Polymer‐Derived Ultra‐High Temperature Ceramics (UHTCs) and Related Materials

Abstract

Ultra‐high temperature ceramics (UHTCs) represent an emerging class of materials capable of providing mechanical stability and heat dissipation upon operation in extreme environments, e.g., extreme heat fluxes, chemically reactive plasma conditions. In the last few decades, remarkable research efforts and progress were done concerning the physical properties of UHTCs as well as their processing. Moreover, there are vivid research activities related to developing synthetic access pathways to UHTCs and related materials with high purity, tunable composition, nano‐scaled morphology, or improved sinterability. Among them, synthesis methods considering preceramic polymers as suitable precursors to UHTCs have received increased attention in the last few years. As these synthesis techniques allow the processing of UHTCs from the liquid phase, they are highly interesting, e.g., for the fabrication of ultra‐high temperature ceramic composites (UHT CMCs), additive manufacturing of UHTCs, etc. In the present review, UHTCs are in particular discussed within the context of their physical properties as well as energetics. Moreover, various synthesis methods using preceramic polymers to access UHTCs and related materials (i.e., (nano)composites thereof with silica former phases) are summarized and critically evaluated.

High‐temperature phase and microstructure evolution of polymer‐derived SiZrCN and SiZrBCN ceramic nanocomposites

“…Employing chemical synthesis to introduce nanoscaled silicon-containing phases into the UHTC matrix is likely to be a better way. 4,12,13 The polymer-derived ceramic (PDC) technique is an applicable chemical approach to synthesize multielement silicon-based ceramics. [14][15][16][17][18][19] In particular, polymer-derived ceramic nanocomposites comprising of highly refractory secondary phases (eg group IV transition metal oxides, carbides, (carbo)nitrides, silicides) dispersed within a PDC-based matrix (such as SiOC, SiCN, SiBCN) have been reported within the last years to exhibit improved thermal stability, and oxidation and corrosion resistance as compared with their PDC counterparts.…”

“…[14][15][16][17][18][19] In particular, polymer-derived ceramic nanocomposites comprising of highly refractory secondary phases (eg group IV transition metal oxides, carbides, (carbo)nitrides, silicides) dispersed within a PDC-based matrix (such as SiOC, SiCN, SiBCN) have been reported within the last years to exhibit improved thermal stability, and oxidation and corrosion resistance as compared with their PDC counterparts. 4,16,[20][21][22][23][24][25][26] The preparation process of polymer-derived ceramic nanocomposites involves in a first step synthesis of suitable single source precursors with tailored compositions and architectures (ie preceramic polymers chemically modified with metal alkoxides, acetylacetonates, acetates, amido complexes etc). 4,21,27 The precursors are thermally converted at temperatures of ~1000°C into a single-phase amorphous ceramic, which upon further heat treatments at higher temperatures undergoes subsequent phase separation and crystallization processes to deliver ceramic nanocomposites.…”

3D‐Printed Multilayered Reinforced Material System for Gas Supply in CubeSats and Small Satellites

“…[33][34][35][36][37] Figure 7 shows a representative design of the proposed printed Ti tank for a small (1U) CubeSat being currently developed by our team. For example, the level of pressure and, hence, the mass of the stored propellant gas that the printed post-treated reinforced polymer tanks can accommodate may be lower as compared with the printed titanium tanks reinforced with, e.g., carbon fibers.…”

“…Lower cost and limited time frame needed to design and fabricate such satellites could be decisive parameters for their use. Possible degradation of the polymer tanks also should be addressed, considering a large body of data on the degradation and stability of various polymers in contact with different agents and gases …”

Combining Soft Polysilazanes with Melt-Shear Organization of Core–Shell Particles: On the Road to Polymer-Templated Porous Ceramics

“…Polymer-derived ceramics (PDCs) and nanocomposites emerged in the last decades as high-potential materials with unique phase compositions and microstructures, as well as outstanding structural and functional properties [1,2,3,4,5,6,7,8]. Their preparative access from liquid or soluble preceramic polymers allows the use of various processing/shaping techniques to prepare (nano)powders, fibers, coatings, or monolithic parts.…”