Polymer derived ceramics on:
[Wikipedia]
[Google]
[Amazon]
Polymer derived ceramics (PDCs) are ceramic materials formed by the pyrolysis of preceramic polymers, usually under inert atmosphere.
The compositions of PDCs most commonly include
In the families of preceramic polymers, polysiloxanes are the most famous preceramic polymers. The backbones comprise carbon and oxygen atoms. Poly(organo)siloxanes are polysiloxanes with organic groups in the backbones, e.g., polyborosiloxanes, poly(carbosiloxanes). Another important category of preceramic polymers are polycarbosilanes and poly(organo)carbosilanes, containing alternating carbon and silicone atoms in the backbones. Similarly, polymers made up of Si-N bonds are classified as polysilazane, poly(organosilazanes) and poly(organosilylcarbodiimides). Different polymer compositions influence processing temperatures, microstructure transitions, ceramic yields and stabilities.
The conversion of preceramic polymers to PDCs can be divided into four phases, shaping, cross-linking, pyrolysis, crystallization. Typically, PDC processing is completed at 1100 °C-1300 °C. To form a crystalline PDC, some materials require higher temperature to crystalize, usually over 1700 °C.
Compared with other coating methods, the thermal treatment (e.g.
Polymer derived ceramics (PDCs) are ceramic materials formed by the pyrolysis of preceramic polymers, usually under inert atmosphere.
The compositions of PDCs most commonly include silicon carbide
Silicon carbide (SiC), also known as carborundum (), is a hard chemical compound containing silicon and carbon. A semiconductor, it occurs in nature as the extremely rare mineral moissanite, but has been mass-produced as a powder and crystal s ...
(SiC), silicon oxycarbide (SiOxCy), silicon nitride
Silicon nitride is a chemical compound of the elements silicon and nitrogen. is the most thermodynamically stable and commercially important of the silicon nitrides, and the term "silicon nitride" commonly refers to this specific composition. It ...
(Si3N4), silicon carbonitride (Si3+xN4Cx+y) and silicon oxynitride (SiOxNy). The composition, phase distribution and structure of PDCs depend on the polymer precursor compounds used and the pyrolysis conditions applied.
The key advantage of this type of ceramic material is the versatility afforded by the use of polymeric precursors in terms of processing and shaping. Polymer derived ceramics can be additively manufactured (3D printed) my means of stereolithography
Stereolithography (SLA or SL; also known as vat photopolymerisation, optical fabrication, photo-solidification, or resin printing) is a form of 3D printing technology used for creating models, prototypes, patterns, and production parts in a lay ...
that uses photopolymerization
In polymer chemistry, polymerization (American English), or polymerisation (British English), is a process of reacting monomer molecules together in a chemical reaction to form polymer chains or three-dimensional networks. There are many fo ...
of preceramic polymers. Such processing of PDCs is used in applications requiring thermally and chemically stable materials in complex shapes that are challenging to achieve through more conventional ceramic processing routes, such as powder sintering and slip casting. PDCs are also valuable for synthesis of porous and mesoporous materials and thin films.
Chemistry
PDCs are mainly fabricated through the pyrolysis of preceramic polymers.
In the families of preceramic polymers, polysiloxanes are the most famous preceramic polymers. The backbones comprise carbon and oxygen atoms. Poly(organo)siloxanes are polysiloxanes with organic groups in the backbones, e.g., polyborosiloxanes, poly(carbosiloxanes). Another important category of preceramic polymers are polycarbosilanes and poly(organo)carbosilanes, containing alternating carbon and silicone atoms in the backbones. Similarly, polymers made up of Si-N bonds are classified as polysilazane, poly(organosilazanes) and poly(organosilylcarbodiimides). Different polymer compositions influence processing temperatures, microstructure transitions, ceramic yields and stabilities.
The conversion of preceramic polymers to PDCs can be divided into four phases, shaping, cross-linking, pyrolysis, crystallization. Typically, PDC processing is completed at 1100 °C-1300 °C. To form a crystalline PDC, some materials require higher temperature to crystalize, usually over 1700 °C.
Properties
PDCs are characteristic with many properties, including: * Mechanical properties: high hardness, modulus and strength. * Stability in extreme environments: good thermostability, high oxidation and corrosion resistance. * Adhesion properties: high adhesive attraction and low surface tension. * Durability: wear resistance, anti- fouling and anti-biofilm formation properties. * Low toxicity andbiocompatibility
Biocompatibility is related to the behavior of biomaterials in various contexts. The term refers to the ability of a material to perform with an appropriate host response in a specific situation. The ambiguity of the term reflects the ongoing de ...
.
The combination of PDCs and other materials with different properties can develop combining properties for PDC-based composite materials. PDC-based composite materials can extend functions and usages of PDCs to a wide range of areas, for example, in biological, medical, electrical, magnetic, engineering and optical applications.
Uses
Coatings
Compared with other coating methods, the thermal treatment (e.g. thermal spraying
Thermal spraying techniques are coating processes in which melted (or heated) materials are sprayed onto a surface. The "feedstock" (coating precursor) is heated by electrical (plasma or arc) or chemical means (combustion flame).
Thermal sprayi ...
) of PDC processing is simple and low-cost. PDC coatings are good components in electronic devices
The field of electronics is a branch of physics and electrical engineering that deals with the emission, behaviour and effects of electrons using electronic devices. Electronics uses active devices to control electron flow by amplification ...
and gas separation membranes. Due to the intrinsic stability of PDC materials, PDC coatings are also commonly used in environmental barrier coatings (EBCs).
3D printing
Specific3D printing
3D printing or additive manufacturing is the construction of a three-dimensional object from a CAD model or a digital 3D model. It can be done in a variety of processes in which material is deposited, joined or solidified under computer co ...
techniques such as direct ink writing (DIW), stereolithography (SLA) and digital light processing (DLP) can control the structure of preceramic polymers from nanoscale to macroscale. 3D printing of PDCs can facilitate the fabrication and integration of advanced ceramic materials.
Biomedical engineering
Biocompatible PDCs and PDC-based composites can be applied in various biological systems. They are usually used to produce interface or surface with multi-functionality and complex shapes for biomedical applications, such as tissue regeneration, implant design, drug delivery, and wound dressing.Electronics
Hybrid PDC materials are feasible and tunable for substrate manufacturing inlithium ion batteries
A lithium-ion or Li-ion battery is a type of rechargeable battery which uses the reversible reduction of lithium ions to store energy. It is the predominant battery type used in portable consumer electronics and electric vehicles. It also see ...
, sensors, actuators, high temperature electrical devices, etc. Common processing strategies of PDC composites for electronic applications include chemical modification, blending with metal or metal oxides, and incorporating with functional fillers.
References
{{reflist Ceramics Polymers articles needing attention