Pub Date : 2021-12-28DOI: 10.1080/17436753.2021.2014276
Chin Sheng Chua, Sean Yong Ow, S. L. Liew, Junyi Liu, C. B. Soh, L. Shen, Shijie Wang
ABSTRACT This paper reports the 3D printing of fibre-reinforced ceramic composite with hierarchical structures. Through printing precursor formulation, short SiC fibres have been successfully incorporated into silicate materials and gradient porous hierarchical structure has been achieved for the printed parts. The mechanical testing shows a 27% improvement in impact strength, 22% improvement in flexural modulus, and 7.5% in flexural strength compared with parts without fibre reinforcement. High-resolution tomography analysis using x-ray microscopy shows that the inner structure has a porosity of 27%, while the outer layer shows a dense structure with little pores formation. This 3D printed ceramic composite with fibre-reinforcement shows high similarity to the gradient porous structures of human bone and tooth. The results indicate that 3D printing of nano/microfibre reinforced ceramic composite with hierarchical structure is a promising method to enhance the fracture toughness of ceramics and allow accurate patient-specific customisation for their implants.
{"title":"3D printing of fibre-reinforced ceramic composites with hierarchical structure","authors":"Chin Sheng Chua, Sean Yong Ow, S. L. Liew, Junyi Liu, C. B. Soh, L. Shen, Shijie Wang","doi":"10.1080/17436753.2021.2014276","DOIUrl":"https://doi.org/10.1080/17436753.2021.2014276","url":null,"abstract":"ABSTRACT This paper reports the 3D printing of fibre-reinforced ceramic composite with hierarchical structures. Through printing precursor formulation, short SiC fibres have been successfully incorporated into silicate materials and gradient porous hierarchical structure has been achieved for the printed parts. The mechanical testing shows a 27% improvement in impact strength, 22% improvement in flexural modulus, and 7.5% in flexural strength compared with parts without fibre reinforcement. High-resolution tomography analysis using x-ray microscopy shows that the inner structure has a porosity of 27%, while the outer layer shows a dense structure with little pores formation. This 3D printed ceramic composite with fibre-reinforcement shows high similarity to the gradient porous structures of human bone and tooth. The results indicate that 3D printing of nano/microfibre reinforced ceramic composite with hierarchical structure is a promising method to enhance the fracture toughness of ceramics and allow accurate patient-specific customisation for their implants.","PeriodicalId":7224,"journal":{"name":"Advances in Applied Ceramics","volume":null,"pages":null},"PeriodicalIF":2.2,"publicationDate":"2021-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73286869","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 : 2021-12-26DOI: 10.1080/17436753.2021.2009296
Wen-Long Jin, Xiang Yang, Zhang Wen, Zhu Cheng-xin, Wang Yi, Cao Jie, Ma Yin-wei, Cao Jian-hui
ABSTRACT Oxide fibres have attracted considerable attention as protective layers for alumina composites. In this study, alumina (Al2O3f/Al2O3) matrix composites reinforced with continuous fibres were fabricated by a sol–gel process and were coated with Y2O3 or ZrO2 to improve their ablation resistance. The ablation behaviour of the coated composites was analysed under the oxyacetylene torch flame test. The results suggested that the Y2O3 and ZrO2 coatings as sacrificial barrier layers could protect the integrity of the composites. The linear ablation rate and mass ablation rate of composites with Y2O3 coating were 0.00251 mm s−1 and 0.00143 g s−1, respectively; the linear ablation rate and mass ablation rate of composites with ZrO2 coating were 0.00142 mm s−1 and 0.00112 g s−1, respectively. After a 120 s ablation test at 2200°C, the coatings still showed a stable structure and a high protection performance.
氧化物纤维作为氧化铝复合材料的保护层引起了广泛的关注。本研究采用溶胶-凝胶法制备连续纤维增强氧化铝(Al2O3f/Al2O3)基复合材料，并在表面涂覆Y2O3或ZrO2以提高其抗烧蚀性能。在氧乙炔炬火焰试验下，分析了涂层复合材料的烧蚀性能。结果表明，Y2O3和ZrO2涂层作为牺牲阻挡层可以保护复合材料的完整性。Y2O3涂层复合材料的线性烧蚀率和质量烧蚀率分别为0.00251 mm s−1和0.00143 g s−1;ZrO2涂层复合材料的线性烧蚀率为0.00142 mm s−1，质量烧蚀率为0.00112 g s−1。经过2200℃120 s的烧蚀试验，涂层结构稳定，防护性能良好。
{"title":"Ablation behaviour of coated Al2O3f/Al2O3 composites under oxyacetylene torch flame","authors":"Wen-Long Jin, Xiang Yang, Zhang Wen, Zhu Cheng-xin, Wang Yi, Cao Jie, Ma Yin-wei, Cao Jian-hui","doi":"10.1080/17436753.2021.2009296","DOIUrl":"https://doi.org/10.1080/17436753.2021.2009296","url":null,"abstract":"ABSTRACT Oxide fibres have attracted considerable attention as protective layers for alumina composites. In this study, alumina (Al2O3f/Al2O3) matrix composites reinforced with continuous fibres were fabricated by a sol–gel process and were coated with Y2O3 or ZrO2 to improve their ablation resistance. The ablation behaviour of the coated composites was analysed under the oxyacetylene torch flame test. The results suggested that the Y2O3 and ZrO2 coatings as sacrificial barrier layers could protect the integrity of the composites. The linear ablation rate and mass ablation rate of composites with Y2O3 coating were 0.00251 mm s−1 and 0.00143 g s−1, respectively; the linear ablation rate and mass ablation rate of composites with ZrO2 coating were 0.00142 mm s−1 and 0.00112 g s−1, respectively. After a 120 s ablation test at 2200°C, the coatings still showed a stable structure and a high protection performance.","PeriodicalId":7224,"journal":{"name":"Advances in Applied Ceramics","volume":null,"pages":null},"PeriodicalIF":2.2,"publicationDate":"2021-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84055162","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 : 2021-12-17DOI: 10.1080/17436753.2021.2014277
Yichen Wang
ABSTRACT High entropy carbides (HECs) are novel materials developed in recent years that have attracted a lot of research interests. Unlike traditional carbides (containing one or two metals), HECs with multiple metals could form a very large number of different compositions that could have interesting and promising properties. The high entropy effect stabilises multi-component carbide phases and forms compositions that might otherwise not be stable. After several years of investigation of HECs, several methods of synthesising HECs have been developed. The microstructures and properties of HECs have been studied and compared with traditional carbides. Many interesting discoveries in HECs have been made. This paper reviews the theories, technologies, findings and insights gained from previous studies on HECs. The basic theory of HECs, the prediction of synthesisability of HEC phases from theoretical calculations, and some rules observed from experimental results are summarised. The preparation methods of HECs (powders, coatings, films and ceramics) and their microstructures are reviewed. Their properties, including thermal and electrical, mechanical and tribological, and oxidation, irradiation, and corrosion resistance of HECs are reviewed and discussed. Compared with traditional carbides, there is a great potential to develop new HECs due to their designable and complex compositions, and this review can guide future studies.
{"title":"Processing and properties of high entropy carbides","authors":"Yichen Wang","doi":"10.1080/17436753.2021.2014277","DOIUrl":"https://doi.org/10.1080/17436753.2021.2014277","url":null,"abstract":"ABSTRACT High entropy carbides (HECs) are novel materials developed in recent years that have attracted a lot of research interests. Unlike traditional carbides (containing one or two metals), HECs with multiple metals could form a very large number of different compositions that could have interesting and promising properties. The high entropy effect stabilises multi-component carbide phases and forms compositions that might otherwise not be stable. After several years of investigation of HECs, several methods of synthesising HECs have been developed. The microstructures and properties of HECs have been studied and compared with traditional carbides. Many interesting discoveries in HECs have been made. This paper reviews the theories, technologies, findings and insights gained from previous studies on HECs. The basic theory of HECs, the prediction of synthesisability of HEC phases from theoretical calculations, and some rules observed from experimental results are summarised. The preparation methods of HECs (powders, coatings, films and ceramics) and their microstructures are reviewed. Their properties, including thermal and electrical, mechanical and tribological, and oxidation, irradiation, and corrosion resistance of HECs are reviewed and discussed. Compared with traditional carbides, there is a great potential to develop new HECs due to their designable and complex compositions, and this review can guide future studies.","PeriodicalId":7224,"journal":{"name":"Advances in Applied Ceramics","volume":null,"pages":null},"PeriodicalIF":2.2,"publicationDate":"2021-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85246814","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 : 2021-12-13DOI: 10.1080/17436753.2021.2009295
Xiang Zhang, Peng Zhang, X. Su, Lei Shan
ABSTRACT The CrAlTiCN coatings have been prepared by multi-arc ion plating technology on 316L and TC4 substrates, respectively. The microstructure of the prepared CrAlTiCN coatings has been characterised by X-ray diffraction, scanning electron microscopy and energy disperse spectroscopy, respectively. The mechanical properties, electrochemical corrosion behaviour and tribological performance of the prepared coatings were tested by microhardness tester, scratch tester, electrochemical workstation, and friction and wear tester, respectively. Results show that all the coatings includes many nanocrystalline and presents compact structure, weak columnar crystal structure and refine grain. The prepared coating on TC4 titanium alloy substrate presents a better tribological performance than that on 316L stainless steel substrate.
{"title":"Preparation and tribological performance of CrAlTiCN coatings on 316L and TC4 substrates in sea water","authors":"Xiang Zhang, Peng Zhang, X. Su, Lei Shan","doi":"10.1080/17436753.2021.2009295","DOIUrl":"https://doi.org/10.1080/17436753.2021.2009295","url":null,"abstract":"ABSTRACT The CrAlTiCN coatings have been prepared by multi-arc ion plating technology on 316L and TC4 substrates, respectively. The microstructure of the prepared CrAlTiCN coatings has been characterised by X-ray diffraction, scanning electron microscopy and energy disperse spectroscopy, respectively. The mechanical properties, electrochemical corrosion behaviour and tribological performance of the prepared coatings were tested by microhardness tester, scratch tester, electrochemical workstation, and friction and wear tester, respectively. Results show that all the coatings includes many nanocrystalline and presents compact structure, weak columnar crystal structure and refine grain. The prepared coating on TC4 titanium alloy substrate presents a better tribological performance than that on 316L stainless steel substrate.","PeriodicalId":7224,"journal":{"name":"Advances in Applied Ceramics","volume":null,"pages":null},"PeriodicalIF":2.2,"publicationDate":"2021-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89407727","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 : 2021-11-17DOI: 10.1080/17436753.2021.1997486
Chaoyu Han, Zhizhong Wang, Li Ma, Bojiang Ma, Guosheng Huang, Yin Ma
ABSTRACT Since invented in 1980s, cold spraying (CS) has received numerous attentions recently because of its low heat input and high efficiency. Severe plastic deformation induced by high-velocity impaction makes the particles with temperature below the melting point deposited on the substrate. Theoretically, the coating obtained by CS is dense and free of oxidation, so excellent thermal and electrical conductivity can be obtained, which is ideal for ceramic metallisation (CM). Many studies have been done on the CS CM to study the coating structures, bonding mechanism and performances. Mechanical occlusion is considered to be the main bonding type at the interface, local melting plays a small role in the bonding, but local melting improves the bonding strength significantly. However, the specific bonding mechanism of CS CM is still unclear, especially in some metal/ceramic systems with bonding strength greater than 10 MPa, the bonding mechanisms need to be further studied. CS is also difficult to metallise some ceramics, which requires complicated design. Thus, aiming to improve the reliability and the extent of the application of CS CM, a thorough review should be made. In the present paper, the bonding mechanisms of CS metal coating on ceramic proposed by previous researches were summarised to help the researchers a better and quicker understanding for the CS CM. The factors influencing the properties were introduced. The author also made an outlook for the future development of CS in CM.
{"title":"Cold spray for ceramic metallisation: a review","authors":"Chaoyu Han, Zhizhong Wang, Li Ma, Bojiang Ma, Guosheng Huang, Yin Ma","doi":"10.1080/17436753.2021.1997486","DOIUrl":"https://doi.org/10.1080/17436753.2021.1997486","url":null,"abstract":"ABSTRACT Since invented in 1980s, cold spraying (CS) has received numerous attentions recently because of its low heat input and high efficiency. Severe plastic deformation induced by high-velocity impaction makes the particles with temperature below the melting point deposited on the substrate. Theoretically, the coating obtained by CS is dense and free of oxidation, so excellent thermal and electrical conductivity can be obtained, which is ideal for ceramic metallisation (CM). Many studies have been done on the CS CM to study the coating structures, bonding mechanism and performances. Mechanical occlusion is considered to be the main bonding type at the interface, local melting plays a small role in the bonding, but local melting improves the bonding strength significantly. However, the specific bonding mechanism of CS CM is still unclear, especially in some metal/ceramic systems with bonding strength greater than 10 MPa, the bonding mechanisms need to be further studied. CS is also difficult to metallise some ceramics, which requires complicated design. Thus, aiming to improve the reliability and the extent of the application of CS CM, a thorough review should be made. In the present paper, the bonding mechanisms of CS metal coating on ceramic proposed by previous researches were summarised to help the researchers a better and quicker understanding for the CS CM. The factors influencing the properties were introduced. The author also made an outlook for the future development of CS in CM.","PeriodicalId":7224,"journal":{"name":"Advances in Applied Ceramics","volume":null,"pages":null},"PeriodicalIF":2.2,"publicationDate":"2021-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90147474","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 : 2021-09-23DOI: 10.1080/17436753.2021.1981749
R. Ferreira, H. Ramlow, C. Marangoni, R. Machado
ABSTRACT Porous hydrophobic ceramic membranes have been increasingly applied in advanced membrane-based separation processes such as Direct Contact Membrane Distillation (DCMD) due to their higher chemical and mechanical resistances. The development of novel ceramic membranes enhanced with porosity is based on conventional techniques such as extrusion and tape casting, and unique processing such as dry–wet spinning and vacuum filtration. The relationships between shaping and surface hydrophobization related to the membrane structure, properties and performance of the ceramic membrane applied to DCMD are explained in this work. The manufacturing technique influences the membrane characteristics, and consequently the permeability in DCMD. Recent research is focused on manufacturing high porous hollow fibre ceramic membranes by dry–wet spinning. In contrast to the grafting of alkylsilanes, the chemical vapour deposition process has been applied as an effective surface modifying technique to enhance membrane hydrophobicity. Ceramic membranes are mostly applied to desalination in DCMD and have been little researched concerning the unique properties they can offer, such as superhydrophobicity and use in a harsh environment. In addition to the review of manufacturing techniques, polymer-derived ceramic (PDC) is proposed as a one-step ceramic membrane processing route for DCMD. Although only a handful of works addressed the use of PDC membranes applied to DCMD, the great potential of these materials is forecast.
{"title":"A review on the manufacturing techniques of porous hydrophobic ceramic membranes applied to direct contact membrane distillation","authors":"R. Ferreira, H. Ramlow, C. Marangoni, R. Machado","doi":"10.1080/17436753.2021.1981749","DOIUrl":"https://doi.org/10.1080/17436753.2021.1981749","url":null,"abstract":"ABSTRACT Porous hydrophobic ceramic membranes have been increasingly applied in advanced membrane-based separation processes such as Direct Contact Membrane Distillation (DCMD) due to their higher chemical and mechanical resistances. The development of novel ceramic membranes enhanced with porosity is based on conventional techniques such as extrusion and tape casting, and unique processing such as dry–wet spinning and vacuum filtration. The relationships between shaping and surface hydrophobization related to the membrane structure, properties and performance of the ceramic membrane applied to DCMD are explained in this work. The manufacturing technique influences the membrane characteristics, and consequently the permeability in DCMD. Recent research is focused on manufacturing high porous hollow fibre ceramic membranes by dry–wet spinning. In contrast to the grafting of alkylsilanes, the chemical vapour deposition process has been applied as an effective surface modifying technique to enhance membrane hydrophobicity. Ceramic membranes are mostly applied to desalination in DCMD and have been little researched concerning the unique properties they can offer, such as superhydrophobicity and use in a harsh environment. In addition to the review of manufacturing techniques, polymer-derived ceramic (PDC) is proposed as a one-step ceramic membrane processing route for DCMD. Although only a handful of works addressed the use of PDC membranes applied to DCMD, the great potential of these materials is forecast.","PeriodicalId":7224,"journal":{"name":"Advances in Applied Ceramics","volume":null,"pages":null},"PeriodicalIF":2.2,"publicationDate":"2021-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74551241","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 : 2021-09-17DOI: 10.1080/17436753.2021.1899729
Jiacheng Li, Ying Hou, Tingting Ye, Tianle Ding, J. Ding, R. Liang
ABSTRACT In this work, a modified sintering method, i.e. the three-step sintering technology, has been applied to fabricate the K0.5Na0.5NbO3 ceramics. The impact of the detailed sintering conditions on the sinterability, dielectric and ferroelectric properties of K0.5Na0.5NbO3 is systematically investigated. Attributed to the three-step sintering, the highest density of 4.07 g cm−3 can be observed, which is strongly improved compared with that of the single-step sintering technique and is increased up to 90% of the theoretical density. Furthermore, through the analysis on the tunability of the dielectric and ferroelectric performances, it is found that the maxima of permittivity and polarisation can be obtained in K0.5Na0.5NbO3 sintering at 1160–1220–1120°C. These results illustrate that both the dielectric and ferroelectric behaviours can be effectively modulated through the simple modification of sintering technique, which would provide a novel route to achieve tunable electrical properties in ferroelectrics.
本文采用一种改进的烧结方法，即三步烧结技术，制备了K0.5Na0.5NbO3陶瓷。系统研究了详细烧结条件对K0.5Na0.5NbO3烧结性能、介电性能和铁电性能的影响。由于采用了三步烧结技术，可以观察到最高密度为4.07 g cm−3，与单步烧结技术相比有了很大的提高，达到了理论密度的90%。此外，通过对介电性能和铁电性能的可调性分析，发现K0.5Na0.5NbO3在1160 ~ 1220 ~ 1120℃烧结时介电常数和极化值达到最大值。这些结果表明，通过对烧结技术的简单修改，可以有效地调制铁电材料的介电和铁电行为，这将为实现铁电材料的电性能可调提供一条新的途径。
{"title":"Tunable ferroelectric properties in (K0.5Na0.5)NbO3 ceramics fabricated by a simple modification of the conventional sintering technique","authors":"Jiacheng Li, Ying Hou, Tingting Ye, Tianle Ding, J. Ding, R. Liang","doi":"10.1080/17436753.2021.1899729","DOIUrl":"https://doi.org/10.1080/17436753.2021.1899729","url":null,"abstract":"ABSTRACT In this work, a modified sintering method, i.e. the three-step sintering technology, has been applied to fabricate the K0.5Na0.5NbO3 ceramics. The impact of the detailed sintering conditions on the sinterability, dielectric and ferroelectric properties of K0.5Na0.5NbO3 is systematically investigated. Attributed to the three-step sintering, the highest density of 4.07 g cm−3 can be observed, which is strongly improved compared with that of the single-step sintering technique and is increased up to 90% of the theoretical density. Furthermore, through the analysis on the tunability of the dielectric and ferroelectric performances, it is found that the maxima of permittivity and polarisation can be obtained in K0.5Na0.5NbO3 sintering at 1160–1220–1120°C. These results illustrate that both the dielectric and ferroelectric behaviours can be effectively modulated through the simple modification of sintering technique, which would provide a novel route to achieve tunable electrical properties in ferroelectrics.","PeriodicalId":7224,"journal":{"name":"Advances in Applied Ceramics","volume":null,"pages":null},"PeriodicalIF":2.2,"publicationDate":"2021-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84017891","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 : 2021-09-16DOI: 10.1080/17436753.2022.2156031
P. Raju, A. Khanra, M. B. Suresh, Y. S. Rao, Roy Johnson
ABSTRACT Pressure Slip Casting (PSC) using polymer moulds offers several advantages over Conventional Slip Casting (CSC) of ceramics such as enhanced productivity in combination with higher green density, homogeneity and low rejections. PSC is currently practiced in table-ware industries however, application to the technical ceramics is limited owing to the collapse of cast part while de-moulding during pressure cast cycle under pneumatic pressure. Current study focuses on this key issue and demonstrated pressure casting process successfully for the fabrication of alumina parts. Slips of a mixture of alumina with different particle sizes in the various proportions and solid loadings were prepared. Slip under PSC resulted in effective interlocking of the particles retaining the shape while de-moulding and achieved a sintered density of 98.6% of theoretical density (TD). Slurry on CSC exhibited a lower sintered density of 97% of TD. Selection of particles with sizes in optimised proportion for PSC results in effective interlocking of particles in green parts as well as grains on sintering as revealed by the microstructure. This leads to higher density and mechanical properties. Slip thus optimised were shaped into solid spheres of ϕ 60 mm by PSC targeting grinding applications.
{"title":"Pressure slip cast processing of alumina (Al2O3) products and comparative evaluation of mechanical properties","authors":"P. Raju, A. Khanra, M. B. Suresh, Y. S. Rao, Roy Johnson","doi":"10.1080/17436753.2022.2156031","DOIUrl":"https://doi.org/10.1080/17436753.2022.2156031","url":null,"abstract":"ABSTRACT Pressure Slip Casting (PSC) using polymer moulds offers several advantages over Conventional Slip Casting (CSC) of ceramics such as enhanced productivity in combination with higher green density, homogeneity and low rejections. PSC is currently practiced in table-ware industries however, application to the technical ceramics is limited owing to the collapse of cast part while de-moulding during pressure cast cycle under pneumatic pressure. Current study focuses on this key issue and demonstrated pressure casting process successfully for the fabrication of alumina parts. Slips of a mixture of alumina with different particle sizes in the various proportions and solid loadings were prepared. Slip under PSC resulted in effective interlocking of the particles retaining the shape while de-moulding and achieved a sintered density of 98.6% of theoretical density (TD). Slurry on CSC exhibited a lower sintered density of 97% of TD. Selection of particles with sizes in optimised proportion for PSC results in effective interlocking of particles in green parts as well as grains on sintering as revealed by the microstructure. This leads to higher density and mechanical properties. Slip thus optimised were shaped into solid spheres of ϕ 60 mm by PSC targeting grinding applications.","PeriodicalId":7224,"journal":{"name":"Advances in Applied Ceramics","volume":null,"pages":null},"PeriodicalIF":2.2,"publicationDate":"2021-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84085849","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 : 2021-09-15DOI: 10.1080/17436753.2021.1978266
Ankit Kumar, P. Kumar, A. S. Dhaliwal
ABSTRACT The phase evolution studies of zirconia, with 4–16 mol-% doping of calcium, have been carried out after sintering the pellets at 1400°C. From the X-ray diffractometer patterns, it is evident that the zirconia exists only in the monoclinic phase. However, Rietveld refinement of calcium-doped zirconia revealed the stabilisation in the monoclinic and cubic phases. With increasing calcium doping, the development of the cubic phase in zirconia is seen and at 16 mol-% doping of calcium, almost fully stabilised cubic phase of zirconia (∼97%) is achieved. The microstructure and elemental analyses of the sintered pellets are done using a field-emission scanning electron microscopy and energy-dispersive spectroscopy, respectively. Raman spectroscopic studies validate the findings of XRD. It is expected that the present study on calcium-doped zirconia opened a new channel for its potential applications in new technology such as oxygen sensors and solid electrolyte.
{"title":"Structural, morphological properties and phase stabilisation criteria of the calcia-zirconia system","authors":"Ankit Kumar, P. Kumar, A. S. Dhaliwal","doi":"10.1080/17436753.2021.1978266","DOIUrl":"https://doi.org/10.1080/17436753.2021.1978266","url":null,"abstract":"ABSTRACT The phase evolution studies of zirconia, with 4–16 mol-% doping of calcium, have been carried out after sintering the pellets at 1400°C. From the X-ray diffractometer patterns, it is evident that the zirconia exists only in the monoclinic phase. However, Rietveld refinement of calcium-doped zirconia revealed the stabilisation in the monoclinic and cubic phases. With increasing calcium doping, the development of the cubic phase in zirconia is seen and at 16 mol-% doping of calcium, almost fully stabilised cubic phase of zirconia (∼97%) is achieved. The microstructure and elemental analyses of the sintered pellets are done using a field-emission scanning electron microscopy and energy-dispersive spectroscopy, respectively. Raman spectroscopic studies validate the findings of XRD. It is expected that the present study on calcium-doped zirconia opened a new channel for its potential applications in new technology such as oxygen sensors and solid electrolyte.","PeriodicalId":7224,"journal":{"name":"Advances in Applied Ceramics","volume":null,"pages":null},"PeriodicalIF":2.2,"publicationDate":"2021-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83690357","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 : 2021-08-23DOI: 10.1080/17436753.2021.1924569
Qi Zhang, Qu Wang, Binbin Dong, G. Wang, Bo Yuan, Peng Liang, Hongxia Li
ABSTRACT Two steps were involved in the preparation of the porous mullite ceramics: preparation of porous green body by foaming method combined with gelcasting, using alumina, silica and AlF3 as raw materials and synthesis of needle-like mullite whiskers by vapor-phase reaction. Owing to the special pore structure of foaming method, the needle-like mullite crystals had enough space to develop with good structure. Most of the needle-like mullite crystals have diameters around 1.5 μm and lengths of >80 μm. By adjusting the amount of foaming agent, the open porosity varied from 66.3 to 85.5%, and the compressive strength and flexural strength decreased evidently, from 23.4 ± 1.8 to 4.9 ± 0.4 MPa and 9.7 ± 0.9 to 1.0 ± 0.1 MPa.
{"title":"Preparation of porous mullite ceramics consisting of needle-like mullite whiskers","authors":"Qi Zhang, Qu Wang, Binbin Dong, G. Wang, Bo Yuan, Peng Liang, Hongxia Li","doi":"10.1080/17436753.2021.1924569","DOIUrl":"https://doi.org/10.1080/17436753.2021.1924569","url":null,"abstract":"ABSTRACT Two steps were involved in the preparation of the porous mullite ceramics: preparation of porous green body by foaming method combined with gelcasting, using alumina, silica and AlF3 as raw materials and synthesis of needle-like mullite whiskers by vapor-phase reaction. Owing to the special pore structure of foaming method, the needle-like mullite crystals had enough space to develop with good structure. Most of the needle-like mullite crystals have diameters around 1.5 μm and lengths of >80 μm. By adjusting the amount of foaming agent, the open porosity varied from 66.3 to 85.5%, and the compressive strength and flexural strength decreased evidently, from 23.4 ± 1.8 to 4.9 ± 0.4 MPa and 9.7 ± 0.9 to 1.0 ± 0.1 MPa.","PeriodicalId":7224,"journal":{"name":"Advances in Applied Ceramics","volume":null,"pages":null},"PeriodicalIF":2.2,"publicationDate":"2021-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87025138","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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