Silicon Carbide Coatings Research Articles

Co/Al–Layered Double Hydroxide-Modified Silicon Carbide Membrane Filters as Persulphate Activator for Aniline Degradation

Novel catalytic silicon carbide membrane filters (SCMFs) are synthesized with Co/Al–layered double hydroxide (Co/Al-LDH)-coated silicon carbide powder. After capsuled in a self-designed membrane shell, the SCMFs are utilized in activating persulphate for aniline degradation. Thermal analysis conducted via TG/DTG/DSC examination shows that the heating treatment is beneficial in elevating the activating ability of SCMFs, and the derived Co3O4 displays superior catalytical efficiency than Co/Al-LDHs precursor. The XRD patterns and SEM images indicate the sheet-like Co/Al-LDHs are uniformly coprecipitated throughout the surface of SCMFs. Within 20 min, around 95% of aniline is eliminated under 0.7 m of flow velocity and 8:1 of persulphate to aniline ratio. Three-dimensional fluorescence and GC chromatography reveal that distinct by-products exist in the early stage of the aniline degradation process between the sintered and non-sintered Co/Al-LDH-coated SCMFs. The integration strategy of Co/Al-LDH coatings and heating treatment endows traditional SCMFs with robust catalytic properties for engineering-oriented applications in wastewater treatment.

Advancing SiC Coatings of Short‐Fiber Using Triethylsilane: Insights from FB‐CVD Deposition Process

AbstractThis study examines the use of triethylsilane (TES) as a non‐halogenated, less hazardous precursor in the Fluidized Bed ‐ Chemical Vapor Deposition (FB‐CVD) process for silicon carbide (SiC) coating on short fibers. It focuses on characterizing a pre‐matrix SiC layer over an interphase boron nitride (BN) coating, aiming to improve short‐fiber‐reinforced silicon carbide ceramic matrix composites (SiC/SiC CMCs). FB‐CVD is highlighted as a promising method for enhancing the applicability of discontinuous SiC/SiC CMCs. Advanced characterization techniquesScanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDX), Auger Electron Spectroscopy (AES), X‐ray Photoelectron Spectroscopy (XPS), and Transmission Electron Microscopy (TEM)—were used to analyze coated fibers. The findings reveal uniform, robust SiC coatings while preserving the BN layer. Notably, a stratified SiC structure, alternating between carbon‐rich and silicon‐rich zones, was observed. Auger spectroscopy and XPS provided insights into SiCx atomic composition and bonding environments. This research demonstrates TES's potential as an effective SiC precursor and advances understanding of FB‐CVD processes for short‐fiber coatings. The results pave the way for optimizing coating properties to enhance performance in SiC/SiC composites, opening new opportunities for further development.

Osteoblast Growth in Quaternized Silicon Carbon Nitride Coatings for Dental Implants.

The demand for dental implants has increased, establishing them as the standard of care for replacing missing teeth. Several factors contribute to the success or failure of an implant post-placement. Modifications to implant surfaces can enhance the biological interactions between bone cells and the implant, promoting better outcomes. Surface coatings have been developed to electrochemically alter implant surfaces, aiming to reduce healing time, enhance bone growth, and prevent bacterial adhesion. Quaternized silicon carbon nitride (QSiCN) is a novel material with unique electrochemical and biological properties. This study aimed to assess the influence of QSiCN, silicon carbide nitride (SiCN), and silicon carbide (SiC) coatings on the viability of osteoblast cells on nanostructured titanium surfaces. The experiment utilized thirty-two titanium sheets with anodized TiO2 nanotubes featuring nanotube diameters of 50 nm and 150 nm. These sheets were divided into eight groups (n = 4): QSiCN-coated 50 nm, QSiCN-coated 150 nm, SiCN-coated 50 nm, SiCN-coated 150 nm, SiC-coated 50 nm, SiC-coated 150 nm, non-coated 50 nm, and non-coated 150 nm. Preosteoblast MC3T3-E1 Subclone 4 cells (ATCC, USA) were used to evaluate osteoblast viability. After three days of cell growth, samples were assessed using scanning electron microscopy (SEM). The results indicated that QSiCN coatings significantly increased osteoblast proliferation (p < 0.005) compared to other groups. The enhanced cell adhesion observed with QSiCN coatings is likely due to the positive surface charge imparted by N+.

Impact of Silicon Carbide Coating and Nanotube Diameter on the Antibacterial Properties of Nanostructured Titanium Surfaces.

This study aimed to comprehensively assess the influence of the nanotube diameter and the presence of a silicon carbide (SiC) coating on microbial proliferation on nanostructured titanium surfaces. An experiment used 72 anodized titanium sheets with varying nanotube diameters of 50 and 100 nm. These sheets were divided into four groups: non-coated 50 nm titanium nanotubes, SiC-coated 50 nm titanium nanotubes, non-coated 100 nm titanium nanotubes, and SiC-coated 100 nm titanium nanotubes, totaling 36 samples per group. P. gingivalis and T. denticola reference strains were used to evaluate microbial proliferation. Samples were assessed over 3 and 7 days using fluorescence microscopy with a live/dead viability kit and scanning electron microscopy (SEM). At the 3-day time point, fluorescence and SEM images revealed a lower density of microorganisms in the 50 nm samples than in the 100 nm samples. However, there was a consistently low density of T. denticola across all the groups. Fluorescence images indicated that most bacteria were viable at this time. By the 7th day, there was a decrease in the microorganism density, except for T. denticola in the non-coated samples. Additionally, more dead bacteria were detected at this later time point. These findings suggest that the titanium nanotube diameter and the presence of the SiC coating influenced bacterial proliferation. The results hinted at a potential antibacterial effect on the 50 nm diameter and the coated surfaces. These insights contribute valuable knowledge to dental implantology, paving the way for developing innovative strategies to enhance the antimicrobial properties of dental implant materials and mitigate peri-implant infections.

Improvement of carbon fiber oxidation resistance by thin ceramic coating using silica particles

Carbon fiber-reinforced plastics have become indispensable materials in energy saving and new energy technologies, such as automobiles, wind power generators, and hydrogen tanks for fuel cells. However, the lack of oxidation resistance limits the high-temperature applications of carbon fibers. In this study, we developed a coating technology for carbon fibers to improve their oxidative resistance. Carbon fibers with silicon carbide coatings were obtained by the adsorption of silica colloids on carbon fibers using electro adsorption, followed by heating. The resulting coating has small thickness and strong chemical connections. The thermogravimetric analysis confirmed that the oxidation start temperature of the coated carbon fibers was higher than that of carbon fibers. Moreover, the mechanical properties of the coated carbon fibers were maintained. Therefore, the proposed coating technology can broaden the application of carbon fibers as the alternative to some SiC fiber applications. Further, it is applicable for recycling carbon fibers to increase their value in terms of thermal oxidation stability.

Design, Construction and Programming of a Low-Cost Pulsed High-Voltage Direct Current Power Supply for the Electrophoretic Deposition of Silicon Carbide Mixed with Graphite and/or Alumina for Thermoelectric Applications

This document describes a proprietary design, construction, programming and testing of a low-cost pulsed high-voltage direct current (HVDC) power supply with an output of 430 V and power of 25 W. The design obtained allows costs to be reduced compared to commercial ones, highlighting that the manufacturing of this HVDC is easy to replicate. To demonstrate the operation of the pulsed power supply prototype, coatings of silicon carbide (SiC) and SiC mixed with graphite (C) and/or alumina (Al2O3) were made using the electrophoretic deposition (EPD) method. After processing, samples underwent a heat treatment at 500 °C to evaluate their thermoelectric (TE) efficiency. The samples were analysed via X-ray diffraction (XRD), scanning electron microscopy (SEM), Raman spectroscopy, Seebeck coefficient, electrical conductivity and thermal conductivity. The Seebeck coefficient, electrical conductivity and thermal conductivity were measured in a temperature range of 100–500 °C in a nitrogen (N2) atmosphere. The electrical conductivity of the SiC 6C-4Al sample was 0.65 S/cm at 500 °C, while the maximum Seebeck coefficient was 2500 μV/K of the SiC 6C-4Al sample at 200 °C. The thermal conductivity of SiC 6C-4Al was in the range of 0.35–0.37 W/m·K, which was much lower than the SiC sample free of alumina and graphite in the same measured temperature range. In conclusion, the SiC 6C-4Al sample presented the highest figure of merit with a ZT ≈ 0.01.

Superior tribological and sealing performance of micro-crystalline diamond coated silicon carbide seals under dry friction and high load

Silicon carbide seals suffer severe wear under the conditions of dry friction and high load, posing a great challenge in achieving a stable performance and a long lifetime. In this work, micro-crystalline diamond coatings were deposited on silicon carbide sealing rings to prevent the failure caused by wear. The deposited micro-crystalline diamond coatings exhibit high-quality crystallinity and strong adhesive strength with the silicon carbide substrate. In sealing tests, the micro-crystalline diamond coated silicon carbide sealing pair demonstrates superior tribological and sealing properties under dry friction and high load of 1800 N, featuring a low coefficient of friction of 0.16, a low wear rate of 4.00 × 10−7 mm3·N−1·m−1 and a high friction limit of 5.24 MPa·m·s−1. Characterizations of morphology, chemical composition and microstructure confirm that the smoothening effect on the contact face and the formation of graphite during the sealing test synergistically contribute to the outstanding tribological and sealing performance.

A study on mechanical and tribological properties of aluminium 6061-SiC-B4C-GO hybrid nanocomposites with a novel optimized mix selection approach

ABSTRACT This research deals with the mechanical and tribological behaviour of different weight percentages of reinforcements (coated silicon carbide, boron carbide, and graphene oxide) dispersed with aluminium matrix (Al 6061) composites. The silicon carbide (SiC) was coated by Titanium oxide (TiO2) using the Electro Phoretic Deposition (EPD) method. The selected mix proportions fabrication process was performed by the stir casting method. The tribological and mechanical behaviour of hybrid aluminium matrix-composite specimens and Scanning Electron Microscopy (SEM) identification revealed that ASB-1 (86 wt% Al 6061 + 2 wt% GO + 10 wt% SiC + 2 wt% B4C) uncovered higher wear resistance and strengths due to reinforcement’s uniform distribution throughout the aluminium matrix and coating of SiC. Moreover, a comparison was performed to determine the effectiveness of hybrid composite specimens. It is concluded that the presented SRNMS framework identified the mix proportions effectively, and the coating of SiC improves the wear resistance.

Pure-SiC ceramic membrane for ultrafiltration: Morphology, pore characteristics and separation performances

Silicon carbide (SiC) ceramic membranes have gained increasing attention due to their excellent chemical and thermal stability serving in harsh conditions. However, the use of SiC ceramic membrane is limited in micro-filtration fields because of the micro-scale pores in the selective layer. Here, a pure-SiC ultrafiltration (UF) membrane was prepared by dip-coating and recrystallization sintering using fine SiC particles of 100 nm and 50 nm in sizes. EDS and XRD analysis confirmed that the membrane was composed of pure-SiC phase, which endowed the UF membrane with strongly chemical resistance. Because of the refinement in particles, the average pore sizes of the ceramic membrane made of 100 nm and 50 nm particles corresponded to 82 nm and 58 nm, respectively. Due to the refinement in pore size, the oil flux increased from 69.50 L/(m2·h) to 99.01 L/(m2·h) and the oil rejection exceeded 98.8 % for the 50 nm membrane.

Deposition behavior and mechanism of thermal sprayed SiC

AbstractIt is widely known that silicon carbide (SiC) is challenging to thermal spray. However, the nature of deposition and the underlying mechanisms are still not clearly understood. In the current work, the process of atmospheric plasma‐sprayed SiC was investigated in detail. SiC exhibits sublimation severely under the plasma spraying (PS). More than 65 mol.% SiC particles lost by sublimation during PS estimated by calculation. Due to the nonuniformity of temperature in plasma flame, a small amount of SiC particles was retained. Moreover, a small amount of Si and SiO2 was experimentally observed after deposition process from the single‐splat characterization. According to the first‐principles calculations, the detachment energy of C atom from the lattice (0.591 eV) is lower than that of Si atom (1.257 eV). The adsorption energies of an O atom on the Si‐ and C‐terminated surfaces are −9.549 and −7.631 eV, respectively. Therefore, C is more likely to form gaseous products after decomposition, and Si is more likely to be retained to form Si and SiO2. Mullite was found on the grain boundaries of molten Si, which was attributed to the rapid diffusion of the Al2O3 substrate along the grain boundaries of Si, promoting the spreading of molten splats. It is difficult to stack particles through self‐diffusion among SiC particles to form coatings. The discovery on thermal deposition mechanism of SiC in PS is helpful to promote the practical application of SiC coatings on preparation optimization and interfacial bonding improvement.

An Extensive Study and Evaluation of Tribological Properties of Fsw Plates Using Linear Reciprocating Tribometer (LRT)

This study extensively focuses on analyzing the fretting wear characteristics of Aluminum-based hybrid Metal Matrix Composites (MMCs) under dry conditions, essential in understanding materials' tribological properties in mining environments. Aluminum-based MMCs offer improved wear resistance and durability, potentially enhancing mining equipment performance. The investigation targeted Aluminum 7075 alloy-based MMCs, comprising 7% fine greenish Silicon Carbide and 3% chopped E-glass fibers (2-3mm length, 10-14 micrometer diameters). Using traditional stir casting and Friction Stir Welding (FSW) techniques, composite plates meeting ASTM standards were fabricated. FSW parameters like rotation speed and tool feed rate were varied.Analyzing fretting wear on the welded zone, employing different loads through Linear Reciprocating Tribometer (LRT), provided insights into the tribological performance of these Aluminum-based hybrid MMCs. The lightweight and exceptional thermal properties of Aluminum have significantly expanded its use across various industries, enabling partial replacement of ferrous materials, especially in MMCs where Aluminum alloys offer distinct advantages over other materials.This research aids in determining the suitability of these MMCs for demanding mining conditions, where materials endure extreme stress. Understanding their tribological behavior is crucial for potential applications in mining equipment, contributing to longevity and improved performance.

Evaluation of equi‐biaxial strength of thin sic coatings using ring‐on‐ring testing and digital image correlation

AbstractTo assess the strength of coatings under multi‐axial stress conditions, a method was developed to evaluate the biaxial strength of thin silicon carbide (SiC) coatings using a ring‐on‐ring test. A graphite substrate was used as an intermediary to transmit stress from the load ring to the coated specimen, and the thin coating was subjected to a uniform equi‐biaxial stress. The strain in the thin film was continuously monitored using digital image correlation, allowing the identification of the time at which and when the initial crack occurred; the stress applied to the loading area at time was determined to be the fracture strength of the thin SiC films. The obtained fracture strength ranged from 209 to 1014 MPa and was dependent on specimen volume. Notably, the thinnest specimen exhibited the highest strength, whereas the strengths of thicker specimens approached previously reported bulk strengths.

Graphene oxide coated silicon carbide films under projectile impacts

The quest for hybrid materials to withstand extreme loading conditions has been a canonical field of research over the past decades. As an emerging hybrid material, graphene oxide (GO)-silicon carbide (SiC) offers remarkable thermo-chemo-mechanical properties with applications in defense, energy, and aerospace engineering. Researches to unravel the various properties of the aforementioned material subjected to different loading conditions have been on the rise to further promote its potential for the pertinent industries. Nonetheless, impact resistance characterization of such composite received less attention due to experimental and computational difficulties. Here, the aforementioned problem is investigated by leveraging ReaxFF molecular dynamics simulations. Accordingly, the response of 4H-SiC thin films coated by GO samples under indentation and high-velocity projectile impact is assessed. It is found that (a) composite films containing GO samples with higher oxidation degree demonstrate softer behavior under indentation, and (b) fracture pattern and penetration-resistance under high-velocity impact are contingent on the oxidation degree of the coating layers. In essence, impact-induced complete perforation is more localized to the impacted zone as oxidation degree of the coating layers increases. Therefore, oxidation content can be considered as a novel tuning factor for the fracture behavior of the GO-SiC thin films under projectile impacts. The influence of oxygen functional groups on the interaction energy between GO and SiC layers are also discussed. The findings of this study reveal some insights into the bottom-up design pathways for developing novel protective barriers in which GO is used as a coating layer or reinforcement for SiC ceramics.

Eddy Current Methodology for Nondestructive Assessment of Thickness of Silicon Carbide Coating on Carbon-Carbon Composites

Eddy current (EC) methodology has been developed for non-destructive assessment of thickness of Silicon carbide (SiC) coating on carbon-carbon (C/C) composite specimens. For coating, polymer precursor route has been employed and approximate coating thickness has been determined by weight gain method. EC probe signal amplitude has been measured before and after the coating. Despite scatter in the baseline data due to surface roughness on C/C specimens, EC methodology could identify undercoated (thickness &lt;20 µm) specimens. A calibration graph has been established between EC signal amplitude and coating thickness (weight gain) to evaluate the performance of the EC methodology. The methodology has evaluated the coating thickness with error less than ±5 µm. Studies confirm that it is possible to assess the efficacy of coating process and to readily identify thinly coated regions using eddy current imaging.

Highly durable zirconium/titanium dioxide–silicon carbide photocatalytic membrane for water and wastewater treatment

Photocatalytic membrane reactors offer an effective method for wastewater treatment by coupling the filtration function of the membrane with photocatalytic activity. This study developed a zirconium doped titanium dioxide coated silicon carbide (Zr/TiO2-SiC) photocatalytic membrane, which was activated by an ultraviolet light emitting diode (UV-LED), and optimum conditions for the photocatalytic synthesis and immobilization were established. The photocatalytic membrane was applied to the degrading of genotoxic and carcinogenic rhodamine B as a typical pollutant of textile wastewater. In addition, humic acid was included, as a relatively large molecule compared to the rhodamine B, to evaluate the antifouling properties of the photocatalytic membrane. The design and operating parameters of the zirconium molar ratio, the photocatalyst loading, and the UV-LED irradiance all affected the performance of the photocatalytic membrane. The results showed that at an optimum concentration of 10 %, the zirconium doping improved the photocatalytic activity by over 20 %. There was also an optimum loading after which the photocatalytic activity decreased. A linear correlation was observed between the reaction rate constant and the irradiance, which can be used for future operation optimization. The photocatalytic membrane was studied further to investigate the durability of the photocatalyst particles attached to the membrane surface, and there was little evidence of deterioration in their photocatalytic activity. The photocatalytic membrane exhibited high antifouling properties when filtering a humic acid solution in a custom-made photocatalytic membrane reactor. The results indicated that the photocatalytic membrane developed has strong potential for industrial application.

Superconformal silicon carbide coatings via precursor pulsed chemical vapor deposition

In this work, silicon carbide (SiC) coatings were successfully grown by pulsed chemical vapor deposition (CVD). The precursors silicon tetrachloride (SiCl4) and ethylene (C2H4) were not supplied in a continuous flow but were pulsed alternately into the growth chamber with H2 as a carrier and a purge gas. A typical pulsed CVD cycle was SiCl4 pulse—H2 purge—C2H4 pulse—H2 purge. This led to growth of superconformal SiC coatings, which could not be obtained under similar process conditions using a constant flow CVD process. We propose a two-step framework for SiC growth via pulsed CVD. During the SiCl4 pulse, a layer of Si is deposited. In the following C2H4 pulse, this Si layer is carburized, and SiC is formed. The high chlorine surface coverage after the SiCl4 pulse is believed to enable superconformal growth via a growth inhibition effect.

Comparative study on infrared properties of PLD-grown DLC film and SiC film

Diamond-like carbon and silicon carbide coatings were grown by pulsed laser deposition under different laser fluences, and their infrared transmission spectra were compared with each other. Raman spectroscopies and their deconvolutions for the silicon carbide films prepared by different laser fluences exhibited no changes nearly in micro-structure, and the infrared spectra showed these layers had high infrared transmission. On the other hand, the obvious changes in micro-structure of the diamond-like carbon films grown by the different laser fluences, which indicated laser fluence played an important role in the growth process of the diamond-like carbon films. A relatively higher laser fluence could grow the diamond-like carbon film with higher sp3 bond content, increasing the infrared property, while a lower one increased the absorption of the layer, reducing its infrared transmission seriously. Nano-scratch test showed that silicon carbide layer can be used as the buffer layer for the multilayer diamond-like carbon film enhancing the adhesive performance of the whole coating on the substrate with the protective and anti-reflective properties.

The impact of co-deposited silicon impurity on oxidation of silicon carbide coatings in the air and in steam at high temperatures

We report a study on the oxidation behaviour of stoichiometric and hyper-stoichiometric silicon carbide (SiC) with silicon impurity. In air, silica growth was parabolic at 1200 °C and 1600 °C on both SiCs but was faster on hyper-stoichiometric SiC. However, the oxidation kinetics was reversed in the steam due to the generation of a larger quantity of gaseous products and pore networks in silica on stoichiometric SiC, which resulted in easy ingress of steam and a reaction-controlled linear oxidation behaviour. In contrast, the pores in silica on hyper-stoichiometric SiC were mostly isolated, resulting in diffusion-controlled parabolic growth of the silica layer.

Non-Oxide Ceramics for Bone Implant Application: State-of-the-Art Overview with an Emphasis on the Acetabular Cup of Hip Joint Prosthesis

A rapidly developing area of ceramic science and technology involves research on the interaction between implanted biomaterials and the human body. Over the past half century, the use of bioceramics has revolutionized the surgical treatment of various diseases that primarily affect bone, thus contributing to significantly improving the quality of life of rehabilitated patients. Calcium phosphates, bioactive glasses and glass-ceramics are mostly used in tissue engineering applications where bone regeneration is the major goal, while stronger but almost inert biocompatible ceramics such as alumina and alumina/zirconia composites are preferable in joint prostheses. Over the last few years, non-oxide ceramics—primarily silicon nitride, silicon carbide and diamond-like coatings—have been proposed as new options in orthopaedics in order to overcome some tribological and biomechanical limitations of existing commercial products, yielding very promising results. This review is specifically addressed to these relatively less popular, non-oxide biomaterials for bone applications, highlighting their potential advantages and critical aspects deserving further research in the future. Special focus is also given to the use of non-oxide ceramics in the manufacturing of the acetabular cup, which is the most critical component of hip joint prostheses.

Fabrication and efficient electromagnetic waves attenuation of three-dimensional porous reduced graphene oxide/boron nitride/silicon carbide hierarchical structures

In this work, hierarchical hybrid composites consisting of porous three-dimensional reduced graphene oxide (3D-rGO) skeleton and lamellar boron nitride (BN)/silicon carbide (SiC) coatings are prepared by chemical vapor infiltration (CVI) process. The graphene framework prepared by 3D printing and frozen self-assembly exhibits a lightweight structure and a perforated conductive network, which extends the transmission path of incident microwaves. The introduced ceramic coatings can effectively tune the impedance matching degree and supply a lossy phase, and the hierarchical structure of the composites enhances the multiple scattering of the incident microwaves. As expected, the 3D-rGO/BN/SiC composites possess an excellent absorbing performance with a minimum reflection loss value of –37.8 dB, and the widest effective absorbing bandwidth (RL < –10 dB) of 5.90 GHz is obtained. The controllable fabrication of composites can provide a guideline for rational design and fabrication of high-performance electromagnetic waves absorbing materials in practical applications.