cluster. Along the orbit, the ram pressure that this galaxy experiences varies with time. In this paper, we focus on the evolution of the radius and mass of the remaining gas disc and compare it with the classical analytical estimate proposed by Gunn & Gott 1972. We find that this simple estimate works well in predicting the evolution of the radius of the remaining gas disc. Only if the ram pressure increases faster than the stripping timescale, the disc radius remains larger than predicted. However, orbits with such short ram pressure peaks are unlikely to occur in other than compact clusters. Unlike the radius evolution, the mass loss history for the galaxy is not accurately described by the analytical estimate. Generally, in the simulations the galaxy loses its gas more slowly than predicted.Comment: 11 pages, 11 figures, accepted by MNRAS, high resolution pdf version available at http://www.faculty.iu-bremen.de/eroediger/PAPERS/eroediger_crossing.pd

Thermal and electrical conductivity relation phenomena within fractal nature synthesized diamonds frontiers

Many areas, like the most known jewelry, medical-surgery, in high professional industry, as well as producing micro components, there are many possibilities for application of synthesized diamonds. These and others specific application of polycrystal diamonds, require permanently research and improvement of their properties. Such exploring could be much better with understanding fundamentals of microstructures. In such investigation, fractal nature analysis could significantly contribute to the revealing of possibilities for improvements. By the experimental procedure, it is noticed that the influence of grain size on thermal and electrical conductivity have notable impact. Considering that, these conductivities affect the possibility of application in many areas, explaining on microstructural nature is of high importance. The influence of relation between the structures and final properties of synthetized diamonds can be achieved by explaining these phenomena based on fractal nature. The aim of the investigation is the establishing thermal and electrical conductivity relation phenomena within fractal nature synthesized diamonds frontiers