One of the main issues regarding graphite oxidation is the potential core collapse problem that may occur following the degradation of graphite mechanical strength.
However, our recent study reveals that the internalmore » pore characteristics play very important roles in the overall graphite oxidation rate. The oxidation process of graphite has known to be affected by various factors, including temperature, pressure, oxygen concentration, types of graphite, graphite shape and size, flow distribution, etc. Graphite oxidation in an air-ingress accident is presently a very important issue for the reactor safety of the very high temperature gas cooled-reactor (VHTR), the concept of the next generation nuclear plant (NGNP) because of its potential problems such as mechanical degradation of the supporting graphite in the lower plenum of the VHTR might lead to core collapse if the countermeasure is taken carefully. The friction coefficient and the specific wear rate were the lowest when the graphite target power density was 23.3 W/cm2.Įffect of Reacting Surface Density on the Overall Graphite Oxidation Rate The hardness firstly increased and then decreased with the increase of graphite target power density, whilst the friction coefficient and the specific wear rate increased slightly after a decrease with the increasing graphite target power density. The results showed that with the increase of graphite target power density, the deposition rate and the ratio of sp2 bond increased obviously. The variation of mechanical and tribological properties with graphite target power density was analyzed. The valence bond and microstructure of films were characterized by AFM, TEM, XPS and Raman spectra. In order to improve the tribological performance, a series of graphite-like carbon (GLC) films with different graphite target power densities were prepared by magnetron sputtering. 1 fig.Įffect of graphite target power density on tribological properties of graphite-like carbon filmsĭong, Dan Jiang, Bailing Li, Hongtao Du, Yuzhou Yang, Chao Hot isostatic pressing at 2,200 C and 30 KSI (206.8 MPa) argon pressure for two hours produces a bulk density of 2.10 g/cc. The refractory metal container is formed of tantalum, niobium, tungsten, molybdenum or alloys thereof in the form of a canister or alternatively plasma sprayed, chemically vapor deposited, or coated by some other suitable means onto graphite. Porous graphite in solid form is hot isostatically pressed in a refractory metal container to produce a solid graphite monolith with a bulk density greater than or equal to 2.10 g/cc.
and 30 KSI (206.8 MPa) argon pressure for two hours produces a bulk density of 2.10 g/cc. High density-high purity graphite prepared by hot isostatic pressing in refractory metal containers In this assessment, BIS specifically examined: • The application of ECCN 1C107.a and related licensing.export licensing process for fine grain, high density graphite controlled by ECCN 1C107.a, especially to China, requires more license conditions and The parameters of 1C107.a stem from controls established by the Missile.Technology Control Regime (MTCR). Critical Technology Assessment: Fine Grain, High Density GraphiteĬontrol Classification Number ( ECCN ) 1C107.a on the Commerce Control List (CCL).
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