Nitride Particles Research Articles

Double-Glow Plasma Surface Alloying of BTi-62421S Alloys: Regulation of Microstructure Properties

In order to meet the design requirements of lightweight artillery and adopt the method of double-glow plasma nitriding to solve the problem of low hardness and poor abrasion resistance of Ti alloy, the BTi-62421S high-performance titanium (Ti) alloy was selected as the experimental material to replace gun steel. To study the effect of different nitrogen (N) concentrations on the heat resistance scouring performance of BTi-62421S high-performance Ti alloy and investigate the influence of alloying elements on the heat resistance scouring performance under the same parameters compared with the commonly used TC4 Ti alloy, argon was used as the protective gas by continuously increasing the N concentration (Ar/N2 = 1:1, 1:2, 1:3). It was found that the honeycomb structure on the surface of the sample and the thickness of the coating increased continuously, reaching a thickness of 15 μm, while the depth of the nitride particles extending from the coating to the substrate also increased, reaching a maximum depth of 26 μm. The orientation of TiN changed from 37° to 62°. The hardness of the coating showed a negative correlation with the coefficient of frictional abrasion, which significantly improved the heat-resistant scouring performance of BTi-62421S high-performance Ti alloy.

Effect of Microstructure on Mechanical Behaviors of Al6061 Metal Matrix Composite Reinforced with Silicon Nitride (Si3N4) and Silicon Carbide (SiC) Micro Particles

Effect of Microstructure on Mechanical Behaviors of Al6061 Metal Matrix Composite Reinforced with Silicon Nitride (Si3N4) and Silicon Carbide (SiC) Micro Particles

Simple Laser-Induced Hexagonal Boron Nitride Nanospheres for Enhanced Tribological Performance

Hexagonal boron nitride, as a layered material with a graphite-like structure, exhibits good mechanical, lubricating and oxidation resistance properties, and is thus expected to become one of the top choices for green lubricating oil additives. However, its poor dispersibility in oil and difficulties in preparing spherical particles when constructing hexagonal boron nitride limit its application. In this paper, spherical hexagonal boron nitride nanoparticles are constructed via a simple laser irradiation method. Under laser irradiation, raw irregular hexagonal boron nitride particles were reshaped into nanospheres via a laser-induced photothermal process and rapid cooling in a liquid-phase environment. Under the optimal concentration, the coefficient of friction and wear spot diameter decreased by 26.1% and 23.2%, and the surface roughness and wear volume decreased by 29.2% and 23.8%, respectively. The enhanced tribological performance is mainly due to the ball bearing, depositional absorption and repair effect of the spherical particles. This simple laser irradiation method provides a new method by which to prepare spherical hexagonal boron nitride lubricating oil additives.

Compatibilized bio-based polybutylene-succinate blended composites filled with surface modified Si3N4 for improved rigidity and thermal performance

In this study, polybutylene succinate was melt blended with polypropylene (PP) to fabricate partially bio-based and miscible composites filled with various loading silicon nitride (Si3N4) particles. Oleic acid and PP-grafted maleic anhydride were used as a functionalizing agent for Si3N4 and as a compatibilizer for polymer blends, respectively. The surface functionalization of the Si3N4 particles enhanced the interfacial adhesion between the filler and the blended polymers, affecting the thermal and mechanical properties of the composites. The thermal conductivity of the composite filled with only 18.6 vol% surface-treated Si3N4 increased by 342% compared to that of the blended polymer. In addition, the surface treatment of Si3N4 significantly improved the Young’s modulus, tensile strength, and thermal stability of the corresponding composites. However, the temperature-dependent storage modulus was unaffected by the surface treatment of Si3N4 and increased as the loading content of the Si3N4 particles increased.

Preparation and mechanical properties of cubic boron nitride reinforced lead glaze layers of a gradient structure

Lead glaze possess excellent radiation ray shielding ability, and it is an efficient way to stop radiation spillover by using lead glazed indoor titles in a building. The merit of low firing temperature of lead glaze is, however, associated with its poor wear resistance. Here super-hard cubic boron nitride (cBN) particles, of a neutron shielding property, are introduced into the soft glass matrix to improve its mechanical properties. Results show that, at meticulously tailored conditions, the lead glaze surface is successfully enriched with cBN particles due to the lower density of cBN relative to the glaze. With 5 wt% cBN particles embedded in the glass matrix, the hardness increases by 51.2% and more importantly, the glaze yields significantly improved wear resistance. The finite element analysis reveals that the cBN particles enhance the toughness of the glaze, a key factor to wear resistance, by reducing the crack tip stress concentration.

Experimental interrogations on morphologies and mechanical delineation of silicon nitride fortified Mg-Al-Zn alloy composites

The smart material used in aerospace and automotive industries has to withstand high load with minimum structural weight. Nowadays, in search of new lightweight materials for the industrial application, magnesium is rapidly replacing aluminium-based alloys. In this research, magnesium (AZ31) matrix composite reinforced with ceramic silicon nitride (Si3N4) particle is fabricated by vacuum stir casting. The proportion of strengthening particle was assorted to a maximum of 10 % in steps of 2 % variation in weight. Microstructural analysis carried out through optical microscope exposes the occurrence and near-uniform spread of Si3N4. The mechanical properties for various weight proportions are studied; microhardness and strength are enhanced at the expense of ductility reduction with rising Si3N4 content in the magnesium metal matrix. The porous nature and composites density rises with higher weight % of Si3N4 particles in the magnesium matrix. The corrosion characteristic was studied by salt spray and cyclic potentiodynamic polarization test, which demonstrates that increasing the reinforcement limits the corrosion by forming phases of Mg2Si intermetallics with galvanic corrosion mechanism. The inferences present that the fabricated composite are ideal for many industrial plans where less structural weight material is required.

Tribological behavior of silicon nitride reinforced polycarbonate nanocomposites

AbstractPolycarbonate (PC) matrix nanocomposites containing 0–20 vol.% nanosize silicon nitride (Si3N4) particles have been prepared by solution mixing method. A combination of X‐ray diffractometry and transmission electron microscopy has been used to characterize phase purity and morphology of Si3N4 nanoparticles. The prepared nanocomposites have been investigated for density, microstructure, microhardness, and tribological behavior. Density and microhardness have been found to increase with increasing volume percent of nanoparticles. The experimental values of density of composites fall close to those of theoretical values predicted from the rule of mixtures thereby suggesting that prepared nanocomposites were nearly pore free. The maximum improvement of microhardness of 189% has been found for nanocomposite with 20 vol.% Si3N4 particles as compared to neat PC. Experimental data of microhardness correlated well with the modified rule of mixtures (with strengthening efficiency factor β = 0.09). Scanning electron micrographs indicated well dispersion of nanoparticles in PC matrix. Tribological (friction and wear) behavior have been evaluated using pin‐on‐disc method. It has been found that 20 vol.% nanocomposite exhibited lowest friction coefficient and highest (~ 68%) wear resistance as compared to neat PC. Based on the results, the prepared nanocomposites are suggested to be used in cams, gears, boat and pump impellers.

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.

Spectroscopic Investigation on Liquid-exfoliated Hexagonal Boron Nitride Nano Particles

Although hexagonal boron nitride and graphene in two-dimensional materials have similar structures, there are great differences in their electronic structures. hBN has a huge energy gap (~ 6 eV) and can be regarded as a semiconductor or insulator, while graphene can be used as a conductor because of its zero-energy gap. Because of their high degree of lattice matching, they often overlap each other and are used as conductive layer and insulating layer in the material process of electronic components. In this study, we tried to prepare nano-sized hexagonal boron nitride particles by a relatively simple method "liquid-assisted ball milling and ultrasonic exfoliating" to solve the high-cost problem of the industrialization of hBN. We prepared hBN nanoparticles using zirconium milling balls, water-proof sonication and ultrasonic crusher, then studied the essential changes to their electronic structures and sizes through Atomic Force Microscope and various spectroscopic methods such as PL, PLE, absorption and Raman spectrum. It helps us to find ways to control the electronic structure and energy gap of hBN, which would help the development of advanced semiconductor manufacturing applications and advanced quantum light sources.

Synthesis and sintering properties of silica-coated titanium nitride particles

Herein, we synthesized silica-coated titanium nitride (TiN/SiO2) particles via a sol–gel method and evaluated the hardness of the sintered bodies fabricated using the as-fabricated TiN/SiO2 particles. Commercially available micron-sized TiN particles were dispersed in a water–ethanol solution at 35 °C and then coated with SiO2 using a sol–gel method, tetraethyl orthosilicate (TEOS), and base catalysts. TiN/SiO2 particles with small specific surface areas owing to the presence of few micropores in their structure were obtained using NaOH as the base catalyst. The Vickers hardnesses of TiN, a mixture of TiN and SiO2 (TiN–SiO2), TiN/SiO2 fabricated using an ammonia solution as the base catalyst (TiN/SiO2A), and TiN/SiO2 fabricated using NaOH as the base catalyst (TiN/SiO2S) increased as follows: TiN (6.35 × 102 Hv) < TiN–SiO2 (1.01 × 103 Hv) < TiN/SiO2A (1.11 × 103 Hv) < TiN/SiO2S (1.15 × 103 Hv). In summary, the SiO2 shell served as a sintering aid, and the NaOH catalyst densified the sintered body and improved its hardness.

Peristaltic pumping of Boron Nitride-Ethylene Glycol nanofluid through a complex wavy micro-channel under the effect of induced magnetic field and double diffusive

The main objective of this work is to present a comprehensive study that scrutinize the influence of DD convection and induced magnetic field on peristaltic pumping of Boron Nitride—Ethylene Glycol nanofluid flow through a vertical complex irregular microchannel. Experimental study showed that the nanofluid created by suspending Boron Nitride particles in a combination of Ethylene Glycol exhibited non-Newtonian characteristics. Further, the Carreau's fluid model provides accurate predictions about the rheological properties of BN-EG nanofluid. In order to imitate complicated peristaltic wave propagation conditions, sophisticated waveforms are forced at the walls. The essential properties of Brownian motion and thermophoresis phenomena are also included in simulating of heat equation as well as viscous dissipation. Mathematical simulation is performed by utilizing the lubrication approach. The resulting nonlinear coupled differential equation system is solved numerically using the built-in command (ND Solve function) in the Mathematica program. Numerical and pictorial evidence is used to illustrate the importance of various physiological features of flow quantities. The major findings demonstrated that the thermal resistance is observed to rise as the Soret and Dufour numbers increase, while the dissolvent concentration and nanoparticles volume fraction have the opposite effect.

Spontaneous Lithiophilic and Lithium-Ion Conductive Functional Layer Formation Enabled by Solution-Casted Zinc Nitride for Highly Stable Lithium Metal Electrode in Carbonate Electrolyte

To improve the reversibility of the Li metal negative electrodes, the simultaneous formation of individually functionalized zinc metal and lithium nitride during the spontaneous conversion reaction of zinc nitride particle is conducted by casting of zinc nitride particles on the lithium electrode. Lithiophilic zinc metal reduces the nucleation polarization of the lithium electrode, whereas the highly ionic conductive and electronically insulating Li3N decreases the concentration polarization from the facile ion conduction and suppression of further electrolyte decomposition during Li plating and stripping. Both these sophisticated characteristics resulted in an improvement in the deposition morphology of lithium electrode, thereby enhancing the reversibility of lithium electrode. Consequently, the cycleability improvement of Li/LiNi0.8Co0.1Mn0.1O2 is achieved through the application of zinc nitride surface-treated lithium electrode.

Application of h‐BN particles using Ca‐assisted carbothermal reduction nitridation to high‐thermal‐conductive resin/h‐BN composites

AbstractHexagonal boron nitride (h‐BN) particles exhibit high thermal conductivity and are promising fillers for resin filling. However, h‐BN particles are plate‐like particles with thermal anisotropy in the planar and thickness directions. Therefore, their applications are limited due to low thermal conductivity in the direction of the thickness of a resin sheet filled with h‐BN particles. In this study, we control the size and thickness of h‐BN particles using carbothermal reduction nitridation (CRN), which involves the carbothermic reduction of boric oxide in an N2 gas atmosphere and develop them into resin sheets. In CRN using a CaO promoter, a novel method is developed to control the shape, size, and thickness of h‐BN particles. Using h‐BN particles grown in the thickness direction, we have successfully provided resin sheets with high thermal conductivity.

Influence of Microstructure on Tribological Behaviors of Al6061 Metal Matrix Composite Reinforced with Silicon Nitride (Si3N4) and Silicon Carbide (SiC) Micro Particles

Dual step stir casting method was utilized to develop Al6061 composite reinforced with SiC (micron) and Si3N4 (submicron) particles in varying proportion and weight percentage. A homogeneous and uniform distribution of hybrid reinforcement without significant porosity was observed in the microstructure of the composites. X-ray diffraction (XRD) results manifest that Si3N4 and SiC particles are thermodynamically stable during the processing and no unwanted phases were detected. Elemental mapping was also performed for phase identification. With reference to the base alloy significant improvement was noticed in physical and tribological properties of hybrid composites. Maximum rise in hardness was 54.64%. Abrasive wear test results from pin on disc reveals that wear resistance get enhanced for all composition and load is found to be most dominating factor affecting wear behavior.

Internal nitridation of Alloy 690 during creep deformation at 1100 °C

This study reports internal nitridation of alloy 690 during creep deformation at 1100 °C. A series of creep tests were conducted at stresses ranging from 7 to 18 MPa, which corresponded to 0.3–0.7 of the alloy's yield stress at 1100 °C. The alloy exhibited normal creep response at 15 and 18 MPa whereas at 7 and 12 MPa, oscillatory creep were observed. The alloy exhibited creep exponent of about 8 and failed by cavitation at all the stresses studied. A higher value of the creep exponent was attributed to the cavitation dominant failure mechanism. Needle shaped nitride precipitates were observed near cracks, which were identified to be of trigonal Cr2N phase. The Cr2N particles formed near cracks which extended to the free surface. These precipitates formed as a result of internal nitridation of the freshly exposed crack surface. The phase stability analysis of the nitride phases in Ni–Cr–10Fe alloys in equilibrium with nitrogen using the Thermo-Calc software supported the formation of the Cr2N phase at a N2 fugacity of 0.79 bar. Atmospheric nitrogen permeated through the creep cracks linked to the outer sample surface. However, the precipitation of nitride particles appeared to have little effect on creep life of the alloy as the precipitation occurred towards the end of tertiary creep regime. The creep fracture at the lowest stress was dominant by transgranular cleavage of stable crack propagation, but tended to be erratic crack propagation at higher stresses.

Columnar and nanocrystalline combined microstructure of the nitrided layer by active screen plasma nitriding on surface-nanocrystalline titanium alloy

The microstructure and formation mechanism of the nitrided layer by active screen plasma nitriding on surface-nanocrystalline TA17 titanium alloy were studied by TEM. The nitrided layer of both the original and shot-peened TA17 samples was composed of two sublayers: the outer TiN layer formed by deposition of titanium nitride particles and the inner Ti2N layer formed by nitrogen diffusion into the titanium substrate. The Ti2N layer was found to be an Al-depleted zone, which was a proof for its formation mode of nitrogen diffusion. Compared with the TiN layer of the original sample filled with columnar grains, the TiN layer of the shot-peened sample was composed of mainly equiaxed nanograins and a small amount of columnar grains. The large number of high-energy grain boundaries on the shot-peened surface provided numerous nucleation sites, resulting in the formation of equiaxed nanocrystalline TiN. During long term nitriding, most of the nano-scale TiN grains were maintained due to their high thermal stability, while the nano grains of the shot-peened substrate surface grew into microscale due to their low thermal stability. With the thickening of the nitrided layer, some equiaxed TiN nanograins grew into columns perpendicular to the substrate surface due to competitive growth.

Solution printable multifunctional polymer-based composites for smart electromagnetic interference shielding with tunable frequency and on–off selectivities

The advances in modern intelligent electronic systems have a pressing need for smart electromagnetic interference (EMI) shielding capabilities in a frequency-selective manner to choose which electromagnetic waves in a certain range to be blocked. Herein, we present multilayered EMI shielding composites that can provide selective on–off characteristics for specific frequency ranges across a broad spectrum. The composites are composed of outermost dielectric layers and conductive interlayers fabricated via solution printing, wherein hexagonal boron nitride (BN) and silver-coated BN particles are embedded, respectively. The EMI shielding frequency range and on–off selectivity are controllable by varying the configuration of the composite structure in terms of the BN content and the number of composite layers, providing different interstitial spaces between the fillers and interfacial dielectric properties. Furthermore, the optimal combination of these layers permits excellent combinatorial properties of EMI shielding effectiveness (32–62 dB), thermal conductivity (7.61 W/m·K), and electrical insulation (4.03 kV/mm) in the through-plane direction. The developed composites and their synthetic pathways have enormous potential for tailored material design and flexible system integration in next-generation EMI shielding technologies.

EFFECT OF PREPROCESSING OF NANOMODIFIERS ON THEIR EFFICIENCY IN LASER SURFACE TREATMENT OF TITANIUM

This study examines the influence of the mechanical processing of a titanium nitride based powder mixture on the change in the morphology of the CO2 laser treated surface, the weld pool morphology, and its cross-sectional structure. Ultrafine titanium nitride particles used as nanomodifier, which have low wettability in the metal melt and are not entrained by its convective flows, accumulate in the subsurface and reduce the structural modification efficiency in the bulk of the treated material. Processing of the modifying Ti + TiN mixture for 9 min leads to the formation of composite particles (5-7 pm) in which ultrafine titanium nitride particles are uniformly distributed over the surface and volume. The composite particles melt during laser irradiation and form ultrafine titanium nitride particles of nanomodifier cladded with a thin titanium layer, which have a smaller contact angle. As a result, the particles are more evenly distributed over the weld pool and the number of crystallization centers increases, leading to the formation of a fine homogeneous structure of the material. The microhardness increases by 32%, and its standard deviation decreases by a factor of 1.5 3.0.

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).

Implication of Pre-Aged Three Step T6 Treatment on the Properties of Granite and Silicon Nitride Particulates Reinforced Al7075 Matrix Composite

Implication of Pre-Aged Three Step T6 Treatment on the Properties of Granite and Silicon Nitride Particulates Reinforced Al7075 Matrix Composite