Polymer derived ceramics (PDCs) are

ceramic A ceramic is any of the various hard, brittle, heat-resistant, and corrosion-resistant materials made by shaping and then firing an inorganic, nonmetallic material, such as clay, at a high temperature. Common examples are earthenware, porcela ...

materials formed by the

pyrolysis Pyrolysis is a process involving the Bond cleavage, separation of covalent bonds in organic matter by thermal decomposition within an Chemically inert, inert environment without oxygen. Etymology The word ''pyrolysis'' is coined from the Gree ...

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 wide bandgap semiconductor, it occurs in nature as the extremely rare mineral moissanite, but has been mass-produced as a powder a ...

(SiC), silicon oxycarbide (SiO_xC_y),

silicon nitride Silicon nitride is a chemical compound of the elements silicon and nitrogen. (''Trisilicon tetranitride'') is the most thermodynamically stable and commercially important of the silicon nitrides, and the term ″''Silicon nitride''″ commonly re ...

(Si₃N₄), silicon carbonitride (Si_3+xN₄C_x+y) and silicon oxynitride (SiO_xN_y). 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) by means of

fused filament fabrication Fused filament fabrication (FFF), also known as fused deposition modeling (with the trademarked acronym FDM), or ''filament freeform fabrication'', is a 3D printing process that uses a continuous filament of a thermoplastic material. Filament is ...

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 laye ...

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 form ...

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 Sintering or frittage is the process of compacting and forming a solid mass of material by pressure or heat without melting it to the point of liquefaction. Sintering happens as part of a manufacturing process used with metals, ceramics, plas ...

and

slip casting Slip casting, or slipcasting, is a ceramic forming techniques, ceramic forming technique, and is widely used in industry and by craft potters to make ceramic forms. This technique is typically used to form complicated shapes like figurative ce ...

. 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. C8ta09054h-f2 hi-res

In the families of preceramic polymers, polysiloxanes are the most famous preceramic polymers. The backbones comprise silicon 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 A material property is an intensive property of a material, i.e., a physical property or chemical property that does not depend on the amount of the material. These quantitative properties may be used as a metric by which the benefits of one mate ...

: high

hardness In materials science, hardness (antonym: softness) is a measure of the resistance to plastic deformation, such as an indentation (over an area) or a scratch (linear), induced mechanically either by Pressing (metalworking), pressing or abrasion ...

, modulus and

strength Strength may refer to: Personal trait *Physical strength, as in people or animals *Character strengths like those listed in the Values in Action Inventory *The exercise of willpower Physics * Mechanical strength, the ability to withstand ...

. * Stability in extreme environments: good

thermostability In materials science and molecular biology, thermostability is the ability of a substance to resist irreversible change in its chemical or physical structure, often by resisting decomposition or polymerization, at a high relative temperature. T ...

, high oxidation and corrosion resistance. *

Adhesion Adhesion is the tendency of dissimilar particles or interface (matter), surfaces to cling to one another. (Cohesion (chemistry), Cohesion refers to the tendency of similar or identical particles and surfaces to cling to one another.) The ...

properties: high adhesive attraction and low

surface tension Surface tension is the tendency of liquid surfaces at rest to shrink into the minimum surface area possible. Surface tension (physics), tension is what allows objects with a higher density than water such as razor blades and insects (e.g. Ge ...

. *

Durability Durability is the ability of a physical product to remain functional, without requiring excessive maintenance or repair, when faced with the challenges of normal operation over its design lifetime. There are several measures of durability in us ...

: wear resistance, anti-

fouling Fouling is the accumulation of unwanted material on solid surfaces. The fouling materials can consist of either living organisms (biofouling, organic) or a non-living substance (inorganic). Fouling is usually distinguished from other surfac ...

and anti-biofilm formation properties. * Low

toxicity Toxicity is the degree to which a chemical substance or a particular mixture of substances can damage an organism. Toxicity can refer to the effect on a whole organism, such as an animal, bacteria, bacterium, or plant, as well as the effect o ...

and

biocompatibility 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 ongoin ...

. 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 Electronics is a scientific and engineering discipline that studies and applies the principles of physics to design, create, and operate devices that manipulate electrons and other electrically charged particles. It is a subfield of physics and ...

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

Fused filament fabrication Fused filament fabrication (FFF), also known as fused deposition modeling (with the trademarked acronym FDM), or ''filament freeform fabrication'', is a 3D printing process that uses a continuous filament of a thermoplastic material. Filament is ...

3D printing-based polymers to use for PDC processing on a wide range of applications such as heat exchangers, heat sinks, scaffolding for bone tissue growth, chemical/ gas filters and custom

open hardware Open-source hardware (OSH, OSHW) consists of physical artifacts of technology designed and offered by the open-design movement. Both free and open-source software (FOSS) and open-source hardware are created by this open-source culture movement ...

. Specific

3D 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 ...

techniques such as direct ink writing (DIW),

(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 in

lithium ion batteries A lithium-ion or Li-ion battery is a type of rechargeable battery that uses the reversible intercalation of Li+ ions into electronically conducting solids to store energy. Li-ion batteries are characterized by higher specific energy, energy d ...

sensor A sensor is often defined as a device that receives and responds to a signal or stimulus. The stimulus is the quantity, property, or condition that is sensed and converted into electrical signal. In the broadest definition, a sensor is a devi ...

actuator An actuator is a machine element, component of a machine that produces force, torque, or Displacement (geometry), displacement, when an electrical, Pneumatics, pneumatic or Hydraulic fluid, hydraulic input is supplied to it in a system (called an ...

s, 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