Hi-Nicalon/celsian composites

Hi-Nicalon/Celsian composites are stable up to use temperature of 1100°C in oxidizing environments and degrade at higher temperatures due to the instability of polymer-derived fibers. The stability of Celsian matrix composites may be extended to higher temperatures by more uniform and stable interface coating(s) and by reinforcement with more advanced silicon carbide fiber (Sylramic) for applications as hot components (combustion liner, air foil, nozzle, etc.) in turbine engines. 

J. Z. Gyekenyesi and N. P. Bansal, High Temperature Tensile Properties of Unidirectional Hi-Nicalon/Celsian Composites in Air, NASA/TM-2000-210214, July 2000. 

Gouadec, G., Colomban, R, and Bansal, N.R, Raman study of Hi-nicalon fiber reinforced celsian composites. Rart I Distribution and nanostructure of different phases, J. Am. Ceram. Soc., 84, 1129, 2001. 

On heat treatment, both hexacelsian and monoclinic celsian phases crystallize in BAS glass [23-25]. Also, hot pressing of barium aluminosilicate (BAS) glass or its composites reinforced with large diameter silicon carbide SCS-6 monofilaments or small diameter multifilament Nicalon or Hi-Nicalon fibers resulted in the crystallization of both hexacelsian andmonoclinic celsian phases [12]. On doping BAS with 5 wt.% monoclinic celsian seeds or 10 wt.% strontium aluminosilicate (SAS), only the celsian phase was formed in hot pressed... 

Tensile properties of unidirectional BN/SiC coated Hi-Nicalon fiber reinforced celsian matrix composites [36-37] from room temperature to 1200°C in air are shown in Table 6, The value of Young s modulus decreased with increase in test temperature indicating the presence of glassy phase in the matrix. The yield stress decreased from room temperature... 

G. Gouadec, P. Colomban, and N. P. Bansal, Raman Study of Hi-Nicalon Fiber-Reinforced Celsian Composites. Part I Distribution and Nanostrueture of Different Phases, J. Am. Ceram. Soc., 84 [5] 1129-1135 (2001). 

N. P. Bansal and J.I. Eldridge, Hi-Nicalon Fiber-Reinforced Celsian Matrix Composites Influence of Interface Modification,/. Mater. Res., 13 [6] 1530-1537 (1998). 

N. P. Bansal, Effects of Thermal Ageing in air on Microstructure and Mechanical Properties of Hi-Nicalon Fiber-Reinforced Celsian Composites, unpublished work. 

Unal and N. P. Bansal, "In-Plane and Interlaminar Shear Strength of a Unidirectional Hi-Nicalon Fiber-Reinforced Celsian Matrix Composite," Ceram. Int., 28[5] 527-40 (2002). 

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