Oxidation Resistance Properties Research Articles

Application and research of nano-biomaterials in meniscus sports injury repair

A polyurethane artificial meniscus material containing a POSS capping agent was prepared by a solvent-melt method, and in vitro properties were studied. Based on cell culture, its physical and chemical properties, biological properties, and toxic effects were analysed. In the PB sample, it is shown that the proportion of cell adhesion is larger; the analysis of immune histochemical staining results shows that the proportion of cells on the surface of the B sample is less than that of the PB sample, suggesting that the cells have fewer adhesion points on the surface, and the density of cells on the surface of the PB sample is higher; finally, fluorescence tracking cell proliferation detection analysis, research suggests that the number of cells on sample B is small, the shape is mainly small circles, and cell fusion is hardly seen. The number of cells and cell fusion can be clearly seen on the surface of the PB sample, suggesting that the surface of the PB sample is more suitable for cell growth and fusion status. Solvent-melt method for the preparation of polyurethane meniscus tissue engineering scaffolds has certain practicality. Among them, POSS-terminated PB materials have better mechanical properties, oxidation resistance, calcification resistance and other physical properties, and have better biological properties. At the same time the in vitro cell culture process reflects a better environment for cell growth and fusion, providing a theoretical basis for subsequent in vivo culture. The PB polyurethane scaffold has good biocompatibility in vivo, can play a better role of meniscus replacement, protect the cartilage of the knee joint, and has certain practical significance. However, the method of firmly fixing the meniscus prosthesis needs further study.

Investigate the deformation mechanisms and microstructural development of produced titanium alloys – A review plasma sintering technology

Abstract Titanium and its alloys possess excellent properties in the form of high strength-to-weight ratio, high fracture toughness, and high elevated temperature strength and are exceptionally resistant to corrosion. Many researchers have since investigated the morphology and the mechanical and corrosive properties of Ti6Al4V alloy reinforced with various ceramic particulates such as SiC, TiC, TiB2, Al2O3, Si3N4, Y2O3, B4C, etc. Titanium and its alloys may have good fatigue, high strength, and good oxidation and corrosion resistance properties, they had a wide application in aero/space and power generation industries. Ti-alloys are excellent structural materials, which fulfil the requirements of lowering fuel costs. Frequent use of Ti-alloys, moving towards the advancement of the next-generation engines. And it is not only reducing the structural weight but also helping in improving the safety standard. The present study includes the preparation of Ti and its alloys by the Spark Plasma Sintering process, which appears to be a promising route to produce Ti-alloys for structural applications. However, owing to the short duration of the process, the diversity and control of microstructures are limited concerning other processes. Though it is this short duration of the process which attributes several advantages at the same time such as producing refined microstructure ensuring rapid turnaround and low-cost. The microstructural evolutions of the synthesized sample were evaluated with the help of a scanning electron microscope (SEM). The phases present in the fabricated sintered composites were observed by an energy-dispersive X-ray diffractionspectrometer (XRD). These efforts may help in developing new alloys and their applications especially for Ti-alloys in aero/space engine in multiple performances such as strength, toughness, creep resistance, fatigue life, and other properties.

Phase stability and microstructural evolution of Ti2AlNb alloys-a review

Ti2AlNb alloys are potential next-generation aerospace materials due to their lightweight and high-temperature strength and oxidation resistance properties. Heat treatment of this alloy results in five major microstructures, including fully B2 and α2 + B2, lamellar, bimodal lamellar, equiaxed, and duplex O-phase microstructure. Recently, widmanstätten and plate-like O phase have also been reported. Modern manufacturing methods have made fabrication of high-temperature alloys easy and economical. However, they need post-heat treatments to improve the microstructure and mechanical properties. In this review article, a sequence of various developments in the study of features and thermo-mechanical control on the evolution of various microstructures of the Ti2AlNb intermetallic alloys will be presented. In addition, other aspects such as orientation relationships between different phases, factors affecting grain growth and, phase evolution mechanisms will be discussed. The effect of each heat treatment on every feature of the microstructure will be summarized in each section.

Preparation and characterization of oxidation-resistant black glass (SiCO) coatings obtained by hydrosilylation of polysiloxanes

Two SiCO coatings deposited on AISI 301 type austenitic stainless steel have been prepared by pyrolysis (at 900 °C) from polysiloxane precursors. These precursors have been obtained by hydrosilylation of polymethylvinylsiloxane (V3) with 2,4,6,8-tetramethylcyclotetrasiloxane (D4H), and polymethylhydrosiloxane (PMHS) with 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane (D4Vi). Polymer coatings and coatings after pyrolysis have been studied using IR spectroscopy to determine the efficiency of the hydrosilylation process, as well as examine the degree of transformation to ceramic layers after pyrolysis. The presence of a free carbon phase in the layers after pyrolysis has been investigated by Raman spectroscopy. Oxidation-resistant properties of SiCO layers have been investigated in air atmosphere under isothermal conditions. In order to determine the physicochemical properties of SiCO layers (before and after corrosion tests), SEM, XRD, AFM and nanoindentation methods have been used.

Effect of Nb and Cu Additions on High Temperature Oxidation Behavior and Mechanical Properties of Al2O3-Forming Austenitic Alloys

The addition of Cu to austenitic steels was found to be effective for decreasing the critical Al content and promoting protective alumina scale formation from our recent studies. It was also reported that Nb addition to the alloy promotes the formation of alumina. These two elements are also known to improve the mechanical properties of steels by forming fine precipitates of Cu and intermetallics such as Laves and γ” phases, thus combined addition of these elements is expected to improve both the oxidation and mechanical properties of steels, however, there is no systematic study on the effects of the combined addition of these elements on the oxidation resistance and mechanical properties of austenitic heat-resistant alloys. The aim of this study was to investigate the effects of Nb and Cu on the oxidation behavior and mechanical properties of austenitic heat-resistant alloys containing Nb and Cu.Fe-25Ni-17Cr-(5~8)Al-(0, 0.5, 1)Nb-(0, 3, 5)Cu (in at.%) alloys were prepared by Ar-arc melting pure constituent metals. The ingots were cold-rolled by 90% and heat-treated at 1200ºC for 1 h, followed by aging at 800 ºC or 600 ºC for up to 500 h. Oxidation samples were cut from the cold-rolled plates and polished down to a 3 µm diamond paste. Oxidation tests were performed at 800°C in a box furnace in air for up to 100 h. The alloys were also subjected to a Vickers hardness test at room temperature and tensile tests at room temperature and 600ºC. The tensile test was performed in Ar at a strain rate of 0.005mm/s. Samples were analyzed by SEM, STEM, TEM, EPMA, GD-OES and XRD.Fig. 1 shows the oxidation kinetics and room temperature hardness of the alloys with/without different Nb and Cu contents. The oxidation kinetics of the alloys with/without different Nb and Cu contents shown in Fig. 1(a) and (b) reveals that the oxidation mass gain of the alloys without Cu decreased significantly by the addition of Nb and it further decreased with increasing Nb content. The oxidation mass gain of the 1Nb doped alloys tended to increase slightly with increasing Cu content. From the STEM-EDS analysis, it was confirmed that the protective alumina scale was formed on the Cu and/or Nb added alloys. An α-alumina was confirmed to develop on the alloys with Nb addition at about 600 ºC during heating, which is much lower temperature than that reported for formation of an α-alumina, suggesting that Nb addition promotes α-alumina formation. Vickers hardness of all alloys at room temperature increased with aging time, however, the maximum hardness was higher for the alloys aged at 600 ºC than 800 ºC. The hardness of the 5Cu alloy was higher than 0Cu alloy, which might be attributed to a formation of very fine Cu precipitates confirmed by TEM observation. Figure 1

In situ graphitization role on oxidation resistance and physicomechanical properties of resin‐bonded Al2O3‐MgO castables

AbstractThe properties of carbon‐containing refractories (CCRs) depend on the presence of carbon with features close to graphite. However, the thermosetting resins that are used to bind such refractories together during the initial preparation stage usually produce non‐graphitic carbon when sintered, which can impair their overall performance. Based on this, ferrocene was used to induce graphitic carbon generation from a resole‐type phenolic resin during a sequential carbonization operation. The resin formulation containing the graphitizing agent was then used to prepare resin‐bonded Al2O3‐MgO castables. The role of in situ graphitization of the modified binder on the properties such as cold crushing strength, apparent porosity, and oxidation resistance was examined. The results show that crystallization of the binder carbon can improve the castable oxidation resistance. At ambient temperature, no significant difference was observed in the samples' physicomechanical properties. Nevertheless, holding time during the initial curing stage at 50°C played a significant role on those properties.

Effects of Al substitution with Si and Sn on tribological performance of Ti3AlC2

Since their discovery, the MAX phases have elicited engineering interest as potential choices for wear resistant parts. One such compound is Ti3AlC2 with nano-layered structure, low density (4.25 g/cm3), good oxidation resistant and self-lubrication properties. The purpose of this investigation was to evaluate the dominant effect of the A-site solid solution elements addition on dry sliding characteristics of Ti3AlC2 against 0.45% C steel (S45C) disk, a material which is widely used in wear-critical applications such as impeller, gear and axles. Dry sliding tribological behaviors of hot-pressed Ti3Al0.94C2, Ti3Al0.78Sn0.22C2 and Ti3Al0.67Si0.28C2 solid solutions were conducted using a block-on-disk type tester at surface sliding speed range from 10 to 30 m/s and in the normal load range from 20 to 80 N. The results show that friction coefficient of Ti3Al0.94C2 is higher than that of Ti3Al0.78Sn0.22C2, but lower than that of Ti3Al0.67Si0.28C2. However, the change in wear rate as a function of normal load for different sliding speed shows almost reversed trend. Difference in the phase composition of friction films were found to be responsible for observed change in tribological behaved after partial substitution of Al in Ti3AlC2 with Sn and Si. This study shows that friction coefficient of Ti3AlC2 can be adjusted from 0.2 to 0.38 by partially substituting Al with Si and/or Sn.

Oxidation resistance properties of refractory high-entropy alloys with varied AlxCrTiMo content

The quaternary light refractory high-entropy alloys of AlxCrTiMo were fabricated by spark plasma sintering method. Investigation of the oxidation kinetics behavior of the alloys with different Al content at 1000 °C shows varying degrees of weight gain, and the curve of the sample with low Al concentration expresses distinctly different variation tendency. Formation process of oxide layers was analyzed and microstructure and cross sections of distribution of elements were examined by scanning electron microscope (SEM) and energy dispersive spectroscopy (EDS). TiO2 and Al2O3 phases were observed on the oxide film after exposure to air at 1000 °C for 1 h and 7 h time intervals. These experiments show that the Al-content in the alloy can promote the formation of Al2O3, and the equilibrium of the volatilization rate of the refractory elements as well as the formation rate of the oxidation protective layer determines the weight gain of the AlxCrTiMo.

On the possibility of simultaneously achieving sufficient oxidation resistance and creep property at high temperatures exceeding 1000 °C in Co-based superalloys

Effects of additions of γ’ (L12)-forming elements (Ta, Ti and Ni; for creep property) and γ (FCC)-forming elements (Cr and Si; for oxidation resistance) on the microstructural stability, oxidation resistance and creep properties of two-phase γ/γ′ Co-based superalloys based on the Co–Al–W systems have been investigated in order to see whether simultaneous achievement of sufficient oxidation resistance and creep property for the usage above 1000 °C is possible or not for Co-based superalloys. A candidate composition ((Co0.8Ni0.2)-6Al–2W–2Ta–6Ti–8Cr–1Si) that provides relatively high γ′ solvus temperature and high γ′ volume fraction is found. The alloy with the candidate composition exhibits superior oxidation resistance when compared to Cr-free alloys but the creep property is not as good as expected from the high γ′ solvus temperature and high γ’ volume fraction and is only comparable to those of Ni-based superalloys of the first generation. The reason for the modest creep properties of the candidate alloy as well as possibilities for further investigation to simultaneously achieve sufficient oxidation resistance and creep property for Co-based superalloys are discussed.

Structure, Oxidation Resistance, Mechanical, and Tribological Properties of N- and C-Doped Ta-Zr-Si-B Hard Protective Coatings Obtained by Reactive D.C. Magnetron Sputtering of TaZrSiB Ceramic Cathode

Coatings in the Ta-Zr-Si-B-C-N system were produced by magnetron sputtering of a TaSi2-Ta3B4-(Ta,Zr)B2 ceramic target in the Ar medium and Ar-N2 and Ar-C2H4 gas mixtures. The structure and composition of coatings were studied using scanning electron microscopy, glow discharge optical emission spectroscopy, energy-dispersion spectroscopy, and X-ray diffraction. Mechanical and tribological properties of coatings were determined using nanoindentation and pin-on-disk tests using 100Cr6 and Al2O3 balls. The oxidation resistance of coatings was evaluated by microscopy and X-ray diffraction after annealing in air at temperatures up to 1200 °C. The reactively-deposited coatings containing from 30% to 40% nitrogen or carbon have the highest hardness up to 29 GPa and elastic recovery up to 78%. Additionally, coatings with a high carbon content demonstrated a low coefficient of friction of 0.2 and no visible signs of wear when tested against 100Cr6 ball. All coatings except for the non-reactive ones can resist oxidation up to a temperature of 1200 °C thanks to the formation of a protective film based on Ta2O5 and SiO2 on their surface. Coatings deposited in Ar-N2 and Ar-C2H4 demonstrated superior resistance to thermal cycling in conditions 20-T−20 °C (where T = 200–1000 °C). The present article compares the structure and properties of reactive and “standard-inert atmosphere” deposited coatings to develop recommendations for optimizing the composition.

Functionalized Gold Nanoparticles: Synthesis, Properties and Biomedical Applications.

Gold nanoparticles have excellent optical and plasmon properties and have enormous research potential when they combine with different ligands. Functionalized gold nanoparticles are widely used in drug delivery, biological detection, sensors, and even clinical treatment. At present, with the rapid development of functionalized gold nanoparticles, we think it is necessary to sort out the recent research results. In this paper, the synthesis, characteristics, and biological applications of the three aspects are introduced. Firstly, the synthetic methods of functionalized gold nanoparticles are reviewed, and the improvement of the commonly used synthetic methods is summarized. Then, the catalytic properties, oxidation resistance, and chirality optical properties are summarized in detail. Finally, we summarize the research progress in the field of biology in recent years.

Fabrication process and mechanical properties of C/SiC corrugated core sandwich panel

Carbon fiber reinforced SiC composite is a kind of promising high-temperature thermal protection structural material owing to the excellent oxidative resistance and superior mechanical properties at high temperatures. In this work, a novel design and fabrication process of lightweight C/SiC corrugated core sandwich panel will be proposed. The compressive and three-point bending of the C/SiC corrugated sandwich panels are conducted by experiment and numerical simulation. The relative density of as-prepared C/SiC sandwich panel and the density composite material are 1.1 and 2.1 g/cm3, respectively. As the density of the C/SiC sandwich panel is only 52.3% of the bulk C/SiC, suggesting that lightweight characteristic is realized. Moreover, the C/SiC sandwich panel manifests itself as linear-elastic behavior before failure in compression and the strength is as high as 15.1 MPa. The failure mode is governed by the core shear failure and panel interlayer cracking. The load capacity under the three-point bending C/SiC composite sandwich panel is 1947.0 N. The main failure behavior is core shear failure. The stress distribution under the compression and three-point bend was simulated by FE analysis, and the results of numerical simulations are in accordance with the experimental results.

Antimicrobial and UV Blocking Properties of Composite Chitosan Films with Curcumin Grafted Cellulose Nanofiber

Chitosan has attracted much attention for use in antimicrobial food packaging because of its unique antibacterial properties and excellent film-forming ability. However, its poor barrier properties to UV light and high water-solubility limit its application. In this study, modified cellulose nanofiber was incorporated into chitosan films to improve their UV blocking, physical, and antibacterial properties. Modified cellulose nanofiber was obtained by grafting curcumin to 2, 2, 6, 6-tetramethylpiperidine-1-oxyl (TEMPO)-oxidized cellulose. Infrared spectroscopy and X-ray photoelectron spectroscopy results indicated that cellulose was successfully modified. Bio-nanocomposite films composed of chitosan (67–100 wt %) and curcumin grafted TEMPO-oxidized cellulose nanofiber (CGTOCNF, 0–33 wt %) were prepared using the casting method. Scanning electron microscopy images and X-ray diffraction analysis showed that the addition of CGTOCNF noticeably affected the morphology of the composite films, with the crystallinity significantly increasing from 21.93% to 87.15%. Moreover, CGTOCNF incorporation improved the oxidation resistance and UV blocking properties of the composite films compared to pure chitosan films. It is also worth mentioning that all of the composite films have excellent antibacterial activity with CGTOCNF partially replacing chitosan. Furthermore, the water solubility of films decreased with the incorporation of CGTOCNF. However, this study demonstrated that incorporation of CGTOCNF at concentrations greater than 10% resulted in a slight decrease in the water vapor barrier properties and mechanical strength of chitosan films. The findings in this work indicate that the addition of 10% CGTOCNF to chitosan films enhances their physical and antibacterial properties, thus increasing their potential for use in food packaging.

ZrO2f-coated Cf hybrid fibrous reinforcements and properties of their reinforced ceramicizable phenolic resin matrix composites

Carbon fiber-reinforced ceramicizable phenolic resin matrix composites have been widely used in the field of thermal protection materials. In this paper, the ZrO2f-coated Cf (ZrO2f/Cf) hybrid fibrous reinforcements were designed to improve oxidation resistance of carbon fiber and ceramicizable composites reinforced by ZrO2f/Cf hybrid fibrous reinforcements were prepared to investigated oxidation resistance and mechanical properties of the composites at high temperature. The results show that ZrO2f/Cf hybrid fibrous reinforcements have good thermal stability and high oxidation resistance, and its ceramicizable composites have good bending strength at high temperature. Weight loss rate of the composites is only 21 %, and bending strength can be as high as 39 MPa when ablation time was 12 min at 1400 °C.

Research Progress of Rare Earth-Based Hydrogen Storage Alloys

As a clean and efficient renewable energy, hydrogen energy will play an important role in the future energy system. The utilization of hydrogen energy involves various fields including production, application, storage and transportation, and the storage of hydrogen has become the main technical bottleneck restricting the wide application of hydrogen energy. Rare earth-based hydrogen storage alloys are promising hydrogen storage medium and have been widely used as anode materials for commercial Ni/MH batteries because of the excellent hydrogen storage and electrochemical properties. In this paper, the research progress of AB5 and R-Mg-Ni-based rare earth-based hydrogen storage alloys is described in detail. The alloy composition, preparation process, heat treatment and surface treatment process have significant influence on the comprehensive properties of rare earth-based hydrogen storage alloys. The effects of element substitution on the hydrogen storage capacity, corrosion resistance, oxidation resistance and electrochemical properties of the alloys are emphasized. This paper provides a guidance and a theoretical basis for the development and application of rare earth-based hydrogen storage materials.

Tribological property of MoS2-Cr3O4 nanocomposite films prepared by PVD and liquid phase synthesis

MoS2-Cr3O4 composite films were prepared by the combination method of PVD and liquid phase synthesis. The microstructure and tribological properties of films have been investigated. The results indicate that the size of Cr3O4 varied from 5 nm to 500 nm and the shape of Cr3O4 changed from nanospheres to nanorods by adjusting concentration of CrCl3. The MoS2-Cr3O4 composite films developed excellent wear resistance and much lower friction coefficient than sputtered MoS2 both in vacuum and 45%RH air. During friction, the Cr3O4@MoS2 core-shell structure with Cr3O4 core of high hardness and soft MoS2 shells were formed and played the role of nano-bearing, which reduced the friction and wear of the composite film. Besides, better oxidation resistance and tribological property of the MoS2-Cr3O4 composite films in humid air were attributed to the Cr3O4 nanoparticles, which occupied the most of dangling bond sites.

Thermophysical properties and high temperature oxidation behavior of [formula omitted] multi-component alloys

This study proposed a multi-component alloy FeCrNiAl0.5 as a candidate materials for structural applications at high temperatures. The phase structure, microstructure and chemical composition of the alloy were characterized. The results show that the alloy possesses only BCC crystal structure consisting of the ordered (Ni,Al) phase and disordered [Fe, Cr] phase. Microstructural observation combined with XRD results clearly show that the as-cast alloy exhibits a non-homogeneous microstructure with pronounced dendritic and interdendritic regions. Besides, the as-cast alloy possesses great electrical and thermal conductivity compared with other HEAs and nickel-based alloy. Moreover, the oxidation behaviors at high temperature were systematically investigated and shows a surprisingly good oxidation resistance property compared with commercially available steels and alloys. The oxidation active energy is 259.3740 kJ/mol ranging from 1173 to 1273 K. The predominant oxide is Al2O3, Cr2O3 and FeCr2O4 and the oxidation mechanisms were further discussed. This study suggests that FeCrNiAl0.5 multi-component alloy exhibites great promise for high temperature structural materials.

Oxidation resistance of Al2O3–SiC–C castables with different grades of andalusite

This work aims to investigate the effect of impurity content of andalusite on the oxidation resistance of Al2O3–SiC–C castables with andalusite as part of the aggregates. Two different grades of andalusite were employed in the Al2O3–SiC–C castables, and their oxidation resistance performances are evaluated. The results show that after firing at 1450 °C × 3 h and 10 times of thermal shock at 950°C-air cooling, the castable containing low-grade andalusite exhibits better oxidation resistance property than that containing high-grade andalusite. The phase composition, microstructure and physical performance analysis indicate that the lower grade andalusite contains more impurities, which would facilitate the liquid phase formation at high temperature. The more generated silica-rich liquid phase would fill the pores in the matrix and have a reaction with the alumina micro-powder in the matrix to form more secondary mullite. Consequently, the addition of the lower grade of andalusite would block the entry of O2 and thus improve the oxidation resistance of the castable to a higher degree.

Enhanced antioxidation and microwave absorbing properties of SiC/SiO2 coating on carbon fiber

In the manuscript, a uniform SiC/SiO2 coating was successfully prepared on the surface of carbon fiber by electrolytic plasma spraying method, which is beneficial to the dielectric loss and interfacial polarization. The antioxidation and absorption capacity of electromagnetic waves were greatly improved. The surface morphology, chemical composition, oxidation resistance and electromagnetic wave absorption properties of the coated carbon fibers were analyzed in detail. The effect of sample thickness on the electromagnetic wave loss was investigated in 2–18 GHz. The absorbing mechanism of the coated carbon fiber was discussed. The coated carbon fiber exhibits superior absorbing properties due to the synergistic effect of dielectric loss and reflection loss. The minimum reflection loss of − 11.6 dB at the thickness of 2.3 mm at 7.1 GHz. Meanwhile, the SiC/SiO2 coating on carbon fiber also has oxidation resistance, which was 28% higher than the bare sample.

Alloying effect on the oxidation behavior of a ductile Al0.5Cr0.25Nb0.5Ta0.5Ti1.5 refractory high-entropy alloy

Refractory high-entropy alloys (RHEAs) are widely studied because of their promising potential for ultrahigh-temperature applications. One key challenge towards the development of RHEAs as high-temperature structural materials is to concurrently achieve optimum oxidation resistance and mechanical properties. Here in this work, the effect of alloying on the oxidation behavior of ductile RHEAs was studied. Specifically, a ductile RHEA, Al0.5Cr0.25Nb0.5Ta0.5Ti1.5, was alloyed with Al and Zr aiming to improve its oxidation resistance. The two modified RHEAs, Al0.75Cr0.25Nb0.5Ta0.5Ti1.5 and Al0.5Cr0.25Nb0.5Ta0.5Ti1.5Zr0.01, indeed show enhanced oxidation resistance at 800 °C and 1,100 °C, compared with Al0.5Cr0.25Nb0.5Ta0.5Ti1.5. In addition, all three RHEAs studied here show an excellent oxidation resistance at 800 °C compared with other RHEAs, although there is still a large space to further improve their performance at 1,100 °C. Internal oxidation and even nitridation are still present after oxidation exposure, indicating further efforts are required to form protective oxide scales on the surface of ductile RHEAs. Nevertheless, the work is expected to shed some light on future directions of improving the oxidation of ductile RHEAs, via the alloying route.