ORIGINAL PAPER Characterization Properties of Diopside Glass (Cu 0.50 Ca 0.75 Mg 0.75 Si 2 O 6 ) Containing Cr 2 O 3 or TiO 2 Reham M.M. Morsi 1 & Gehan T. El-Bassyouni 2 & Esmat M. A. Hamzawy 3 Received: 28 June 2021 /Accepted: 31 August 2021 # Springer Nature B.V. 2021 Abstract The characterization of diopside –based glass of the composition Cu 0.50 Ca 0.75 Mg 0.75 Si 2 O 6 containing small additions of Cr 2 O 3 or TiO 2 was explored. The techniques used for the characterization process include AC conductivity (σ ac ), X-ray diffraction (XRD) and Scanning electron microscopy (SEM). However, the prepared dark green glasses show very little devitrification of traces diopside, cuprite and tenorite. The SEM shows a massive structure at the nanoscale with little scattered clusters of nano crystals of the latter phases. The σ ac was measured within the frequency range of 0.042 kHz -1 MHz and at the temperature range of 298– 573 (K). The electrical conductivity measurements proved that the incorporation of Cr 2 O 3 and TiO 2 results in higher conductivity values than those of the free glass sample. The activation energy of each of these glasses was estimated at high temperature range. The calculated activation energy values measured at 100 kHz and 1 MHz of the glass samples lie in the range 0.55–0.98 (eV). The prepared glass samples exhibited semiconducting nature. Keywords Cu- containing glass . Devitrification . Electrical properties . Diopside glass 1 Introduction Diopside (MgCaSi 2 O 6 ) is a monoclinic prismatic mineral that arranges in a patchily colored patter. However, it frequently has a dull green clear to translucent crystals [1]. Diopside of interlaced structure; encompasses chain structure. The bene- fits of the core crystal phase with diopside have good mechan- ical properties, chemical stability, and the crystallization abil- ity of pyroxene is remarkable [2]. Diopside based glass has numerous exceptional properties, such as chemical and me- chanical properties [3–5]. The bases of raw materials are dif- ferent, and its preparation is simple. The adding of operative nucleating agents such as Cr 2 O 3 and TiO 2 [6–9] could be used for epitaxial growth, to tempt the precipitation of diopside, in the CaO–MgO–Al 2 O 3 –SiO 2 (CMAS) glass ceramics. The role of the nucleating agents must be elucidated [10]. In 2016, Sycheva et al., reflected that spinel (MgCr 2 O 4 ) or spinel-like solid solution (Mg, Fe) (Al, Fe, Cr) 2 O 4 , can be used as the basic of diopside (CaMgSi 2 O 6 ) crystallization [11]. Depending on the high chemical stability of diopside and its coefficient of thermal expansion, diopside (CaMgSi 2 O 6 ) based glass have been known as promising ma- terials for solid oxide cell (SOC) sealing applications [12, 13]. Liu et al. emphasized that amorphous metal oxide semicon- ductors are of essential and technological interest owing to their high carrier mobility and large-area uniformity [14]. Differential thermal analyses, X-ray diffraction, scanning electron microscopy as well as physical and dielectric proper- ties were used to characterize and investigate the influence of the Cr 2 O 3 content on the structure and properties of glass ceramics [15]. The heat treatment temperature and the per- centage of TiO 2 were found to affect the microwave dielectric properties of the glass-ceramic composite material, where the dielectric constant was influenced by the crystallite size and the TiO 2 content [16]. The addition of Cr 2 O 3 into glass ceram- ic was found to affect the crystallization, flexural strength, microstructure, thermal expansion, and the electrical proper- ties [17]. The nanostructure/ microstructure of diopside based glass ceramics have been studied by several authors [18–20]. It was reported that by varying the composition of some * Reham M.M. Morsi morsi_reham@yahoo.com 1 Physical Chemistry Department, National Research Centre, 33 El Buhouth St, Dokki, Giza 12622, Egypt 2 Refractories, Ceramics and Building Materials Department, National Research Centre, 33 El Buhouth St, Dokki, Giza 12622, Egypt 3 Glass Department, National Research Centre, 33 El Buhouth St, Dokki, Giza 12622, Egypt Silicon https://doi.org/10.1007/s12633-021-01370-3