Highly Oriented Pyrolytic Graphite Sheet

Highly oriented pyrolytic graphite (HOPG) is a kind of "crystal" graphite with good crystalline structure, strong preferred orientation and high degree of graphitization. Because of its good carbon atomic structure, it has been widely used as standard samples and key components in scientific research, instrument manufacturing and industrial production.
HOPG has a very high reflectivity for X-rays, which can eliminate the high background intensity caused by white light, fluorescence and stray light in the X-ray tube (without HOPG monochromator, the background intensity is as high as 40×103), so that the diffraction line annihilated in the background intensity is clearly revealed (with HOPG monochromator, the background intensity is reduced to (1 ~ 2)×103). Thus the sensitivity and precision of the instrument are improved. The HOPG monochromator is already a necessary part of the X-ray diffractometer.
The filtering effect of HOPG on neutron flow from nuclear reactor is better than that of polycrystalline beryllium and quartz crystals. HOPG with a Mosaic of 3.5° has become an efficient standard filter for neutron diffraction, and the reflection intensity of HOPG is better than that of beryllium monochromators, so it is also used as a neutron monochromator and analyzer

L.T Group has a comprehensive product and technology portfolio that focuses on four field of graphite - ultrafine particle graphite mould,graphite electrode, graphite crucible, as well as other products mainly made of graphite.

Graphite materials exhibit unique properties such as good electrical and thermal conductivity, heat and corrosion resistance, low friction, and reduced weight while at the same time maintaining high strength. Due to the shortage of energy and raw materials, our high performance products made from graphite are in increasingly high demand in industries. They also play a progressively important role in everyday life, thereby substituting traditional materials.

Mosaic spread, △δ, is used to describe the distribution of the grain (002) plane along the deposition plane in the pyrolytic graphite polycrystal. The smaller △δ is, the closer the polycrystal is to a single crystal. Mosaic is an indicator of the degree of microcrystal orientation (preferred orientation) along the C-axis in polycrystalline graphite. In sheet (film, wafer) polycrystalline inks, the half-width of the resulting strength function (the curve related to the specimen azimuth of the peak intensity of the 002 diffraction line) is obtained when the counter (2θ axis) is fixed at the position of the peak indicated by the (002) X-ray diffraction line and the specimen is rotated only (θ axis). This value is usually determined by reflection method. In highly oriented graphite, because the carbon hexagonal mesh surface is roughly parallel to the plane orientation of the sample, the Mosaic degree is below a number of degrees, and the intensity becomes the maximum by reflection method near θ=13.3°. For example, in the highly oriented pyrolytic graphite (HOPG) commodity, MS= about 0.3°, which indicates that the C-axis shift of the microcrystalline perpendicular to the direction of the HOPG surface is within ±0.6°. In the Mosaic degree determination, the X-ray irradiation area changes with the rotation of the sample (θ axis), so the orientation function is not necessarily correct, but the obtained MS value is within a few degrees, as an indicator of C-axis orientation, it is of great significance