Oxidation behavior of SiC–SiBCN ceramics

Adv Compos Hybrid Mater

Kong

Luo

et al. 2018

Self-healing functionality is an important issue of ceramics or ceramic matrix composites used in high temperature and oxidation environment. In this contribution, we reported the cross significant crack self-healing behaviors and mechanism of SiBCN ceramics derived from hyperbranched polyborosilazanes. The self-healing ability of cracks and indention cross sign are enhanced with the increase of oxidation time. And the temperature also influences the healing self-behaviors. The crack healing and indention sign occurred at 1000°C in air atmosphere. The ceramics with high content of boron show much more obvious self-healing performance because the silicon and boron atoms can be reacted with the available oxygen at high temperature to form SiO 2 (l), B 2 O 3 (l), and B 2 O 3 .SiO 2 . The liquid-like products will fill the crack and prevents the destructive of substrates. The preceramic precursor-derived SiBCN ceramics show good self-healing performance and possess great potential in aeronautics, aerospace, and nuclear power industries.

Section: Phase Structure Analysis Of Sibcn Ceramicsmentioning

confidence: 65%

High temperature self-healing SiBCN ceramics derived from hyperbranched polyborosilazanes

Adv Compos Hybrid Mater

Kong

Luo

et al. 2018

“…All molar Gibbs free energies of the above reactions at 1350 to 1650 °C were negative, which means that these reactions may occur during the oxidation process. B 2 O 3 will evaporate rapidly above 1200 °C while SiO 2 reacts with some B 2 O 3 to form borosilicate glass . A BNC phase is considered to exist in SiBCN ceramic and the oxidation of the BNC phase is divided into reactions (1), (2), (6), (7), and (10) .…”

Section: Resultsmentioning

confidence: 99%

“…B 2 O 3 will evaporate rapidly above 1200°C [19] while SiO 2 reacts with some B 2 O 3 to form borosilicate glass. [16] A BNC phase is considered to exist in SiBCN ceramic [35] and the oxidation of the BNC phase is divided into reactions (1), (2), (6), (7), and (10). [18,36] The calculated Gibbs free energies of reactions between 1350 and 1650°C are shown in Figure 5.…”

Section: Bn Smentioning

confidence: 99%

“…For non‐oxide CMCs, oxidation resistance at high temperature is the key factor to ensure the reliability in service conditions . Thus, many investigations were carried out to explore the oxidation kinetics of SiBCN ceramic as well as its oxidation mechanism . Generally, polymer‐derived SiBCN ceramics were considered to demonstrate better oxidation resistance than SiC and Si 3 N 4 ceramics prepared via chemical vapor deposition (CVD) .…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Oxidation behavior of a 2D‐SiC_f/BN/SiBCN composite at 1350–1650 °C in air

Tan

Cao

et al. 2018

Materials & Corrosion

A continuous SiC fiber reinforced SiBCN composite (2D‐SiCf/BN/SiBCN) was fabricated via resin transfer molding (RTM) and polymer infiltration and pyrolysis (PIP). The oxidation behavior of the composite was studied in air at 1350, 1500, and 1650 °C as a function of time. The microstructure, morphology, phase composition of the oxide scales, oxidation kinetics, and residual strength of the composite were determined. Composite self‐healing and logarithmic oxidation kinetics were observed. The residual flexural strength of the composite after oxidation was also evaluated. The composite seems promising in applications for high temperature structural materials above 1350 °C.

“…The SiBCN matrix should be orderly inserted into SiC f /SiC via CVI and PIP technologies. Thirdly, the borosilicate or SiO 2 glass generates in virtue of the oxidation of SiBCN at high temperatures and oxidizing atmorsphere [13][14][15]. The self-healing performance can be obtained via viscous flow of borosilicate glass or SiO 2 , and the service life of SiBCN matrix modified SiC f /SiC composites can be prolonged [16].…”

mentioning

confidence: 99%

Enhanced mechanical property and tunable dielectric property of SiCf/SiC-SiBCN composites by CVI combined with PIP

Song

et al. 2021

J Adv Ceram

The SiBCN matrix via chemical vapor infiltration (CVI) or/and polymer infiltration pyrolysis (PIP) technologies was orderly introduced to SiCf/SiC composites to optimize the mechanical property and electromagnetic (EM) shielding effectiveness simultaneously. The BN interface with the thickness of 350 nm was designed to obtain a little stronger interface bonding. The flexural strength of SiCf/SiC-SiBCN composites reached 545.45±29.59 MPa thanks to the crack deflection between the CVI SiC and CVI SiBCN, as well as CVI SiBCN and PIP SiBCN matrix because of the modulus difference between them. The fracture toughness (KIC) with the value of 16.02±0.94 MPa·m1/2 was obtained owing to the extension of crack propagation path. The adverse effect of stronger interface bonding was eliminated by the design of matrix microstructure for SiCf/SiC-SiBCN composites. The thermal conductivity in the thickness direction was 7.64 W·(m·K)−1 at 1200 °C and the electric resistivity decreased to 1.53×103 Ω·m. The tunable dielectric property was obtained with the coordination of wave-absorption CVI SiBCN matrix and impedance matching PIP SiBCN matrix, and the total shielding effectiveness (SET) attained 30.01 dB. It indicates that the SiCf/SiC-SiBCN composites have great potential to be applied as structural and functional materials.