Rajat Durgesh Ramteke, James G. Hemrick, Manoj K. Mahapatra
{"title":"Phase formation in the CaO–Al2O3–ZnO system as an analogue to CaO–Al2O3–MgO in spinel containing refractories","authors":"Rajat Durgesh Ramteke, James G. Hemrick, Manoj K. Mahapatra","doi":"10.1111/jace.20393","DOIUrl":"https://doi.org/10.1111/jace.20393","url":null,"abstract":"<p>Recently, gahnite (ZnAl<sub>2</sub>O<sub>4</sub>) is gaining attraction as a potential refractory ceramic because of the similarity of its structure and properties with those of magnesium aluminate (MgAl<sub>2</sub>O<sub>4</sub>) spinel refractories. Formation of MgO and hibonite solid solution (CaMg<i><sub>x</sub></i>Al<sub>12−</sub><i><sub>x</sub></i>O<sub>19−0.5</sub><i><sub>x</sub></i>; 0 ≤ <i>x</i> ≤ 0.18), CAM-I (Ca<sub>2</sub>Mg<sub>2−3</sub><i><sub>x</sub></i>Al<sub>28+2</sub><i><sub>x</sub></i>O<sub>46</sub> (0 ≤ <i>x</i> ≤ 0.3), and CAM-II (CaMg<sub>2−3</sub><i><sub>x</sub></i>Al<sub>16+2</sub><i><sub>x</sub></i>O<sub>27</sub>, 0 ≤ <i>x</i> ≤ 0.2) phases with platelet and interlocking microstructure in the CaO–Al<sub>2</sub>O<sub>3</sub>–MgO ternary system significantly enhances the high temperature mechanical properties of refractory castables. The CaO–Al<sub>2</sub>O<sub>3</sub>–ZnO ternary system has been studied, for the first time to our knowledge, in a selected compositional range with reference to the CaO–Al<sub>2</sub>O<sub>3</sub>–MgO system from 1650°C to 1700°C. The formation of ZnO and hibonite solid solution (CaZn<i><sub>x</sub></i>Al<sub>12−</sub><i><sub>x</sub></i>O<sub>19−0.5</sub><i><sub>x</sub></i>; 0 < <i>x</i> < 0.18), CAZ-I (Ca<sub>2</sub>Zn<sub>2−3</sub><i><sub>x</sub></i>Al<sub>28+2</sub><i><sub>x</sub></i>O<sub>46</sub>; 0 ≤ <i>x</i> ≤ 0.3), and CAZ-II (CaZn<sub>2−3</sub><i><sub>x</sub></i>Al<sub>16+2</sub><i><sub>x</sub></i>O<sub>27</sub>; 0 ≤ <i>x</i> ≤ 0.2) phases with platelet and interlocking morphology have been found. The crystal structures and lattice parameters of ZnO and hibonite solid solution, CAZ-I, and CAZ-II are comparable, respectively, with MgO and hibonite solid solution, CAM-I, and CAM-II. Furthermore, CAZ-I and CAZ-II phases also form due to reaction between hibonite (CaO·6Al<sub>2</sub>O<sub>3</sub>) and ZnAl<sub>2</sub>O<sub>4</sub>.</p>","PeriodicalId":200,"journal":{"name":"Journal of the American Ceramic Society","volume":"108 5","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/jace.20393","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143530225","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Qinqin Xu, Ibrahim Goda, Yanming Zhang, Stefanos Papanikolaou
{"title":"Nanoindentation and deformation behaviors of \u0000 \u0000 α\u0000 $alpha$\u0000 -\u0000 \u0000 \u0000 \u0000 Al\u0000 2\u0000 \u0000 \u0000 O\u0000 3\u0000 \u0000 \u0000 ${rm Al}_2 {rm O}_3$\u0000 : A molecular dynamic study","authors":"Qinqin Xu, Ibrahim Goda, Yanming Zhang, Stefanos Papanikolaou","doi":"10.1111/jace.20390","DOIUrl":"https://doi.org/10.1111/jace.20390","url":null,"abstract":"<p>Studying the nanoindentation behavior of materials at the atomic level is crucial for advancing technologies involving energetic atom bombardment, ion implantation, and nanomechanical testing. Using molecular dynamics simulations with two typical rigid ion interatomic potentials (fixed charges), we showed that the mechanical responses and dislocation nucleation of alumina (<span></span><math>\u0000 <semantics>\u0000 <mi>α</mi>\u0000 <annotation>$alpha$</annotation>\u0000 </semantics></math>-<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msub>\u0000 <mi>Al</mi>\u0000 <mn>2</mn>\u0000 </msub>\u0000 <msub>\u0000 <mi>O</mi>\u0000 <mn>3</mn>\u0000 </msub>\u0000 </mrow>\u0000 <annotation>${rm Al}_2 {rm O}_3$</annotation>\u0000 </semantics></math>) are highly temperature- and orientation-dependent. The complex behavior in dislocation dynamics has been rationalized by computing the distribution of stacking fault energy. It is further found that SHIK potential provides better accuracy in describing dislocation dynamics at a much lower computational cost.</p>","PeriodicalId":200,"journal":{"name":"Journal of the American Ceramic Society","volume":"108 5","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143530228","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}