Si-based ceramics

Gu, H., (2004), Electron energy-loss spectroscopy characterization of 1 nm-thick amorphous film at grain boundaries in Si-based ceramics , Mater. Trans., 45 (7), 2091-2098. 

Corrosion Rate of Si-Based Ceramics and High-Si Steel in Concentrated H2SO4 at High Temperature... 

Boise W (1998) Formation and development of disordered networks in Si-based ceramics under ion bombardment. Nucl Instr MethB14L133-139... 

L. V. Interrante, C. W. Whitmarsh, C-Y. Yang, W. Sherwood, W. Schmidt, P. S. Marchetti, and G. E. Maciel, Processing of Si-based ceramics and ceramic composites using hydridopoly-carbosilane (HPCS), in Silicon-Based Structural Ceramics, Ceramic Transactions, Vol. 42,1994,... 

In the passive oxidation regime, the ability of Si based ceramics to form a continuous protective layer of silica depends upon their silicon content and the volume change occurring during oxidation. It is often characterized with a parameter. A, defined as ... 

Auger M.L., Sarin V.K. A kinetic investigation of CVD muUite coatings on Si-based ceramics. Int. 

Si-based ceramics have a remarkable potential for various structural applications at high temperatures as already described. However, their catastrophic fracture behavior sometimes limit further use of Si-based ceramic materials. Therefore, considerable efforts have been made in order to improve the toughness of Si-based ceramics especially by whisker and fiber reinforcement. 

Polymer precursor routes based on the synthesis of polycarbosilanes have been studied most extensively. The chain backbone of these polymers contains the Si-C bond. The polycarbosilane route was used by Yajima et al. (56) to produce fibers with high Si-C content and, as outlined above, formed an important contribution to the polymer pyrolysis route for Si-based ceramics. We shall use this system as an example to illustrate some basic steps in the process. The initial step [Eq. (1.9)] is the condensation reaction between Na and dimethyldichlorosilane, (CH3)2SiCl2, in xylene to produce an insoluble poly(dimethylsilane), [(CH3)2Si] , where n 30. 

T. Fukudome, S. Tsuruzono, T. Tatsumi, Y. Ichikawa, T. Hisamatsu, I. Yuri, Developments of Silicon Nitride Components for Gas Turbine, presented at ISASC-2004/Intemational Symposium of New Frontier of Advanced Si-based Ceramics and Composites, Gyeongju, Kore, June 2004. 

S. Ueno, N. Kondo, T. Ohji, S. Kanzaki, J. Doni, High Temperature Hydro Corrosion Resistance of Silica Based Oxide Ceramics , American Society of Mechanical Engineers, International Gas Turbine Institute, Turbo Expo (Publication) IGTl, v 1, 2003, p 625-632. K. N. Lee, Key Durability Issues With Mullite-Based Environmental Barrier Coatings for Si-Based Ceramics , Journal of Engineering for Gas Turbines and Power, Vol. 122, 632-636, October (2000). 

K. N. Lee, Current Status of Environmental Barrier Coatings for Si-Based Ceramics, Surf. Coatings Tech. 133-134 1-7 (2000). 

D. Zhu, and Milelr, "Multi-functionally graded environmental barrier coatings for Si-based ceramic components, U.S. Patent No. 7,740,960 Bl, 2010. 

Figure 14.11 demonstrates the relationship between mass change of CVD SiC and Po at 1873 K in Ar-02. P02 increased step by step with time from 16.7 to 160 Pa. Mass loss (active oxidation) occurred up to Po. = 146 Pa, and at Po = 160 Pa it drastically changed to slight gain of mass (passive oxidation). The Po for the transition from active to passive oxidation ( 02) is 160 Pa at 1873 K. This transition phenomenon can be commonly observed in the oxidation of Si-based ceramics and many kinds of metals. 

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