Compressibility of the structural and functional ceramic nanopowders

Metal-ceramic composite development based on its modelling results

“…An improvement of the strength of such a composite is also possible when using a fine powder of boron carbide which would effectively fill the space between the densely packed particles of the matrix alloy. The powder compressibility characterization has been performed by plotting the compaction curves ρ(P) obtained for the conditions of uniaxial quasi-static pressing with loading-reloading cycles and using an approximation by a logarithmic equation in a dimensionless form [7,8]: (2) where ρ is the relative density of the green body; P is the applied compaction pressure; P cr is the critical pressure (pressure enabling compaction up to full density of the powder material); b is a material constant defining densification pressure sensitivity. Due to the limitations on the values of the relative density ( 01   ), equation (2) is valid for a limited range of the values of the applied pressure:…”

An insight into formation of nanostructured coatings on metallic substrates by planetary ball milling

“…Several mechanisms have been proposed for the densification or compaction of ceramic powders [24,25]. Some of the characteristics of ceramic powder compaction could be applied to the process of MC.…”

Nanostructured coatings produced by a novel ultrasonic-assisted method: Coating characterisation and formation mechanism

“…[15] and ceramic powders, e.g. [16,17]. It is pertinent to briefly consider here some features of ceramic powder compaction by using, for instance, a die and punch assembly.…”

“…It should be noted that the van der Waals forces are undesirable in most fine powder die compaction processes because they significantly retard the mutual rearrangement of particles. This is, along with the above-mentioned effect of die-wall friction, another reason why densification of nanosized powders requires enormous pressures [16]. Similarly, in the UMCA coating process, attractive forces between TiN nanoparticles can impede their ability to rearrange.…”

“…Therefore, in order to describe the compaction process quantitatively, we adopted the equation of Khasanov et al [16], which was verified experimentally for a die compaction of ceramic nanopowders. The equation reveals that the relative density of a compact, ρ, is dependent on the compaction pressure, P c as follows:…”