Study on the influence of different additives on the rheological properties of gadolinium oxysulfide slurry prepared for tape casting

Abstract

Gadolinium oxysulfide (Gd2O2S, GOS) doped with rare earth elements was often used as imaging materials for X-Ray imaging equipment because of its excellent properties of absorbing incident X-rays and converting them into visible light. The flat-panel detector based on the GOS phosphor screen is the core imaging component of the digital radiography. In this paper, GOS slurry was prepared to form phosphor screen by tape casting, and the influence of slurry solvents and different additives on the rheological properties of the slurry was systematically studied. Based on the results of rheological properties, the optimal solid content of the slurry and the optimal addition range of the additives, like dispersants, binders and plasticizers, were determined. The solid content of the slurry is 70%, and the best amount of dispersant is 0.5%~1% of the powder mass. The optimized dosage of binder is 4.5%~7% of the powder mass, and the best plasticizer content is 1.0~1.5 times of the binder content. Then, the GOS fluorescent layer with smooth and flat surface, uniform and controllable thickness, and good bonding ability, was successfully prepared by tape casting the optimized slurry.