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19 pages, 8537 KB

Open AccessArticle

Effects of Ti Containing Cu-Based Alloy on Sintering Mechanism, Element Diffusion Behavior and Physical Properties of Glass-Ceramic Bond for Cubic Boron Nitride Abrasive Tool Materials

by Xianglong Meng, Bing Xiao and Hengheng Wu

Micromachines 2023, 14(2), 303; https://doi.org/10.3390/mi14020303 - 24 Jan 2023

Cited by 8 | Viewed by 2132

Abstract

Ti containing Cu-based (TC) alloy reinforced glass-ceramic bond was fabricated for cubic boron nitride (CBN) abrasive tool materials, and its crystal composition, phase transformation, sintering activation energy, microstructure, element diffusion mathematical model, physical properties, and the bonding mechanism between the TC alloy reinforced [...] Read more.

Ti containing Cu-based (TC) alloy reinforced glass-ceramic bond was fabricated for cubic boron nitride (CBN) abrasive tool materials, and its crystal composition, phase transformation, sintering activation energy, microstructure, element diffusion mathematical model, physical properties, and the bonding mechanism between the TC alloy reinforced glass-ceramic bond and the CBN grains were systematically investigated. The results showed that the structure, composition and sintering behavior of glass-ceramic were influenced by TC alloy adding. The generated TiO₂ affected obviously the precipitation of β-quartz solid solution Li₂Al₂Si₃O₁₀, thus improving the relative crystallinity, mechanical strength and thermal properties. By establishing the mathematical model for element diffusion, the element diffusion coefficients of Ti and Cu were 7.82 and 6.98 × 10⁻¹¹ cm²/s, respectively, which indicated that Ti diffused better than Cu in glass-ceramic. Thus, Ti⁴⁺ formed a strong Ti–N chemical bond on the CBN surface, which contributed to improving the wettability and bonding strength between CBN and glass-ceramic bond. After adding TC alloy, the physical properties of the composite were optimized. The porosity, bulk density, flexural strength, Rockwell hardness, CTE, and thermal conductivity of the composites were 5.8%, 3.16 g/cm³, 175 MPa, 90.5 HRC, 3.74 × 10⁻⁶ °C⁻¹, and 5.84 W/(m·k), respectively. Full article

(This article belongs to the Special Issue Micro- and Nanoscale Science, Technology and Engineering in Nanjing University of Aeronautics and Astronautics: Celebrating 70th Anniversary)

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17 pages, 6519 KB

Open AccessArticle

Experimental Investigations into the Pyrolysis Mechanism and Composition of Ceramic Precursors Containing Boron and Nitrides with Different Boron Contents

by Yiqiang Hong, Guoxin Qu, Youpei Du, Tingting Yuan, Shuangshuang Hao, Wei Yang, Zhen Dai and Qingsong Ma

Materials 2022, 15(23), 8390; https://doi.org/10.3390/ma15238390 - 25 Nov 2022

Cited by 2 | Viewed by 2106

Abstract

In this work, a novel ceramic precursor containing boron, silicon, and nitrides (named SiBCN) was synthesized from liquid ceramic precursors. Additionally, its pyrolysis, microstructure, and chemical composition were studied at 1600 °C. The results showed that the samples with different boron contents had [...] Read more.

In this work, a novel ceramic precursor containing boron, silicon, and nitrides (named SiBCN) was synthesized from liquid ceramic precursors. Additionally, its pyrolysis, microstructure, and chemical composition were studied at 1600 °C. The results showed that the samples with different boron contents had similar structural composition, and both of the two precursors had stable amorphous SiBN structures at 1400 °C, which were mainly composed of B-N and Si-N and endowed them with excellent thermo-oxidative stability. With the progress of the heating process, the boron contents increased and the structures became more amorphous, significantly improving the thermal stability of the samples in high-temperature environments. However, during the moisture treatment, the introduction of more boron led to worse moisture stability. Full article

(This article belongs to the Special Issue Advanced Composite Material Design and Manufacturing Technology for Aerospace Engineering)

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47 pages, 3932 KB

Open AccessFeature PaperReview

Recent Progress in Fabrication and Application of BN Nanostructures and BN-Based Nanohybrids

by Dmitry V. Shtansky, Andrei T. Matveev, Elizaveta S. Permyakova, Denis V. Leybo, Anton S. Konopatsky and Pavel B. Sorokin

Nanomaterials 2022, 12(16), 2810; https://doi.org/10.3390/nano12162810 - 16 Aug 2022

Cited by 80 | Viewed by 8219

Abstract

Due to its unique physical, chemical, and mechanical properties, such as a low specific density, large specific surface area, excellent thermal stability, oxidation resistance, low friction, good dispersion stability, enhanced adsorbing capacity, large interlayer shear force, and wide bandgap, hexagonal boron nitride ( [...] Read more.

Due to its unique physical, chemical, and mechanical properties, such as a low specific density, large specific surface area, excellent thermal stability, oxidation resistance, low friction, good dispersion stability, enhanced adsorbing capacity, large interlayer shear force, and wide bandgap, hexagonal boron nitride (h-BN) nanostructures are of great interest in many fields. These include, but are not limited to, (i) heterogeneous catalysts, (ii) promising nanocarriers for targeted drug delivery to tumor cells and nanoparticles containing therapeutic agents to fight bacterial and fungal infections, (iii) reinforcing phases in metal, ceramics, and polymer matrix composites, (iv) additives to liquid lubricants, (v) substrates for surface enhanced Raman spectroscopy, (vi) agents for boron neutron capture therapy, (vii) water purifiers, (viii) gas and biological sensors, and (ix) quantum dots, single photon emitters, and heterostructures for electronic, plasmonic, optical, optoelectronic, semiconductor, and magnetic devices. All of these areas are developing rapidly. Thus, the goal of this review is to analyze the critical mass of knowledge and the current state-of-the-art in the field of BN-based nanomaterial fabrication and application based on their amazing properties. Full article

(This article belongs to the Special Issue Boron Nitride-Based Nanomaterials)

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12 pages, 6368 KB

Open AccessArticle

Mechanical Properties and Microstructure of Hot-Pressed Silica Matrix Composites

by Weili Wang, Jianqi Chen, Xiaoning Sun, Guoxun Sun, Yanjie Liang and Jianqiang Bi

Materials 2022, 15(10), 3666; https://doi.org/10.3390/ma15103666 - 20 May 2022

Cited by 3 | Viewed by 2337

Abstract

Silica is one of the most widely used ceramics due to its excellent chemical stability and dielectric property. However, its destructive brittle nature inhabits it from wider application as a functional ceramic. An improvement in toughness is a challenging topic for silica ceramic, [...] Read more.

Silica is one of the most widely used ceramics due to its excellent chemical stability and dielectric property. However, its destructive brittle nature inhabits it from wider application as a functional ceramic. An improvement in toughness is a challenging topic for silica ceramic, as well as other ceramics. In the paper, silica ceramic with different types of boron nitride powders and alumina platelets was fabricated by hot-pressing. Introduction of the additives had great influence on the composites’ mechanical properties and microstructure. The silica matrix composite containing micro-sized boron nitride powders possessed the best mechanical properties, including the bending strength (134.5 MPa) and the fracture toughness (1.85 Mpa·m^1/2). Meanwhile, the introduction of alumina platelets combined with boron nitride nanosheets achieved an effective enhancement of fracture toughness while maintaining the bending strength. Compared with the monolithic silica, the composite with simultaneous addition of alumina platelets and boron nitride nanosheets had a fracture toughness of 2.23 Mpa·m^1/2, increased by approximately 27% (1.75 Mpa·m^1/2). The crack deflection and platelet pullout were contributing to enhancement of the fracture toughness. The improved mechanical properties, combined with the intrinsic excellent dielectric and chemical properties, make the silica matrix composites promising wave transparent and thermal protection materials. Full article

(This article belongs to the Special Issue Advanced Ceramics and Composites: Design, Structure, Processing, Properties, and Applications)

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13 pages, 2918 KB

Open AccessArticle

Characteristic and Synthesis of High-Temperature Resistant Liquid Crystal Epoxy Resin Containing Boron Nitride Composite

by Li-Chuan Wu, Yi-Wen Huang, Yao-Ming Yeh and Chih-Hung Lin

Polymers 2022, 14(6), 1252; https://doi.org/10.3390/polym14061252 - 20 Mar 2022

Cited by 13 | Viewed by 3788

Abstract

Five liquid crystal epoxy resins and composites containing flat boron nitride (f-BN) and spherical boron nitride (s-BN) were successfully synthesized. The chemical structures, crystal diffraction, and thermal conductivity of the liquid crystal (LC) epoxy composites were measured using Nuclear Magnetic Resonance (NMR), Differential [...] Read more.

Five liquid crystal epoxy resins and composites containing flat boron nitride (f-BN) and spherical boron nitride (s-BN) were successfully synthesized. The chemical structures, crystal diffraction, and thermal conductivity of the liquid crystal (LC) epoxy composites were measured using Nuclear Magnetic Resonance (NMR), Differential Scanning Calorimetry (DSC), X-ray, and Discovery Xenon Flash. In this study, the molecular arrangement of five LC epoxy resins and the thermal conductivity of their composites were carefully discussed. Several different amounts of flat boron nitride and spherical boron nitride were added to the five LC epoxy resins. The influence of nano-scale ceramic materials, f-BN, and s-BN, on the thermal conductivity of the LC epoxy resins, was studied. It is worth noting that the thermal conductivity of the spherical boron nitride composite demonstrated a better result than that of the flat boron nitride composite. In simpler terms, the thermal conductivity of the composites is closely related to the molecular arrangement of the LC resin and the amount of BN added. The results demonstrate that the SBPDAE/s-BN (60%) composite shows the highest thermal conductivity of 9.36 W/mK in the vertical direction. These data prove that the LC alignment of the matrix will greatly enhance the thermal conductivity of the composites. Full article

(This article belongs to the Special Issue Advances in Polymer Composites)

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11 pages, 28589 KB

Open AccessArticle

Characterization and Microstructural Evolution of Continuous BN Ceramic Fibers Containing Amorphous Silicon Nitride

by Yang Li, Min Ge, Shouquan Yu, Huifeng Zhang, Chuanbing Huang, Weijia Kong, Zhiguang Wang and Weigang Zhang

Materials 2021, 14(20), 6194; https://doi.org/10.3390/ma14206194 - 18 Oct 2021

Cited by 5 | Viewed by 3567

Abstract

Boron nitride (BN) ceramic fibers containing amounts of silicon nitride (Si₃N₄) were prepared using hybrid precursors of poly(tri(methylamino)borazine) (PBN) and polycarbosilane (PCS) via melt-spinning, curing, decarburization under NH₃ to 1000 °C and pyrolysis up to 1600 °C under [...] Read more.

Boron nitride (BN) ceramic fibers containing amounts of silicon nitride (Si₃N₄) were prepared using hybrid precursors of poly(tri(methylamino)borazine) (PBN) and polycarbosilane (PCS) via melt-spinning, curing, decarburization under NH₃ to 1000 °C and pyrolysis up to 1600 °C under N₂. The effect of Si₃N₄ contents on the microstructure of the BN/Si₃N₄ composite ceramics was investigated. Series of the BN/Si₃N₄ composite fibers containing various amounts of Si₃N₄ from 5 wt% to 25 wt% were fabricated. It was found that the crystallization of Si₃N₄ could be totally restrained when its content was below 25 wt% in the BN/Si₃N₄ composite ceramics at 1600 °C, and the amorphous BN/Si₃N₄ composite ceramic could be obtained with a certain ratio. The mean tensile strength and Young’s modulus of the composite fibers correlated positively with the Si₃N₄ mass content, while an obvious BN (shell)/Si₃N₄ (core) was formed only when the Si₃N₄ content reached 25 wt%. Full article

(This article belongs to the Special Issue Microstructural Design and Processing Control of Advanced Ceramics)

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12 pages, 9235 KB

Open AccessArticle

Basic Bio-Tribological Performance of Insulating Si₃N₄-Based Ceramic as Human Body Replacement Joints

by Huaqiang Li, Wei Chen, Hongxing Shi, Chen Zhang, Xingwei Liu and Lisheng Zhong

Coatings 2021, 11(8), 938; https://doi.org/10.3390/coatings11080938 - 5 Aug 2021

Cited by 7 | Viewed by 2586

Abstract

The paper presents an in-depth study of the bio-tribological performance on silicon nitride matrix ceramic composites containing hexagonal boron nitride (hBN) with different content. Ultra-high molecular weight polyethylene (UHMWPE) under simulated body fluid lubrication, and the simulated body fluid-lubricated sliding tests were performed [...] Read more.

The paper presents an in-depth study of the bio-tribological performance on silicon nitride matrix ceramic composites containing hexagonal boron nitride (hBN) with different content. Ultra-high molecular weight polyethylene (UHMWPE) under simulated body fluid lubrication, and the simulated body fluid-lubricated sliding tests were performed on a universal friction and wear tester. The results showed that the incorporation of hBN into silicon nitride matrix reduced the friction coefficients from 0.27 for Si₃N₄/UHMWPE pair to 0.16 for Si₃N₄-20%hBN/UHMWPE with full immersion in simulated body fluid lubrication. Scanning electron microscopy (SEM), laser scanning microscope, X-ray photoelectron spectroscopy (XPS) were utilized to characterize the wear surface. The analysis results indicated that, with simulated body fluid lubrication, the interfacial between hBN and Si₃N₄ facilitated the wear pits to form on the wear surface, and the residual wear particles deposited in the pits. Then, tribochemical products were formed on the wear surface, which protected and smoothed the wear surface of the sliding pair in the simulated body fluid. Full article

(This article belongs to the Special Issue Trends and Advances in Anti-wear Materials)

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17 pages, 11115 KB

Open AccessArticle

Study on the Preparation of High-Temperature Resistant and Electrically Insulating h-BN Coating in Ethanol Solution by Electrophoretic Deposition

by Kun Jia, Xu Meng and Wei Wang

Processes 2021, 9(5), 871; https://doi.org/10.3390/pr9050871 - 15 May 2021

Cited by 8 | Viewed by 3873

Abstract

A hexagonal boron nitride (h-BN) coating of micron thickness is deposited directly on 316L stainless steel (SS316L) cathode through efficient, adjustable electrophoretic deposition (EPD) in a suspension system containing surfactant and ethanol. It is based on the mixing of h-BN with polyethyleneimine (PEI) [...] Read more.

A hexagonal boron nitride (h-BN) coating of micron thickness is deposited directly on 316L stainless steel (SS316L) cathode through efficient, adjustable electrophoretic deposition (EPD) in a suspension system containing surfactant and ethanol. It is based on the mixing of h-BN with polyethyleneimine (PEI) resulting in positively charged ceramic powder making cathodic electrophoretic deposition possible. The thickness of the resulting h-BN coatings deposited on SS316L could be controlled by varying the time and the voltage of electrophoretic deposition. The deposition kinetics and mechanism have been discussed. After soaking in Al(H₂PO₄)₃ solution and high-temperature annealing, the h-BN coatings exhibited good adhesive strength. Furthermore, a novel method has been used for the evaluation of the adhesive strength to explore the appropriate experimental conditions. X-ray diffraction spectroscopy (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) were employed to characterize the h-BN coatings. The h-BN coatings are applied for the DC breakdown performance test and exhibit remarkable breakdown voltage and breakdown strength. Full article

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