I had read many books and articles about ceramics and synthesis of ceramics powder and composite materials. I found the term matrix many times but I couldn't understand what is it and how can it be made. Can someone give me details about this term?
Can you provide an example of the use this term? Are you referring to ceramic matrix composites?
Dear Khalid
Ceramic matrix composites (CMCs) are a subgroup of composite materials as well as a subgroup of technical ceramics. They consist of ceramic fibers embedded in a ceramic matrix, thus forming a ceramic fiber reinforced ceramic (CFRC) material. The matrix and fibers can consist of any ceramic material, whereby carbon and carbon fibers can also be considered a ceramic material [Wikipedia].
The importance of ceramic matrix composites:
There is an impending need to develop new stronger and tougher structural materials in order to meet the challenges and demanding needs in materials application for the twenty-first century in diverse strategic fields from building to transportation and energy. Ceramic matrix composites (CMCs) have emerged as potential candidates in view of their excellent physical and mechanical properties. CMCs are heterogeneous materials in which a second phase is embedded within a ceramic matrix. They combine ceramic characteristics (i.e. high strength, hardness and temperature stability) with specific tailored properties (i.e. toughness, self-healing or functional) depending on the nature of the reinforcing phase. The unique ability of CMCs to repair themselves through self-healing of cracks is one of the topics reviewed in the book ref. "Low, It-Meng, ed. Advances in ceramic matrix composites. Woodhead Publishing, 2014" .
The ceramic can be formed by a base material (high fraction) called matrix and one or more other components generally added in order to mechanically strengthen the matrix. The added agents must be well strong and dispersed into the matrix to give good properties. A simple example is mullite-zirconia ceramics. Mullite represents the matrix and zirconia represents the reinforcement.
Matrix is the primary phase in composite, having a continuous character. While ,The second phase (or phases) is embedded in the matrix in a discontinuous form. For example, in case of Silicon carbide reinforced Aluminium matrix composite, SiC is the dispersed phase while aluminium is in continues form. so aluminium is the matrix in this case. therefor we say it SiC reinforced metal matrix composite.
All the previous answers to your question deal with advanced composite ceramics, but the term matrix is also used for traditional ceramics, exactly with the same significance. In fact traditional ceramics are ceramic materials too. In conclusion, I strongly agree with Jun's anwer: matrix is the phase uniformly distributed into the material, and it surround all the discontinuous phases. The matrix is not necessarily a simple compound; as it occurs in traditional ceramicson, it can be constituted by a mixture of different compounds, including amorphous material, for example in porcelain.
"it can be constituted by a mixture of different compounds, including amorphous material, for example in porcelain."
There is only one matrix phase here - the glass, and this is true of most polyphase ceramics (the exceptions are bicontinuous, and sintered crystalline - which may or may not have other phases dispersed in them). Any other phase present is disperse, by definition. Do not confuse composition identity (i.e. with simple substances) with phase description. A glass is defined only by the solubility limits of all components present. The matrix glass is amorphous. Whether other phases (i.e. disperse) in such composite structures are amorphous is entirely irrelevant. (Bicontinuous glass in sintered alumina, for example, is worth pondering, but there is no conflict.)
For Brian. I completely agree with you. Presumably my sentence was not well written. II try to explain what I wanted to say. In traditional ceramics, the matrix is not necessarily a simple compund is related to those ceramic typologies where the matrix is constituted by the fine fired material, which can be partially amorphous or even glass not continuously distributed, as it is in gres. The case of porcelain is simply the best example to say that the matrix can be a completely melted phase.
BF: OK, thanks. I was trying to avoid commenting on use of English ;-) - but I was concerned that your remarks would be misunderstood, and tried to clarify earlier comments at the same time. One of the problems is that terms get abused and confused in the primary literature as well, and that is no help to students.
Others: Strength is not the only reason for creating a composite (of any system), and even if the disperse phase(s) are stronger, for the composite to be stronger as well requires interfacial bonding to achieve matrix constraint. Be careful always in defining what you wish for.
The term matrix correspond to the 'main' phase, in other word the phase which give the shape of a ceramic artefact, as in the case of a CMC. Additional phases are dispersed in the matrix or coated on it.
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