# Ceramic Matrix Composites for Aero Engine Applications--A Review
## 9 Outcome  
Ceramic-composite matrix (CMC) materials are separated into two base material categories. These categories include oxide and non-oxide ceramic composite materials. Oxide CMCs include alumina and aluminosilicate base matrices, whereas non-oxide CMCs include carbon, silicon carbide, titanium carbide, and tungsten carbide base matrices. Each one of these CMCs has different mechanical and thermal properties, which are considered the crucial factor for selecting the correct material for the needed applications. The main difference between oxide and non-oxide CMCs is that oxide CMCs have greater creep and oxidation resistance properties when exposed to ultra-high temperatures. This occurs because oxide CMCs are predisposed to oxidation and creep even though their mechanical properties can withstand the amounts of pressure that are applied at those temperatures. Moreover, oxide CMC materials are mainly used for high-temperature structural applications, with the most common base matrix being alumina oxide. According to the literature, alumina oxide CMCs are being used and tested often in aero engine applications where the combination of silica and mullite can also be used as filler or reinforcements, enhancing the overall composite performance outcome. Non-oxide CMCs are also known to be used in a similar type of aero-engine applications long before the implementation of oxide CMCs, with silicon carbide and carbon being the most used type of reinforcement or base matrix materials. A very important aspect of the development of a CMC component is the selection of the correct manufacturing process and processing steps, which will allow for a properly manufactured component without any microcracks, and which will not lead the material to creep and oxidation over a certain period, as well as a catastrophic failure. Manufacturing processes are also chosen from the compositional type of the material; for example, sintering and sol-gel processes are mainly used for the creation of oxide CMCs due to the oxidizing atmospheres in which the ceramic particles are exposed. In continuous, some of the most famous manufacturing techniques regarding high-temperature CMCs are the chemical vapor infiltration and pyrolysis processes. In this type of process, SiC/SiC and C/C are mostly created for aero-engine applications as they have been proven to be the safest option for the creation of a component without microcracks and are able to resist high pressure and temperatures without falling apart and have a greater and longer life cycle. The combination of the correct manufacturing process, in addition to the correct combination of base matrix and filler/reinforcements, leads to a CMC composite with very good mechanical and thermal properties, allowing it to be used in a wide range of applications, according to the needs and requirements of every sector, for example, the aerospace application requires low thermal expansion coefficient and thermal conductivity, as well as high hardness and stress and strain values. The present research focused on the classification of the available oxide and non-oxide CMC materials, their manufacturing processes, and available applications. Subsequently, a comparison of the mechanical and thermal properties of the classified CMC program allowed for a closer estimation of the chosen mechanical and thermal values of these materials. The roadmap presented several important development goals regarding ceramic matrix composites usage in aerospace and turbine engine applications. They can be separated into different research groups, which allow for sustainable development and growth of CMC materials in the aerospace industry. These groups include novel ceramics with greater and more innovative properties, enhanced processing technology, and high-performance rotary and static components for aerospace applications. Furthermore, these development goals have been researched and processed since the early 90s, and their progress completion is estimated until the year 2030, according to the literature.