Addition Of Nitride Research Articles

Identification of Thermophysical and Rheological Properties of SAE 5w-30 with Addition of Hexagonal Boron Nitride

This research uses SAE 5W-30 lubricant base material with the addition of Hexagonal Boron Nitride (hBN) nanoparticle additives. This study aims to analyze the thermophysical and rheological properties of lubricants with the addition of nanoparticles. The method in this study uses a two-step method where nanoparticles are first prepared separately, then added with nanoparticles with varying volume fractions of 0.05%, 0.10%, 0.15% into the base fluid as a processing step. The next step is the stirring process using a magnetic stirrer, and ultrasonic homogenizer process. Furthermore, the nanolubricant was tested for thermophysical properties including viscosity, density, thermal conductivity, and sedimentation.

Worn Surface Analysis and Wear Map Mechanism of AA4032 Composites

Abstract The present research work exhibits the effect of reinforcement particles on the mechanical and wear properties of AA4032 hybrid and unhybrid metal matrix composites (MMCs). The unhybrid MMCs were prepared by incorporating titanium carbide (TiC) particles onto the AA4032, whereas the hybrid MMCs were prepared by the addition of hexagonal boron nitride (h-BN) particles to unhybrid AA4032-TiC composite. The tribological study conducted on the composites reveals that the wear rate was augmented at a higher applied load because of the formation of plastic deformation with some cracks. The generation of shear stress at an elevated applied load increases the coefficient of friction (COF). However, the addition of TiC and h-BN particles decreases the COF and wear rate because of the abrasion resistance and self-lubrication property of TiC and h-BN, respectively. The wear mechanism map study confirms that the hybrid MMCs have better wear resistance properties than the unhybrid MMCs with minimum delamination.

Developing Improved Corrosion-Resistant AA5083—BN/WC Composites for Tribological Applications

In this study, corrosion-resistant AA5083-BN/WC composites were developed for tribological applications through adequate control of the reinforcement content (WC and BN) in the matrix (AA5083 alloy). The effects of 6% and 12% tungsten carbide (WC) as well as 6% and 12% boron nitride (BN) additions on the corrosion behavior of AA5083 aluminum composite in 3.5% NaCl solution were carried out. Electrochemical techniques such as cyclic potentiodynamic polarization (CPP), changes in the chronoamperometric current with time (CCT), and electrochemical impedance spectroscopy (EIS) were utilized. The polarization results showed that the addition of 6% WC to the AA5083 alloy matrix improved its resistance to corrosion (RP). Rp exhibited an additional increase by adding 12% WC to the matrix. The values of RP were observed to increase for the AA5083 composite when adding 6% BN, and the highest RP values were recorded for the composite that contains 12% BN. The results obtained by the CPP method were confirmed by CCT and EIS measurements, where the presence of WC and BN protected the developed AA5083- BN/WC composites against corrosion. The corrosion resistance revealed an additional improvement with an increase in WC and BN content from 6% to 12%. The results also confirm that pitting corrosion decreased in the presence of WC and BN in the fabricated composites.

From Waste to Wealth: Upcycling Waste Polypropylene/Polyethylene for Thermal Management via Pressure-Induced, Flow-Enhanced Segregated Structurizing with Hexagonal Boron Nitride

The low value of recycled products is the main roadblock for sustainable development of polymers. In this work, waste polypropylene and waste polyethylene were chosen to be recycled for value-added thermal management with the addition of hexagonal boron nitride (hBN). Through specific design of melt flow indexes (MFIs), we proposed a novel pressure-induced, flow-enhanced segregated structurization (PiF-SS) process. The segregated structures were visually confirmed by various microscopies at different scales. The highest in-plane thermal conductivities of ∼7.48 W/mk was obtained for the sample with a low hBN loading of 20 wt %. Ultimately, we evaluated the thermal management performance of all samples with various compositions. In this work, we believe that the concept of combinational utilization of a high-MFI polymer and a low-MFI polymer to perform PiF-SS can not only work for the sustainable reuse of waste polymers but also be used for manufacturing advanced functional materials.

Investigation into the influence of boron nitride addition on the properties of SPEEK/PBI based electrolyte membrane

To overcome the limitation of SPEEK/PBI membrane, BN was introduced to the membrane in different percentages. Firstly, boron nitride was functionalized by introducing hydroxyl group using KMNO4, H2O2, as oxidation agents. At the same time SPEEK was prepared by sulfonating PEEK at 80 °C using sulfonic acid. Further, a SPEEK/PBI/BN blend was prepared by dissolving SPEEK/BN in DMCs and then mixed with PBI heated solution. The percentage of the BN were 10%, 15 and 20%. The prepared membranes were characterized, however, SPEEK/PBI/BN-10% showed the optimum physicochemical properties; in which the degree of sulfonating, ion exchange capacity, water uptake, tensile stress, ionic conductivity, and thermal stability were 80.53%, 2.18 meq.g−1, 6.13%,8.61 MPa, 245 mS/cm, and 316.6 °C. The results show that the addition of BN influenced the characteristics of the membrane remarkably in a positive way as the protonic conductivity increased remarkably from 170 mS/cm to 245 mS/cm. Moreover, there was a huge enhancement in the thermal stability and the ionic conductivity.

Analysis of the Structure and the Thermal Conductivity of Semi-Crystalline Polyetheretherketone/Boron Nitride Sheet Composites Using All-Atom Molecular Dynamics Simulation

Thermal transport simulations were performed to investigate the important factors affecting the thermal conductivity based on the structure of semi-crystalline polyetheretherketone (PEEK), and the addition of boron nitride (BN) sheets. The molecular-level structural analysis facilitated the prediction of the thermal conductivity of the optimal structure of PEEK reflecting the best parameter value of the length of amorphous chains, and the ratio of linkage conformations, such as loops, tails, and bridges. It was found that the long heat transfer paths of polymer chains were induced by the addition of BN sheets, which led to the improvement of the thermal conductivities of the PEEK/BN composites. In addition, the convergence of the thermal conductivities of the PEEK/BN composites in relation to BN sheet size was verified by the disconnection of the heat transfer path due to aggregation of the BN sheets.

Recent advances in the application and biological mechanism of silicon nitride osteogenic properties: a review.

Silicon nitride, an emerging bioceramic material, is highly sought after in the biomedical industry due to its osteogenesis-promoting properties, which are a result of its unique surface chemistry and excellent mechanical properties. Currently, it is used in clinics as an orthopedic implant material. The osteogenesis-promoting properties of silicon nitride are manifested in its contribution to the formation of a local osteogenic microenvironment, wherein silicon nitride and its hydrolysis products influence osteogenesis by modulating the biological behaviors of the constituents of the osteogenic microenvironment. In particular, silicon nitride regulates redox signaling, cellular autophagy, glycolysis, and bone mineralization in cells involved in bone formation via several mechanisms. Moreover, it may also promote osteogenesis by influencing immune regulation and angiogenesis. In addition, the wettability, surface morphology, and charge of silicon nitride play crucial roles in regulating its osteogenesis-promoting properties. However, as a bioceramic material, the molding process of silicon nitride needs to be optimized, and its osteogenic mechanism must be further investigated. Herein, we summarize the impact of the molding process of silicon nitride on its osteogenic properties and clinical applications. In addition, the mechanisms of silicon nitride in promoting osteogenesis are discussed, followed by a summary of the current gaps in silicon nitride mechanism research. This review, therefore, aims to provide novel ideas for the future development and applications of silicon nitride.

Effect of Incorporation of Boron Nitride Nanoparticles on Impact Strength and Surface Roughness of Heat Cure Poly Methyl Methacrylate Resin: An In Vitro Study

Background: The objective of this research was to explore how the addition of boron nitride (BN) nanoparticles in the concentrations of 1% and 1.5% w/w affect the impact strength and surface roughness of heat-cured poly methyl methacrylate resin (PMMA). Methods: Sixty specimens were made from heat-cured acrylic resin and then divided into control, 1%, and 1.5% w/w BN groups. The impact strength and surface roughness were investigated. One-way ANOVA and Tukey’s post hoc test were used for data analysis. Results: Statistically significant difference is found among the three study groups regarding impact strength (P = 0.011) and surface roughness test (P < 0.001). The post hoc test showed significant differences for all multiple comparisons for the surface roughness test (P < 0.001). Yet, multiple comparisons for the impact strength test revealed only a significant difference between the 1.5% BN and control groups (P = 0.005). Conclusion: The addition of boron BN into PMMA improves impact strength with 1.5% concentration; while adversely increase the surface roughness.

Inorganic Adsorption on Thermal Response and Wear Properties of Nanosilicon Nitride-Developed AA6061 Alloy Nanocomposite

Inorganic-based ceramic reinforcements are promising superior thermal behaviour and are lightweight and developed with aluminium alloy matrix for automobile applications. The AA6061 alloy nanocomposite containing 0 wt%, 4 wt%, 8 wt%, and 12 wt% of silicon nitride nanoparticles(50 nm) was synthesized by stir cast. The influences of thermal adsorption on silicon nitride (nano) additions, density, thermal response, hardness, and wear characteristics of AA6061 matrix nanocomposites are studied. Based on the rule of mixture, the density of nanocomposites is evaluated. The differential thermal and thermogravimetric analysis techniques are used to find the thermal response nanocomposite. The differential scanning calorimeter is used to find the heat flow between 400°C and 700°C. The micro Vickers hardness and wear characteristics of AA6061 nanocomposite were experimentally investigated by ASTM E384 and ASTM G99-05 standards. The adsorption of inorganic nanosilicon nitride particles (12 wt%) in AA6061 alloy showed a decreased mass loss with increased temperatures 0° to 700°C. The differential thermal analysis of nanocomposite reveals the transformation of solid-to-liquid phase under high temperature (528°C).

Experimental Investigation and Comparative Analysis of Aluminium Hybrid Metal Matrix Composites Reinforced with Silicon Nitride, Eggshell and Magnesium.

In today’s scenario, composite materials play a vital role in automobile, aerospace, and defence sectors because of their higher strength, light weight and other mechanical properties. Aluminium alloy Al6082 is a medium strength alloy with good corrosion resistance properties; hence, it is used for high-stress applications, bridges, cranes, etc. The present work focuses on comparing the mechanical properties of Al6082 and Al6082 with the addition of silicon nitride, magnesium, and bio waste of eggshells. Samples of Al6082 reinforced with 2% of silicon nitride (Si3N4), 5% of eggshell, and 1% magnesium reinforcements were prepared using the crucible casting process. Mechanical properties were evaluated through hardness test, tensile test and compressive tests, which varied with the additives of reinforcement materials. The results showed that the reinforced materials could increase mechanical properties. Further, it will be analysed by the machining parameters involved through the CNC turning process. Analysis of variance from optimisation technique shows a noteworthy increment of material removal rate (MRR) and significant decrement in surface roughness (Ra) and machining time compared to standard aluminium. Additionally, the analysis of mechanical testing has been predicted with the outcomes of stresses and displacements using the ANSYS platform.

Graphene and Hexagonal Boron Nitride in Molybdenum Disulfide/Epoxy Composites for Significant X-ray Shielding Enhancement

Lead (Pb) is commonly used as a X-ray shielding material but has many limitations because of its heaviness and toxicity; thus, it is imperative to be replaced with lightweight and Pb-free shielding materials. To address this problem, molybdenum disulfide (MoS2)/epoxy (MoS2-EP) composites were considered as a possible solution. However, the low compatibility between MoS2 and an epoxy (EP) matrix and an unideal particle dispersion he lack of their distribution have hindered their designed X-ray shielding performance. To overcome this problem, this paper presented how the combination of graphene (GN) and hexagonal boron nitride (hBN) additives can significantly enhance the X-ray shielding performance of MoS2-EP composites. The results showed that when GN or hBN were introduced into the EP-MoS2 composite, X-ray transmission was reduced to 9.8% at 30 kVp and 40.3% at 80 kVp for EP-MoS2-GN and 7.1% at 30 kVp and 34.3% at 80 kVp for EP-MoS2-hBN. These results were explained due to the high aspect ratio of GN, which improved the MoS2 distribution within the EP matrix in the case of hBN, and the electrostatic forces at the interface of hBN and EP leading to better dispersion and interaction with the EP matrix compared to GN. Moreover, by employing an equal amount of the GN–hBN mixture, the synergistic effect of the EP-MoS2-GN-hBN composite film was observed with a significant X-ray shielding enhancement of 52.1% at 30 kVp and 33.2% at 80 kVp compared to that of the EP-MoS2 composite with the same thickness (2 mm) and density. These results were attributed to the molecular bonding of GN or hBN, which improved the compatibility between MoS2 and the EP matrix, providing other benefits of reduced surface roughness (0.46 μm) and improved composite hardness (65.7 HD). This work highlights a new strategy using combined GN and/or hBN for other high atomic number (Z) compounds–polymer composites and the development of advanced non-Pb X-ray shielding applications.

Trilateral Multi-Functional Polyamide 12 Nanocomposites with Binary Inclusions for Medical Grade Material Extrusion 3D Printing: The Effect of Titanium Nitride in Mechanical Reinforcement and Copper/Cuprous Oxide as Antibacterial Agents.

In this work, for the first time, polyamide 12 (PA12) nanocomposites with binary inclusions in material extrusion (MEX) 3D printing were developed. The aim was to achieve an enhanced mechanical response with the addition of titanium nitride (TiN) and antibacterial performance with the addition of copper (Cu) or cuprous oxide (Cu2O), towards the development of multi-functional nanocomposite materials, exploiting the 3D printing process benefits. The prepared nanocomposites were fully characterized for their mechanical properties. The thermal properties were also investigated. Morphological characterization was performed with atomic force microscopy (AFM) and scanning electron microscopy (SEM). The antibacterial performance was investigated with an agar-well diffusion screening process. Overall, the introduction of these nanofillers induced antibacterial performance in the PA12 matrix materials, while at the same time, the mechanical performance was significantly increased. The results of the study show high potential for expanding the areas in which 3D printing can be used.

Permeability and Load Capacity of Iron Porous Bearings with the Addition of Hexagonal Boron Nitride.

Due to their properties, porous sliding bearings are considered to be maintenance-free, which means that no lubrication is required during operation. Their design enables operation at low rotational speeds with high load. Another effect of this bearing design is the lubrication continuity in the tribological pair. In this study, the selected tribological properties (such as load capacity and permeability) of new-generation iron porous bearings with boron nitride powder were experimentally investigated. Tests were carried out under various conditions, using unique test apparatus. The addition of 3% (weight) of hexagonal boron nitride (hBN) significantly increased the load capacity of tested porous bearings in comparison to the same standard bearings containing 2.5% copper. The obtained pgr·v rating reached almost 7 MPa, which is a value almost three times higher than the requirements for this type of bearing. It is worth emphasizing that such a result was obtained despite a noticeable deterioration in the air and oil permeability of the bearing.

The effect of boron nitride, carbon nanotubes, and their synergy on the properties of LLDPE and LLDPE/wax blend

AbstractThis study deals with the effect of two types of conductive fillers (viz., boron nitride and single walled carbon nanotubes) on the properties of the linear low‐density polyethylene (LLDPE) matrix and LLDPE/paraffin wax (PW) blend. Pure LLDPE and paraffin wax/LLDPE blend (30/70) were melt‐mixed with 2 wt% content of boron nitride (BN) and single walled carbon nanotube (SWCNT), as well as their synergy at 2 wt%. Because it is well‐known that both conductive fillers were able to improve the thermal conductivity of the paraffin wax/polymer blends, the aim of this study was to focus on the effect of both conductive fillers on the dispersion of paraffin wax into LLDPE matrix, mechanical properties, crystallization behavior, and thermal stability of the LLDPE/wax blend. Scanning electron microscopy (SEM) images of the LLDPE/paraffin wax blends depicted a phase separated system, which was further supported by two separate peaks from the differential scanning calorimetry (DSC). The morphology of the system showed that the addition of boron nitride (BN) into the LLDPE/paraffin wax blend had no affinity with the paraffin wax, while the addition of single walled carbon nanotubes (SWCNT) showed better dispersion into the LLDPE/paraffin wax/BN blend composites. The incorporation of the SWCNT and its synergy with BN enhanced the thermal stability of the LLDPE.

Improving the activity and CO tolerance by the nitrides-modified Pd/C electrocatalysts for methanol and formic acid oxidation reactions

Direct methanol and formic acid fuel cells attracted extensive attention with high specific energy and low operating temperature. The efficient electrocatalyst was one of the important factors to limit their commercial applications. Here, the nitrides-modified Pd/C catalysts (Pd–NbN/C, Pd–Mo2N/C, Pd-VN/C and Pd-BN/C) were prepared using sodium citrate as a reducing agent in ethylene glycol solution. The mass activities followed the trend of Pd–NbN/C > Pd–Mo2N/C > Pd-VN/C > Pd-BN/C > Pd/C, where Pd–NbN/C exhibited the highest mass activity (4052.19 A gPd−1) for MOR, 19.2 times that of the commercial Pd/C (210.53 A gPd−1). Electrochemical measurements (LSV, Tafel, EIS, CA) indicated that the addition of nitrides increased the charge-transfer kinetics, reaction rate and CO tolerance of catalysts for MOR in alkaline media. The rate-determining step was COads oxidation process. Combined the structural analysis (HRTEM, XRD, XPS, ICP) with electrochemical results, the enhanced catalytic performance was ascribed to that higher ECSAs and the charge transfer between Pd and nitrides, leading to the negative shift of the d-band center towards the Fermi level. The linear correlations were found for the d-band center VS the mass activities and the onset potential of CO oxidation VS the d-band center, indicating that the activity and anti-CO poisoning ability could be enhanced by controlling the d-band structure of catalysts for MOR. Furthermore, the higher mass activity for FAOR in acidic media suggested that nitrides-modified Pd/C may be the promising bi-functional materials.

Effect of cubic and hexagonal boron nitride additions on the microstructure and properties of bulk MgB2 superconductors

MgB2 is a promising material for intermediate temperature applications where conventional low temperature superconductors cannot be used, especially if the range of magnetic fields over which is has acceptable current carrying performance can be expanded. However, its applicability is limited by poor properties at elevated magnetic fields. Carbon-based dopants can be used to dramatically improve the high-field performance of MgB2, but at the cost of a reduction in the superconducting transition temperature (T c) that limits the operation temperature to 20 K or below. Here we report an enhancement of superconducting performance of MgB2 with the addition of cubic and hexagonal boron nitride (BN), without any significant reduction in T c. Ex-situ bulk samples of MgB2 with two forms of BN addition were manufactured by the field assisted sintering technique after high energy ball milling of powder mixtures. We find that hexagonal BN (hBN) nanoparticles mixed homogenously with MgB2 powder react much more easily to produce Mg–N–B impurities than larger cubic BN (cBN) particles (∼10 µm) under the same processing conditions. The addition of 1 wt% hBN or 5 wt% cBN combined with 6 h of milling has been demonstrated to improve the critical current density (J c) of MgB2 over the entire magnetic field range. It is proposed that the nano-sized Mg–N–B impurities, that typically reside at MgB2 grain boundaries, increase pinning strength by introducing additional flux pinning centres. In addition, excess Mg may benefit the low-field performance by improving the connectivity. This work shows the significance of microstructural characterization on inhomogeneous superconducting materials to analyse their performance.

Performance of silica bricks with ferrosilicon nitride as the mineralizer

Novel silica bricks were made of crystalline silica with ferrosilicon nitride as the mineralizer. The phase, microstructure, pore characteristics and high-temperature properties of the novel silica bricks prepared by adding 1%, 1.5% and 2% ferrosilicon nitride were characterized. The results showed that, compared to conventional silica bricks (with mineralizers of calcium hydroxide and iron scale), the novel silica bricks with the addition of ferrosilicon nitride contained less calcium oxide, less residual quartz and more tridymite. The ferrosilicon nitride was gradually oxidized to form SiO2 and Fe2SiO4 during the firing stage of the silica bricks. After adding ferrosilicon nitride, the degree of particle breakage was reduced, and the pore size of interconnected pores increased. With the increase in ferrosilicon nitride content, the silica brick structure gradually densified. The silica brick sample with 2% ferrosilicon nitride achieved better creep resistance at high temperature (1550 °C, 0.2 MPa), but the refractoriness under load of the bricks was slightly reduced by using ferrosilicon nitride as a mineralizer. An optimization model of ferrosilicon nitride as a mineralizer was established.

Form-stable phase change composites with high thermal conductivity and electrical insulation

The commercialization of phase change materials (PCMs) based on paraffin is obstructed by the drawbacks of leakage and low thermal conductivity. Herein, we developed form-stable phase change composites via trapping paraffin into triblock copolymer. The hybrid filler, namely boron nitride and Ag-coated hollow glass microspheres (Ag@HGMs), was introduced to enhance the thermal conductivity of the composites. The latent heat values of composites could be easily tailored in a range of 157.6–192.4 J g−1 by changing the loading of filler. Interestingly, the addition of boron nitride and Ag@HGMs hybrid filler has little impact on electrical insulation property, and displays a synergistic effect on the heat transfer improvement within the composites. The sample BN/Ag@HGMs-4 exhibits excellent latent heat, electrical insulation performance, thermal recycling properties and stability, and the thermal conductivity reaches up to 1.54 W m−1 K−1, which has great potential application in thermal management and heat energy collection system.

Paste Extrusion of Polytetrafluoroethylene: Temperature, Blending and Processing Aid Effects

Abstract Blends of different PTFE fine powder resins have been prepared and extruded in an attempt of improving the PTFE paste extrusion process and/or the extrudates. The extrusion pressure and the mechanical properties of the extrudates were found to fall between those exhibited by the pure components. While this is an expectable behavior, it offers opportunities for controlling the degree of fibrillation needed in the final products by mixing highly fibrillated with low fibrillated PTFE resins. Boron nitride and organically modified montmorillonite clays (solid lubricants) are also tested as additives to the lubricants used in the PTFE paste extrusion in order to identify enhanced processing aids. It was found that the addition of boron nitride and clays increase the extrusion pressure but at the same time improve the mechanical properties of the final extrudates in most cases. This again offers possibilities for controlling the final mechanical properties by controlling the degree of fibrillation, i. e., by adding a small amount of solid lubricants to adjust pressure, fibrillation, and thus the final mechanical properties. Finally, it is shown that fibrillation depends on temperature. Moreover, the mechanical properties of extrudates increase as the temperature goes through its two transition temperatures of 19 °C and 30 °C that render PTFE particles more deformable and prone to fibrillation.

Fabrication and mechanical properties of nacre-like alumina with addition of silicon nitride

How to deal with the brittleness of ceramic materials is always one of the hot topics in the field of materials science. Design of layered ceramics with textured structure is one of the effective methods to improve their fracture toughness. The introduction of additives as interlayer phases can balance fracture toughness and flexural strength. However, the research about addition of interlayer phases and their mechanisms in the layered ceramics is still limited. In this work, nacre-like alumina ceramics were successfully fabricated by freeze casting followed by hot pressing. Silicon nitride was incorporated as the interlayer phase, and the effect on the mechanical properties of the nacre-like alumina was investigated. The addition of silicon nitride was beneficial to improvement of interlayer bonding between the alumina layers due to formation of sialon phase, leading to increase of flexural strength but decease of fracture toughness. When the content of silicon nitride was 3.3 wt%, flexural strength and fracture toughness of the sample was 468 MPa and 6.2 MPa m1/2, respectively. Compared with the sample without silicon nitride, the flexural strength was enhanced significantly. Additionally, both flexural strength and fracture toughness were improved as compared the sample without any additives. This work can provide available references for design and fabrication of high-strength and high-toughness ceramics by properly tuning the layer structure and interlayer phase composition.