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About this book

This book investigates the effect of sintering temperature on willemite based glass-ceramic doped with different content of Er2O3. It is the first to report research on producing willemite by using waste materials and using trivalent erbium (Er3+) as a dopant. This book provides a survey of the literature on glass and glass-ceramic, while comprehensive experiments and analysis have been performed on the material used.

Table of Contents


Chapter 1. Introduction to Glass and Glass-Ceramic Background

Glass is a product of inorganic fusion obtained by cooling down molten inorganic materials to a rigid condition. Glass ceramics are known, which include an amorphous phase and one or more crystalline phases. Nowadays, glass ceramics are used in different fields such as communications technology and electrical devices. Sintering is known as a shaping process for materials, such as glass and glass ceramics, with extremely high melting points. For instance, in the fabrication of semiconductors, impurities are usually introduced into the host lattice to modify their electrical and optical properties. Doping processes are mainly important for the creation of electronic junctions in silicon and for manufacturing of semiconductor devices. At present, phosphate glasses are commonly utilized for bulk laser applications. However, they are not very suitable for integrated optics purposes, because of their poor chemical stability and low transition temperatures. Conversely, silicate glasses have much better chemical stability, which is important for ion exchange techniques to fabricate optical wave guides. Among oxide glasses, phosphate and silicate glasses are the two most important materials, and they have been used extensively for lasers and fiber. Compared with silicate glasses, phosphate glasses are more limited in their use because they are hydroscopic in nature and have a lower glass transition temperature.
Gholamreza Vahedi Sarrigani, Iraj Sadegh Amiri

Chapter 2. Literature Review of Glass-Ceramic and Willemite Production from Waste Materials

The first attempt to produce a glass ceramic from waste material was reported as early as the 1960s and involved use of several types of slag of ferrous and nonferrous metallurgy, ash, and waste from the mining and chemical industries. Willemite (Zn2SiO4), which is a good host for rare earths to be used in telecommunications, has been produced by different methods from pure materials. However, there is a lack of research on preparation of willemite using waste materials. To date, most research has been carried out on soda lime silicate (SLS) glass doped with different ingredients and rare earths, but little research has been carried out on willemite-based glass ceramics prepared using waste material and doped with erbium oxide (Er2O3). However, use of waste materials, such as SLS glass, as a main source for producing silicate will be economical, inexpensive, and helpful for reducing the aggregation of waste materials in landfills. The main objective of this study is to determine the effects of addition of erbium oxide (Er2O3) on the physical and optical properties of willemite-based glass ceramic sintered at different temperatures.
Gholamreza Vahedi Sarrigani, Iraj Sadegh Amiri

Chapter 3. Methodology for Preparation Samples from Waste and Techniques for Characterization

The samples were produced via melt-quenching technique followed by powdering, pressing, and sintering. In the first stage the soda-lime-silicate (SLS) glasses were crushed, grounded, and sieved to gain the expected particle size. The prepared powder was mixed with ZnO followed by melting at the temperature of 1400 °C and quenching in water to obtain fritz glass. The prepared fritz glass was crushed using mortar and pestle to the size of 63 μm. After that the prepared powder was heat treated at the temperature of 1000 °C to produce willemite. The willemite-based glass-ceramic was doped with trivalent erbium (Er3+) in the ([(ZnO)0.5(SLS)0.5]1-x[Er2O3]x) composition where x = 1–5 wt.%. At the end, the powder was pressed, and different pallets were prepared and finally sintered at different temperatures ranging from 500 to 1100 °C. The crystal (phase) changes with different contents of Er2O3, and different sintering temperatures were investigated using X-ray diffraction (XRD); the binding structure was explored by Fourier-transform infrared spectroscopy (FTIR); the microstructure, morphology, and chemical composition were studied using field emission scanning electron microscope (FESEM) along with EDAX; and the optical properties were analyzed by UV-VIS spectroscopy.
Gholamreza Vahedi Sarrigani, Iraj Sadegh Amiri

Chapter 4. Result and Discussion

The XRD results show that well crystalline willemite (Zn2SiO4) with the contribution of dopant (Er3+) in the lattice can be achieved at the temperature of 900 °C. The XRD results also show that rhombohedral crystalline willemite was formed by mixing ZnO and SLS glass and optimum heat treatment of 1000 °C to produce willemite-based glass-ceramics, the solid-state reaction between well-crystallized willemite and Er3+ was obtained at 900 °C sintering temperature, and Er3+ can be completely dissolved in the lattice at this temperature. FTIR results confirmed the appearance of the vibrations of SiO4 and ZnO4 groups which clearly suggests the formation of the Zn2SiO4 phase; the compositional evaluation of the FTIR properties of the [(ZnO)0.5(SLS)0.5]1−x[Er2O3]x system indicates that the presence of erbium ions affects the surrounding of the Si–O and trivalent erbium occupies their position; these agree with the XRD data at the peak positioned at 20.29°. The most significant modification produced by the addition of erbium and the increase of the heat treatment temperature of the studied samples shows a drop in the intensity of FTIR band located at 513 cm−1, which indicates that the addition of erbium oxide and increase in the sintering temperature decline the presence of SiO4 group. The microstructure analysis of the samples using FESEM shows that the average grain size of samples tends to increase from 325.29 to 625.2 nm as the sintering temperature increases. Finally, the UV-VIS spectra of all doped glass-ceramics depict absorption band due to host matrix network and the presence of Er2O3. The results show that the intensity of the bands tends to grow by increasing the Er2O3 content in the range of 1–5 wt.% and the sintering temperature in the 500–900 °C range, followed by a drop at the temperatures of 1000 and 1100 °C. By adding the Er2O3 content to the host network and increasing the sintering temperature from 500 to 900 °C , the intensity of UV-VIS bands situated between 400 and 1800 nm increased due to the absorption of Er3+ions and the host crystal structure. The intensity of the UV bands was observed to have dropped when the sintering temperature was increased to 1000 and 1100 °C, which indicates that by going to the temperature of 1000 and 1100 °C, the Er2O3 particles tend to produce cluster that causes the decrease in the UV absorption bands. For the sample with x = 5 wt.% Er2O3, two strong absorption bands situated at about 1535 and 523 nm were observed. These bands were attributed to the optical transition from 4I15/2 to 4I13/2 and 4S3/2 state, respectively.
Gholamreza Vahedi Sarrigani, Iraj Sadegh Amiri

Chapter 5. Conclusion and Future Research in the Glass-Ceramic Field

This book has focused on the effect of the sintering temperature on willemite-based glass ceramic doped with different percentages of Er2O3. The willemite-based glass ceramic was prepared using waste soda lime silicate (SLS) glass and ZnO. Er2O3 was used as a rare earth, in different percentages, to dope the willemite, and the prepared samples were sintered at a temperature of 500–1100 °C. Finally, 35 samples were prepared.
Gholamreza Vahedi Sarrigani, Iraj Sadegh Amiri


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