en گروه سرامیک Ceramic Materials and Engineering Research Paper Research Paper <span style="font-size:12.0pt"><span new="" roman="" style="font-family:" times="">This study systematically investigates the crystallization behavior, phase evolution, and dielectric properties of a BaO-Al₂O₃-SiO₂ glass system modified with 10 wt% TiO₂. Thermal characterization revealed that TiO₂ addition notably reduced the glass transition temperature (from 781.6&deg;C to 779.4&deg;C) and softening point (from 838&deg;C to 824.8&deg;C) compared to the TiO₂-free glass, consequently decreasing the calculated nucleation temperature (from 810&deg;C to 800&deg;C). While differential thermal analysis indicated sluggish crystallization kinetics, isothermal heat treatments identified 1000&deg;C as the optimal processing temperature, leading to the development of a multiphase crystalline assemblage that beneficially included the target monoclinic Ba_3.75Al_7.5Si_8.5O₃₂ phase, which was absent in the TiO₂-free glass<b>.</b> X-ray diffraction identified this phase, along with celsian (BaAl₂Si₂O₈) polymorphs and barium titanate crystallites, as the dominant crystalline phases. SEM revealed anisotropic crystal growth (1.14-1.52 &mu;m length). Dielectric characterization in the Ku-band (12.4-18 GHz) demonstrated significant property enhancements, with the relative permittivity decreasing from 10.40 to 6.38 and loss tangent improving from 0.3 to 0.2 after crystallization. These improvements, attributed to the specifically tailored crystalline phase assemblage facilitated by TiO₂, make this glass-ceramic system particularly suitable for advanced microwave applications requiring low dielectric loss and high-frequency stability. The effectiveness of TiO₂ as a crystallization modifier for achieving optimized dielectric properties through controlled devitrification and targeted phase formation is underscored.</span></span> Barium aluminosilicate glass-ceramics,crystallization,Ku-band dielectric constant,Dielectric loss tangent,TiO2 nucleating agent 104 113 http://ijmse.iust.ac.ir/browse.php?a_code=A-10-134-10&slc_lang=en&sid=1 Farhood Heydari farhood_heydari@metaleng.iust.ac.ir 1800319475328460021063 1800319475328460021063 No School of Metallurgy and Materials Engineering, Iran University of Science & Technology seyed mohammad Mirkazemi mirkazemi@iust.ac.ir 1800319475328460021064 1800319475328460021064 Yes School of Metallurgy and Materials Engineering, Iran University of Science & Technology Bijan Eftekhari Yekta BEftekhari@iust.ac.ir 1800319475328460021065 1800319475328460021065 No School of Metallurgy and Materials Engineering, Iran University of Science & Technology Seyyed Salman Seyyed Afghahi salmanafghahi@gmail.com 1800319475328460021066 1800319475328460021066 No Department of Materials Science and Engineering, Imam Hossein University, Tehran, Iran