TiN Particles Research Articles

Pt Nanoparticles Supported on N-Doped Carbon/Mesoporous TiN Particle Composites as Catalysts for the Methanol Oxidation Reaction

Pt Nanoparticles Supported on N-Doped Carbon/Mesoporous TiN Particle Composites as Catalysts for the Methanol Oxidation Reaction

Effect of Non-Uniform Concentration Field on TiN Growth in Two-Phase Region with Electropulsing

Ti microalloyed steel has the advantages of high toughness and high strength, but it is easy to form TiN particles with large dimensions at high temperatures, which is harmful to the metal and seriously affects the quality of cast billets. In this paper, by analyzing the kinetic characteristics of Ti element diffusion in the two-phase region with electropulsing, the influence mechanism of pulsed current on the growth of TiN particles in the two-phase region is investigated. The results show that the pulsed current improves the flow rate of Ti and N elements in the molten steel, reduces the concentration of Ti in the liquidoid along the solid-liquid interface, and the more the current intensity, the more obvious the impact; in addition, with the increase of the flow rate, the diffusion flux of Ti elements is also gradually improved. Therefore, the pulsed current promotes the diffusion of Ti elements by improving the concentration field of Ti and other solute elements in the two-phase region, thus inhibiting the growth of TiN.

Microstructural optimization of active element and reinforcement proportion of Si3N4/42CrMo joints

Micron-TiN particles and Ti powder were introduced into the AgCu powder filler to design a particle-reinforced composite filler. This TiN particle (TiNp) modified brazing material was adopted to reliably braze Si3N4 ceramics onto 42CrMo steel. The ratio of active element Ti and TiNp reinforcement was optimized according to the joints’ microstructuret. The reaction layer’s thickness close to the Si3N4 increased by decreasing the TiNp content or increasing the Ti content according to the microstructural observation. In addition, higher Ti content would result in more Cu-Ti intermetallics precipitation in the joint and Ti2N could be detected instead of TiNp when 10 wt.% of Ti was used.

Research on tin-copper bimetallic phosphide nanoparticles as anode for sodium-ion batteries

The SnCuP/PC-X was prepared by one-step solvothermal phosphating method, in which the introduction of copper not only affected the morphology of SnCuP/C-X, promoted the electrical conductivity, but also inhibited the growth of tin particles.

Effects of Ti and N contents on the sizes of TiN particles and prior austenite grains in low-alloy steels

Effects of Ti and N contents on the sizes of TiN particles and prior austenite grains in low-alloy steels

Nitrogen-assisted laser-based powder bed fusion fabricated NiTi with high hardness and low modulus

The role of the protective gases in laser-based powder bed fusion (L-PBF) is mainly to avoid the oxidation of metals during the melting and solidification process. However, the gaseous environment can also interact with metals, and result in changes in microstructure and properties. In a NiTi alloy, we found the L-PBF processes in the N2 gaseous environment can induce TiN particles and facilitate the formation of a precipitate-dislocation network and therefore improve mechanical properties. Nitrogen segregation also led to grain refinement and the generation of high-angle grain boundaries. The as-printed NiTi in N2 loses its shape memory effect, however, an aging process at 500 °C resulted in unchanged grain size, parallel arrays of Ni4Ti3 precipitates around TiN, and a recovery of shape memory effect. The optimization of microstructure finally resulted in a high hardness of ∼4.0 GPa and a low reduced elastic modulus of ∼57.5 GPa. The manufacturing process presented in this study opens a new way for making biomedical devices with low elastic constant, high strength to weight, and high resistance to wear.

Determining the Role of Acicular Ferrite Carbides in Cleavage Fracture Crack Initiation for Two Medium Carbon Microalloyed Steels.

Two medium-carbon microalloyed steels with a predominant acicular ferrite microstructure were investigated in this study in order to determine the initial micro-crack formation mechanism and the role of acicular ferrite structure in cleavage fracture. In order to ensure cleavage fracture, samples were investigated at -196 °C for uniaxial tension and four point bending fracture. Previous investigations have shown that cleavage fracture for steels with a predominant acicular ferrite microstructure has not been initiated by the fracture of coarse TiN particles as in ferrite-pearlite, bainite, or martensitic microalloyed steels. The average maximal thickness of cementite plates measured in this work is 0.798 µm and 0.966 µm, for V and TiV steel, respectively. The corresponding stress values required for their fracture according to Griffith's equation are 1970 MPa and 1791 MPa, respectively. Estimated values of the effective surface energy for the V steel with an average cementite volume fraction of 3.8% range from 40 Jm-2 to 86 Jm-2, and for the TiV steel with an average cementite volume fraction of 18.3% range from 55 Jm-2 to 82 Jm-2. The fracture of coarse cementite plates was found to not to be responsible for the cleavage fracture initiation in case of both steels.

Microstructure and performance enhancement of the TiN/Fe-based cladding layer induced by mechanical vibration assisted underwater wet laser cladding

It is challenging to obtain the underwater wet laser cladding layer with excellent properties while maintaining formability. In this paper, the method of using synchronous mechanical vibration assisted in the underwater wet laser cladding process of TiN/Fe-based cladding layer was introduced. The effect of mechanical vibration frequency on the dilution rate, microstructure, corrosion resistance, tribo-corrosion behavior of the cladding layer was studied. The result displayed that with increase of mechanical vibration frequency, the dilution effect of the substrate was obviously weakened and the phase changed from ferrite to ferrite and austenite, and TiN particles were evenly distributed. In addition, the grain size of the cladding layer showed a tendency to decrease first and then increase. When the mechanical vibration frequency was 400 Hz, the grain refinement phenomenon was the most obvious and the average grain size was 8.39 μm. Based on the effect of dispersion strengthening and fine grain strengthening, the microhardness and wear resistance of the cladding layer assisted at 400 Hz were improved, and the wear rate was 1.17 × 10−15m3N−1 m−1. While the cladding layer assisted at 400 Hz exhibited better corrosion resistance by forming a dense passivation film. In addition, the mechanism of mechanical vibration on microstructure evolution and performance enhancement of the cladding layer was also analyzed. This study provided the theoretical support for the formability of the underwater laser wet cladding assisted by mechanical vibration.

Fabrication and mechanical properties of TiN whisker toughening TiB2 based ceramic cutting tool composite

A TiB2 based ceramic cutting tool composite toughened by TiN whisker was developed. The results show that when the content of TiN whisker powder is 30 vol%, the flexural strength, Vickers hardness and fracture toughness of the composite are 862 MPa, 22.5 GPa, and 8.1 MPa m1/2, respectively. Compared with the composite reinforced by 30 vol% TiN particle, the fracture toughness of the composite toughened by 30 vol% TiN whisker only increases by 11.0 %. Improvement in the fracture toughness of the TiN particle reinforcing composite can be mainly due to the contribution of the mechanisms such as crack deflection and ductile metal phase toughening. These toughening mechanisms almost disappear in the TiN whisker toughening composite because of the high proportion of transgranular fracture. At the same time, the TiN whisker toughening composite also faces the problem of difficulty in whisker pullout. These problems mean that there is still a possibility of further improvement in the fracture toughness of the TiN whisker toughening TiB2 based ceramic cutting tool composite.

Effect of different heat-treated temperatures upon structural and abrasive performance of Ni-TiN composite nanocoatings

This study reports the synthesis of Ni-TiN composite nanocoatings on a Q235 steel matrix using the electrodeposition technique, and were then treated at different temperatures. The surface morphology, structure, hardness, and abrasion performances of composite nanocoatings were investigated using scanning electron microscopy (SEM), X-ray diffraction (XRD), and friction-abrasion testing machine. SEM images illustrated smooth/dense surface morphology for Ni-TiN composite nanocoatings treated at 250 °C. XRD patterns revealed Ni and TiN phase appearance within Ni-TiN composite nanocoatings. The broader and low-intensity XRD peaks were observed for the composite following heat treatment at 250 °C, indicating the smallest size of TiN particle and Ni grain. Furthermore, Ni-TiN composite nanocoatings exhibited the highest hardness of 821 Hv following heat treatment at 250 °C. The frictional coefficient, wear rate, and indentation depth for Ni-TiN composite nanocoatings were found to be lowest at 0.45, 0.58 mg/min, and 13.8 μm, respectively after heat treatment at 250 °C. Furthermore, the Ni-TiN composite nanocoatings had peak abrasion resistance across three composite nanocoatings following heat treatment at 250 °C.

Fabrication of Ni-TiN nanocomposite coatings by ultrasonic assisted jet electrodeposition

Ni-TiN composite coating is widely used as a protective coating due to its good mechanical properties and corrosion resistance. In this study, Ni-TiN nanocomposite coatings were prepared by ultrasonic-assisted jet electrodeposition. The growth mechanism and properties of the composite coatings in ultrasonic-assisted jet electrodeposition were studied. It was found that the surface morphology of the composite coating changed significantly with the increase in the concentration of nano TiN particles. Ultrasonic affects the selective orientation of the coating, and both lead to grain refinement. The addition of ultrasonic promotes the growth of (111) crystalline surfaces of the coating. Ultrasonic-assisted jet electrodeposition reduced tip discharge and nanoparticle agglomeration, and the surface quality, physical and chemical properties of the nanocomposite coating were significantly improved. The microhardness of the Ni-TiN composite coating was as high as 622.4 HV, the maximum adhesion was 27.2 N, and the corrosion resistance was the best with the corrosion current density at 1.898 μA cm−2, when the amount of nano TiN was 10 g/L. This method will provide a reference for improving the growth uniformity of jet electrodeposition.

Understanding the Effect of Deposition Potential on the Electrodeposited Tin Anodes for Lithium-Ion Batteries

Tin (Sn) is an emerging anode candidate for Li-ion batteries. Due to its high availability and low cost, researchers are studying Sn anode as a next-generation anode alternative for Li-ion batteries (LIB). In this study, we have investigated the electroplated Sn anode obtained from the aqueous media. We have utilized the electrodeposition method for synthesizing pure tin anode on the copper current collector. Aqueous media comprised of tin salt, surface activator, adhesive agent, buffering, and the complexing agent was utilized for obtaining pure tin without using any binder and a conductive agent. Deposition potentials and their effect on the particle morphology and crystal structure were investigated. To enhance the electrochemical performance, we coated the tin anode with the conducting polymer coating and further analyzed the effect of the heat treatment on the polymer-coated tin anodes. The electrochemical performance and physicochemical properties of the electrodeposited Sn electrode were characterized by, Scanning electron microscopy, X-ray Diffraction, and electrochemical techniques. As the voltage of the coating potential increases, it has been observed that the tin particles further enlarge. No difference is observed in X-ray diffraction results for the tin electrodes obtained at different voltages. Coating voltage values of -0.8V and -0.9V have provided ideal electrochemical results. Although polymer coating has a positive effect on the initial capacity value, it has been observed that it does not have sufficient improvement in cycle life.

A model for the competition between strain-induced precipitation and epitaxial growth in microalloyed austenite

A model has been developed for describing the competition between the formation of microalloyed carbonitrides by strain-induced precipitation (SIP) and by epitaxial growth on pre-existing TiN particles in γ-Fe. It is assumed that Nb and C/N atoms in the matrix will either feed the growth of pre-existing TiN precipitates or precipitate as new strain-induced particles. The model is successfully applied to the data set obtained by transmission electron microscopy (TEM) in a model alloy. Using this model, it is possible to estimate the effects of process parameters (T, applied strain), the number density of pre-existing TiN, and the Nb, C, N and Mn content on precipitate evolution and precipitation hardening. Notably, it is shown that the presence of a high number density of pre-existing TiN precipitates can suppress SIP. The conditions where epitaxial growth dominates and those in which strain-induced precipitation dominates are predicted and summarized in the form of processing maps.

Effects of Ti/N Ratio on Coarse-Grain Heat-Affected Zone Microstructure Evolution and Low-Temperature Impact Toughness of High Heat Input Welding Steel

Coarse-grain heat-affected zone (CGHAZ) properties of steel deteriorate when it is welded using high heat input, which always restricts the promotion and use of high heat input welding steel. TiN particles significantly inhibit the growth of austenite and improve the microstructure and properties of high heat input welding steel. Effects of different Ti/N ratios on the CGHAZ microstructure and properties of high heat input welding steel were studied using welding thermal simulations and in situ observations. Results showed that a higher Ti/N ratio led to the abnormal growth of austenite grains and promoted the nucleation and growth of lath ferrite, which made the microstructure of the CGHAZ heterogeneous. In contrast, austenite grains were more uniform at a lower Ti/N ratio. Thus, the microstructure was refined, the brittle structure was reduced, and the properties of the CGHAZ were improved. In addition, when Ti/N = 5.85, the impact absorption energy of the CGHAZ obviously fluctuated. However, when Ti/N = 2.82, the impact absorption energy of the CGHAZ was higher and more stable. These results provided a new idea for the development of high heat input welding steel based on TiN theory.

Direct Imaging of Surface Melting on a Single Sn Nanoparticle.

Despite previous studies, understanding the fundamental mechanism of melting metal nanoparticles remains one of the major scientific challenges of nanoscience. Herein, the kinetics of melting of a single Sn nanoparticle was investigated using in situ transmission electron microscopy heating techniques with a temperature step of up to 0.5 °C. We revealed the surface premelting effect and assessed the density of the surface overlayer on a tin particle of 47 nm size using a synergetic combination of high-resolution scanning transmission electron microscopy imaging and low electron energy loss spectral imaging. Few-monolayer-thick disordered phase nucleated at the surface of the Sn particle at a temperature ∼25 °C below the melting point and grew (up to a thickness of ∼4.5 nm) into the solid core with increasing temperature until the whole particle became liquid. We revealed that the disordered overlayer was not liquid but quasi-liquid with a density intermediate between that of solid and liquid Sn.

Improvement of the Bond Strength in Al Laminates via APB Process Using Tin Particles

Improvement of the Bond Strength in Al Laminates via APB Process Using Tin Particles

Influences of nano-green lubricants in the friction-stir process of TiAlN coated alloys

The present article investigates the effect of the friction stir process on the ultimate tensile strength and microhardness of an TiN-coated AA 6061 alloy using a green nanolubricant to reduce wear and minimise environmental impacts. In this study, a one-variable-at-a-time approach is utilized to conduct the experiment using aluminium oxide nanoparticles mixed with sunflower oil as a green lubricant. The matrix material used is AA6061 alloy, and TiN particles are used as reinforcement to form the aluminium surface composite (AA6061/TiN) through the friction stir process. The input parameters considered to improve the tensile strength and microhardness of the surface composites are axial thrust, tool speed, table travel speed, and percentage of TiN. The results indicate that by increasing the tool speed, table speed, axial thrust, and mixed TiN particle percentages, the maximum tensile strength and microhardness of the aluminium composites can be achieved. However, the lowest response values are obtained at their lowest values. To summarize, the findings suggest that the friction stir process can effectively enhance the mechanical properties of the aluminium composites by optimizing the processing parameters.

Tin-functionalized silicon oxycarbide as a stable, high-capacity anode material for Na-ion batteries

In this study tin-functionalized silicon oxycarbide, Sn/SiOC, composite anode materials are synthesized using a carbon-rich polysiloxane as the preceramic polymer and nano-sized SnO2, which converts to metallic tin via carbothermal reduction at approximately 700 °C. The in-situ Sn formation leads to a uniform distribution of tin particles within a carbon-rich SiOC matrix. Raman spectra show no significant changes despite the carbothermal reduction of SnO2. The composite material provides a stable reversible capacity of 234 mAh g-1. By adjusting the composition and pyrolysis temperature a reversible capacity of 131 mAh g-1 at a high current rate of 2380 mA g-1 is achieved.

Enhancing Mechanical and Corrosion Properties of AISI 420 with Titanium-Nitride Reinforcement through High-Power-Density Selective Laser Melting Using Two-Stage Mixed TiN/AISI 420 Powder.

This study investigates the effect of laser volume energy density (VED) on the properties of AISI 420 stainless steel and TiN/AISI 420 composite manufactured by selective laser melting (SLM). The composite contained 1 wt.% TiN and the average diameters of AISI 420 and TiN powders were 45 µm and 1 µm, respectively. The powder for SLMing the TiN/AISI 420 composite was prepared using a novel two-stage mixing scheme. The morphology, mechanical, and corrosion properties of the specimens were analyzed, and their correlations with microstructures were investigated. The results showed that the surface roughness of both SLM samples decreases with increasing VED, while relative densities greater than 99% were achieved at VEDs higher than 160 J/mm3. The SLM AISI 420 specimen fabricated at a VED of 205 J/mm3 exhibited the highest density of 7.7 g/cm3, tensile strength (UTS) of 1270 MPa, and elongation of 3.86%. The SLM TiN/AISI 420 specimen at a VED of 285 J/mm3 had a density of 7.67 g/cm3, UTS of 1482 MPa, and elongation of 2.72%. The microstructure of the SLM TiN/AISI 420 composite displayed a ring-like micro-grain structure consisting of retained austenite on the grain boundary and martensite in the grain. The TiN particles strengthened the mechanical properties of the composite by accumulating along the grain boundary. The mean hardnesses of the SLM AISI 420 and TiN/AISI 420 specimens were 635 and 735 HV, respectively, which exceeded previously reported results. The SLM TiN/AISI 420 composite exhibited excellent corrosion resistance in both 3.5 wt.% NaCl and 6 wt.% FeCl3 solutions, with a resulting corrosion rate as low as 11 µm/year.

Radiation attenuation effectiveness of polymer-based radiation shielding materials for gamma radiation

Polymer materials are increasingly being utilised in radiation shielding applications due to their unique characteristics such as flexibility, durability, and cost-effectiveness. These properties have attracted the attention of researchers who have been exploring the potential of these materials in such applications. Recently, new radiation shielding materials have been developed by incorporating elements into polymer matrices. The purpose of this study was to assess the effectiveness of lead-free polymer-based radiation shielding bricks in attenuating gamma radiation at 140 keV and 364 keV. The study evaluated the radiation shielding capability of five different polymer-based bricks, which were prepared using an open-mould casting technique with thicknesses of 0.7 cm and 1.4 cm. The bricks were fabricated by loading 90% filler powder and 10% epoxy resin and hardener. The filler powders used in this study were tungsten carbide, tungsten carbide cobalt, bismuth oxide, barium sulphate, and tin powder. The effectiveness of the fabricated bricks in attenuating gamma radiation was evaluated at 140 keV and 364 keV, and their microstructural properties were analysed using field emission scanning electron microscopy (FESEM). The study found that the newly developed polymer-based radiation shielding bricks can attenuate gamma radiation up to 98% at 140 keV and 65% at 364 keV of the incident gamma radiation. The FESEM analysis showed that the fillers were evenly distributed within the epoxy matrix. In conclusion, the incorporation of tungsten carbide, tungsten carbide cobalt, bismuth oxide, barium sulphate, and tin particles into the epoxy matrix improves the radiation shielding effectiveness of polymer-based materials, making them suitable for gamma radiation shielding applications.