**5. Conclusions**

In current investigation the authors have shown the possibility for carrying out successful synthesis depending on the temperature and the applied atmosphere of well-sintered glass-ceramics and/or glass-ceramic foams.

It was shown that synthesis in inert environment leads to the production of materials with higher degree of sintering.

If properly engineered, the practice and experience show that a glassy-crystalline material with low density and high porosity of about 80% can be obtained, which can be considered as more than a satisfactory result [1, 22]. In addition thus obtained foams are characterized by fire resistance features up to 1100°C as well.

By applying a double-stage heat treatment, first stage, low temperature sintering at 950°C, and second stage, foaming at 1100°C, foam materials with improved properties and differences in the structure have been successfully obtained.

The SEM images from the fractures of both glass-ceramic foam species reveal a well-sintered material. They show a good degree of sintering and total porosity below 10–15%.

**83**

**Author details**

Nicolai B. Jordanov1

and Alexander Karamanov1

, Esmat M.A. Hamzawy2

2 Glass Research Department, National Research Centre, Cairo, Egypt

1 Institute for Physical Chemistry, Bulgarian Academy of Sciences, Sofia, Bulgaria

© 2019 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium,

\*

The authors declare no conflict of interest.

\*Address all correspondence to: karama@ipc.bas.bg

provided the original work is properly cited.

, Dragomir Tatchev1

*Sintered Iron-Rich Glass-Ceramics and Foams Obtained in Air and Argon*

Inorganic materials obtained by thermal foaming like these subjects of current investigation can be used as modern building materials, as construction materials and as insulation materials in various fields and industries, e.g., as panels or arbi-

Inorganic glassy-crystalline foam materials can be considered generally speaking as low-cost thermal insulating, soundproof and fire-resisting low-weight materials.

N.B. Jordanov gratefully acknowledges the financial support of the National Program Young Scientists and Post-docs of the Ministry of Education and Science of Republic of Bulgaria under the project "Sintered self-glazed glass-ceramics and foams from iron-rich industrial wastes." D. Tatchev and A. Karamanov express their gratitude for the support of Project BG05M2OP001-1.002-0019: "Clean technologies for sustainable environment—waters, waste, energy for circular economy." All authors are thankful for the financial support for realization of the closed experimental setup for measurements in a dual environment of the Bulgarian Science Fund (FNI) under Project DN 19/7 "Theory and application of

*DOI: http://dx.doi.org/10.5772/intechopen.88941*

trary shaped.

**Acknowledgements**

sinter-crystallization."

**Conflict of interest**

*Sintered Iron-Rich Glass-Ceramics and Foams Obtained in Air and Argon DOI: http://dx.doi.org/10.5772/intechopen.88941*

Inorganic materials obtained by thermal foaming like these subjects of current investigation can be used as modern building materials, as construction materials and as insulation materials in various fields and industries, e.g., as panels or arbitrary shaped.

Inorganic glassy-crystalline foam materials can be considered generally speaking as low-cost thermal insulating, soundproof and fire-resisting low-weight materials.
