Method for the modification of graphite subsurface layer to a solid mixture of SiC and graphite

We studied the interaction of molten Si and graphite surface during annealing in different atmospheres (CO, vacuum, Ar). The studies have shown that during annealing in CO atmosphere a composite material of SiC and graphite in a thick subsurface layer of the graphite is being formed, whereas at vacuum and Ar atmosphere the modified layer is either thin or absent. The composition and structure of both the composite material itself and the interface between the composite material and the graphite matrix were investigated using the methods of scanning electron microscopy and Raman spectroscopy. Studies have shown that the composite material obtained by this method has a branched fibrous structure consisting of small tubular layers of silicon carbide interspersed with large monocrystalline grains of silicon carbide of the cubic polytype, which leads to significant strengthening of the material. Thus the proposed method can be used to form a thermal protective, chemically resistant coating on graphite surface.

FABRICATION OF PROTECTIVE SiC/TiO2/SiO2 COATINGFOR GRAPHITE ELECTRODES

Today, there is a rapid growing demand for graphite electrodes used at steel making factories. Graphite electrodes are expensive materials that are used at steel making factories. Increasing the working longevity of these materials can significantly improve the benefit of steel melting process. Therefore, the increase in the stability of graphite at high elevated temperatures in electric arc furnaces is necessary. The mixture of SiC/TiO2/SiO2 coating can desirably reduce the oxidation of the graphite matrix at high temperatures. Evidently, the SiC/TiO2/SiO2 coating can specially decrease the mass loss rate of the graphite at high elevated temperatures and improve its working longevity in these conditions. Moreover, this coating can effectively improve the stability and thermal shock properties of graphite at the temperatures up to 1000∘C.

A study of the application of graphite MALDI to the analysis of short-chain polyethylene glycols

MALDI-MS using colloidal graphite matrix doped with lithium chloride for the successful analysis of low molecular weight polymers.

AN IMPROVED DOUBLE HETEROGENEITY MODEL FOR PEBBLE-BED REACTORS IN DRAGON-5

In pebble-bed reactors, the fuel is contained in small grains, which are included in a graphite matrix. Some burnable poison particles may also be present. In this work, an additional ’double heterogeneity’ model is introduced in the DRAGON5 lattice code. The model is based on the legacy work of She (INET) and has been improved to overcome intrinsic limitations. It is based on a simplified physical model whereas the two already existing models were based on the collision probability analysis or on renewal theory. The advantage of this new model is its simplicity to implement. The theory shows that the correction suggested in the original model should not be arbitrary, but a constant equivalent particle fraction of 0.63. Numerical comparison between the models is generally good. However it does not support the theory of a constant equivalent fraction. Additional work is needed to reduce the discrepancy between the models in some cases.