HOPG, Highly Oriented Pyrolytic Graphite is a new kind of carbon material with high purity. It is a new kind of carbon material prepared by pyrolysis of graphite at high temperature and high pressure. Its properties are close to that of single crystal graphite.
To study X applications include X-ray monochromator, neutron filter and graphite monochromator, basic properties, large size, high thermal conductivity of graphite intercalation compounds and application in the field of application. The monochromator can provide a reusable smooth surface for microscopic analysis personnel. Unlike mica, HOPG is completely nonpolar, suitable for elemental analysis, and has only carbon background signals in the analysis. HOPG has excellent surface smoothness so that it can be used as a blank background unless resolution reaches atomic level.
The most prominent function of HOPG is to have a very smooth surface and electrical conductivity. HOPG has a layered structure, making sample preparation very simple. With a double adhesive press on the HOPG and then peel off, a new smooth conductive surface can be obtained. HOPG can be used for surface roughness measurement, surface characterization of micro properties, and other substrates used. This is due to the fact that the HOPG surface is almost a graphite layer, and the standard, highly ordered, six square atomic order is arranged to make the surface roughness less than 0.1nm. The size of the standard HOPG substrate is 10mm * 10mm * 1mm (sometimes 12mm * 12mm * 1mm). According to the Mosaic Spread HOPG value, generally can be divided into A, B, C three level, a class of products can reach 0.4 degrees, B class products are usually 0.6-1.0 degrees, C grade products for more than 1 degrees, usually used products for the B level.
Because of its special structure, ink has the following special properties:
1) high temperature resistance: Graphite melting point of 3850 + 50 degrees, boiling point of 4250 degrees, even after the ultra-high temperature arc ignition, the weight loss is very small, the thermal expansion coefficient is very small. The strength of graphite increases with the increase of temperature, and the strength of graphite is doubled at 2000 degrees centigrade.
2) conduction and thermal conductivity: the conductivity of graphite is one hundred times higher than that of ordinary non-metallic minerals. Heat conductivity exceeds steel, iron, lead and other metal materials. The coefficient of thermal conductivity decreases with increasing temperature, and even at extremely high temperatures, the graphite becomes hot. Graphite can conduct electricity because each carbon atom in the graphite and other carbon atoms form only 3 covalent bonds, each carbon atom still retains 1 free electrons to transport the charge.
3) lubricity: the lubricity of graphite depends on the size of graphite scales. The larger the scale, the smaller the coefficient of friction and the better the lubricity.
4) chemical stability: graphite has good chemical stability at room temperature, and can resist acid, alkali and organic solvent corrosion.
5) plasticity: the toughness of graphite is good, can be rolled into very thin slices.
6) thermal shock resistance: when graphite is used at normal temperature, it can withstand the drastic change of temperature without damaging. When the temperature changes suddenly, the volume of graphite changes little and no cracks occur.
