The Preparation And Properties Of Vanadate Glass-ceramic

The glass ceramics containing Ba₃?VO₄?₂ and Sr6V2O11 were prepared by melting quenching method.The optimum ratios of raw materials were determined by optimizing the formula composition.The heat treatment method,crystallization,micro morphology,thermal properties and mechanical properties of the samples were studied.The effects of SiO₂/B₂O₃ on the crystallization and properties of glass ceramics containing Ba₃?VO₄?₂ were analyzed by using XRD,expanding curves and hardness measurement etc..The results indicated that the best heat treatment method the glass ceramics containing Ba₃?VO₄?₂ samples: crystallization temperature of is 540?,for 2h;the transition temperature?Tg?and the softening temperature?Tf?are 320 ?and 500?,respectively,the coefficient of thermal expansion is 17.81×10-6?-1,and the hardness is 388 HV.The samples can achieve sealing material requirements used to replace the traditional lead sealing material;The glass ceramics containing Sr6V2O11 samples were obtained by two-step crystallization heat treatment: the nucleation temperature is 520 for 1h,the crystallization ?temperature is 600 ?for 2h,Tg and Tf are 375 ?and 520?,respectively,the thermal expansion coefficient of glass ceramics is 13.2×10-6?-1,the hardness value is 437 HV.The samples can achieve sealing material requirements.The crystalline degree changes and the coefficient of thermal expansion decreases and the hardness increases with the increase of SiO₂/B₂O₃.When the ratio of SiO₂/B₂O₃ is 4:1,the crystal phase is changed.