Pub Date : 2022-01-02DOI: 10.1080/0371750X.2022.2032359
Jyoti, V. Pandey, M. Yadav, K. Mohanta, V. Singh
The present study is focused on the scope of aloe vera (AV) gel and sucrose as a binder to prepare green ceramic compact samples through dry pressing. The alumina compacts having 0-14 wt% (0-2.8 wt% on dry basis) AV gel and 0-2 wt% sucrose binder have been prepared as a function of moisture content at optimum compaction pressure. The green properties of the resulting samples have been characterized through SEM, FTIR, etc and compared with other binders. Primary results revealed that alumina compact with an optimum binder content attained maximum green density and flexural strength. The maximum green density and maximum green flexural strength are 64% and 13.5 Mpa, respectively. The experimental results have also been correlated with the microstructure of green compacts. Dry pressed compacts are sufficiently strong for green machining. The strength of binder-based green ceramic samples has been attributed to better particle packing due to adsorbing and plasticizing properties of AV gel and sucrose binder, as revealed by IR analysis. The sintered properties of fired samples at 1600°C have exhibited minimum (2.3%) porosity. Therefore, the current study creates a scope of AV gel and sucrose as a binder for the green processing of alumina based compacts. GRAPHICAL ABSTRACT
{"title":"Green Properties of Dry Pressed Alumina Compact Prepared Using Aloe Vera Gel and Sucrose as a Binder","authors":"Jyoti, V. Pandey, M. Yadav, K. Mohanta, V. Singh","doi":"10.1080/0371750X.2022.2032359","DOIUrl":"https://doi.org/10.1080/0371750X.2022.2032359","url":null,"abstract":"The present study is focused on the scope of aloe vera (AV) gel and sucrose as a binder to prepare green ceramic compact samples through dry pressing. The alumina compacts having 0-14 wt% (0-2.8 wt% on dry basis) AV gel and 0-2 wt% sucrose binder have been prepared as a function of moisture content at optimum compaction pressure. The green properties of the resulting samples have been characterized through SEM, FTIR, etc and compared with other binders. Primary results revealed that alumina compact with an optimum binder content attained maximum green density and flexural strength. The maximum green density and maximum green flexural strength are 64% and 13.5 Mpa, respectively. The experimental results have also been correlated with the microstructure of green compacts. Dry pressed compacts are sufficiently strong for green machining. The strength of binder-based green ceramic samples has been attributed to better particle packing due to adsorbing and plasticizing properties of AV gel and sucrose binder, as revealed by IR analysis. The sintered properties of fired samples at 1600°C have exhibited minimum (2.3%) porosity. Therefore, the current study creates a scope of AV gel and sucrose as a binder for the green processing of alumina based compacts. GRAPHICAL ABSTRACT","PeriodicalId":23233,"journal":{"name":"Transactions of the Indian Ceramic Society","volume":"81 1","pages":"7 - 14"},"PeriodicalIF":1.2,"publicationDate":"2022-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42465985","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 : 2022-01-02DOI: 10.1080/0371750X.2022.2038672
Jingren Li, Wen‐Zhong Lu, Hai Jiang
Effects of two-step hot-pressing on microstructure, thermal conductivity and flexural strength of silicon carbide (SiC) ceramics were investigated. A novel combination of aluminium nitride (AlN), La2O3 and LaF3 was employed as sinter additives in this study. SiC ceramics prepared through both one-step (OS samples) and two-step (TS samples) hot-pressing method exhibited high relative densities. Compared with OS samples, the TS samples yielded finer microstructures with both higher thermal conductivities and flexural strengths. Impedance spectroscopy analysis was employed to reinforce the investigation on thermal conductivity variations in different samples. According to the analysis results, TS samples exhibited higher fitting grain and grain boundary resistances, which stood for a lower concentration of vacancies, indicating that two-step hot-pressing is more beneficial to the elimination of defects and improvement of thermal conductivity in SiC ceramics. On the other hand, TS samples were strengthened by a combined effect of finer microstructure and formation of SiC-AlN solid solution, thereby obtained higher flexural strengths. Hence, the present study suggests that two-step hot-pressing is more favorable to the improvement of both thermal conductivity and flexural strength of SiC ceramics with AlN-La2O3-LaF3 additive combinations. GRAPHICAL ABSTRACT
{"title":"Thermal Conductivity and Flexural Strength of Two-Step Hot-Pressed SiC Ceramics","authors":"Jingren Li, Wen‐Zhong Lu, Hai Jiang","doi":"10.1080/0371750X.2022.2038672","DOIUrl":"https://doi.org/10.1080/0371750X.2022.2038672","url":null,"abstract":"Effects of two-step hot-pressing on microstructure, thermal conductivity and flexural strength of silicon carbide (SiC) ceramics were investigated. A novel combination of aluminium nitride (AlN), La2O3 and LaF3 was employed as sinter additives in this study. SiC ceramics prepared through both one-step (OS samples) and two-step (TS samples) hot-pressing method exhibited high relative densities. Compared with OS samples, the TS samples yielded finer microstructures with both higher thermal conductivities and flexural strengths. Impedance spectroscopy analysis was employed to reinforce the investigation on thermal conductivity variations in different samples. According to the analysis results, TS samples exhibited higher fitting grain and grain boundary resistances, which stood for a lower concentration of vacancies, indicating that two-step hot-pressing is more beneficial to the elimination of defects and improvement of thermal conductivity in SiC ceramics. On the other hand, TS samples were strengthened by a combined effect of finer microstructure and formation of SiC-AlN solid solution, thereby obtained higher flexural strengths. Hence, the present study suggests that two-step hot-pressing is more favorable to the improvement of both thermal conductivity and flexural strength of SiC ceramics with AlN-La2O3-LaF3 additive combinations. GRAPHICAL ABSTRACT","PeriodicalId":23233,"journal":{"name":"Transactions of the Indian Ceramic Society","volume":"81 1","pages":"15 - 21"},"PeriodicalIF":1.2,"publicationDate":"2022-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43428916","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 : 2022-01-02DOI: 10.1080/0371750X.2022.2044382
S. Baghshahi, C. Sorrell, M. Brungs, H. Kim
Glasses with the general compositions xNd 2O3.20Al2O3.(80–x)SiO2 and 15Nd2O3.yAl2O3.(85–y)SiO2 (x = 10, 15, 20, and y = 20, 25, 30) were prepared by melting at 1550°C. The glasses also contained varying amounts of TiO2 as nucleating agent. The microstructural evolution of the undoped and TiO2-containing glass-ceramics was then studied. Crystallization of the glasses was feasible in the range 1000° to 1250°C. The crystallization rates were evaluated. TiO2 addition influenced only the growth rate and not the nucleation of the crystalline phases observed in this study. Glasses of higher SiO2 content showed a rise in growth rate. It was found that when TiO2 was present, a new unreported crystalline compound with the stoichiometric composition of TiO2.Nd2O3.Al2O3.2SiO2 was formed GRAPHICAL ABSTRACT
{"title":"The Formation of a New Phase during Crystallization of TiO2-Doped Nd2O3-Al2O3-SiO2 Glasses","authors":"S. Baghshahi, C. Sorrell, M. Brungs, H. Kim","doi":"10.1080/0371750X.2022.2044382","DOIUrl":"https://doi.org/10.1080/0371750X.2022.2044382","url":null,"abstract":"Glasses with the general compositions xNd 2O3.20Al2O3.(80–x)SiO2 and 15Nd2O3.yAl2O3.(85–y)SiO2 (x = 10, 15, 20, and y = 20, 25, 30) were prepared by melting at 1550°C. The glasses also contained varying amounts of TiO2 as nucleating agent. The microstructural evolution of the undoped and TiO2-containing glass-ceramics was then studied. Crystallization of the glasses was feasible in the range 1000° to 1250°C. The crystallization rates were evaluated. TiO2 addition influenced only the growth rate and not the nucleation of the crystalline phases observed in this study. Glasses of higher SiO2 content showed a rise in growth rate. It was found that when TiO2 was present, a new unreported crystalline compound with the stoichiometric composition of TiO2.Nd2O3.Al2O3.2SiO2 was formed GRAPHICAL ABSTRACT","PeriodicalId":23233,"journal":{"name":"Transactions of the Indian Ceramic Society","volume":"81 1","pages":"22 - 29"},"PeriodicalIF":1.2,"publicationDate":"2022-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47045348","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 : 2021-10-02DOI: 10.1080/0371750X.2021.2004238
P. Sehrawat, R. Malik, R. Punia, M. Sheoran, Manisha Bedi, Hina Dalal
In the current prospective study, novel monoclinic symmetry type Ba2YAlO5:Er3+ nanocrystals with an emanation of vivid greenish light have been manufactured via an ideal, economical and ecological propellant combustion approach. Topographical investigations disclose roughly spherical agglomerated particles of nano-conduct (40-65 nm). Optimized content of the activator (Er3+) has been determined as x = 0.03, after the exigency of luminance quenching directed by the dipole-dipole kind interactions among the nearest Er3+ ions. The nanocrystals report an intense peak at 549 nm as per 4S3/2→4I15/2 characteristics transition, excited by 379 nm wavelength, hence proclaims glowing green luminescence. Decay lifetimes of target samples have been found to decline from 3.4556±0.0552 to 1.3063±0.0187 ms, with escalating Er3+ content. Excellent luminescent profile is reflected in terms of colour parameters like green colour coordinates (0.2630, 0.6205) and 90.79% colour purity, which have been contiguous to standard TV, SD colour green coordinates (0.300, 0.600), European Broadcasting Union (EBU, 0.290, 0.600) and NICHIA LED ( NCSGE17A) green coordinates (0.252, 0. 651). Hence, the overview of present research results insinuate their optimistic candidacy for advanced illuminating appliances like white light-emitting diodes (WLEDs) and other lighting applications. GRAPHICAL ABSTRACT
{"title":"Low-Cost Combustion Synthesis, Spectroscopic and Optoelectronic Analysis of Novel Ba2YAlO5:Er3+ Nanomaterials for Competent Illumination Applications","authors":"P. Sehrawat, R. Malik, R. Punia, M. Sheoran, Manisha Bedi, Hina Dalal","doi":"10.1080/0371750X.2021.2004238","DOIUrl":"https://doi.org/10.1080/0371750X.2021.2004238","url":null,"abstract":"In the current prospective study, novel monoclinic symmetry type Ba2YAlO5:Er3+ nanocrystals with an emanation of vivid greenish light have been manufactured via an ideal, economical and ecological propellant combustion approach. Topographical investigations disclose roughly spherical agglomerated particles of nano-conduct (40-65 nm). Optimized content of the activator (Er3+) has been determined as x = 0.03, after the exigency of luminance quenching directed by the dipole-dipole kind interactions among the nearest Er3+ ions. The nanocrystals report an intense peak at 549 nm as per 4S3/2→4I15/2 characteristics transition, excited by 379 nm wavelength, hence proclaims glowing green luminescence. Decay lifetimes of target samples have been found to decline from 3.4556±0.0552 to 1.3063±0.0187 ms, with escalating Er3+ content. Excellent luminescent profile is reflected in terms of colour parameters like green colour coordinates (0.2630, 0.6205) and 90.79% colour purity, which have been contiguous to standard TV, SD colour green coordinates (0.300, 0.600), European Broadcasting Union (EBU, 0.290, 0.600) and NICHIA LED ( NCSGE17A) green coordinates (0.252, 0. 651). Hence, the overview of present research results insinuate their optimistic candidacy for advanced illuminating appliances like white light-emitting diodes (WLEDs) and other lighting applications. GRAPHICAL ABSTRACT","PeriodicalId":23233,"journal":{"name":"Transactions of the Indian Ceramic Society","volume":"80 1","pages":"234 - 241"},"PeriodicalIF":1.2,"publicationDate":"2021-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45100173","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 : 2021-10-02DOI: 10.1080/0371750X.2021.2014637
Runping Li, Jianhua Liu
In this study, microwave hydrothermal synthesis of magnesium-aluminium spinel from pseudo-boehmite (AlOOH.nH2O) (n=0.62) and magnesium hydroxide (Mg(OH)2) for different reaction times is researched. X-ray diffraction (XRD) and Fourier transform infrared (FT-IR) are used to find out how the reaction time affects the synthesis of magnesium aluminium spinel precursors. The superficial properties of magnesium aluminium spinel precursors are investigated with scanning electron microscopy (SEM). According to XRD analysis, magnesium hydroxide reacts with pseudo-boehmite to form magnesium aluminium hydroxide hydrate. The median diameter of the samples obtained at 200 min was 5.958 μm. The agglomeration phenomenon was very serious especially when the synthesis time is greater than 200 min. The sintered sample obtained at 150°C for 200 min had more dense structure and smaller average grain size. The average grain size of the sintered sample was 0.527 μm. The best reaction time for microwave isothermal synthesis and sintering of magnesium aluminium spinel is 200 min. GRAPHICAL ABSTRACT
本文研究了以拟薄水铝石(AlOOH.nH2O) (n=0.62)和氢氧化镁(Mg(OH)2)为原料，在不同的反应时间下，微波水热合成镁铝尖晶石。利用x射线衍射(XRD)和傅里叶变换红外(FT-IR)研究了反应时间对镁铝尖晶石前驱体合成的影响。用扫描电镜研究了镁铝尖晶石前驱体的表面性能。XRD分析表明，氢氧化镁与拟薄水铝石反应生成氢氧化铝镁。在200 min时得到的样品中位直径为5.958 μm。当合成时间大于200 min时，结块现象非常严重。在150℃下烧结200 min后，烧结试样的组织更加致密，平均晶粒尺寸更小。烧结试样的平均晶粒尺寸为0.527 μm。微波等温合成和烧结镁铝尖晶石的最佳反应时间为200 min
{"title":"Effect of Reaction Time on the Synthesis and Sintering of Magnesium-Aluminium Spinel by Microwave Hydrothermal Synthesis","authors":"Runping Li, Jianhua Liu","doi":"10.1080/0371750X.2021.2014637","DOIUrl":"https://doi.org/10.1080/0371750X.2021.2014637","url":null,"abstract":"In this study, microwave hydrothermal synthesis of magnesium-aluminium spinel from pseudo-boehmite (AlOOH.nH2O) (n=0.62) and magnesium hydroxide (Mg(OH)2) for different reaction times is researched. X-ray diffraction (XRD) and Fourier transform infrared (FT-IR) are used to find out how the reaction time affects the synthesis of magnesium aluminium spinel precursors. The superficial properties of magnesium aluminium spinel precursors are investigated with scanning electron microscopy (SEM). According to XRD analysis, magnesium hydroxide reacts with pseudo-boehmite to form magnesium aluminium hydroxide hydrate. The median diameter of the samples obtained at 200 min was 5.958 μm. The agglomeration phenomenon was very serious especially when the synthesis time is greater than 200 min. The sintered sample obtained at 150°C for 200 min had more dense structure and smaller average grain size. The average grain size of the sintered sample was 0.527 μm. The best reaction time for microwave isothermal synthesis and sintering of magnesium aluminium spinel is 200 min. GRAPHICAL ABSTRACT","PeriodicalId":23233,"journal":{"name":"Transactions of the Indian Ceramic Society","volume":"80 1","pages":"265 - 269"},"PeriodicalIF":1.2,"publicationDate":"2021-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47893203","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 : 2021-10-02DOI: 10.1080/0371750X.2021.2004237
S. Bhattacharyya, S. K. Medda, M. Naskar
TiO2-ZrO2 composite coating was prepared onto glass substrate via sol-gel dip-coating technique using aquo-based titanium(IV) oxysulphate (TOS) and zirconium(IV) n-propoxide (ZP) as the precursor sources of TiO2 and ZrO2, respectively followed by calcination at 500oC/1 h. The samples were characterized by FTIR, Raman, UV/visible/ NIR, GIXRD, FESEM, TEM and XPS studies. The thickness and RI of the coating were measured ellipsometrically. The coated glasses with coating thicknesses of 110±10 nm having refractive index of 1.95±0.05 were found to be uniform with good hardness (≥3H) and adhesion properties. The bonding nature of Ti-O and Zr-O was confirmed by FTIR and XPS analyses while Raman and GIXRD studies revealed the crystalline nature of TiO2-ZrO2 composite. FESEM and TEM images revealed crack-free and spider web-like nature of the deposited coating, respectively. The coated TiO2-ZrO2 composite showed >20% of average reflection within wavelength range of 350-2500 nm. The above nanocomposite based coated glass could be used as heat reflecting window for efficient energy saving building components. GRAPHICAL ABSTRACT
{"title":"A Preparative Approach of TiO2-ZrO2 Coating Using Aquo-Based TiO2 Precursor Useful for Light Reflective Application","authors":"S. Bhattacharyya, S. K. Medda, M. Naskar","doi":"10.1080/0371750X.2021.2004237","DOIUrl":"https://doi.org/10.1080/0371750X.2021.2004237","url":null,"abstract":"TiO2-ZrO2 composite coating was prepared onto glass substrate via sol-gel dip-coating technique using aquo-based titanium(IV) oxysulphate (TOS) and zirconium(IV) n-propoxide (ZP) as the precursor sources of TiO2 and ZrO2, respectively followed by calcination at 500oC/1 h. The samples were characterized by FTIR, Raman, UV/visible/ NIR, GIXRD, FESEM, TEM and XPS studies. The thickness and RI of the coating were measured ellipsometrically. The coated glasses with coating thicknesses of 110±10 nm having refractive index of 1.95±0.05 were found to be uniform with good hardness (≥3H) and adhesion properties. The bonding nature of Ti-O and Zr-O was confirmed by FTIR and XPS analyses while Raman and GIXRD studies revealed the crystalline nature of TiO2-ZrO2 composite. FESEM and TEM images revealed crack-free and spider web-like nature of the deposited coating, respectively. The coated TiO2-ZrO2 composite showed >20% of average reflection within wavelength range of 350-2500 nm. The above nanocomposite based coated glass could be used as heat reflecting window for efficient energy saving building components. GRAPHICAL ABSTRACT","PeriodicalId":23233,"journal":{"name":"Transactions of the Indian Ceramic Society","volume":"80 1","pages":"227 - 233"},"PeriodicalIF":1.2,"publicationDate":"2021-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46887475","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 : 2021-10-02DOI: 10.1080/0371750X.2021.2004443
Xinyi Xu, J. Young, A. Goel
The transition of dental ceramics and glass-ceramics (for fixed all-ceramics and metal-ceramics restorations and prostheses) from laboratory to clinic requires the materials to pass through a series of tests following the protocols and requirements discussed in the standard ISO 6872:2015. However, the literature reveals that the researchers in the dental ceramics community usually do not adhere to the ISO standard’s specifications when measuring their materials’ flexural strength, assuming that these deviations from the protocols exhibit minimal or no impact on the materials’ strength. Therefore, the present study aims to fill that gap by elucidating the impact of the following experimental protocols – (i) polishing, (ii) edge chamfering and (iii) adhesive tape on the non-tensile side – on three-point flexural strength of lithium disilicate based glass-ceramics. The result reveals that polishing increases flexural strength and tends to introduce edge or corner flaws in the specimen. Though edge chamfering of specimens did not help remove the edge defects in our study, it leads to a tighter flaw distribution, increasing the reliability of the flexural strength results. The application of adhesive tape (on the compressive side) exhibits an insignificant impact on the glass-ceramic specimens’ flexural strength. Accordingly, revisions have been suggested in the ISO 6872 standard. GRAPHICAL ABSTRACT
{"title":"Impact of Experimental Protocols on the Flexural Strength Testing of Lithium Disilicate-Based Dental Glass-Ceramics","authors":"Xinyi Xu, J. Young, A. Goel","doi":"10.1080/0371750X.2021.2004443","DOIUrl":"https://doi.org/10.1080/0371750X.2021.2004443","url":null,"abstract":"The transition of dental ceramics and glass-ceramics (for fixed all-ceramics and metal-ceramics restorations and prostheses) from laboratory to clinic requires the materials to pass through a series of tests following the protocols and requirements discussed in the standard ISO 6872:2015. However, the literature reveals that the researchers in the dental ceramics community usually do not adhere to the ISO standard’s specifications when measuring their materials’ flexural strength, assuming that these deviations from the protocols exhibit minimal or no impact on the materials’ strength. Therefore, the present study aims to fill that gap by elucidating the impact of the following experimental protocols – (i) polishing, (ii) edge chamfering and (iii) adhesive tape on the non-tensile side – on three-point flexural strength of lithium disilicate based glass-ceramics. The result reveals that polishing increases flexural strength and tends to introduce edge or corner flaws in the specimen. Though edge chamfering of specimens did not help remove the edge defects in our study, it leads to a tighter flaw distribution, increasing the reliability of the flexural strength results. The application of adhesive tape (on the compressive side) exhibits an insignificant impact on the glass-ceramic specimens’ flexural strength. Accordingly, revisions have been suggested in the ISO 6872 standard. GRAPHICAL ABSTRACT","PeriodicalId":23233,"journal":{"name":"Transactions of the Indian Ceramic Society","volume":"80 1","pages":"258 - 264"},"PeriodicalIF":1.2,"publicationDate":"2021-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43279215","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 : 2021-10-02DOI: 10.1080/0371750X.2021.2004239
Ju‐mei Zhang, Kai Wang, X. Duan, An‐rong Hou, Jia‐cheng Li, Hui Cai, Zhihu Wang
In order to further improve the corrosion resistance of the micro-arc oxidization (MAO) film on LA103Z magnesium-lithium alloy, a Mg-Al-Co layered double hydroxide (LDH) film was fabricated on MAO film by an in-situ hydrothermal method. The results showed that with the extension of hydrothermal treatment time, the dense LDH film sealed the micro-pores and cracks in the MAO film successfully. In addition, LDH film treated with a hydrothermal treatment at 90°C for 24 h has the best electrical insulation. The hydrogen evolution rates (mL.cm–2.h−1) of the LDH/MAO composite films rank as LDH/MAO-24 h ≈ LDH/MAO-30 h (0.12) < LDH/MAO-18 h (0.15) < LDH/MAO-12 h (0.16) < MAO (0.25). Meanwhile, the results of potentiodynamic polarization curves showed that the corrosion potential of LDH/MAO-24 h film increased from –1.5349 to −1.388 V, and the corrosion current density decreased by three orders of magnitude. Therefore, the LDH/MAO film has better corrosion resistance than a single MAO film and adds long-term corrosion resistance to the magnesium alloy, which owes to the sealing effect of LDH on inherent defects and trapping effect on corrosion ions. GRAPHICAL ABSTRACT
{"title":"A Novel Mg-Al-Co LDH/ MAO Composite Films on LA103Z Magnesium-Lithium Alloy and Its Active Anti-corrosion Performance","authors":"Ju‐mei Zhang, Kai Wang, X. Duan, An‐rong Hou, Jia‐cheng Li, Hui Cai, Zhihu Wang","doi":"10.1080/0371750X.2021.2004239","DOIUrl":"https://doi.org/10.1080/0371750X.2021.2004239","url":null,"abstract":"In order to further improve the corrosion resistance of the micro-arc oxidization (MAO) film on LA103Z magnesium-lithium alloy, a Mg-Al-Co layered double hydroxide (LDH) film was fabricated on MAO film by an in-situ hydrothermal method. The results showed that with the extension of hydrothermal treatment time, the dense LDH film sealed the micro-pores and cracks in the MAO film successfully. In addition, LDH film treated with a hydrothermal treatment at 90°C for 24 h has the best electrical insulation. The hydrogen evolution rates (mL.cm–2.h−1) of the LDH/MAO composite films rank as LDH/MAO-24 h ≈ LDH/MAO-30 h (0.12) < LDH/MAO-18 h (0.15) < LDH/MAO-12 h (0.16) < MAO (0.25). Meanwhile, the results of potentiodynamic polarization curves showed that the corrosion potential of LDH/MAO-24 h film increased from –1.5349 to −1.388 V, and the corrosion current density decreased by three orders of magnitude. Therefore, the LDH/MAO film has better corrosion resistance than a single MAO film and adds long-term corrosion resistance to the magnesium alloy, which owes to the sealing effect of LDH on inherent defects and trapping effect on corrosion ions. GRAPHICAL ABSTRACT","PeriodicalId":23233,"journal":{"name":"Transactions of the Indian Ceramic Society","volume":"80 1","pages":"251 - 257"},"PeriodicalIF":1.2,"publicationDate":"2021-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49080623","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 : 2021-10-02DOI: 10.1080/0371750X.2021.2001693
Santa Kolay, P. Bhargava
K2O plays an important role as glass modifier in glass systems. In the present study,the effect of K2O:Al2O3 ratio on crystallization and microstructural evolution in Li2O-SiO2- K2O-MgO-Al2O3-ZnO-ZrO2-P2O5 glass system has been reported. K2O mol% has been varied from 1 to 3 mol% while keeping Al2O3 at 2 mol%. The glass structure was analyzed by MAS-NMR spectroscopy. Heat treated glass systems were studied by using XRD, SEM and DTA to analyse the sintering and crystallization behavior. Increased amount of K2O modified the role of Al2O3, which acted as glass network former and formed [AlO4/2] tetrahedron unit, which eventually polymerized the glass structure. Consequently, lithium disilicate (LS2) crystallization was suppressed and crystallization of lithium metasilicate (LS) was promoted. As a result, while in the sample with 1 mol% K2O LS2 appeared as the main crystalline phase and LS as minor phase, 3 mol% K2O samples did not show any lithium disilicate throughout the sintering temperature range. The K2O:Al2O3 ratio did not have a significant impact on densification of these glass-ceramics. GRAPHICAL ABSTRACT
{"title":"Effect of K2O:Al2O3 Ratio on Crystallization Phenomena and Microstructure of Lithium Silicate Glass-Ceramics","authors":"Santa Kolay, P. Bhargava","doi":"10.1080/0371750X.2021.2001693","DOIUrl":"https://doi.org/10.1080/0371750X.2021.2001693","url":null,"abstract":"K2O plays an important role as glass modifier in glass systems. In the present study,the effect of K2O:Al2O3 ratio on crystallization and microstructural evolution in Li2O-SiO2- K2O-MgO-Al2O3-ZnO-ZrO2-P2O5 glass system has been reported. K2O mol% has been varied from 1 to 3 mol% while keeping Al2O3 at 2 mol%. The glass structure was analyzed by MAS-NMR spectroscopy. Heat treated glass systems were studied by using XRD, SEM and DTA to analyse the sintering and crystallization behavior. Increased amount of K2O modified the role of Al2O3, which acted as glass network former and formed [AlO4/2] tetrahedron unit, which eventually polymerized the glass structure. Consequently, lithium disilicate (LS2) crystallization was suppressed and crystallization of lithium metasilicate (LS) was promoted. As a result, while in the sample with 1 mol% K2O LS2 appeared as the main crystalline phase and LS as minor phase, 3 mol% K2O samples did not show any lithium disilicate throughout the sintering temperature range. The K2O:Al2O3 ratio did not have a significant impact on densification of these glass-ceramics. GRAPHICAL ABSTRACT","PeriodicalId":23233,"journal":{"name":"Transactions of the Indian Ceramic Society","volume":"80 1","pages":"242 - 250"},"PeriodicalIF":1.2,"publicationDate":"2021-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44228669","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 : 2021-10-02DOI: 10.1080/0371750X.2021.2011786
S. Kitouni
The aim of the current work is to investigate selected thermal and rheological properties of porcelains. Dilatometry and shrinkage were investigated in order to clarify the thermal porcelain behavior. Densification behavior indicated that specimen sintered at 1200°C for 2 h with a heating rate of 5°C.min–1 has firing shrinkage ratio of about 11.38%. This value is fairly accurate for the usual porcelain products (12.00%). Development of thermal expansion coefficient of those samples without calcination and calcined at the temperature range of 32°-1000°C with heating rate of 5°C.min–1 in air atmosphere has also been investigated. In other way, it has been found that NaCl addition was effective to bring down the porcelain slurries viscosity. Suspensions with concentrations of 1, 2 and 3 mass% have been prepared. It has also been found that NaCl addition was effective to decrease the viscosity of porcelain slurries. GRAPHICAL ABSTRACT
{"title":"An Economic Formulation to Elaborate Resistant Technical Porcelains Using Abundant Raw Materials: Thermal and Rheological Properties Characterization","authors":"S. Kitouni","doi":"10.1080/0371750X.2021.2011786","DOIUrl":"https://doi.org/10.1080/0371750X.2021.2011786","url":null,"abstract":"The aim of the current work is to investigate selected thermal and rheological properties of porcelains. Dilatometry and shrinkage were investigated in order to clarify the thermal porcelain behavior. Densification behavior indicated that specimen sintered at 1200°C for 2 h with a heating rate of 5°C.min–1 has firing shrinkage ratio of about 11.38%. This value is fairly accurate for the usual porcelain products (12.00%). Development of thermal expansion coefficient of those samples without calcination and calcined at the temperature range of 32°-1000°C with heating rate of 5°C.min–1 in air atmosphere has also been investigated. In other way, it has been found that NaCl addition was effective to bring down the porcelain slurries viscosity. Suspensions with concentrations of 1, 2 and 3 mass% have been prepared. It has also been found that NaCl addition was effective to decrease the viscosity of porcelain slurries. GRAPHICAL ABSTRACT","PeriodicalId":23233,"journal":{"name":"Transactions of the Indian Ceramic Society","volume":"80 1","pages":"270 - 277"},"PeriodicalIF":1.2,"publicationDate":"2021-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43228265","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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