Effect of CeO ₂ on Viscosity and Structure of B ₂ O ₃ ‐SiO ₂ ‐Al ₂ O ₃ ‐Na ₂ O‐BaO‐TiO ₂ Glass Lubricant

ABSTRACT Glass lubricants with suitable viscosity are essential in the hot extrusion forming of Ti‐6Al‐4 V alloy. In this work, the effect of CeO 2 content on viscosity and structure of (25.5‐0.255 x )B 2 O 3 ‐(39.95‐0.400 x )SiO 2 ‐(5.95‐0.060 x )Al 2 O 3 ‐(11.05‐0.111 x )Na 2 O‐(14.55‐0.146 x )BaO‐(3‐0.030 x )TiO 2 ‐ x CeO 2 glass lubricant was investigated. At 950°C, the viscosity decreased by 42.1%, from 46.6 to 27.0 Pa·s, with an increased CeO 2 content from 0 to 12 wt.%. Using X‐ray photoelectron spectroscopy and molecular dynamics simulation, it was found that the percentages of BO, Q 4 , Q 3 , Q 2 , [AlO 4 ], [TiO 4 ], and [BO 3 ] in the melt were reduced with an increased CeO 2 content, while those of NBO, Q 1 , Q 0 , [BO 4 ], [AlO 5 ], [AlO 6 ], [TiO 5 ], and [TiO 6 ] were increased. Meanwhile, the Ce oxidation state shifted from Ce 4 + to Ce 3 + when CeO 2 content was increased, accompanied by a change in the coordination of Ce cations from predominantly 4‐coordination to 5‐ and 6‐coordination. The structural analysis showed that increasing CeO 2 content gradually depolymerized the glass network, forming unstable units that weakened the network and lowered viscosity. Furthermore, a comparative analysis of TiO 2 , CeO 2 , and BaO revealed that, at the same mass fraction, CeO 2 exhibited a weaker viscosity‐reducing capability but enhanced the thermal stability of the melt.