The relationship between the intrinsic properties of seven different types of fly ash and the compressive strength of the resulting geopolymers was investigated. A comprehensive examination of the effect of chemical and mineralogical compositions, particle size distribution, on the compressive strength of the fly ash-based geopolymers were performed. Results revealed that particle size distribution had a more significant impact on reaction activity than amorphous phase content or average particle size alone. Therefore, a novel concept of 'reaction volume' based on the geopolymerization reaction mechanism was proposed, which reveals a high correlation between the reactivity of fly ash and the compressive strength of geopolymers, thereby enhancing the predictability of the process. The degree of reactivity, formulated through the integration of reaction volume and amorphous silica-aluminum content, was identified as a robust predictor of compressive strength, which can serve as a crucial tool for evaluating fly ash for the production of alkali-activated materials.
{"title":"Innovative assessment of reactivity in fly ash: The role of particle size distribution characteristics","authors":"Rui Gao , Zhangjian Zhou , Jing Yang , Jinquan Zhang","doi":"10.1016/j.oceram.2024.100680","DOIUrl":"10.1016/j.oceram.2024.100680","url":null,"abstract":"<div><div>The relationship between the intrinsic properties of seven different types of fly ash and the compressive strength of the resulting geopolymers was investigated. A comprehensive examination of the effect of chemical and mineralogical compositions, particle size distribution, on the compressive strength of the fly ash-based geopolymers were performed. Results revealed that particle size distribution had a more significant impact on reaction activity than amorphous phase content or average particle size alone. Therefore, a novel concept of 'reaction volume' based on the geopolymerization reaction mechanism was proposed, which reveals a high correlation between the reactivity of fly ash and the compressive strength of geopolymers, thereby enhancing the predictability of the process. The degree of reactivity, formulated through the integration of reaction volume and amorphous silica-aluminum content, was identified as a robust predictor of compressive strength, which can serve as a crucial tool for evaluating fly ash for the production of alkali-activated materials.</div></div>","PeriodicalId":34140,"journal":{"name":"Open Ceramics","volume":"20 ","pages":"Article 100680"},"PeriodicalIF":2.9,"publicationDate":"2024-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2666539524001445/pdfft?md5=39c22ce4413049a67538525701dc09c6&pid=1-s2.0-S2666539524001445-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142312648","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-17DOI: 10.1016/j.oceram.2024.100681
Frank Kern, Bettina Osswald
4.4 Ca-TZP was hot pressed in the temperature range between 1200 and 1325 °C for 1 h at 60 MPa pressure. The material was characterized with respect to phase composition, mechanical properties and microstructure. The mechanical properties and phase composition of the Ca-TZP react very sensitively to changes in sintering temperature and average grain size. Fracture toughness continuously increases with sintering temperature from 5 MPa√m to 8.5 MPa√m while bending strength reaches an optimum of 1160 MPa combined with fracture toughness of 5 MPa√m at 1250 °C sintering temperature. The microstructure of the materials is ultrafine. The onset of monoclinic and cubic phase formation is observed at a sintering temperature of 1300 °C and a grain size of ∼140 nm. Indentation at elevated temperature was applied to suppress crack trapping which would lead to extreme overestimation of indentation toughness values.
{"title":"Structure property relations in hot pressed 4.4 mol% calcia stabilized zirconia","authors":"Frank Kern, Bettina Osswald","doi":"10.1016/j.oceram.2024.100681","DOIUrl":"10.1016/j.oceram.2024.100681","url":null,"abstract":"<div><div>4.4 Ca-TZP was hot pressed in the temperature range between 1200 and 1325 °C for 1 h at 60 MPa pressure. The material was characterized with respect to phase composition, mechanical properties and microstructure. The mechanical properties and phase composition of the Ca-TZP react very sensitively to changes in sintering temperature and average grain size. Fracture toughness continuously increases with sintering temperature from 5 MPa√m to 8.5 MPa√m while bending strength reaches an optimum of 1160 MPa combined with fracture toughness of 5 MPa√m at 1250 °C sintering temperature. The microstructure of the materials is ultrafine. The onset of monoclinic and cubic phase formation is observed at a sintering temperature of 1300 °C and a grain size of ∼140 nm. Indentation at elevated temperature was applied to suppress crack trapping which would lead to extreme overestimation of indentation toughness values.</div></div>","PeriodicalId":34140,"journal":{"name":"Open Ceramics","volume":"20 ","pages":"Article 100681"},"PeriodicalIF":2.9,"publicationDate":"2024-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2666539524001457/pdfft?md5=87343c4067854ad2b24f977ea3d3e84f&pid=1-s2.0-S2666539524001457-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142312649","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Mg-stabilised Na-β’’-alumina solid electrolyte (Mg-BASE) for Na-ion batteries was synthesised and fabricated into 3D structures via direct ink writing (DIW), an extrusion-based additive manufacturing process. To produce a water-based ink with optimum viscoelastic properties and supreme printing quality, a comprehensive investigation of ink formulation and printing parameters was conducted. The sintered 3D structures of Mg-BASE, fabricated via direct ink writing, achieved relative density of 98.0 ± 1.1 % with β’’ phase fraction of 99.7 wt% whilst bulk ionic conductivity of 0.081 S⋅cm−1 at 350 °C was obtained. XRD results indicated that Mg-BASE fabricated via DIW may have different c-axis orientation than conventional dry-pressed pellets, leading to the improved bulk ionic conductivity.
{"title":"Performance of Mg stabilised Na-β’’-alumina solid electrolytes prepared by direct ink writing","authors":"Dongrui Xie , Athanasios Goulas , Bala Vaidhyanathan , Sina Saremi-Yarahmadi","doi":"10.1016/j.oceram.2024.100674","DOIUrl":"10.1016/j.oceram.2024.100674","url":null,"abstract":"<div><div>Mg-stabilised Na-β’’-alumina solid electrolyte (Mg-BASE) for Na-ion batteries was synthesised and fabricated into 3D structures via direct ink writing (DIW), an extrusion-based additive manufacturing process. To produce a water-based ink with optimum viscoelastic properties and supreme printing quality, a comprehensive investigation of ink formulation and printing parameters was conducted. The sintered 3D structures of Mg-BASE, fabricated via direct ink writing, achieved relative density of 98.0 ± 1.1 % with β’’ phase fraction of 99.7 wt% whilst bulk ionic conductivity of 0.081 S⋅cm<sup>−1</sup> at 350 °C was obtained. XRD results indicated that Mg-BASE fabricated via DIW may have different c-axis orientation than conventional dry-pressed pellets, leading to the improved bulk ionic conductivity.</div></div>","PeriodicalId":34140,"journal":{"name":"Open Ceramics","volume":"20 ","pages":"Article 100674"},"PeriodicalIF":2.9,"publicationDate":"2024-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142421935","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-16DOI: 10.1016/j.oceram.2024.100678
Abel W. Ourgessa , Jozef Kraxner , Hamada Elsayed , Dušan Galusek , Enrico Bernardo
In this work, waste fiberglass was up-cycled, alone, or mixed with used alumina-zirconia-silica (AZS) refractory from dismantled glass melting furnaces. Alkali activation was performed by suspending fiberglass and fiberglass/AZS powders in NaOH aqueous solution of various concentrations (8M, 6M, and 3M). The activation of waste fiberglass with 8M NaOH yields a gel with calcium and sodium-containing aluminosilicate hydrates. The addition of AZS refractory enabled the release of aluminates into the solution, which had beneficial effects on the mechanical properties. Low molarity activation yielded weaker materials which could be used as precursors for firing at moderate temperatures (800 °C and 1000 °C) to create cellular glass-ceramics, with a total porosity of up to 92 %. The firing of 8M activated samples resulted in glass ceramics with a 66–75 % porosity range and compressive strength of 10–23Mpa. The compressive strength-to-density ratio before and after firing was comparable to that of established commercial construction materials.
{"title":"Sustainable construction materials from alkali-activated waste fiberglass and waste refractory","authors":"Abel W. Ourgessa , Jozef Kraxner , Hamada Elsayed , Dušan Galusek , Enrico Bernardo","doi":"10.1016/j.oceram.2024.100678","DOIUrl":"10.1016/j.oceram.2024.100678","url":null,"abstract":"<div><div>In this work, waste fiberglass was up-cycled, alone, or mixed with used alumina-zirconia-silica (AZS) refractory from dismantled glass melting furnaces. Alkali activation was performed by suspending fiberglass and fiberglass/AZS powders in NaOH aqueous solution of various concentrations (8M, 6M, and 3M). The activation of waste fiberglass with 8M NaOH yields a gel with calcium and sodium-containing aluminosilicate hydrates. The addition of AZS refractory enabled the release of aluminates into the solution, which had beneficial effects on the mechanical properties. Low molarity activation yielded weaker materials which could be used as precursors for firing at moderate temperatures (800 °C and 1000 °C) to create cellular glass-ceramics, with a total porosity of up to 92 %. The firing of 8M activated samples resulted in glass ceramics with a 66–75 % porosity range and compressive strength of 10–23Mpa. The compressive strength-to-density ratio before and after firing was comparable to that of established commercial construction materials.</div></div>","PeriodicalId":34140,"journal":{"name":"Open Ceramics","volume":"20 ","pages":"Article 100678"},"PeriodicalIF":2.9,"publicationDate":"2024-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2666539524001421/pdfft?md5=783a37ab9bb7d678dcb2dc28be7e36df&pid=1-s2.0-S2666539524001421-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142312601","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In recent years, porous ceramics have been widely studied because of their excellent technological properties. The intrinsic technological characteristics depend on the forming process and the application for which the materials are intended. A clay raw material (75 mass%) which is rich in melting oxides and waste peanut shells (25 mass%) were used to manufacture porous ceramics for the removal of arsenic from borehole water in Burkina Faso. A borehole water analysis shows a concentration of arsernic of 39 μg L−1 above the WHO standard. The porous ceramics were obtained from samples shaped by unidirectionnal pressing and after sintering at 900 °C (MKOR9) or 1100 °C (MKOR11). Unlike MKOR9 materials, MKOR11 materials consist of 27 % mullite phases. MKOR9 and MKOR11 porous materials presented a diametrical compression stress to rupture greater than 0.15 MPa, as recommended in the literature for ceramic filters. The obtained permeability value of MKOR11 ceramic materials (53,802 L/h.m2.bar) is much higher than that of MKOR9 (18596 L/h m2 bar), although its open porosity (61 %) is lower than that of MKOR9 materials (65 %). The removal rate obtained with MKOR9 is 24 % compared to 95 % for MKOR11. MKOR11 filters almost completely reduce arsenic concentration below the WHO limit values, which is not the case for MKOR9 materials. The adsorption kinetics and thermodynamic parameters showed that the adsorption process is the chemisorption. This work has shown that MKOR11 ceramic filters have a very impressive effectiveness, and they could be manufactured for the benefit of the remote population.
{"title":"Mullite effect on the ceramic filters effectiveness in the removal of arsenic from borehole water from Burkina Faso","authors":"Kassoum Barry , Gisèle Laure Lecomte‐Nana , Nassio Sory , Moussa Ouedraogo , Loukou Sawadogo , Moustapha Sawadogo , Issaka Sanou , Mohamed Seynou , Lamine Zerbo , Philippe Blanchart","doi":"10.1016/j.oceram.2024.100679","DOIUrl":"10.1016/j.oceram.2024.100679","url":null,"abstract":"<div><div>In recent years, porous ceramics have been widely studied because of their excellent technological properties. The intrinsic technological characteristics depend on the forming process and the application for which the materials are intended. A clay raw material (75 mass%) which is rich in melting oxides and waste peanut shells (25 mass%) were used to manufacture porous ceramics for the removal of arsenic from borehole water in Burkina Faso. A borehole water analysis shows a concentration of arsernic of 39 μg L<sup>−1</sup> above the WHO standard. The porous ceramics were obtained from samples shaped by unidirectionnal pressing and after sintering at 900 °C (MKOR9) or 1100 °C (MKOR11). Unlike MKOR9 materials, MKOR11 materials consist of 27 % mullite phases. MKOR9 and MKOR11 porous materials presented a diametrical compression stress to rupture greater than 0.15 MPa, as recommended in the literature for ceramic filters. The obtained permeability value of MKOR11 ceramic materials (53,802 L/h.m2.bar) is much higher than that of MKOR9 (18596 L/h m<sup>2</sup> bar), although its open porosity (61 %) is lower than that of MKOR9 materials (65 %). The removal rate obtained with MKOR9 is 24 % compared to 95 % for MKOR11. MKOR11 filters almost completely reduce arsenic concentration below the WHO limit values, which is not the case for MKOR9 materials. The adsorption kinetics and thermodynamic parameters showed that the adsorption process is the chemisorption. This work has shown that MKOR11 ceramic filters have a very impressive effectiveness, and they could be manufactured for the benefit of the remote population.</div></div>","PeriodicalId":34140,"journal":{"name":"Open Ceramics","volume":"20 ","pages":"Article 100679"},"PeriodicalIF":2.9,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2666539524001433/pdfft?md5=48081fe340f3d52875c863e0f52688c9&pid=1-s2.0-S2666539524001433-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142316155","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this study YAG (Y3Al5O12) nanopowders have been synthetized by a reverse co-precipitation method with two different designs of reactors: batch and plug-flow. The impact of both the reactor design and the synthesis temperature on the features of nanopowders so-synthetized was studied. The reactor design governs the pH evolution and precipitation kinetics during synthesis. Correlations were found between the reactor design and nanopowders stoichiometry and morphology. The plug-flow reactor allows obtaining homogeneous, well-crystallized and single-phased YAG nanopowders after calcination. Then, the sintering ability of as-obtained nanopowders was investigated. Fully dense YAG-based ceramics were obtained with the nanopowders made from the plug-flow reactor by combining uniaxial pressing and sintering at 1700 °C. Finally, a plug-flow reactor with very simple and inexpensive design would allow easier upscale of the synthesis process of YAG-based nanopowders with well-controlled morphology and stoichiometry. As a result, YAG based transparent ceramic were obtained without sintering additive.
{"title":"Elaboration of Yttrium Aluminum Garnet (YAG) nanopowders and ceramics: Comparison between batch and plug-flow reactor","authors":"Florian Delaunay, Lucie Chrétien, Rémy Boulesteix, Alexandre Maître","doi":"10.1016/j.oceram.2024.100675","DOIUrl":"10.1016/j.oceram.2024.100675","url":null,"abstract":"<div><div>In this study YAG (Y<sub>3</sub>Al<sub>5</sub>O<sub>12</sub>) nanopowders have been synthetized by a reverse co-precipitation method with two different designs of reactors: batch and plug-flow. The impact of both the reactor design and the synthesis temperature on the features of nanopowders so-synthetized was studied. The reactor design governs the pH evolution and precipitation kinetics during synthesis. Correlations were found between the reactor design and nanopowders stoichiometry and morphology. The plug-flow reactor allows obtaining homogeneous, well-crystallized and single-phased YAG nanopowders after calcination. Then, the sintering ability of as-obtained nanopowders was investigated. Fully dense YAG-based ceramics were obtained with the nanopowders made from the plug-flow reactor by combining uniaxial pressing and sintering at 1700 °C. Finally, a plug-flow reactor with very simple and inexpensive design would allow easier upscale of the synthesis process of YAG-based nanopowders with well-controlled morphology and stoichiometry. As a result, YAG based transparent ceramic were obtained without sintering additive.</div></div>","PeriodicalId":34140,"journal":{"name":"Open Ceramics","volume":"20 ","pages":"Article 100675"},"PeriodicalIF":2.9,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142421925","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-10DOI: 10.1016/j.oceram.2024.100671
A.D. Chertova , A. Yu. Potanin , P. Feng , X. Ren , E.A. Levashov , Ph. V. Kiryukhantsev-Korneev
This study focuses on fabrication of a Mo30Si60B10 coating with elevated silicon content, which enhances working properties of Mo-alloy based on the Т2 phase (t-Mo5SiB2). The Mo30Si60B10 coating has a columnar structure. The alloy is characterized by hardness of 17 GPa; Young's modulus of 304 GPa, and elastic recovery of 29 %. Deposition of the coating increased hardness by 40 %; the Young's modulus, by 18 %; and elastic recovery, by 25 %. Oxidation tests at 1200 °C demonstrated that the specific mass loss of the alloy with Mo30Si60B10 coating was 1.5-fold lower than that of the uncoated alloy. An 18 μm thick oxide layer based on a-SiВO and containing MoO2 particles was formed on the alloy surface. The coating contributes to a ∼14-fold reduction of oxide layer thick. The increase in oxidation resistance of alloy after coating deposition is related to sealing of substrate defects and formation of an a-SiВO layer with elevated silicon content.
{"title":"The oxidation-resistant Mo30Si60B10 coating for protection of the T2 phase-based molybdenum alloy","authors":"A.D. Chertova , A. Yu. Potanin , P. Feng , X. Ren , E.A. Levashov , Ph. V. Kiryukhantsev-Korneev","doi":"10.1016/j.oceram.2024.100671","DOIUrl":"10.1016/j.oceram.2024.100671","url":null,"abstract":"<div><div>This study focuses on fabrication of a Mo<sub>30</sub>Si<sub>60</sub>B<sub>10</sub> coating with elevated silicon content, which enhances working properties of Mo-alloy based on the Т<sub>2</sub> phase (t-Mo<sub>5</sub>SiB<sub>2</sub>). The Mo<sub>30</sub>Si<sub>60</sub>B<sub>10</sub> coating has a columnar structure. The alloy is characterized by hardness of 17 GPa; Young's modulus of 304 GPa, and elastic recovery of 29 %. Deposition of the coating increased hardness by 40 %; the Young's modulus, by 18 %; and elastic recovery, by 25 %. Oxidation tests at 1200 °C demonstrated that the specific mass loss of the alloy with Mo<sub>30</sub>Si<sub>60</sub>B<sub>10</sub> coating was 1.5-fold lower than that of the uncoated alloy. An 18 μm thick oxide layer based on a-SiВO and containing MoO<sub>2</sub> particles was formed on the alloy surface. The coating contributes to a ∼14-fold reduction of oxide layer thick. The increase in oxidation resistance of alloy after coating deposition is related to sealing of substrate defects and formation of an a-SiВO layer with elevated silicon content.</div></div>","PeriodicalId":34140,"journal":{"name":"Open Ceramics","volume":"20 ","pages":"Article 100671"},"PeriodicalIF":2.9,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2666539524001354/pdfft?md5=f4d37c845da45b3223e556cf4839d164&pid=1-s2.0-S2666539524001354-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142312647","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-10DOI: 10.1016/j.oceram.2024.100673
Parisa Naghadian Moghaddam , Ivana Parchovianská , Branislav Hruška , Anna Prnová , Amirhossein Pakseresht , Milan Parchovianský , Dušan Galusek
This study investigated the impact of La2Zr2O7 (LZ) and different types of glass on the performance of polymer-derived ceramic (PDC) coatings on AISI 441 stainless steel substrates. Four double-layer PDC-based glass-ceramic coatings containing LZ and different glass fillers were prepared by dip coating. The LZ powder was synthesised by solid-state reaction (SSR): powder morphology, crystal structure, and thermal stability were analysed. X-ray diffraction (XRD) detected a LZ pyrochlore phase after annealing at 1300 and 1400 °C with a trace of t-ZrO2. Four different glass compositions, namely BaO-Al2O3-SiO2 (BAS), BaO-Al2O3-La2O3-B2O3-SiO2 (BALBS), CaO-B2O3-SiO2 (CBS), and BaO-ZnO-MgO-B2O3-SiO2 (BZMBS), were also synthesised as fillers for PDC coatings. The glass transition and crystallisation temperatures of the glasses were determined using differential scanning calorimetry (DSC). The coating systems, consisting of a Durazane 2250 bond coat and a top coat (Durazane 1800 + LZ filler + different glass sealants), were prepared. After pyrolysis of the coatings at 900 °C, some of the glasses partially crystallised. Scanning electron microscopy (SEM) revealed that the layers containing BAS, BALBS and CBS glass were dense, with good adhesion to the substrate, and with occasional presence of larger pores and cracks. Delamination of the upper layer was observed in the coating with the BZMBS glass filler.
{"title":"Polymer-derived coatings with La2Zr2O7 and glass fillers: Preparation and characterisation","authors":"Parisa Naghadian Moghaddam , Ivana Parchovianská , Branislav Hruška , Anna Prnová , Amirhossein Pakseresht , Milan Parchovianský , Dušan Galusek","doi":"10.1016/j.oceram.2024.100673","DOIUrl":"10.1016/j.oceram.2024.100673","url":null,"abstract":"<div><p>This study investigated the impact of La<sub>2</sub>Zr<sub>2</sub>O<sub>7</sub> (LZ) and different types of glass on the performance of polymer-derived ceramic (PDC) coatings on AISI 441 stainless steel substrates. Four double-layer PDC-based glass-ceramic coatings containing LZ and different glass fillers were prepared by dip coating. The LZ powder was synthesised by solid-state reaction (SSR): powder morphology, crystal structure, and thermal stability were analysed. X-ray diffraction (XRD) detected a LZ pyrochlore phase after annealing at 1300 and 1400 °C with a trace of t-ZrO<sub>2</sub>. Four different glass compositions, namely BaO-Al<sub>2</sub>O<sub>3</sub>-SiO<sub>2</sub> (BAS), BaO-Al<sub>2</sub>O<sub>3</sub>-La<sub>2</sub>O<sub>3</sub>-B<sub>2</sub>O<sub>3</sub>-SiO<sub>2</sub> (BALBS), CaO-B<sub>2</sub>O<sub>3</sub>-SiO<sub>2</sub> (CBS), and BaO-ZnO-MgO-B<sub>2</sub>O<sub>3</sub>-SiO<sub>2</sub> (BZMBS), were also synthesised as fillers for PDC coatings. The glass transition and crystallisation temperatures of the glasses were determined using differential scanning calorimetry (DSC). The coating systems, consisting of a Durazane 2250 bond coat and a top coat (Durazane 1800 + LZ filler + different glass sealants), were prepared. After pyrolysis of the coatings at 900 °C, some of the glasses partially crystallised. Scanning electron microscopy (SEM) revealed that the layers containing BAS, BALBS and CBS glass were dense, with good adhesion to the substrate, and with occasional presence of larger pores and cracks. Delamination of the upper layer was observed in the coating with the BZMBS glass filler.</p></div>","PeriodicalId":34140,"journal":{"name":"Open Ceramics","volume":"20 ","pages":"Article 100673"},"PeriodicalIF":2.9,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2666539524001378/pdfft?md5=9ab7d47fa6c3b26ccbccd169aaa21b01&pid=1-s2.0-S2666539524001378-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142230637","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-08DOI: 10.1016/j.oceram.2024.100672
T.M. Gross, D.E. Baker, L. Cai, B.M. Abel, I. Dutta, B.J. Rice
An immiscible glass system consisting of a continuous silica-rich phase and a discontinuous droplet phase enriched in phosphorus form the glassy framework for a novel magnetite glass-ceramic. Upon cooling from the molten state, the material phase separates into the droplet-in-matrix structure and magnetite precipitates spontaneously within the phosphorus-enriched droplet phase. Magnetic hysteresis curves of an exemplary magnetite glass-ceramic show a saturation magnetization of ∼20 emu/g and magnetic remanence of 2.6 emu/g for a maximum externally applied field of 30 kOe. This novel material space provides a simple and economical means to produce magnetite glass-ceramics with potential suitability for a variety of biomedical applications.
由连续的富硅相和不连续的富磷液滴相组成的不相溶玻璃体系构成了新型磁铁矿玻璃陶瓷的玻璃框架。从熔融状态冷却后，材料相分离成液滴-基质结构，磁铁矿自发沉淀在富磷液滴相中。示例磁铁矿玻璃陶瓷的磁滞曲线显示，在最大外加磁场为 30 kOe 时，饱和磁化率为 ∼20 emu/g，磁剩磁为 2.6 emu/g。这种新型材料空间为生产磁铁矿玻璃陶瓷提供了一种简单而经济的方法，具有适合各种生物医学应用的潜力。
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Pub Date : 2024-09-07DOI: 10.1016/j.oceram.2024.100668
Enrico Storti , Patricia Kaiser , Marc Neumann , Alban Metallari , Filippo Gobbin , Hamada Elsayed , Jana Hubálková , Paolo Colombo , Christos G. Aneziris
In this work, refractory components based on alumina were produced by binder jetting using a large-scale 3D printer. The formulation contained several particle fractions up to a grain size of 3 mm, equal to the printer resolution. The binder system contained fine dead burnt magnesia, milled citric acid and reactive alumina, which were added to the aggregate mixture to create the powder bed. Deionized water was deposited from the printer's nozzles and triggered the binding reaction between the magnesia and citric acid. After 24 h, the printed samples were removed from the powder bed, dried and sintered at 1600 °C for 5 h. Reactive alumina contributed to the in situ creation of magnesium aluminate spinel at high temperature. The samples were characterized in terms of Young's modulus of elasticity, bending and compressive strength in 2 directions (parallel and perpendicular to the printing direction). The broken parts were used to investigate physical properties such as the open porosity and bulk density. The microstructure was studied by means of computed tomography. Finally, powder samples were used to determine the phase composition at different stages of production by means of XRD.
在这项工作中，使用大型 3D 打印机通过粘合剂喷射生产出了基于氧化铝的耐火材料。配方中包含几种颗粒，最大粒度为 3 毫米，相当于打印机的分辨率。粘合剂系统包含细碎的烧镁砂、研磨的柠檬酸和活性氧化铝，将其添加到骨料混合物中以形成粉末床。去离子水从打印机喷嘴喷出，引发氧化镁和柠檬酸之间的粘合反应。24 小时后，从粉末床中取出打印样品，干燥并在 1600 °C 下烧结 5 小时。样品在两个方向（平行于印刷方向和垂直于印刷方向）的杨氏弹性模量、弯曲强度和抗压强度方面进行了表征。破碎部分用于研究物理性质，如开放孔隙率和体积密度。通过计算机断层扫描对微观结构进行了研究。最后，利用 XRD 对粉末样品进行分析，以确定不同生产阶段的相组成。
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