Densification kinetics

Koval chenko, M.S. and Yulyugin, V.K., Densification Kinetics of Porous Metai Based on Molybdenum Disulfide in Hot Pressing, Soviet Powder Metallurgy and Metal Ceramics, 19, 324, (1980). 

Sherer, G.W., Calas, S., and Sempere, R., Densification kinetics and structural evolution during sintering of silica aerogel, J. Non-Crystl. Solids, 240, 118, 1998. 

For I-CVI processes the overall densification kinetics of a preform with initial density (po) follows an exponential pattern to a final density value (pj) as shown in Figure 5.7, which can be expressed as follows [10] ... 

Using computer-interactive (APL programming language) methods " , it is possible to determine the models of densification kinetics of boron carbides. The simplest is ... 

Given an oxygen-deficient MO oxide that is difficult to densify, for which it is known that < an- Detail a strategy for enhancing the densification kinetics of this oxide. 

It is assumed that, during the SPS process, powder compact is pressed in a rigid die, i.e., Ey = 0, the densification kinetics can be given by ... 

Normally we measure the density of the composite, but in many cases we may need to determine the density of the matrix phase of the composite in order to compare its densification kinetics with those of the free matrix. If and are the densities (i.e., mass/volume) of the composite and the matrix, respectively, then by simple geometry we can show that... 

Although more labor-intensive and less efficient, information on the densification kinetics and densification can also be obtained from density measurements on different individual samples as a function of time for otherwise identical sintering conditions. Bulk density measurements on <92% dense sintered samples containing open porosity can be determined from the measured mass and dimensions of the compact, while Archimedes method works well for closed pore, >92% dense bodies. The density of closed pore samples can also be determined by pycnome-try (e.g., helium pycnometry),, 37 mercury porosimetry, and by the sink-float method (i.e., whereby the buoyancy of the sample is assessed and compared in different density liquids). Density can also be estimated from micrographs using quantitative stereology. 

Experimental Studies of Diffusive Sintering presents the limited data available on the densification kinetics of crystalline gels. A given composition is shown to sinter much more slowly if it is allowed to crystallize first. 

This section describes studies of densification kinetics that illustrate the principles discussed in Section 1. A broad discussion of viscous sintering in the preparation of glass bodies is provided in a review by Rabinovich [35]. 

Comparison of densification kinetics of conventionally processed alumina powder and seeded alumina gels. From Yeh and Sacks [103]. 

Comparison of densification kinetics of polycrystalline and amorphous cordierite. The crystalline material is stoichiometric and has mean particle size of 8.6/tm the amorphous material is melted and crushed glass with some BjOj and P2O5 and slight excess of SiOj and MgO relative to stoichiometric cordierite and has a mean size of 10urn. From Ewsuk era/[109). 

In the third region (>30 wt% rod-shaped particles), the densification kinetics was very slow and controlled by the rod-shaped particles. 

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