Thermal behavior, mass stability, and apparent high-temperature mass-loss kinetics of lead tungstate (PbWO4) single crystals
CrystEngComm, 2026 (SCI-Expanded, Scopus)
- Yayın Türü: Makale / Tam Makale
- Basım Tarihi: 2026
- Doi Numarası: 10.1039/d6ce00660d
- Dergi Adı: CrystEngComm
- Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Chemical Abstracts Core, Compendex, Academic Search Ultimate (EBSCO), Engineering Source (EBSCO)
- Gazi Üniversitesi Adresli: Evet
Özet
Lead tungstate (PbWO4) is a well-established scheelite-type oxide valued for its density, optical transparency, and radiation hardness. While the optical properties of PbWO4 have been extensively investigated, its fundamental thermal characteristics remain comparatively underexplored, despite their critical influence on device performance and long-term stability. In this work, single-crystalline PbWO4 grown by the Czochralski method was systematically examined by combining X-ray diffraction, thermogravimetric analysis (TGA), differential thermal analysis (DTA), and differential scanning calorimetry (DSC) techniques. Powder X-ray diffraction and qualitative full-pattern comparison supported the assignment of the as-grown crystal to the tetragonal scheelite PbWO4 structure. TGA indicated only a minor mass decrease of approximately 0.5% up to ∼560 °C, followed by a gradual mass loss of approximately 6.8% between 560 and 780 °C and an additional rapid terminal decrease, resulting in a residual mass of approximately 89.3% at 790 °C. Coats–Redfern analysis of the high-temperature mass-loss step yielded an apparent, model-dependent activation energy of 99.2 kJ mol−1. DSC measurements showed an endothermic feature at 340–350 °C at all three heating rates, with no corresponding pronounced mass-loss feature in the TGA trace. The peak minimum shifted toward higher temperatures with increasing heating rate. Kissinger analysis yielded an approximate apparent activation energy of 420 kJ mol−1; however, the physical or structural origin of this feature could not be identified from the present measurements. The results characterize the mass-change and heat-flow behavior of PbWO4 under flowing argon and provide apparent kinetic parameters for the observed thermal events. These findings provide condition-specific information relevant to the thermal processing and high-temperature use of PbWO4.