Addition Of Silicon Nitride Research Articles

Effect of Si3N4 Additive on Microstructure and Mechanical Properties of Ti(C,N)-Based Cermet Cutting Tools.

Development of high-performance cutting tool materials is one of the critical parameters enhancing the surface finishing of high-speed machined products. Ti(C,N)-based cermets reinforced with and without different contents of silicon nitride were designed and evaluated to satisfy the requirements. In fact, the effect of silicon nitride addition to Ti(C,N)-based cermet remains unclear. The purpose of this study is to investigate the influence of Si3N4 additive on microstructure, mechanical properties, and thermal stability of Ti(C,N)-based cermet cutting tools. In the present work, α-Si3N4 "grade SN-E10" was utilized with various fractions up to 6 wt.% in the designed cermets. A two-step reactive sintering process under vacuum was carried out for the green compact of Ti(C,N)-based cermet samples. The samples with 4 wt.% Si3N4 have an apparent solid density of about 6.75 g/cm3 (relative density of about 98 %); however, the cermet samples with 2 wt.% Si3N4 exhibit a superior fracture toughness of 10.82 MPa.m1/2 and a traverse rupture strength of 1425.8 MPa. With an increase in the contents of Si3N4, the Vickers hardness and fracture toughness of Ti(C,N)-based cermets have an inverse behavior trend. The influence of Si3N4 addition on thermal stability is clarified to better understand the relationship between thermal stability and mechanical properties of Ti(C,N)-based cermets.

Fabrication and characterization of sodium alginate-silicon nitride-PVA composite biomaterials with damping properties

Silicon nitride is utilized clinically as a bioceramic for spinal fusion cages, owing to its high strength, osteoconductivity, and antibacterial effects. Nevertheless, silicon nitride exhibits suboptimal damping properties, a critical factor in mitigating traumatic bone injuries and fractures. In fact, there is a scarcity of spinal implants that simultaneously demonstrate proficient damping performance and support osteogenesis. In our study, we fabricated a novel sodium alginate-silicon nitride/poly(vinyl alcohol) (SA-SiN/PVA) composite scaffold, enabling enhanced energy absorption and rapid elastic recovery under quasi-static and impact loading scenarios. Furthermore, the study demonstrated that the incorporation of physical and chemical cross-linking significantly improved stiffness and recoverable energy dissipation. Concerning the interaction between cells and materials, our findings suggest that the addition of silicon nitride stimulated osteogenic differentiation while inhibiting Staphylococcus aureus growth. Collectively, the amalgamation of ceramics and tough hydrogels facilitates the development of advanced composites for spinal implants, manifesting superior damping, osteogenic potential, and antibacterial properties. This approach holds broader implications for applications in bone tissue engineering.

Improved mechanical properties and dimensional accuracy of silica-based ceramic cores by Si3N4 addition

Silica-based ceramic cores are extensively used to form the complex hollow structure inside turbine blade. However, the excellent mechanical properties and high dimensional accuracy of ceramic cores are very crucial to obtain the hollow turbine blade with high precision, which is still a challenging work. In this study, silica-based ceramic cores with silicon nitride addition were prepared for improving the mechanical properties and dimensional accuracy. Results showed that the linear shrinkage of silica-based ceramic cores significantly decreased from 1.21 % to 0.087 % and the porosity gradually increased from 17.9 % to 22.1 % with the increase of Si3N4 content. The weight gain of cristobalite in the core samples after sintering first increased and then decreased, where the sample with 5 wt% Si3N4 had the maximum cristobalite content of 4.4 wt%. The appropriate Si3N4 content (5 wt%) in the silica-based ceramic cores could enhance the flexural strength at room temperature to 16.84 MPa by promoting densification process. However, the excess Si3N4 content (more than 10 wt%) could hinder the densification process and enlarge their porosity, decreasing the flexural strength at room temperature. Meanwhile, the high temperature strength at 1500 °C was decreased owing to the increasing porosity caused by the re-oxidation of Si3N4 particles. Therefore, it was concluded that the silica-based ceramic cores with 5 wt% Si3N4 showed higher mechanical properties and lower linear shrinkage, which offered a way to maintain the excellent mechanical properties and high dimensional accuracy of ceramic cores.

The addition of silicon nitride to PMMA bone cements reduces bacterial attachment while supporting preosteoblast viability

Injectable poly (methyl methacrylate) (PMMA) bone cements are widely used in orthopaedics to stabilize fractures and for implant fixation. However, bacterial attachment to bone cements leads to significant complications that can create a need for implant revision. Common attempts at reducing bacterial attachment are through the addition of antibiotics or antibacterial nanometals to the bone cements. However, clinical data is inconclusive on the effectiveness of antibiotic-loaded bone cements and a negative osteoblastic response has been reported for certain additive concentrations. There is therefore a need for an additive that can positively affect osteoblastic behaviour while inhibiting bacterial attachment. Silicon nitride (Si3N4) could be such an additive, with initial studies showing promise in achieving antipathogenic properties. The aim of this study was hence to investigate the possibility of creating a bone cement that can support osteoblast growth while reducing bacterial attachment by introducing silicon nitride powders into an injectable PMMA cement. To this end, commercially available bone cements were doped with 5%, 10% and 20% weight/weight (w/w) of Si3N4. Their mechanical properties were examined through compression testing and their radiopacity was evaluated through fluoroscopy imaging. The samples that fulfilled compressive strength requirements had their biological properties tested using Staphylococcus epidermidis bacteria for antibacterial properties and MC3T3-E1 preosteoblasts for the examination of cytotoxicity. Bone cements that were doped with up to 20% w/w Si3N4 were radiopaque (only 13% reduction in optical density compared to radiopaque controls) and retained their compressive strength (85.35 ± 2.1 MPa compared to 83.4 ± 1.9 MPa for the commercial cements), while significantly reducing bacterial attachment by more than 90% compared to commercial cements and achieving a similar level of preosteoblast metabolic activity. This study supports further evaluation of Si3N4 as an additive to injectable bone cements as a way to create mechanically stable, radiopaque, bacteriostatic bone cements that could improve osteointegration.

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.

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.

Silicon nitride modified enamel coatings enable high thermal shock and corrosion resistances for steel protection

Vitreous enamel is a durable inorganic material that has been extensively used in our daily life for decoration and protection of the metallic substrates. It guarantees optimal corrosion protection to the covered substrates, but, on the other side, the brittle nature of its matrix highly limits its application. Here new enamel coatings were synthesized by adding silicon nitride with the contents of 0, 1.5, 2.5, 3.5, 5, and 7.5 wt%. Scanning electron microscope (SEM), X-ray diffraction (XRD), micro indentation, impact, thermal shock, and potentiodynamic polarization tests were conducted to evaluate the microstructure and engineering properties of the studied enamel coatings. Results showed that the addition of silicon nitride leads to a high internal porosity of the enamel coating, which consequently improves the resistances against cracking under indentation and impact loads. Especially, the silicon nitride modified enamel coatings were found to survive more than 100 cycles of thermal shocks. Despite the porosity rising, the addition of silicon nitride enhanced the corrosion resistance of enamel coatings at early immersion age, and all enamel coatings kept around 10 times lower corrosion rate than that of the uncoated steel at later immersion age. The findings of this work may provide a solution to steel protection against harsh high-temperature exposure and corrosive environments.

Manufacturing of Al-Li-Si3N4 metal matrix composite for weight reduction

Abstract The present analysis was aimed to identify the properties of Al 2024 composite reinforced with lithium and silicon nitride to make it applicable for automobiles, sports and aerospace applications. An effort was made to reduce the density and increase the hardness and impact properties of aluminum 2024 matrix with individual and multiple reinforcements using the double casting method under non-reactive environment. Aluminum alloy matrices with lithium, silicon nitride and the combination of both were fabricated. The microstructure, density, hardness and impact strength properties of the fabricated aluminum metal matrices were analyzed. The microstructure study reveals the uniform dispersion of reinforcements in the matrix alloy. From the results, it is understood that the hardness and impact toughness increase with the addition of silicon nitride. Density is reduced with the addition of lithium as reinforcement. When both reinforcements were added in the matrix, it was observed that there was an increase in hardness and impact strength of the composites with decrease in density of the metal matrix composite making it suitable for light weight and high strength applications.

Mechanical and tribological characteristics of Si3N4 reinforced aluminium matrix composites: A short review

Abstract The aluminium matrix composite (AMCs) plays a significant role in enhancing the properties of the material that are applicable in automotive industries, marine, aerospace, etc. Whereas these AMCs were further researched with the integration of reinforcing particulates in different percentages with the aim of enhancing the characteristics of parent aluminium matrix. Introducing ceramic particulate reinforcements into aluminium matrix produces a composite with better physical, mechanical and tribological properties in comparison to the traditional engineering materials. The main purpose of producing aluminium matrix composites (AMCs) is to develop lightweight materials having high stiffness and high specific strength. There are different effects observed with subsequent addition of reinforcements on the aluminium matrix composite. This paper attempts to present a review concerning the mechanical and tribological characteristics of aluminium matrix composite synthesized via stir casting route. This literature review provides an insight to the effects encountered after incorporating hard Si3N4 particulates in aluminium matrix along with its performance. It also attempts to highlight the impact of addition of silicon nitride (Si3N4) in AMCs, as this ceramic possesses superior wear and mechanical characteristics. Moreover, the effect of different reinforcements upon minimizing the resultant friction as well as wear for attaining superior lubrication will also be discussed in detail.

Improving the flexural-strength-to-density ratio in alumina ceramics with the addition of silicon nitride

Alumina (Al2O3) and silicon nitride (Si3N4) ceramic compositions were studied as prospective materials for ballistic ceramics. Alumina ceramics with contents of 0, 5, 10 and 15 wt% of silicon nitride studied in order to improve their flexural strength/density ratio. Samples were molded by uniaxial pressing and sintered at 1600 °C. Retraction, density, water absorption and mass loss of the samples were determined, as well as their hardness, mechanical strength and fracture toughness. Ceramics produced in the presence of Si3N4 exhibited an interior with a very different aspect from their external surface. X-ray diffractometry showed that most compositions presented two phases, alumina and mullite, while the interior of the 15 wt% composition presented four phases: alumina, mullite, silicon nitride and X–SiAlON. Samples with 10 wt% of silicon nitride displayed the highest fracture toughness and the best flexural strength. Furthermore, this sample achieved a density approximately 21% lower than that of the control samples, providing the best flexural strength/density ratio, roughly 53% higher than that of alumina without Si3N4. Thus, these ceramics show great potential for utilization in advanced ceramic protections, where weight is a major limiting factor.

Silicon Nitride Whisker-Reinforced Aluminum Matrix Composites: Twinning and Precipitation Behavior

Aluminum composites reinforced with ceramic whiskers exhibited a unique combination of high specific strength and superior specific modulus. A 20 vol.% Si3N4w/Al-11.5Si-1.0Mg-0.5Cu-0.5Ni (wt.%) composite was fabricated via squeeze casting in the present study. It was observed that the addition of silicon nitride (Si3N4) whiskers in the Al-Si cast alloy promoted extensive twinning in the eutectic silicon particles due to a coupled role of thermal stresses between the matrix and silicon and residual stresses present in the composite. Double aging peaks were present in the age-hardening curves. The precipitation mechanism involved the formation of Mg2Si and Al2CuMg phases. The presence of Si3N4 whiskers in the composite retarded the nucleation process of Mg2Si precipitate while enhancing its growth rate.

Highly porous silica foams prepared via direct foaming with mixed surfactants and their sound absorption characteristics

The highly porous silica ceramics were fabricated by direct foaming with mixed surfactants and the influence of silicon nitride addition and solid content on the microstructures and properties were investigated. The results showed that silicon nitride can impede the formation of cristobalite and facilitates the sintering of silica ceramics. When the addition of silicon nitride powders reached 15 wt%, the highest compressive strength of silica ceramic foams could be obtained. The porosity of silica ceramic foams was tailored in the range of 84.61%–91.35% by adjusting the solid content, and the compressive strength of the obtained ceramic foams ranged from 5.89 MPa to 0.94 MPa. Sound absorption characteristics of silica ceramics foams were investigated. With the porosity of ceramic foams increased from 84.61% to 91.35%, the sound absorption coefficients in the entire sound wave frequency were enhanced due to the reduction of flow resistances, besides, the sound absorption peak varied from 4200 Hz to 2300 Hz, and became more intense and sharper.

Influence of Flyash & Silicon Nitride on Mechanical & Tribological Properties of Aa 7075 Hybrid Composite

The main objective of this research work is to study the effect of Silicon Nitride (Si3N4) and Flyash on the mechanical and tribological properties of AA 7075 hybrid composite. The Stir casting technique has been used for the fabrication of composite material. sAA 7075 were reinforced with 2 wt. % of Silicon Nitride and 2.5, 5, 7.5 wt. % of Flyash. Pin-on-disc equipment is used to evaluate the wear rate of the base alloy and hybrid composite. Dry sliding wear test were performed with the contact load which is varied by 10, 20 & 30 N. Sliding velocity is varied by 1, 1.5 and 2 m/s. Sliding distance is kept constant at 1000 m. The Scanning Electron Microscope (SEM), Energy Dispersive X Ray Spectroscopy (EDAX) and X-ray diffraction (XRD) were used for the characterization of the composites. The maximum hardness of 173 HV is achieved for 5 wt% Flyash and 2 wt% of Silicon Nitride addition. The percentage increase in hardness is 155 % above the base metal. AA 7075 with the 5 wt % reinforcement of Flyash shows the minimum wear rate. With respect to the base the wear rate is reduced by 59 %.

Improving the Dimensional Stability and Mechanical Properties of AISI 316L + B Sinters by Si3N4 Addition

The following paper describes a new and effective method to obtain high-density sinters with simultaneously decreased distortions, produced by one press and sinter operation. This effect was achieved through the induced disappearance of the eutectic liquid phase. The study was carried out on AISI 316L stainless steel powder that was mixed with elemental boron and silicon nitride. Boron was used as a sintering process activator. The scientific novelty of this publication consists of the use of a silicon nitride as a solid-state nitrogen carrier that was intended to change the borides’ morphology by binding boron. Based on the thermodynamic calculations, 20 blends of various compositions were tested for physical properties, porosity, microstructure, and mechanical properties. Moreover, phase compositions for selected samples were analyzed. It was shown that the addition of silicon nitride as a nitrogen carrier decreases the boron-based eutectic phase volume and both increases the mechanical properties and decreases after-sintering distortions. An explanation of the observed phenomena was also proposed.

Stable phosphate-based glass for low-temperature sealing applications: Effect of Si3N4 dopant

Phosphate glass is advantageous as a low temperature sealing material, especially in solar cells, micro-motor systems, vacuum engineering and the like, but the poor chemical stability restricts its wide application, especially in humid environments. To overcome this shortcoming, a certain proportion of silicon nitride is added to tailor the structural, chemical and thermal properties of phosphate glass. The results show that the addition of silicon nitride improves the water resistance and remarkably reduces the mass loss in humid environments from 60 to 3 wt% after 120 h. With the addition of silicon nitride, the softening temperature of glass is in the range of 330–372 °C. In particular, the coefficient of thermal expansion of phosphate glass can be tailored ranging from 14.9 × 10−6 K−1 to 17.4 × 10−6 K−1 by adjusting the content of silicon nitride, making it thermally compatible with various substrates. These findings provide useful information on the development of reliable low-temperature sealing glass.

Enhancement in thermal property of phase change microcapsules with modified silicon nitride for solar energy

Thermal behavior is one of the most important properties for phase change microcapsules in solar energy storage. Here, a new type of phase change microcapsules was synthesized based on n-octadecane core and polymethylmethacrylate shell supplemented with modified silicon nitride powders, aiming to achieve improvement of thermal property in the phase change materials. SEM micrographs showed that the as-prepared microcapsules have a regular spherical shape with a well-defined core-shell structure. FTIR curves and EDS spectrogram demonstrated that silicon nitride can be well cross-linked with microcapsules after surface modification. In addition, TGA, forward looking infra-red system and DSC (before and after 500 heating and cooling cycles) analyses were performed to investigate the thermal property of the as-prepared microcapsules. The results indicated that the microcapsules have high thermal storage capability, enhanced thermal reliability and stability, and increased thermal conductivity. Especially, the thermal conductivity of microcapsules is enhanced by 56.8% compared with that of the microcapsules without the addition of silicon nitride.

Bulk titanium nitride ceramics – Significant enhancement of hardness by silicon nitride addition, nanostructuring and high pressure sintering

Dense nanocomposites consisting of titanium nitride (TiN) and 1.7–8.1mol% silicon nitride (a-Si3N4) have been prepared by high-pressure sintering at 6.5GPa and at temperatures up to 1300°C. Microstructure, hardness, indentation fracture toughness, elastic modulus and the correlation of these parameters to the silicon nitride content of the obtained TiN–Si3N4 ceramics have been determined. The results demonstrate that even the addition of small amounts of Si3N4 leads to a considerable increase in Vickers hardness to HV500g∼25GPa and indentation fracture toughness up to 6MPam½. This significant enhancement of mechanical properties can be related to interfacial bonds between titanium nitride crystals strengthened by nano-size effects and amorphous silicon nitride forming an intergranular matrix. Realignment and rotation of such interlocked titanium nitride crystallites under deformational stress is suppressed and crack propagation reduced by a crack deflection mechanism.

Thermal diffusivity of kaolinite–mullite ceramic matrix composite with silicon nitride nanoparticle filler

Thermal diffusivity of mullite fused ceramics was determined from room temperature up to 500°C at intervals of 100°C. The ceramic material was formed by combining kaolinite as the matrix and silicon nitride as the filler powder. The ceramics were sintered at 1000°C, 1100°C, and 1200°C to study the structural differences. Thermal diffusivity data showed that the addition of silicon nitride affects the composites heat flow and this behavior is noticeable at 1100°C and 1200°C samples. The thermal diffusivity data was plotted on 1000/T graph to demonstrate a linear relation for filler effects of silicon nitride on the mullite matrix. Additions of 25% and 30% silicon nitride sintered at 1200°C exhibited thermal diffusivity values lower than pure mullite crystal at 0.55–0.45mm2/s. These values suggest that heat conduction across the system was interrupted by silicon nitride nanoparticle additions via micropore formations. These samples have potential applications for high temperature thermal insulation.

The Effect of Silicon Nitride Addition on Microstructure and Microhardness of SN100C Solder Alloy Using Powder Metallurgy

The effect of Si3N4particulate addition on the commercial SN100C solder alloy has been investigated. The SN100C/Si3N4composite solder was fabricated via powder metallurgy (PM) technique. In this study five different Si3N4composition which have been chosen were (0 wt. %, 0.25 wt. %, 0.5 wt. %, 0.75 wt. %, and 1.0 wt. %).The results showed that Si3N4particulate has remain as foreign particles and precipitate at the grain boundaries thus improved the physical properties of the composite solder compared to monolithic solder alloy. The addition of 1.0 wt. % Si3N4give highest hardness value to the composite solder.

High density polyethylene and silane treated silicon nitride nanocomposites using high-density polyethylene functionalized with maleate ester: Mechanical, tribological and thermal properties

In this study, attempt has been made to improve the overall performance of high-density polyethylene (HDPE) composites by blending with silane treated silicon nitride (SN) using HDPE grafted dibutyl maleate as compatibilizer. A small quantity of surface modified nanoclay has also been added in order to improve the mechanical properties. The mechanical properties show that both silane modification of silicon nitride accompanied by nanoclay addition has led to the substantial enhancement in mechanical properties. In addition, compatibilization has further improved the mechanical properties showing 10% (w/w of silicon nitride) as optimal compatibilizer content. The wear results showed that, as SN content increased, the slide wear loss decreased. Addition of SN along with compatibilizer also improved the thermal stability of the nanocomposites.