Dielectric Characterizations and Microwave Heating Behavior of Zinc Compound in Microwave Field

The microwave absorption capabilities of zinc acetate dihydrate and ZnO are explored by measuring the dielectric characterizations (real part, imaginary part and loss tangent) from room temperature to 900∘C\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$900\, {^{\circ }}\hbox {C}$$\end{document} using the microwave cylindrical resonant cavity technique at 2450 MHz. The dielectric characterizations of zinc acetate dihydrate increase substantially below 100∘C\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$100\, {^{\circ }}\hbox {C}$$\end{document} and present a linearly with temperature due to the evaporation of crystal water. As the temperature continues to increase, the three parameters decrease dramatically. Additionally, variations of ε′\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\varepsilon '$$\end{document}, ε′′\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\varepsilon ''$$\end{document} and tan δ\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\updelta $$\end{document} are presented narrowly at different temperatures for ZnO. The decreasing penetration depth within the room temperature to 100∘C\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$100\, {^{\circ }}\hbox {C}$$\end{document} indicates the microwave absorption capability of crystal water is realized much more positive than Zn(OAc)2\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\hbox {Zn(OAc)}_{2}$$\end{document} and ZnO. And the results also show that the absorption capability of free water is much larger than crystal water. Heating curves of zinc acetate dihydrate and ZnO at different power levels (400, 600 and 800 W) further suggest that the absorption capability of ZnO is perceived most poor. A higher crystallinity and smaller particle size can be obtained by microwave heating compared with conventional heating.