Optical Coating on Cf/SiC Composites via Aqueous Slurry Painting and Reaction Bonding

doi:10.15541/jim20160275

Abstract

Abstract:

A novel surface modification method for C_f/SiC composites is proposed with aqueous slurry painting together with reaction bonding. Stable slurries were obtained by dispersing SiC to carbon black in aqueous solution, under centain binder content and solid loading conditions. The results show that porous carbonaceous C/SiC tape with porosity of 49% could be obtained by aqueous slurry painting. Si/SiC coating with high density and strong bonding onto the substrate is realized by infiltrating liquid silicon into the as-prepared tape. A reaction layer of ~15 μm in thickness is formed between the coating and the substrate. This Si/SiC coating exhibits excellent mechanical properties, with HV hardness of (14.19 ± 0.46) GPa and fracture toughness of (3.02 ± 0.30) MPa·m^1/2. The coating is achieved fine surface of 2.97 nm RMS in roughness after precision grinding and polishing.

Key words: Si/SiC coating, Cf/SiC, aqueous slurry painting, reaction bonding

CLC Number:

TQ174

SONG Sheng-Xing, YIN Jie, ZHU Yun-Zhou, HUANG Yi-Hua, LIU Xue-Jian, HUANG Zheng-Ren. Optical Coating on C_f/SiC Composites via Aqueous Slurry Painting and Reaction Bonding[J]. Journal of Inorganic Materials, 2017, 32(2): 210-214.

Figures/Tables 6

Fig. 1 Zeta potential curves of SiC with and without TMAH (a) and PVP modified carbon black (b)

Fig. 2 Viscosity (a) and shear stress (b) of 35vol% solid loading suspensions with various PVA contents at different shear rates

Fig. 3 Viscosity (a) and shear stress (b) of 6wt% PVA content suspensions with various solid loadings at different shear rates

Fig. 4 Macroscopic photograph of as-prepared sample (a) and SEM image of the porous green tape (b)

Fig. 5 SEM images of the sintered Si/SiC coating (a) and its interface between the coating and the substrate (b)

Fig. 6 Surface topography and roughness of the Si/SiC coating (a, b) and indentation image on the polished surface of the sintered coating (c)

References 17

[1]	BOITIER G, DARZENS S, CHERMANT J L,et al. Microstructural investigation of interfaces in CMCs.Compos. Part A- Appl. S., 2002, 33(10): 1467-1470.
[2]	KRENKEL W.Carbon fiber reinforced CMC for high-performance structures.Int. J. Appl.Ceram.Tec., 2004, 1(2): 188-200.
[3]	NASLAIN R.Design, preparation and properties of non-oxide CMCs for application in engines and nuclear reactors: an overview.Compos. Sci. Technol., 2004, 64(2): 155-170.
[4]	SCHMIDT S, BEYER S, KNABE H,et al. Advanced ceramic matrix composite materials for current and future propulsion technology applications.Acta Astronaut., 2004, 55(3-9): 409-420.
[5]	KRODEL M R, OZAKI T.HB-Cesic Composite for Space Optics and Structures. Optical Engineering and Applications, San Diego, 2007: 66660E.
[6]	KROEDEL M, KUTTER G S, DEYERLER M, et al. Short Carbon Fiber Reinforced Ceramic-Cesic-for Optomechanical Applications. International Symposium on Optical Science and Technology,Seattle, 2002: 230-242.
[7]	KRENKEL W, BERNDT F.C/C-SiC composites for space applications and advanced friction systems.Mat. Sci. Eng. A, 2005, 412(1/2): 177-181.
[8]	ZHANG D K, CAO Y B, LIU R J,et al. Progress and prospect of C/SiC composites used in space opto-mechanical structures.Mat. Rev., 2012, 26(7): 7-11.
[9]	GOELA J S, PICKERING M A, TAYLOR R L.Chemical Vapor Deposited Silicon and Silicon Carbide Optical Substrates for Severe Environments. Optical Surfaces Resistant to Severe Environments, San Diego, 1991: 25-38.
[10]	KESKI R A, OSANTOWSKI J F, LEVITON D B,et al. Chemical vapor deposited silicon carbide mirrors for extreme ultraviolet applications.Opt. Eng., 1997, 36(1): 157-161.
[11]	TANG H D, HUANG Z R, TAN S H, et al. PVD SiC and PVD Si Coatings on RB SiC for Surface Modification. 2nd International Symposium on Advanced Optical Manufacturing and Testing Technologies: Advanced Optical Manufacturing Technologies, Xi’an, 2006: 61490A.
[12]	ANSTIS G R, CHANTIKUL P, LAWN B R,et al. A critical evaluation of indentation techniques for measuring fracture toughness: I, direct crack measurements.J. Am. Ceram. Soc., 1981, 64(9): 533-538.
[13]	WEI WC J, WANG S C, HO F Y.Electrokinetic properties of colloidal zirconia powders in aqueous suspension.J. Am. Ceram. Soc., 1999, 82(12): 3385-3392.
[14]	WU H B, LI Y S, YAN Y J,et al. Processing, microstructures and mechanical properties of aqueous gelcasted and solid-state- sintered porous SiC ceramics.J. Eur. Ceram. Soc., 2014, 34(15): 3469-3478.
[15]	GANESH I, JANA D C, SHAIK S,et al. An aqueous gelcasting process for sintered silicon carbide ceramics.J. Am. Ceram. Soc., 2006, 89(10): 3056-3064.
[16]	LI W, CHEN P, GU M Y,et al. Effect of TMAH on rheological behavior of SiC aqueous suspension.J. Eur. Ceram. Soc., 2004, 24(14): 3679-3684.
[17]	JOHNSON S G.SiC Coatings on RB SiC Mirrors for Ultrasmooth Surfaces. International Symposium on Optics, Imaging, and Instrumentation, San Diego, 1993: 237-247.