Composite microstructure

Fig. $8,9,$ and $10$ show the microstructure of the NPS$,800PS,$ and $1200PS$ pellets. Via laser

confocal microscopy $($Fig$.8$a$,9$a$,$ and $10$a$)$ the matrix is shown by darker areas, with brighter

regions denoting the presence of Mo channels. The formation of uniform and interconnected

Mo channels was found to decrease with the pre$-$sintering of the $U{O}_2$ granules, as shown in

$8$a$,9$a$.$ From these images it appears that the uniformity and interconnectivity of Mo channels

within the samples is decreased as a result of pre$-$sintering at both temperatures trialled.

$1200$PS Pellets generally had thinner Mo channels than those seen in other samples, although

a smaller number of channels within this sample are significantly thicker. Within the $1200$PS

the channel distribution of Mo is much less uniform, with some regions appearing to contain

high volume fractions, while others have very little Mo present. Mo channels in the $1200$PS

pellets were found to contain more Mo and less $U{O}_2$ than those in the $800$PS or NPS pellets,

as shown in Fig. $8$c$,9$c$,$ and $10$c$.$