J Mater sci(2006041:8093-8100 DoI10.1007/s10853-006-0646-y The preparation of LPs SiC-fibre -reinforced sic ceramics using electrophoretic deposition S. Novak·K. Mejak·G. Drazic Received: 12 January 2006/Accepted: 6 July 2006/Published online: 28 October 2006 o Springer Science+Business Media, LLC 2006 Abstract With the aim of determining the possibility main role of the fibres is to cause the deflection of any of producing Sic-based ceramic-matrix composi initiated crack and hence to dissipate its energy using the electrophoretic deposition(EPD)technique, order to protect the material from catastrophic frac the effect of the composition of Sic-based suspensions ture. Due to their outstanding high-temperature on the deposition was studied. Ethanol suspensions of behaviour, Sic-fibre-reinforced Sic ceramics are used two different grades of Sic powders, with and without in various applications that are subject to extreme the addition of a sintering aid, were used for depositing conditions, for example, in aerospace. Lately, Sicf/Sic on steel electrodes or on SiC-fibres. The pH of the composites have also been considered to be one of the suspensions, the solids loading and the particle size best candidates for use in future fusion reactors, where were shown to have a strong influence on the deposi- in addition to the high-temperature mechanical and tion process and on the properties of the fresh deposits. physical properties of the SiC, a low neutron activation The overall results demonstrate that by using appro- is one of the critical requirements for the material 3, priate conditions for the EPD, a firm SiC-based deposit 4. At present, the main limitation when it comes to can be collected at the Sic-fibres and after suitable producing a material to meet the requirements of this ermal treatment, a pore-free Sic-matrix, well highly demanding application is a lack of suitable adhered to the sic fibres can be achieved manufacturing technique. Various methods of Sic fibre-preform infiltration have been considered, such as chemical vapour infiltration(CVi), polymer infiltration and pyrolysis(PIp), nanopowder infiltration and tran sient eutectoid(NITE)as well as the simple immersion of ceramic slurries and combinations of these methods Introduction 5-10] From among these methods the most attractive for producing a material for fusion applications Continuous-fibre-reinforced ceramics are a group of appears to be CVI; however, this is an extremely slow materials with significantly better mechanical proper- and costly process and seems to be unable to produce ties than monolithic or particulate composites. In the material without open pores, and consequently one of past decade various composites with fibres were the important requirements-gas impermeability-is developed in which continuous fibres of carbon, difficult to achieve. In other processes, the high alumina or silicon carbide were used to provide the temperatures needed to produce sufficient density reinforcement for various ceramic matrixes [1, 2]. The and a large shrinkage of the material present serious drawbacks S. Novak(國)·K. Mejak.G. Drazic In our investigations we looked at the potential of Department of Nanostructured Materials, Jozef Stefan electrophoretic deposition(EPD)as a possible tech Institute, Jamova 39, Ljubljana SI-1000, Slovenia nique for the infiltration of a Sic-fibre preform to e-mail: sasa. novak@ijs produce a SiC/SiC composite, providing that a suitable 2 SpringerAbstract With the aim of determining the possibility of producing SiC-based ceramic-matrix composites using the electrophoretic deposition (EPD) technique, the effect of the composition of SiC-based suspensions on the deposition was studied. Ethanol suspensions of two different grades of SiC powders, with and without the addition of a sintering aid, were used for depositing on steel electrodes or on SiC-fibres. The pH of the suspensions, the solids loading and the particle size were shown to have a strong influence on the deposi￾tion process and on the properties of the fresh deposits. The overall results demonstrate that by using appro￾priate conditions for the EPD, a firm SiC-based deposit can be collected at the SiC-fibres and after suitable thermal treatment, a pore-free SiC-matrix, well adhered to the SiC fibres, can be achieved. Introduction Continuous-fibre-reinforced ceramics are a group of materials with significantly better mechanical proper￾ties than monolithic or particulate composites. In the past decade various composites with fibres were developed in which continuous fibres of carbon, alumina or silicon carbide were used to provide the reinforcement for various ceramic matrixes [1, 2]. The main role of the fibres is to cause the deflection of any initiated crack and hence to dissipate its energy in order to protect the material from catastrophic frac￾ture. Due to their outstanding high-temperature behaviour, SiC-fibre-reinforced SiC ceramics are used in various applications that are subject to extreme conditions, for example, in aerospace. Lately, SiCf/SiC composites have also been considered to be one of the best candidates for use in future fusion reactors, where, in addition to the high-temperature mechanical and physical properties of the SiC, a low neutron activation is one of the critical requirements for the material [3, 4]. At present, the main limitation when it comes to producing a material to meet the requirements of this highly demanding application is a lack of suitable manufacturing technique. Various methods of SiC- fibre-preform infiltration have been considered, such as chemical vapour infiltration (CVI), polymer infiltration and pyrolysis (PIP), nanopowder infiltration and tran￾sient eutectoid (NITE) as well as the simple immersion of ceramic slurries and combinations of these methods [5–10]. From among these methods the most attractive for producing a material for fusion applications appears to be CVI; however, this is an extremely slow and costly process and seems to be unable to produce material without open pores, and consequently one of the important requirements—gas impermeability—is difficult to achieve. In other processes, the high temperatures needed to produce sufficient density and a large shrinkage of the material present serious drawbacks. In our investigations we looked at the potential of electrophoretic deposition (EPD) as a possible tech￾nique for the infiltration of a SiC-fibre preform to produce a SiCf/SiC composite, providing that a suitable S. Novak (&)
K. Mejak
G. Drazˇic´ Department of Nanostructured Materials, Jozef Stefan Institute, Jamova 39, Ljubljana SI-1000, Slovenia e-mail: sasa.novak@ijs.si J Mater Sci (2006) 41:8093–8100 DOI 10.1007/s10853-006-0646-y 123 The preparation of LPS SiC-fibre-reinforced SiC ceramics using electrophoretic deposition S. Novak Æ K. Mejak Æ G. Drazˇic´ Received: 12 January 2006 / Accepted: 6 July 2006 / Published online: 28 October 2006
Springer Science+Business Media, LLC 2006