Hydrothermal electrophoretic deposition of yttrium silicate coating on SiC–C/C composites

. In the present work we used the sol-gel process to prepare Y2SiO5 precursor sols suitable for electrophoretic deposition (EPD). The sol synthesis was performed through the controlled hydrolysis of alkoxide solutions of tetraethoxysilane and yttriumoxoisopropoxide. During sol development emphasis was put on characterization of particles size and zeta potential of the formed aggregates. We succeeded in synthesizing a clear sol containing polymeric aggregates with acceptable particle charge. The electrophoretic deposition on glassy carbon or C/C-SiC slabs led to homogenous layers. At low sol concentrations micro cracks in the deposited layers were observed whereas higher concentrations led to thin and dense layers. During constant current EPD a constant voltage was recorded indicating that the deposited layer does not lead to an increase in resistivity in this kind of EPD system.

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Impedance study of the electrophoretic deposition of yttrium silicate from a polymeric precursor sol

Journal of the European Ceramic Society ◽

10.1016/j.jeurceramsoc.2009.07.020 ◽

2010 ◽

Vol 30 (5) ◽

pp. 1089-1096 ◽

Cited By ~ 3

Author(s):

Oliver Schneider ◽

Jana Große-Brauckmann ◽

Christos Argirusis

Keyword(s):

Electrophoretic Deposition ◽

Polymeric Precursor ◽

Yttrium Silicate ◽

Impedance Study

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Galvanostatic Electrophoretic Deposition of Yttriumsilicate on C/C-Si-SiC Composites

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.412.243 ◽

2009 ◽

Vol 412 ◽

pp. 243-248

Author(s):

Jana Grosse-Brauckmann ◽

Tanja Damjanović ◽

Christos Argirusis

Keyword(s):

Electrophoretic Deposition ◽

Chemical Vapour ◽

Constant Current ◽

Particle Charge ◽

Low Oxygen ◽

Solid State Method ◽

Yttrium Silicate ◽

Current Densities ◽

Sic Composites ◽

Protection Coating

The use of carbon fibre reinforced carbon composites in oxidizing atmospheres is limited to temperatures below 400 °C. To benefit from their excellent mechanical strength that is still preserved at high temperatures, suitable oxidation protection coating systems have to be developed. Composites which are capillary infiltrated with Si and coated with SiC via chemical vapour deposition show significantly enhanced oxidation resistance. For the increase of service temperature above 1300 °C, high temperature stable materials with low oxygen diffusivities such as yttrium silicates have to complement the SiC coating. The electrophoretic deposition performed under constant current conditions leads to relatively high green densities and therefore good sinterability of the applied coatings. In this work we present the preparation of suspensions, their characterization regarding particle size and electrophoretic mobility for yttrium silicate powder prepared by the solid state method. Depending on particle charge and conductivity of the investigated suspensions iodine is employed to increase particle charge. The use of current densities between 0.5-5mA/cm² leads to smooth and homogeneous layers. Layers sintered as low as 1400 °C for 2h already show promising protection of the C/C-Si-SiC substrate during thermogravimetric analysis.

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An impedance study of the electrophoretic deposition from yttrium silicate suspensions

Journal of Materials Science ◽

10.1007/s10853-006-0417-9 ◽

2006 ◽

Vol 41 (24) ◽

pp. 8059-8067 ◽

Cited By ~ 5

Author(s):

Chr. Argirusis ◽

T. Damjanović ◽

O. Schneider

Keyword(s):

Electrophoretic Deposition ◽

Yttrium Silicate ◽

Impedance Study

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Effect of Sintering Temperature on the Celsian/Yttrium Silicate Oxidation Resistant Coatings for C/SiC Composite

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1033-1034.882 ◽

2014 ◽

Vol 1033-1034 ◽

pp. 882-886

Author(s):

Xiao Hui Zheng ◽

Chun Yu Wang ◽

Song Tao Ding ◽

Chi Yong Liang

Keyword(s):

Silicon Carbide ◽

Weight Loss ◽

Sintering Temperature ◽

Silicate Coating ◽

Yttrium Silicate ◽

Carbide Matrix ◽

Oxidation Resistant ◽

Silicon Carbide Matrix ◽

And Performance ◽

Microstructure And Performance

A novel celsian/yttrium silicate coating was deposited on carbon fiber reinforced silicon carbide matrix (C/SiC) composite, using BaO-Al2O3-SiO2 (BAS) glass andY2O3 powder as starting materials. The effects of sintering temperatures on microstructure and performance of coatings were studied. The results show that the final phases of sintered coatings are composed of celsian, yttrium silicate and remnant glass. The coating are dense, crack-free and pore-free in macroscopic scales when sintered at temperatures above 1400°C. The crystal grains in the coating grow too large, and the coating is loose in microstructure when sintered at temperatures higher than 1450°C. The coated samples sintered at 1450°C for 30min, which have the densest morphology and microstructure, have the lowest weight loss of 0.13 % after oxidation at 1500°C for 90 min.

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Synthesis and Electrophoretic Deposition of an Yttrium Silicate Coating System for Oxidation Protection of C/C-Si-SiC Composites

Materials Science Forum ◽

10.4028/www.scientific.net/msf.494.451 ◽

2005 ◽

Vol 494 ◽

pp. 451-456 ◽

Cited By ~ 5

Author(s):

Christos Argirusis ◽

Tanja Damjanović ◽

M. Stojanović ◽

Günter Borchardt

Keyword(s):

Electrophoretic Deposition ◽

Oxygen Permeability ◽

Pechini Method ◽

Yttrium Silicate ◽

Low Thermal Expansion ◽

Deposition Voltage ◽

Coating Method ◽

Sic Composites ◽

Controlled Deposition ◽

Sic Coatings

Due to favorable chemical and mechanical properties of yttrium silicate coatings (low Young’s modulus, low thermal expansion coefficient, low evaporation rate and oxygen permeability, good erosion resistance), this material is a promising complement to SiC coatings for protecting C/C-Si-SiC composites. For the preparation of silicate powders, the Pechini method was used. As a coating method, electrophoretic deposition from stable suspensions based on isopropanol was chosen. Under controlled deposition voltage and duration, coatings of various thicknesses were deposited. The deposited layers were characterized by SEM and EDX analysis. The protectiveness of these coatings was tested by isothermal thermogravimetry.

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