Characterization of Carbon Nanofibers/ ZrO2 Ceramic Matrix Composite

Abstract

Carbon micro/nanofibers prepared by catalytic chemical vapor deposition have been characterized in the form of powders and in the form of filaments, intercorporated in the matrix of ZrO 2 . Scanning electron microscopy, transmission electron microscopy, high resolution electron microscopy, electron spectroscopy for chemical analysis and Raman spectroscopy have been used. The outer diameter of the fibers varied from 50 nm to 600 nm with an average diameter of 120 nm, length from several micrometers to several tens of micrometers and inner diameters from 20 nm to 230 nm. Two types of fibers have been identified; cylindrical which consists of a distinct graphite layers parallel to the fiber axes and bamboo -shaped fibers with walls which are built from domains with different orientations of graphite layers. The fibers contain 99.05 at.% carbon and 0.95 at.% oxygen with a binding energy of O (1s) electrons of 532.7 eV which corresponds to carbon in C-O bonds. In the first-order Raman spectra, the position of the band G was found at 1600 cm −1 and D at 1282 cm −1 . The CNFs in ZrO 2 + CNFs composite have been relatively well dispersed, however clusters of CNFs together with porosity are present as a result of the difficulty of dispersing, too. TEM and HREM revealed that the CNFs are usually located at the grain boundaries of ZrO 2 in the form of undamaged nanofibers or disordered graphite.Keywords: Carbon nanofibers, Nanocomposites, Transmission electron microscopy, High resolution transmission electron microscopy, Raman spectroscopy Włókna węglowe przygotowane metodą osadzania z par (tzw. Chemical Vapour Deposition), były badane bezpośrednio po wytworzeniu oraz po wprowadzeniu do osnowy ceramicznej metodami elektronowej mikroskopii skaningowej, transmisyjnej oraz spektroskopii ramanowskiej. Średnica włókien wahała się pomiędzy 50 nm, a 600 nm przy średniej wartości ∼120 nm, podczas gdy ich długość wynosiła od kilku do kilkudziesieciu mikrometrów. Identyfikowano dwa rodzaje budowy włókien, tj. cylindryczne oraz z wewnętrznymi przekładkami typu "łodygi bambusa". Włókna węglowe zawierały do 0.95 at. % tlenu o energi wiązania O (1s) ∼532.7 eV, co odpowiada wiązaniu C-O. Na pierwszym widmie Ramana pasmo G identyfikowano dla 1600 cm −1 , a pasmo D dla 1282 cm −1 . Badania kompozytu wykazałay równomierny rozkład włókien w ceramicznej osnowie. W sąsiedztwie większych aglomeratów stwierdzono tendencje do występowania pustek. W czasie spiekania przeważająca część włókien zachowała swoją rurkową strukturę, natomiast pozostały materiał węglowy uległ przemianie do słabo uprządkowanych struktur grafitu lub nawet uległ amorfizacji.

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Influence of Electrolytical Oxidising of Silumine Surfaces on the Quality of Bonding with Epoxy Resin

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