Structure Analysis and Properties of Si–C–N Ceramics Derived from Polysilazanes

Abstract

Pyrolysis of different polysilazanes has been used to prepare novel covalent amorphous ceramics composed of silicon, carbon, and nitrogen. The formation and structure of the as‐pyrolyzed amorphous state and its devitrification into stable crystalline phases have been investigated by means of nuclear magnetic resonance spectroscopy, infrared spectroscopy, thermogravimetry, mass spectroscopy, X‐ray and neutron diffraction, and by transmission electron microscopy. Additionally, the electrical conductivity and the compression creep behaviour of the as‐received materials have been analyzed.

Preparation and characterization of high temperature SiCN/ZrB2 ceramic composite

“…The absence of υ(N-H), υ(C-H, vinyl) and υ(Si-NH-Si) results from dehydrogenation during heat treatments [17]. Peak intensity of PSN/ZrB 2 decreases with pyrolysing temperatures rising to 500 1C/700 1C, which is the same rule with PSN.…”

Thermodynamic modeling of amorphous Si–C–N ceramics derived from polymer precursors

“…Summarizing the information available from extensive research on the structure of amorphous Si-C-N ceramics [10][11][12][13][16][17][18][19]9,[20][21][22][23], the following characteristics of the am-SICN phase can be noted:…”

“…1). The amorphous character of these materials has been demonstrated by X-ray diffraction and microscopic analysis [11][12][13]. As mentioned above, a significant common feature is the relatively high temperatures (ranging above 1700 K) needed to obtain complete crystallization of such ceramics.…”

“…This range exceeds considerably the known crystallization temperatures of amorphous SiC [14] (T cr $ 1270 K) and of amorphous Si 3 N 4 [15] (T cr $ 1470 K). To explain this peculiarity, the modifications of the atomic structure formed in the course of annealing at different temperatures have been extensively investigated by means of nuclear magnetic resonance, high resolution electron microscopy, and by neutron and electron diffraction [11][12][13][16][17][18][19]9,[20][21][22][23]. These investigations have revealed primarily a separation into amorphous carbon and an amorphous domain called throughout this paper the Ôam-SICNÕ phase.…”

Formation kinetics of crystalline Si3N4/SiC composites from amorphous Si–C–N ceramics

“…During the last years non-oxide ceramics derived from organo-elemental precursors in the system Si-C-N became a field of growing research interest [1][2][3][4][5][6][7]. Amorphous ceramic solids are prepared by solid state thermolysis of pre-ceramic polymers at temperatures of about 1100°C.…”