Pub Date : 2021-01-02DOI: 10.1080/0371750X.2020.1863863
Subhrojyoti Mazumder, Kishor Kumar Sadhu, K. Ghosh, Poulomi Roy, N. Mandal
ABSTRACT This work was carried out to establish a noble technique to enhance tribological characteristics of zirconia toughened alumina (ZTA) ceramic composite by adding 10 wt% nano CaF2 (∼50 nm) via chemical co-precipitation method. Result of the tribological tests, carried out using ball-on-disk tribo-pair in dry sliding, showed a considerable improvement in coefficient of friction up to ∼55% and the wear rate ∼35% in CaF2/ZTA composite as compared to pure ZTA composite fabricated via chemical processing route followed by hot pressing. In the later stage, a similar CaF2/ZTA ceramic composite was fabricated by traditional physical mixing process of commercial CaF2 and ZTA powders followed by hot pressing using the same parameters and the tribological performances were compared. The specimen fabricated via chemical route possessed better responses in terms of tribo-mechanical behaviors as compared to the specimen fabricated via traditional mixing. Various phases of the composites were examined by X-ray diffraction. Elemental distribution and the worn surface were characterized by energy dispersive X-ray analysis and field emission scanning electron microscopy, respectively. GRAPHICAL ABSTRACT
{"title":"An Effective Approach of Nanoscale CaF2 Addition into ZTA Composite to Enhance Tribological Characteristics in Dry Sliding","authors":"Subhrojyoti Mazumder, Kishor Kumar Sadhu, K. Ghosh, Poulomi Roy, N. Mandal","doi":"10.1080/0371750X.2020.1863863","DOIUrl":"https://doi.org/10.1080/0371750X.2020.1863863","url":null,"abstract":"ABSTRACT This work was carried out to establish a noble technique to enhance tribological characteristics of zirconia toughened alumina (ZTA) ceramic composite by adding 10 wt% nano CaF2 (∼50 nm) via chemical co-precipitation method. Result of the tribological tests, carried out using ball-on-disk tribo-pair in dry sliding, showed a considerable improvement in coefficient of friction up to ∼55% and the wear rate ∼35% in CaF2/ZTA composite as compared to pure ZTA composite fabricated via chemical processing route followed by hot pressing. In the later stage, a similar CaF2/ZTA ceramic composite was fabricated by traditional physical mixing process of commercial CaF2 and ZTA powders followed by hot pressing using the same parameters and the tribological performances were compared. The specimen fabricated via chemical route possessed better responses in terms of tribo-mechanical behaviors as compared to the specimen fabricated via traditional mixing. Various phases of the composites were examined by X-ray diffraction. Elemental distribution and the worn surface were characterized by energy dispersive X-ray analysis and field emission scanning electron microscopy, respectively. GRAPHICAL ABSTRACT","PeriodicalId":23233,"journal":{"name":"Transactions of the Indian Ceramic Society","volume":"80 1","pages":"19 - 27"},"PeriodicalIF":1.2,"publicationDate":"2021-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/0371750X.2020.1863863","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48652807","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-02DOI: 10.1080/0371750X.2020.1855252
Ju‐mei Zhang, Yang Zhang, Kai Wang, X. Duan, Cai Hui, Zhihu Wang
ABSTRACT A solution of Al(NO3)3.9H2O and NaOH was used to perform Mg-Al LDH plugging treatment on the LA103Z magnesium-lithium alloy micro-arc oxidation ceramic layer. The effect of treatment temperature on the micro-arc oxidation ceramic layer structure and corrosion resistance was studied. The formation mechanism of Mg-Al LDH film and corrosion mechanism of the film layer were discussed. The results show that the sealing essence of Mg-Al LDH is that the Mg2+ obtained by dissolving the MgO component of the MAO film layer is combined with OH– in the hydrothermal solution to form a layered Mg(OH)2, the formation of LDH tends to be inside the pores. In the lower temperature range, the temperature increase is conducive to the increase and thickening of the LDH layer and the film layer is dense and corrosion resistant. In the higher temperature range, the increase in temperature is conducive to the increase in the size of the LDH layer. The layer is loose and coarse, and the corrosion resistance is reduced. The composite film is the densest at 90oC, and its insulation and corrosion resistance are better than the composite film obtained at other temperatures, the MAO film and the substrate. GRAPHICAL ABSTRACT
{"title":"Morphology and Corrosion Resistance of MAO/Mg-Al LDH Composite Film Obtained on LA103Z Mg-Li Alloy at Different Temperatures","authors":"Ju‐mei Zhang, Yang Zhang, Kai Wang, X. Duan, Cai Hui, Zhihu Wang","doi":"10.1080/0371750X.2020.1855252","DOIUrl":"https://doi.org/10.1080/0371750X.2020.1855252","url":null,"abstract":"ABSTRACT A solution of Al(NO3)3.9H2O and NaOH was used to perform Mg-Al LDH plugging treatment on the LA103Z magnesium-lithium alloy micro-arc oxidation ceramic layer. The effect of treatment temperature on the micro-arc oxidation ceramic layer structure and corrosion resistance was studied. The formation mechanism of Mg-Al LDH film and corrosion mechanism of the film layer were discussed. The results show that the sealing essence of Mg-Al LDH is that the Mg2+ obtained by dissolving the MgO component of the MAO film layer is combined with OH– in the hydrothermal solution to form a layered Mg(OH)2, the formation of LDH tends to be inside the pores. In the lower temperature range, the temperature increase is conducive to the increase and thickening of the LDH layer and the film layer is dense and corrosion resistant. In the higher temperature range, the increase in temperature is conducive to the increase in the size of the LDH layer. The layer is loose and coarse, and the corrosion resistance is reduced. The composite film is the densest at 90oC, and its insulation and corrosion resistance are better than the composite film obtained at other temperatures, the MAO film and the substrate. GRAPHICAL ABSTRACT","PeriodicalId":23233,"journal":{"name":"Transactions of the Indian Ceramic Society","volume":"80 1","pages":"6 - 11"},"PeriodicalIF":1.2,"publicationDate":"2021-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/0371750X.2020.1855252","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41340325","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-02DOI: 10.1080/0371750X.2020.1864664
Rajeshwari Gangadharachar, G. Chandrappa
In the present work, yttrium orthovanadate (YVO4) nanopowder has been synthesized via solution combustion route using citric acid as fuel. The primary aim is to establish a facile solution combustion reaction to produce YVO4 nanopowder with lower band gap using vanadium pentoxide (V2O5.nH2O) gel as precursor and then investigation of its photocatalytic activity against anionic and cationic dyes in presence of visible light. The powder X-ray diffraction (PXRD) analysis reveals the formation of pure YVO4 with tetragonal phase having crystallite size ∼30.95 nm. Scanning electron micrograph (SEM) exhibits highly porous nature of the product. Breauner-Emmet-Teller (BET) surface area analysis of YVO4 nanopowder shows a relatively large specific surface area of ∼46.57 m2.g–1. Transmission electron microscopy (TEM) exhibits uniform particle size distribution with average particle sizes varying in the range of 20-100 nm. The band gap of 2.16 eV is calculated using the ultraviolet diffuse reflectance spectrum (UV-DRS) of YVO4. The photoluminescence spectrum of YVO4 nanopowder shows emission peak at 572.2 nm. The photocatalytic degradation of methylene blue (MB) using YVO4 as photocatalyst shows 92% decolorization in presence of visible radiation. Photocatalytic activity has also been extended to investigate the degradation of amaranth dye and rhodamine-B (Rh-B) under visible light irradiation which reveals 80% degradation of amaranth dye but Rh-B shows only 65% decolorization using YVO4 nanopowder. Hence YVO4 nanopowder shows good photocatalytic activity for MB and amaranth dye compared to Rh-B. GRAPHICAL ABSTRACT
{"title":"Solution Combustion Synthesis of YVO4 Nanopowder Using V2O5.nH2O Gel: Photodegradation Studies","authors":"Rajeshwari Gangadharachar, G. Chandrappa","doi":"10.1080/0371750X.2020.1864664","DOIUrl":"https://doi.org/10.1080/0371750X.2020.1864664","url":null,"abstract":"In the present work, yttrium orthovanadate (YVO4) nanopowder has been synthesized via solution combustion route using citric acid as fuel. The primary aim is to establish a facile solution combustion reaction to produce YVO4 nanopowder with lower band gap using vanadium pentoxide (V2O5.nH2O) gel as precursor and then investigation of its photocatalytic activity against anionic and cationic dyes in presence of visible light. The powder X-ray diffraction (PXRD) analysis reveals the formation of pure YVO4 with tetragonal phase having crystallite size ∼30.95 nm. Scanning electron micrograph (SEM) exhibits highly porous nature of the product. Breauner-Emmet-Teller (BET) surface area analysis of YVO4 nanopowder shows a relatively large specific surface area of ∼46.57 m2.g–1. Transmission electron microscopy (TEM) exhibits uniform particle size distribution with average particle sizes varying in the range of 20-100 nm. The band gap of 2.16 eV is calculated using the ultraviolet diffuse reflectance spectrum (UV-DRS) of YVO4. The photoluminescence spectrum of YVO4 nanopowder shows emission peak at 572.2 nm. The photocatalytic degradation of methylene blue (MB) using YVO4 as photocatalyst shows 92% decolorization in presence of visible radiation. Photocatalytic activity has also been extended to investigate the degradation of amaranth dye and rhodamine-B (Rh-B) under visible light irradiation which reveals 80% degradation of amaranth dye but Rh-B shows only 65% decolorization using YVO4 nanopowder. Hence YVO4 nanopowder shows good photocatalytic activity for MB and amaranth dye compared to Rh-B. GRAPHICAL ABSTRACT","PeriodicalId":23233,"journal":{"name":"Transactions of the Indian Ceramic Society","volume":"80 1","pages":"47 - 54"},"PeriodicalIF":1.2,"publicationDate":"2021-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/0371750X.2020.1864664","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46886745","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-02DOI: 10.1080/0371750X.2020.1869101
R. Anand, Anshuman Mohanty, S. Behera
Mullite ceramics was synthesized using boehmite (-AlOOH) as alumina source and polymethysilsesquioxanes (PMS), a novel class of preceramic polymer, as silica source. Quantitative mullitization was calculated from the X-ray diffractograms of powder samples of appropriate stoichiometry of the precursors calcined for various holding times between 1200o and 1300oC, using Rietveld analysis, and the kinetics of phase formation was studied. The rate constant and activation energy of mullitization was calculated by the Johnson-Mehl-Avrami equation. This approach holds great potential for the commercial use of polymeric silica precursor for the fabrication of highly pure mullite and other silicate systems for various application such as thermal and environmental barrier coatings. GRAPHICAL ABSTRACT
{"title":"Kinetics of Mullitization from Polysilsesquioxane and Boehmite Precursors","authors":"R. Anand, Anshuman Mohanty, S. Behera","doi":"10.1080/0371750X.2020.1869101","DOIUrl":"https://doi.org/10.1080/0371750X.2020.1869101","url":null,"abstract":"Mullite ceramics was synthesized using boehmite (-AlOOH) as alumina source and polymethysilsesquioxanes (PMS), a novel class of preceramic polymer, as silica source. Quantitative mullitization was calculated from the X-ray diffractograms of powder samples of appropriate stoichiometry of the precursors calcined for various holding times between 1200o and 1300oC, using Rietveld analysis, and the kinetics of phase formation was studied. The rate constant and activation energy of mullitization was calculated by the Johnson-Mehl-Avrami equation. This approach holds great potential for the commercial use of polymeric silica precursor for the fabrication of highly pure mullite and other silicate systems for various application such as thermal and environmental barrier coatings. GRAPHICAL ABSTRACT","PeriodicalId":23233,"journal":{"name":"Transactions of the Indian Ceramic Society","volume":"80 1","pages":"55 - 59"},"PeriodicalIF":1.2,"publicationDate":"2021-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/0371750X.2020.1869101","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45692235","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-02DOI: 10.1080/0371750X.2020.1857308
Guozhen Li, Liping Lu, Haiying Sun
ABSTRACT Y(Lu)AG:Ce3+,Sm3+ yellow phosphors were prepared by molten salt method with 0.1NaCl-0.1KCl-0.8NaF as the molten salt. The effects of multi-factor variables on the properties of Y(Lu)AG:Ce3+,Sm3+ phosphors were comprehensively studied by orthogonal experiments which is a method to study the experiment with multi-factor variables and select some representative ones from the comprehensive experiment to find the optimal experimental conditions. The optimum synthesis conditions were as follows: Ce3+ concentration 0.06 mol%, Lu3+ concentration 0.5 mol%, Sm3+ concentration 0.02 mol%, calcination temperature 1300oC, insulation time 1.5 h. The effects of introduction of Lu3+ on the crystal structure, temperature stability and luminescence properties of YAG:Ce3+,Sm3+ were studied. The results showed that due to the introduction of Lu3+ ions, the matrix lattice slightly changed (belonging to the cubic crystal system), the emission peak was blue shifted, temperature stability improved and decay reduced, which plays an important role in improving the lifetime of white LEDs. GRAPHICAL ABSTRACT
{"title":"Effect of Introduction of Lu on Thermal Stability and Luminescence Properties of YAG:Ce3+,Sm3+ Using Orthogonal Experiments","authors":"Guozhen Li, Liping Lu, Haiying Sun","doi":"10.1080/0371750X.2020.1857308","DOIUrl":"https://doi.org/10.1080/0371750X.2020.1857308","url":null,"abstract":"ABSTRACT Y(Lu)AG:Ce3+,Sm3+ yellow phosphors were prepared by molten salt method with 0.1NaCl-0.1KCl-0.8NaF as the molten salt. The effects of multi-factor variables on the properties of Y(Lu)AG:Ce3+,Sm3+ phosphors were comprehensively studied by orthogonal experiments which is a method to study the experiment with multi-factor variables and select some representative ones from the comprehensive experiment to find the optimal experimental conditions. The optimum synthesis conditions were as follows: Ce3+ concentration 0.06 mol%, Lu3+ concentration 0.5 mol%, Sm3+ concentration 0.02 mol%, calcination temperature 1300oC, insulation time 1.5 h. The effects of introduction of Lu3+ on the crystal structure, temperature stability and luminescence properties of YAG:Ce3+,Sm3+ were studied. The results showed that due to the introduction of Lu3+ ions, the matrix lattice slightly changed (belonging to the cubic crystal system), the emission peak was blue shifted, temperature stability improved and decay reduced, which plays an important role in improving the lifetime of white LEDs. GRAPHICAL ABSTRACT","PeriodicalId":23233,"journal":{"name":"Transactions of the Indian Ceramic Society","volume":"80 1","pages":"12 - 18"},"PeriodicalIF":1.2,"publicationDate":"2021-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/0371750X.2020.1857308","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43296962","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-02DOI: 10.1080/0371750X.2020.1864663
Nasir Ahmed, F. Mir
ABSTRACT In this work, we have reported the preparation of a flat circular ceramic membrane (53 mm diameter and 5 mm thick) by paste casting method from locally available Kashmir clay. The membrane was obtained by sintering the clay disc at 850oC for 5 h. The raw material and the membrane were characterized by X-ray fluorescence (XRF), X-ray diffraction (XRD), thermo-gravimetric analysis (TGA), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), porosity, and pure water permeability. The XRF and XRD analysis of the clay confirmed the presence of components required for ceramic membrane preparation. Average pore size, apparent porosity, and pure water permeability of the membrane was obtained as 5.88 µm, 24.30%, and 0.9865 l.m–2.h–1.kPa–1, respectively. Chemical stability was carried out by keeping the membrane in HCl (pH=1) and NaOH (pH=14) solutions for one week. The prepared membrane showed excellent chemical resistance in both the media. The overall fabrication cost of the membrane was estimated as 301 $/m2. These results indicate that the clay used in this work could serve as an alternative raw material to kaolin based ceramic microfiltration membranes for cheaper use in different chemical and biochemical processes. GRAPHICAL ABSTRACT
{"title":"Fabrication of a Cost Effective Ceramic Microfiltration Membrane by Utilizing Local Kashmir Clay","authors":"Nasir Ahmed, F. Mir","doi":"10.1080/0371750X.2020.1864663","DOIUrl":"https://doi.org/10.1080/0371750X.2020.1864663","url":null,"abstract":"ABSTRACT In this work, we have reported the preparation of a flat circular ceramic membrane (53 mm diameter and 5 mm thick) by paste casting method from locally available Kashmir clay. The membrane was obtained by sintering the clay disc at 850oC for 5 h. The raw material and the membrane were characterized by X-ray fluorescence (XRF), X-ray diffraction (XRD), thermo-gravimetric analysis (TGA), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), porosity, and pure water permeability. The XRF and XRD analysis of the clay confirmed the presence of components required for ceramic membrane preparation. Average pore size, apparent porosity, and pure water permeability of the membrane was obtained as 5.88 µm, 24.30%, and 0.9865 l.m–2.h–1.kPa–1, respectively. Chemical stability was carried out by keeping the membrane in HCl (pH=1) and NaOH (pH=14) solutions for one week. The prepared membrane showed excellent chemical resistance in both the media. The overall fabrication cost of the membrane was estimated as 301 $/m2. These results indicate that the clay used in this work could serve as an alternative raw material to kaolin based ceramic microfiltration membranes for cheaper use in different chemical and biochemical processes. GRAPHICAL ABSTRACT","PeriodicalId":23233,"journal":{"name":"Transactions of the Indian Ceramic Society","volume":"80 1","pages":"41 - 46"},"PeriodicalIF":1.2,"publicationDate":"2021-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/0371750X.2020.1864663","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46250357","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-10-01DOI: 10.1080/0371750x.2020.1808078
Peng Chen, X. Niu, Xihui Chen, Zhigang Sun, P. Zou, Yingdong Song
Based on the oxidation kinetics of C/SiC composites at 900o-1200oC in stress-oxidation environment, a non-uniform model of oxidation has been suggested in this paper. Combined with fiber notch model, Curtin’s strength model and BHE model, the non-uniform model is able to predict the failure time and residual strength of C/SiC composites accurately. Besides, the initial defects of the model (matrix coating crack and open porosity), the effects of coating were taken into account, and the fiber strength and broken ratio were analyzed. Furthermore, the effects of oxidation time, stress, temperature, Si C coating thickness and volume fraction of fiber on the failure time and residual strength were discussed, and the predicted results showed a good consistency with the experimental data. GRAPHICAL ABSTRACT
{"title":"Modeling the Failure Time and Residual Strength of C/SiC Composites under Stress-Oxidation Environment","authors":"Peng Chen, X. Niu, Xihui Chen, Zhigang Sun, P. Zou, Yingdong Song","doi":"10.1080/0371750x.2020.1808078","DOIUrl":"https://doi.org/10.1080/0371750x.2020.1808078","url":null,"abstract":"Based on the oxidation kinetics of C/SiC composites at 900o-1200oC in stress-oxidation environment, a non-uniform model of oxidation has been suggested in this paper. Combined with fiber notch model, Curtin’s strength model and BHE model, the non-uniform model is able to predict the failure time and residual strength of C/SiC composites accurately. Besides, the initial defects of the model (matrix coating crack and open porosity), the effects of coating were taken into account, and the fiber strength and broken ratio were analyzed. Furthermore, the effects of oxidation time, stress, temperature, Si C coating thickness and volume fraction of fiber on the failure time and residual strength were discussed, and the predicted results showed a good consistency with the experimental data. GRAPHICAL ABSTRACT","PeriodicalId":23233,"journal":{"name":"Transactions of the Indian Ceramic Society","volume":"79 1","pages":"212 - 220"},"PeriodicalIF":1.2,"publicationDate":"2020-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/0371750x.2020.1808078","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47832653","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-10-01DOI: 10.1080/0371750x.2020.1798815
Neeraj Pandey, S. Ram, I. Chakrabarty, M. R. Majhi
In this investigation, powder metallurgy route was employed to synthesize SiO2 (5, 10 and 15 vol%) coated aluminium borate whisker (ABOw) reinforced aluminium composites. Commercial pure aluminium powder was used as matrix material and SiO2 coated ABOw was used as reinforcements. M icrostructures of the composites were characterized using scanning electron microscopy and high resolution scanning electron microscopy. Energy dispersive spectroscopy was employed to confirm the weight percentages of elements present in the composites. Transmission electron microscopic analysis was performed to observe morphological changes in the composites. X-ray diffraction analysis was carried out to confirm the phases of developed reinforcement and composites. A universal testing machine was employed for the observation of mechanical properties, viz. flexural strength, Young’s modulus and diametral compressive strength, and it was found that the mechanical strength improved by 50-55% in the case of 10 vol% SiO2 coated Al-ABOw composite. The effect of SiO2 coating on the hardness of fabricated composite was also evaluated and the maximum microhardness value was observed to be 46.2 HV in 10 vol% SiO2 coated composite. Themicrostructural analysis showed that excellent grain refined structures with improved mechanical strength were obtained. GRAPHICAL ABSTRACT
{"title":"Effect of SiO2 Coating on Microstructure and Mechanical Behavior of Al-ABOw Composite Synthesized by Powder Metallurgy Technique","authors":"Neeraj Pandey, S. Ram, I. Chakrabarty, M. R. Majhi","doi":"10.1080/0371750x.2020.1798815","DOIUrl":"https://doi.org/10.1080/0371750x.2020.1798815","url":null,"abstract":"In this investigation, powder metallurgy route was employed to synthesize SiO2 (5, 10 and 15 vol%) coated aluminium borate whisker (ABOw) reinforced aluminium composites. Commercial pure aluminium powder was used as matrix material and SiO2 coated ABOw was used as reinforcements. M icrostructures of the composites were characterized using scanning electron microscopy and high resolution scanning electron microscopy. Energy dispersive spectroscopy was employed to confirm the weight percentages of elements present in the composites. Transmission electron microscopic analysis was performed to observe morphological changes in the composites. X-ray diffraction analysis was carried out to confirm the phases of developed reinforcement and composites. A universal testing machine was employed for the observation of mechanical properties, viz. flexural strength, Young’s modulus and diametral compressive strength, and it was found that the mechanical strength improved by 50-55% in the case of 10 vol% SiO2 coated Al-ABOw composite. The effect of SiO2 coating on the hardness of fabricated composite was also evaluated and the maximum microhardness value was observed to be 46.2 HV in 10 vol% SiO2 coated composite. Themicrostructural analysis showed that excellent grain refined structures with improved mechanical strength were obtained. GRAPHICAL ABSTRACT","PeriodicalId":23233,"journal":{"name":"Transactions of the Indian Ceramic Society","volume":"79 1","pages":"188 - 195"},"PeriodicalIF":1.2,"publicationDate":"2020-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/0371750x.2020.1798815","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45542795","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-10-01DOI: 10.1080/0371750x.2020.1832581
Soja K. Vijay, R. Prabhu, D. Annie, V. Chandramouli, S. Anthonysamy, Ashish Jain
ABSTRACT Nanocrystalline boron carbide was synthesized using a precursor. The precursor was prepared by the thermal decomposition of a condensed product formed by boric acid and mannitol. The condensed product was formed by microwave-assisted heating of the aqueous solution of boric acid and mannitol. The condensed product was thermally decomposed at various temperatures, viz. 400°, 500° and 600°C for 2 h. The thermally decomposed condensed product was further heat treated at temperatures from 1000° to 1600°C for 10-240 min to optimize the temperature and duration of heating in order to synthesize boron carbide with a lower free carbon impurity phase. All the products were characterized for phase purity and chemical composition (boron, total carbon and free carbon contents). The formation of boron carbide was found to occur even at a lower temperature of 1000°C. The free carbon content in the product at 1600°C was found to be <0.5 wt%. GRAPHICAL ABSTRACT
{"title":"Microwave-assisted Preparation of Precursor for the Synthesis of Nanocrystalline Boron Carbide Powder","authors":"Soja K. Vijay, R. Prabhu, D. Annie, V. Chandramouli, S. Anthonysamy, Ashish Jain","doi":"10.1080/0371750x.2020.1832581","DOIUrl":"https://doi.org/10.1080/0371750x.2020.1832581","url":null,"abstract":"ABSTRACT Nanocrystalline boron carbide was synthesized using a precursor. The precursor was prepared by the thermal decomposition of a condensed product formed by boric acid and mannitol. The condensed product was formed by microwave-assisted heating of the aqueous solution of boric acid and mannitol. The condensed product was thermally decomposed at various temperatures, viz. 400°, 500° and 600°C for 2 h. The thermally decomposed condensed product was further heat treated at temperatures from 1000° to 1600°C for 10-240 min to optimize the temperature and duration of heating in order to synthesize boron carbide with a lower free carbon impurity phase. All the products were characterized for phase purity and chemical composition (boron, total carbon and free carbon contents). The formation of boron carbide was found to occur even at a lower temperature of 1000°C. The free carbon content in the product at 1600°C was found to be <0.5 wt%. GRAPHICAL ABSTRACT","PeriodicalId":23233,"journal":{"name":"Transactions of the Indian Ceramic Society","volume":"79 1","pages":"244 - 250"},"PeriodicalIF":1.2,"publicationDate":"2020-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/0371750x.2020.1832581","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47111990","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract MgAl2O4:M (M = Ti, Mn, Co, Ni) phosphors were successfully prepared by a modified polyacrylamide gel method. Calcination temperature and metal particle has significant effects on the phase transition, optical and color properties of Mg Al2O4: M phosphors. Ti, M n, Co and Ni metal particles introduced into the MgAl2O4 system can produce a variety of colours from white, grayish black, blue to turquoise blue. Mn, Co and Ni metal particles added into MgAl2O4 system can extend their light absorption to visible light range, while the Ti metal particles clad into the system did not improve significantly. Co metal particles appended into the MgAl2O4 system can cause fluorescence quenching of emission peak at 395 nm and enhancement of emission peak at 405 nm, while the Ti and Mn metal particles infused into the system can bring the enhancement of visible emission peak at 425 nm. The fluorescence quenching of the peak at 395 nm can be ascribed to the wavelength of Co metal particles matching the surface plasmon absorbance band of MgAl2O4:M phosphor. A reduction in emission intensity at 425 nm can be assigned to electron transfer from the conduction band (CB) of MgAl2O4 to the CB of metal particles causing non-radiative decay. GRAPHICAL ABSTRACT
{"title":"Optical and Photoluminescence Properties of the MgAl2O4:M (M = Ti, Mn, Co, Ni) Phosphors: Calcination Behavior and Photoluminescence Mechanism","authors":"Shifa Wang, Huajing Gao, H. Yu, Peiying Li, Yanwu Li, Chaoli Chen, Yong Wang, Liang Yang, Zijuan Yin","doi":"10.1080/0371750x.2020.1817789","DOIUrl":"https://doi.org/10.1080/0371750x.2020.1817789","url":null,"abstract":"Abstract MgAl2O4:M (M = Ti, Mn, Co, Ni) phosphors were successfully prepared by a modified polyacrylamide gel method. Calcination temperature and metal particle has significant effects on the phase transition, optical and color properties of Mg Al2O4: M phosphors. Ti, M n, Co and Ni metal particles introduced into the MgAl2O4 system can produce a variety of colours from white, grayish black, blue to turquoise blue. Mn, Co and Ni metal particles added into MgAl2O4 system can extend their light absorption to visible light range, while the Ti metal particles clad into the system did not improve significantly. Co metal particles appended into the MgAl2O4 system can cause fluorescence quenching of emission peak at 395 nm and enhancement of emission peak at 405 nm, while the Ti and Mn metal particles infused into the system can bring the enhancement of visible emission peak at 425 nm. The fluorescence quenching of the peak at 395 nm can be ascribed to the wavelength of Co metal particles matching the surface plasmon absorbance band of MgAl2O4:M phosphor. A reduction in emission intensity at 425 nm can be assigned to electron transfer from the conduction band (CB) of MgAl2O4 to the CB of metal particles causing non-radiative decay. GRAPHICAL ABSTRACT","PeriodicalId":23233,"journal":{"name":"Transactions of the Indian Ceramic Society","volume":"79 1","pages":"221 - 231"},"PeriodicalIF":1.2,"publicationDate":"2020-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/0371750x.2020.1817789","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45023816","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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