The sintering mechanism in

From uranium(IV) oxalate to sintered UO 2 : Consequences of the powders' thermal history on the microstructure

“…In this framework, the sintering of these compounds has been widely investigated during the past decades [2][3][4][5]. Nevertheless, such studies frequently started from samples prepared through powder metallurgy methods and thus mainly focused their interest on parameters related to the physico-chemical characteristics of the powders (grain size, specific surface area, .…”

Finite‐difference calculation on an uncertainty evaluation of the kinetic parameters from initial sintering of UO2

“…However, later experimental studies on sintering were conducted using powder compacts without sufficient verification that the use of compacts, instead of a spherical particle array, is reasonable. Therefore, the question arises as to whether the application of Equation to UO 2 powder compacts in order to determine the apparent kinetic parameters is reasonable.…”

“…A study on the sintering of UO 2 was initiated around the same time that clarified an appropriate sintering condition to densify fuel pellets . The effects of O/U ratio on the sintering kinetics of UO 2 have been examined, and the activation energy for densification of UO 2 and the diffusion coefficients have been evaluated . These kinetic constants, such as the activation energy and the diffusion coefficient, are essential parameters to understand the sintering behavior and to simulate the sintering process using a computational method.…”

“…As mentioned above, the sintering kinetics of UO 2 have been experimentally investigated, and the kinetic constants for sintering have been evaluated based on the results of sintering experiments under various heating conditions. The origin of the evaluation method dates back to the early studies, which evaluated the kinetic parameters using spherical particles of metals or oxides.…”

“…The origin of the evaluation method dates back to the early studies, which evaluated the kinetic parameters using spherical particles of metals or oxides. Strictly speaking, although the theory is adaptable only to a series of particles, subsequent studies for sintering kinetics have been carried out using powder compacts with particles of various size . Therefore, the question arises as to whether the extension of the sintering theory from a series of particles to powder compacts in order to determine kinetic parameters is reasonable.…”