# Ceramic Matrix Composites for Aero Engine Applications--A Review
## 5 Non-Oxide CMCs
### Carbon Matrix CMCs
The fabrication of CMCs quite frequently results in the generation of microcracks [118; 124]. Carbon-fiber-reinforced ceramic matrix composites, however, exhibit fewer microcracks and allow for higher mechanical strength combined with lower density [125]. The manufacturing processes used to create carbon/resin composites are expensive and time-consuming. However, they are frequently preferred as they can be used in applications where a high strength-to-weight ratio and stiffness are required [126]. Many attempts to reduce the processing times and cost have allowed for the development of a large variety of fabrication methods, which create complex geometries without harming the fiber and protecting the composite from oxidation due to the reaction of carbon fiber with oxygen at any temperature as low as 500 \({}^{\circ}\)C [126]. Some of the most used manufacturing procedures are precursor polymer infiltration and pyrolysis (PIP), which turns out to be similar to the formation process of C/C CMCs, due to allowing for low processing temperature, easy-to-control ceramic compositions, near net shape technologies, and a range of complex reinforcements [127]. Carbon/resin composites are mostly known for their use in automotive applications, used as fuel cells, offering high power and strength, and high modulus, which allows for battery bipolar board to have better wear resistance and longer lifetime and reduces the weight of the vehicle [128]. Another characteristic example of carbon/resin composite usage is in aerospace primary structures, such as autoclaves, and further research claims that they can be used for manufacturing rotor blades [129]. Carbon/Metal matrix CMCs  
According to the literature review, composites made of carbon-fiber/metal-matrix will be the basis for the breakthrough in aerospace materials. They are high-temperature composites based on refractory metals and high entropy alloys, as well as on intermetallics [130]. Carbon ceramic materials have mostly been recorded to be used as fibers and fillers in metal base matrices creating metal matrix composite materials. More recently metal impregnated carbon ceramic matrix composite materials have also been researched. The base matrix of the composite includes carbon as the base material and a metal-impregnated carbon fiber as a filler reinforcement. Various manufacturing approaches for fabricating CMC composite and metal matrix composite materials have been tested. The metal particulates may be selected from a range of magnetism-susceptible metals. These metals include nickel, nickel alloys, iron, and alloys of iron/steels, cobalt, and cobalt alloys. The particles may also be more thermally conductive composite materials, comprised of particles that have a metallic layer over an inorganic particle, allowing them to be less mechanical and thermal properties limitations [131]. In addition, the metal particulates are finished at a fine level, which allows them to facilitate infiltration into inter-fiber spaces in plies. An embodiment example would include plies from carbon fiber, and the metal particulates may be nickel, sized in the range from about 1 nm to about 100 microns.