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1 – 10 of 98Mohammed Fahad and Bavanish B.
The aviation field requires a material with the ability to withstand severe environmental conditions. The purpose of this paper is to provide higher wear resistance and improve…
Abstract
Purpose
The aviation field requires a material with the ability to withstand severe environmental conditions. The purpose of this paper is to provide higher wear resistance and improve the lifetime of aircraft. Hence, it is vital to enhance the wear resistance and strength of the material.
Design/methodology/approach
In this investigation, the Az91D magnesium alloy was reinforced with lanthanum (La2O3) and cerium oxide (CeO2) nanoparticles by stir casting and heat treatment process and the tribological and mechanical properties were analyzed.
Findings
The results showed the Az91D/CeO2 composite exhibited higher density (1.96 g/cm3) and lower porosity (1.01%) compared to other materials due to the diffusion of CeO2 nanoparticles in between the atoms of Az91D alloy. The hardness of Az91D/ CeO2 & Az91D/ La2O3 was improved by 38% and 34%, respectively, compared to Az91D alloy owing to the reinforcing effect of hard nanoparticles. Further, the inclusion of nanoparticles decreased the mass loss and showed lower wear rate compared to the Az91D alloy due to the pinning effect of nanoparticles. In addition, the friction coefficient was observed in the order of Az91D > Az91D/ La2O3 > Az91D/ CeO2. Moreover, the heat treatment displayed positive results on the properties of all the materials.
Originality/value
This work is original as the combination of cerium oxide nanoparticles with Az91D magnesium alloy is not tried by earlier investigators. Further, the comparative performance of both lanthanum and cerium oxide nanoparticles on the tribological and mechanical behavior of Az91D alloy has been analyzed for aviation application. This study will provide new information to the scientific world to increase the lifetime of aviation structures.
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A.K. Mishra, R. Balasubramaniam and S. Tiwari
The research work in this paper aims to focus on understanding the corrosion inhibition of 6061‐8 (vol.%) SiC in 3.5 per cent NaCl solution using different concentrations (250…
Abstract
Purpose
The research work in this paper aims to focus on understanding the corrosion inhibition of 6061‐8 (vol.%) SiC in 3.5 per cent NaCl solution using different concentrations (250, 500, 750 and 1,000 ppm) of cerium and lanthanum chloride.
Design/methodology/approach
The corrosion inhibition of 6061‐SiC in 3.5 per cent NaCl solution using the rare earth chloride inhibitors was analyzed by different electrochemical techniques. The techniques employed were linear polarization, Tafel extrapolation and electrochemical impedance spectroscopy (EIS). Further, surface characterization, before and after inhibitor addition, was studied using scanning electron microscopy (SEM) and energy dispersive analysis using X‐ray.
Findings
It was observed that the polarization resistance increased after addition of LaCl3 and CeCl3, with maximum increase noticed for 250 ppm LaCl3 and 1,000 ppm CeCl3. CeCl3 addition showed better improvement in polarization resistance value compared with LaCl3 addition. Pitting nucleation resistance also increased with addition of LaCl3 and CeCl3, with maximum obtained for 250 ppm LaCl3 and 500 ppm CeCl3. EIS studies showed that there was a significant increase in resistance of areas not covered by the surface film after addition of LaCl3 and CeCl3, when compared with the case without inhibitor, with a maximum increase observed with 1,000 ppm CeCl3. Rare earth chloride addition resulted in an increase in resistance on both cathodic intermetallic sites as well as the pitted regions by formation of precipitates of their oxide/hydroxide on those locations. This gave the high pitting nucleation resistance as well as improved corrosion resistance.
Research limitations/implications
It was observed that optimum concentrations of CeCl3 and LaCl3 resulted in good corrosion resistance properties on 6061‐SiC in 3.5 per cent NaCl solutions. Even small quantities of these inhibitors resulted in high corrosion resistance. However, it should be noted that both LaCl3 and CeCl3 did not follow a simple increase in corrosion resistance with composition, despite both being rare earth chloride inhibitors, and this issue merits further research.
Practical implications
Metal matrix composites (MMC) are of great use in the aerospace, military and automotive industries due to their good mechanical strength/density and stiffness/density ratios. A typical example might be the reinforcement of Al alloys with SiC particulates, which leads to a new generation of engineering materials. However, the addition of a reinforcing phase can cause discontinuities in any protective surface film, increasing the number of sites where corrosion can be initiated and rendering the composite liable to severe attack. Thus, this research work was performed to investigate if a suitable concentration of lanthanide salts (LaCl3 and CeCl3) could be identified that could improve both uniform and pitting corrosion resistance.
Originality/value
Earlier studies on the corrosion inhibition of 6061‐SiC used cerium conversion coatings. More recently (i.e. during the last 1‐2 years) work has started on lanthanum conversion coating on Al alloys. However, little work has been carried out on use of these lanthanide salts (CeCl3 and LaCl3) as corrosion inhibitors for 6061‐SiC. The present research work was performed in order to better understand the effectiveness of these inhibitors to reduce corrosion attack on 6061‐8(vol.%) SiC.
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Considers the role of a range of materials being used in advanced sensor technology, including diamond, fullerenes, silicon carbide, superconductors, rare earths and III‐V…
Abstract
Considers the role of a range of materials being used in advanced sensor technology, including diamond, fullerenes, silicon carbide, superconductors, rare earths and III‐V compounds. Sensors based on these materials are described and their applications discussed.
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Arun M., Muthukumaran M. and Balasubramanian S.
Dissimilar materials found applications in the structural fields to withstand the different types of loads and provide multi-facet properties to the final structure. Aluminum…
Abstract
Purpose
Dissimilar materials found applications in the structural fields to withstand the different types of loads and provide multi-facet properties to the final structure. Aluminum alloy materials are mostly used in aerospace and marine industries to provide better strength and safeguard the material from severe environmental conditions. The purpose of this study is to develop new material with superior strength to challenge the severe environmental conditions.
Design/methodology/approach
In the present investigation, friction stir welding (FSW) dissimilar joints were prepared from AA6061 and AA5083 aluminum alloys, and the weld nugget (WN) was reinforced with hard reinforcement particles such as La2O3 and CeO2. The tribological and mechanical properties of the prepared materials were tested to analyze the suitability of material in the aerospace and marine environmental conditions.
Findings
The results showed that the AA6061–AA5083/La2O3 material exhibited better mechanical and tribological characteristics. The FSW dissimilar AA6061–AA5083/La2O3 material exhibited lower wear rate of 7.37 × 10−3 mm3/m and minimum friction coefficient of 0.31 compared to all other materials owing to the reinforcing effect of La2O3 particles and the fine grains formed by FSW process at WN region. Further, FSW dissimilar AA6061–AA5083/La2O3 material displayed a maximum tensile strength and hardness of 378 MPa and 118 HV, respectively, among all the other materials tested.
Originality/value
This work is original and novel in the field of materials science engineering focusing on tribological characteristics of friction stir welded dissimilar aluminum alloys by the reinforcing effect of hard particles such as La2O3 and CeO2.
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Hongqiang Fan, Shuying Li, Zhicong Shi, Xuefei LV and Zongchang Zhao
The aim of this paper is to investigate the synergism effect between lanthanum salt (La(NO3)3) and benzotriazole (BTAH) on the corrosion inhibition of commercial brass and to…
Abstract
Purpose
The aim of this paper is to investigate the synergism effect between lanthanum salt (La(NO3)3) and benzotriazole (BTAH) on the corrosion inhibition of commercial brass and to further study the inhibition mechanism.
Design/methodology/approach
Potentiodynamic polarization curves were carried out on bare brass and brass treated with additions of optimum concentration of BTAH, La salt and La salt+BTAH to the basal deposition solutions in 3.5 wt. percent sodium chloride solution. The inhibition mechanism of the composite conversion coatings on brass obtained in optimal deposition techniques were investigated by electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM), X‐ray diffraction (XRD), and FT‐IR reflection spectra.
Findings
A “Critical La(NO3)3 content” and “Critical BTAH content” were both observed, at which the coatings prepared performs the highest protectiveness, and La(NO3)3 and BTAH had an excellent synergism effect on the corrosion inhibition of brass. The corrosion mechanisms for uncoated and coated brass are different. A remarkable enhancement of the brass's corrosion protection was obtained by the formation of composite conversion coatings consisted of Cu(I)BTA and La coordinate thing except for Cu2O and La2O3, which acted as a barrier avoiding the release of metal ions and inhibited the diffusion of the oxygen.
Originality/value
The results from this paper showed that La(NO3)3 and BTAH could be used together to prepare the novel composited conversion coatings on commercial brass for the good corrosion inhibition.
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Yanhong Yan, Chengwen Yang, Wenbin Dong, Pengjuan Yan, Peilong Wang, Xiaocui Yan and Zhining Jia
This paper aims to investigate the tribological properties of polytetrafluoroethylene (PTFE) composites modified by nano-serpentine and nano-lanthanum oxide in a seawater…
Abstract
Purpose
This paper aims to investigate the tribological properties of polytetrafluoroethylene (PTFE) composites modified by nano-serpentine and nano-lanthanum oxide in a seawater environment.
Design/methodology/approach
In this paper, seven PTFE composites were prepared by unified design method and vacuum thermoforming method, and their hardness, water absorption and tribological properties were measured under seawater environment. The modification effects and thermal stability of the materials were analyzed by Fourier transform infrared spectroscopy, thermal gravimetry and differential scanning calorimetry. This paper analyzed the wear mechanism of PTFE composites by scanning electron microscopy and energy spectroscopy.
Findings
The results showed that the hardness of the PTFE composites were all improved, but the water absorption was increased with the increase of additives. The modification of nano-serpentine was successful and the thermal stability of PTFE composites was better. The lowest coefficient and minimum wear rate are 0.0267 and 8.67 × 10−5 · mm3 · (N · m)−1 respectively, which is 34.9% and 76% less than the pure PTFE.
Originality/value
The analysis showed that the wear mechanism of PTFE composites was abrasive wear and a small amount of adhesive wear, and when the additive content was appropriate, it easily formed a transfer film on the surface mating parts.
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Rare earths mining in Australia and globally.
Details
DOI: 10.1108/OXAN-DB241260
ISSN: 2633-304X
Keywords
Geographic
Topical
Yuanhao Yu, Jingfu Song, Gai Zhao and Qingjun Ding
This paper aims to study the effect of different rare earth oxide on the tribological properties of polyimide (PI) nanocomposites based on the CNT and GO reinforcements.
Abstract
Purpose
This paper aims to study the effect of different rare earth oxide on the tribological properties of polyimide (PI) nanocomposites based on the CNT and GO reinforcements.
Design/methodology/approach
The PI nanocomposites filled with different rare earth oxide based on the carbon nanotubes and graphene oxide were designed and prepared by hot press sintering. The mechanical and tribological properties of PI nanocomposites were carried out, and their reinforcement mechanisms were discovered.
Findings
Rare earth oxide had a weak influence on the impact strength of PI nanocomposites. Filling La2O3 can dramatically reduce the friction coefficient and wear rate of PI nanocomposites.
Originality/value
The PI nanocomposites filled with rare earth oxide based on the CNT and GO reinforcements were designed, and their mechanical and tribological properties were studied.
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Andrea Kalendova, Martina Hejdová and David Vesely
The purpose of this paper is to synthesize anticorrosion pigments of the perovskite type, YXO3, where X = Ti, Zr, Mn or Al and Y = Ca, Sr, La or Fe, for coating materials intended…
Abstract
Purpose
The purpose of this paper is to synthesize anticorrosion pigments of the perovskite type, YXO3, where X = Ti, Zr, Mn or Al and Y = Ca, Sr, La or Fe, for coating materials intended for corrosion protection of metals. Also, to synthesize pigments containing hexavalent Mo and W (double perovskites).
Design/methodology/approach
The anticorrosion pigments were synthesized from oxides or carbonates by a high-temperature process. The following pigments were synthesized: CaTiO3, SrTiO3, CaZrO3, SrZrO3, LaTiO3, LaMnO3, CaMnO3, SrMnO3, LaFe2O3, SrFe2O3, LaAlO3, Ca2ZnWO6 and Ca2ZnMoO6. The pigments were characterized by the physico-chemical properties of the powders, by X-ray diffraction analysis and by scanning electron microscopy. Epoxy-ester coating materials containing the pigments at a volume concentration PVC = 10 per cent were prepared and subjected to tests examining their physico-mechanical properties and tests in simulated corrosion atmospheres.
Findings
The perovskite structure was identified in the majority of the pigments. The pigments were found to impart good corrosion inhibiting properties to coating materials. The highest calculated anticorrosion efficiency was found for paints containing CaMnO3 or SrMnO3 as the pigments.
Practical implications
The pigments synthesized can be used with advantage in paints intended for corrosion protection of the substrate metals.
Originality/value
The use of the above pigments in anticorrosion coating materials to protect metals is new. Especially beneficial are the uses and procedures for the synthesis of anticorrosion pigments which do not contain heavy metals and are acceptable from the environmental protection aspect.
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Saikrishnan G., Jayakumari L.S., Vijay R. and Lenin Singaravelu D.
The purpose of this study is to investigate the influence of commercially available iron–aluminum alloy compared to copper, iron and aluminum powders on the tribological…
Abstract
Purpose
The purpose of this study is to investigate the influence of commercially available iron–aluminum alloy compared to copper, iron and aluminum powders on the tribological performances of friction composites. The main objective is to replace copper from the friction composite formulations.
Design/methodology/approach
In this study, friction composites were fabricated as of standard brake pads using commercially available iron–aluminum alloy and compared to copper powder, iron powder and aluminum powder-based without varying the other ingredients. The brake pads were developed as per the industrial procedure. The physical, mechanical and thermal properties of the developed brake pads were analyzed as per industrial standards. Tribological properties were analyzed using the chase test. Initial speed and deceleration tests in a real-time braking scenario were performed using a full-scale inertia brake dynamometer. Worn surface analysis was done using a scanning electron microscope.
Findings
The results indicate that iron–aluminum alloy (mechanomade)-based friction composites possess good physical, chemical, thermal and mechanical properties with stable fade and recovery characteristics due to its composition and flake morphology. During initial speed and deceleration braking conditions, iron–aluminum alloy also showed good tribological behavior.
Originality/value
This paper explains the influence of commercially available iron–aluminum alloy in friction composites in enhancing tribological performance by its composition and flake morphology, which could potentially replace copper in friction composites by solving subsequent problems.
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