*Article* **Processing of Calcium Magnesium Silicates by the Sol–Gel Route**

**Andrada-Elena Alecu, Claudiu-Constantin Costea, Vasile-Adrian Surdu , Georgeta Voicu, Sorin-Ion Jinga and Cristina Busuioc \***

> Department of Science and Engineering of Oxide Materials and Nanomaterials, Faculty of Chemical Engineering and Biotechnologies, University Politehnica of Bucharest, RO-060042 Bucharest, Romania

**\*** Correspondence: cristina.busuioc@upb.ro

**Abstract:** In this work, calcium magnesium silicate ceramics were processed through the sol–gel method in order to study the crystalline and morphological properties of the resulting materials in correlation with the compositional and thermal parameters. Tetraethyl orthosilicate and calcium/magnesium nitrates were employed as sources of cations, in ratios specific to diopside, akermanite and merwinite; they were further subjected to gelation, calcination (600 ◦C) and thermal treatments at different temperatures (800, 1000 and 1300 ◦C). The properties of the intermediate and final materials were investigated by thermal analysis, scanning electron microscopy, energy dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction and Rietveld refinement. Such ceramics represent suitable candidates for tissue engineering applications that require porosity and bioactivity.

**Keywords:** silicates; diopside; akermanite; merwinite; sol–gel; tissue engineering

**Citation:** Alecu, A.-E.; Costea, C.-C.; Surdu, V.-A.; Voicu, G.; Jinga, S.-I.; Busuioc, C. Processing of Calcium Magnesium Silicates by the Sol–Gel Route. *Gels* **2022**, *8*, 574. https:// doi.org/10.3390/gels8090574

Received: 25 August 2022 Accepted: 7 September 2022 Published: 9 September 2022

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