  Understanding the microstuctural evolution during the sintering process is of
high relevance as it is a key part in many industrial manufacturing processes.
Simulations are one avenue to achieve this understanding, especially
field-resolved methods such as the phase-field method. Recent papers have shown
several weaknesses in the most common phase-field model of sintering, which the
present paper aims to ameliorate. The observed weaknesses are shortly
recounted, followed by presenting model variations aiming to remove these
deficiencies. The models are tested in the classical two-particle geometry,
with the most promising model being run on large-scale three-dimensional
packings to determine representative volume elements. A densification that is
strongly dependent on the packing size is observed, which suggests that the
model requires further improvement.
