Evaluation of Physico-Chemical, Thermal and Mechanical Properties of Sintered Graphite and Mesophase Formulations

Abstract

Carbon/graphite materials are widely applied to the areas of seal and friction materials. These applications exploit the exceptional properties of carbon/graphite, such as its excellent mechanical behavior at high temperature and low reactivity. However, Owing to high open porosity, and low strength conventional carbon/graphite materials prepared using pulverized coke as filler and pitch as binder fall across enormous challenge. Therefore, it is necessary to reduce the open porosity and increase in the strength along with thermal conductivity. Using natural graphite as filler instead of coke to prepare carbon blocks can avoid high-temperature graphitization and repeated dipping owing to the high degree of graphitization and high thermal stability of natural graphite; thus it can simplify the working process, save energy and reduce cost. Carbonaceous mesophase has inherent properties, such as a high softening point, high fluidity, high carbon yield, and graphitizability, which make it suitable for the fabrication of polygranular carbon materials. Furthermore, it can be used as a binder. The sintering was performed in a static furnace with argon atmosphere and compared with the same compound sintered in passage furnace with hydrogen and nitrogen atmosphere. The analysis of the properties of the tested material was performed with the aid of metallography using a scanning electron microscope, which verified the particle size distribution, chemical elements and pores present. However, for the graphite powder and zinc stearate, present in smaller percentages were disregarded its influence on the physical properties of the compound generated. Compressibility and compaction are parameters that indicate and describe the behavior of metal powders as they are compressed. The ability of a powder densification is related to compressibility. Already compaction is defined as the stability of the structure of the pressed compacted to a certain working pressure. Therefore, the natural graphite as filler and mesophase pitch as binder can be able to produce high density graphite blocks. The main aim of this work is to produce isotropic graphite material and evaluation of its properties such as high density, high thermal conductivity, high electrical resistivity, low coefficient of thermal expansion, and high compressive strength from natural graphite powder mesophase pitch.

Photocatalytic degradation of salicylic acid employing TIO2 and ZNO in aqueous suspension / Degradação fotocatalítica do ácido salicílico empregando TIO2 e ZNO em suspensão aquosa

“…In this way, the surface of the titanium in an acid medium will remain positively charged and negatively charged in an alkaline medium. It has been reported that titanium dioxide has a higher oxidizing activity at a lower pH, but the excess of H + ions can decrease the reaction rate [26].…”

Method for Resistivity Measurement of Grainy Carbon and Graphite Materials

“…The resistivity and high-temperature resistance enable the graphite to be used for refractory materials, batteries and other fuel cells [ 1 ]. Graphite is the material ensuring efficient lubrication so, it can be used for electric motors brushes and sealing materials [ 2 ]. In such cases, the carbon material is compacted under a high compressive load and the measurements are being made on the ready to use products [ 3 ].…”