J Mater sci(2006041:8093-8100 7 The current change during the deposition of a suspension of nano-SiC powder with the addition of aluminum phosphate on a bundle of Sic-fibres(solids content: 10 wt %);(b)-an E: den se of the bi 012345678910 time(min Fig 8(a),(b)-SEM micrographs of the sintered material with SiC-fibres;(c) and(d) TEM micrograph and EDS spectrum of the SiC 500 sr 00 The results showed that the conductivity of the The deposits with the highest packing density were suspensions is strongly dependent on the amount of obtained from highly loaded acidic suspensions of free ions. In the case of submicron Sic powder, the submicron Sic powder. The EPD of the nano-SiC major charge carriers were ions, while the contribution powder was much less effective than that for the of the nano-sized Sic powder is probably not negligi micron SiC. This is presumably connected to the ble. The solids content in the fresh as-formed deposit oxide layer on the particles, however, a full expla increased with the surface charge on the particles. The nation will require further detailed studies. Alumin solids content was also observed to have a beneficial ium phosphate, added as a sintering aid for Sic,as effect in the analysed range, i. e, up to 70 wt % During well as the use of nano-Sic powder, significantly the depositions, a current drop was normally observed changed the behaviour of the suspension. The large for porous deposits containing bubbles. This suggests current at the used potential of 60 V and the that the current drop was not caused by the inhibited formation of bubbles on the steel electrode were transport of the charge carriers due to the accumula- observed. In contrast, when the suspension with the tion of the deposit, but rather by the reduced active nano-Sic powder and the sintering additive was urface of the electrode deposited on the bundle of Sic fibres, the current 2 SpringerThe results showed that the conductivity of the suspensions is strongly dependent on the amount of free ions. In the case of submicron SiC powder, the major charge carriers were ions, while the contribution of the nano-sized SiC powder is probably not negligi￾ble. The solids content in the fresh as-formed deposit increased with the surface charge on the particles. The solids content was also observed to have a beneficial effect in the analysed range, i.e., up to 70 wt.%. During the depositions, a current drop was normally observed for porous deposits containing bubbles. This suggests that the current drop was not caused by the inhibited transport of the charge carriers due to the accumula￾tion of the deposit, but rather by the reduced active surface of the electrode. The deposits with the highest packing density were obtained from highly loaded acidic suspensions of submicron SiC powder. The EPD of the nano-SiC powder was much less effective than that for the submicron SiC. This is presumably connected to the oxide layer on the particles, however, a full expla￾nation will require further detailed studies. Alumin￾ium phosphate, added as a sintering aid for SiC, as well as the use of nano-SiC powder, significantly changed the behaviour of the suspension. The large current at the used potential of 60 V and the formation of bubbles on the steel electrode were observed. In contrast, when the suspension with the nano-SiC powder and the sintering additive was deposited on the bundle of SiC fibres, the current Fig. 8 (a), (b) - SEM micrographs of the sintered material with SiC-fibres; (c) and (d) TEM micrograph and EDS spectrum of the SiC￾matrix, respectively 0 1 2 3 4 5 0 2 4 5 6 7 8 9 10 time [min] Current [mA] 1 mm 1 3 a b Fig. 7 (a) - The current change during the deposition of a suspension of nano-SiC powder with the addition of aluminum phosphate on a bundle of SiC-fibres (solids content: 10 wt. %); (b) - an image of the bundle with deposit J Mater Sci (2006) 41:8093–8100 8099 123