Preceramic polymers were proposed over 30 years ago as precursors for the fabrication of mainly Si-based advanced ceramics, generally denoted as polymer-derived ceramics (PDCs). The polymer to ceramic transformation process enabled significant technological breakthroughs in ceramic science and technology, such as the development of ceramic fibers, coatings, or ceramics stable at ultrahigh temperatures (up to 2000°C) with respect to decomposition, crystallization, phase separation, and creep. In recent years, several important advances have been achieved such as the discovery of a variety of functional properties associated with PDCs. Moreover, novel insights into their structure at the nanoscale level have contributed to the fundamental understanding of the various useful and unique features of PDCs related to their high chemical durability or high creep resistance or semiconducting behavior. From the processing point of view, preceramic polymers have been used as reactive binders to produce technical ceramics, they have been manipulated to allow for the formation of ordered pores in the meso-range, they have been tested for joining advanced ceramic components, and have been processed into bulk or macroporous components. Consequently, possible fields of applications of PDCs have been extended significantly by the recent research and development activities. Several key engineering fields suitable for application of PDCs include high-temperature-resistant materials (energy materials, automotive, aerospace, etc.), hard materials, chemical engineering (catalyst support, food- and biotechnology, etc.), or functional materials in electrical engineering as well as in micro/nanoelectronics. The science and technological development of PDCs are highly interdisciplinary, at the forefront of micro- and nanoscience and technology, with expertise provided by chemists, physicists, mineralogists, and materials scientists, and engineers. Moreover, several specialized industries have already commercialized components based on PDCs, and the production and availability of the precursors used has dramatically increased over the past few years. In this feature article, we highlight the following scientific issues related to advanced PDCs research: (1) General synthesis procedures to produce silicon-based preceramic polymers.
(2) Special microstructural features of PDCs.
(3) Unusual materials properties of PDCs, that are related to their unique nanosized microstructure that makes preceramic polymers of great and topical interest to researchers across a wide spectrum of disciplines.
(4) Processing strategies to fabricate ceramic components from preceramic polymers.
(5) Discussion and presentation of several examples of possible real-life applications that take advantage of the special characteristics of preceramic polymers. Note: In the past, a wide range of specialized international symposia have been devoted to PDCs, in particular organized by the American Ceramic Society, the European Materials Society, and the Materials Research Society. Most of the reviews available on PDCs are either not up to date or deal with only a subset of preceramic polymers and ceramics (e.g., silazanes to produce SiCN-based ceramics). Thus, this review is focused on a large number of novel data and developments, and contains materials from the literature but also from sources that are not widely available.

Polymer-Derived Ceramics: 40 Years of Research and Innovation in Advanced Ceramics

https://hal.archives-ouvertes.fr/hal-00120432/document

Raman Spectroscopy of Nanomaterials: How Spectra Relate to Disorder, Particle Size and Mechanical Properties

Electrical components and vacuums. In some aspects, the invention provides an electrical component including a housing defining a passageway, a motor supported by the housing, the motor being selectively electrically connectable with a power source, a fan connected to the motor and operable to generate an airflow through the passageway, an electrical circuit supported by the housing, the electrical circuit being selectively electrically connectable with the power source, and a power-tool battery electrically connectable with the electrical circuit such that power is selectively transferred between the battery and the electrical circuit, the battery being connectable to the housing. In some aspects, the invention provides a vacuum.

Air flow-producing device, such as a vacuum cleaner or a blower

A vacuum cleaner includes an electric air blower; a dust separator placed at an upstream side of the electric air blower and having a filtration filter for taking in dust-containing air sucked by the electric air blower and separating the dust from the air; and a dust accommodating section for accommodating the dust separated by the dust separator. The filtration filter includes a plurality of through-holes penetrating from an upstream surface at an upstream side to a downstream surface at the downstream side, and a central axis of the through-hole is inclined with respect to a normal line direction of a surface of the filtration filter.

Electric vacuum cleaner

Continuous SiC fiber, CVI SiC matrix composites for nuclear applications: Properties and irradiation effects

A polytitanocarbosilane, which is useful as the precursor polymer for ceramic fibre, was synthesized using polydimethylsilane, polyborodiphenylsiloxane and titanium tetraisopropoxide. The polytitanocarbosilane was melt-spun and using the continuous heat-treatment process from the polymer fibre to ceramic fibre, flexible Si-Ti-C-O fibre was produced. The density, tensile strength and Young's modulus of this amorphous ceramic fibre were found to be 2.35 g cm−3, 3.0±0.2 and 220±10 GPa, respectively. The Si-Ti-C-O fibre retained its high tensile strength to higher temperatures (about 1200° C). The specific resistance of this ceramic fibre covered a wide range of 107 to 10−1ωcm. This ceramic fibre is considered to be useful as reinforcement fibre for composites.

Development of a new continuous Si−Ti−C−O fibre using an organometallic polymer precursor

A fiber and fibrous material for producing composite materials, fiber-reinforced metals, fiber-reinforced plastics and fiber-reinforced ceramics, in which short fibers, whiskers or powders made of heat resistant material are deposited on continuous fibers made of heat resistant material. The composite materials, such as fiber-reinforced metals, plastics, and ceramics, contain the fibrous material in a matrix, and have improved control of the fiber volume ratio and mechanical characteristics. Processes for producing the fiber, fibrous materials and composite materials are also disclosed.

Fibrous material for composite materials, fiber-reinforced composite materials produced therefrom, and processes for producing same

Fabrication and Mechanical Properties of New Improved Si‐M‐C‐(O) Tyranno Fiber

Thermal Stability and Chemical Corrosion Resistance of Newly Developed Continuous Si‐Zr‐C‐O Tyranno Fiber

In situ fibre strength Weibull parameters and fibre pullout length distributions were investigated for a 3D woven SiC/SiC-based composite with glass sealant oxidation protection system after tensile testing at 1000°C and 1200°C in air. Results were similar to those previously observed for unsealed specimens tested in vacuum (1200–1380°C), but significantly different from the case of unsealed specimens tested in air (1100–1200°C). Overall, it was concluded that the glass sealant provided excellent oxidation protection for the composite at the test conditions employed, i.e. short-term exposure up to 1200°C in air.

Masaki Shibuya

Papers

Development of a new continuous Si−Ti−C−O fibre using an organometallic polymer precursor

Fibrous material for composite materials, fiber-reinforced composite materials produced therefrom, and processes for producing same

Fabrication and Mechanical Properties of New Improved Si‐M‐C‐(O) Tyranno Fiber

Thermal Stability and Chemical Corrosion Resistance of Newly Developed Continuous Si‐Zr‐C‐O Tyranno Fiber

Fibre and interfacial properties measured in situ for a 3D woven SiC/SiC-based composite with glass sealant