Preparation And Characterization Of Barium-based Titanate Ceramic Fibers

Along with the development of technology, the requirement becomes stricter and stricter with the materials, especially some properties in high temperature, such as chemical stability, structural stability and reliability. Many researches indicated that continuous ceramic fibrous materials have excellent potent in this points which differ from conventional ceramic sinter. In the semiconductor materials including titanium, BaTiO₃ has reached a higher degree and possess representation to a certainty either in realistic applications or in theoretical depth. Perovskite BaTiO₃ are of interest owing to their excellent ferroelectric and dielectric properties. It has been extensively applied in the preparation of high dielectric capacitors, positive temperature coefficient (PTC) resistors, transducers and ferroelectric memories. At present, with the rapid development of the electronic and micro-electronic industries, the exploitation and appliance of advanced composite materials in sophisticated technical areas, the research and preparation of BaTiO₃ ceramic fibers become increasingly outstanding.To date, many investigations have focused on the ceramic fibers, and some methods such as melt/drawing method, slurry method, solution dipping method, CVD (chemical vapor deposition)method, CVR(chemical vapor reaction) method, sol-gel method, preceramic polymer method, hydrothermal method have been developed for the preparation of the ceramic fibers. The processes have their advantages and disadvantages, compared with other methods, sol-gel method has its advantages. So in this paper we introduce sol-gel process to synthesize barium titanate ceramic fibers.The main work is as the follows:1. The preparation of stable sol In order to synthesize the ceramic BaTiO₃-based fibers with high-performance, the preparation of the stable sol is a very important step. Based on many literatures, we have done some researches on the influences of different raw materals, solvent, water, catalyst, HAc, chelating agents and concentration, respectively on the stabilization of sol, microstructure and morphology of the fibers. We have gotten the optimum condition here.2. The preparation and characterization of BaTiO₃ ceramic fibersAccording to the optimum condition which we have chosen to synthesize the BaTiO₃ precursor sol and depend on the TGA-DTA,FT-IR,XRD and SEM, we have studied the influences of annealing temperature, annealing time and heating rate on the morphology and microstructure of the fibers.3. The preparation and characterization of alkaline–earth metals doping BaTiO₃ ceramic fibersA series of alkaline earth metals (Mg,Ca,Sr) doped BaTiO₃ ceramic fibers were prepared by sol-gel process. We have investigated the effect of alkaline-earth metals doping on the unit cell parameters, grain-size, microstructure and morphology of BaTiO₃ fibers. According to the experiment, we have found that alkaline-earth metals could change the microstructure, unit cell parameters and morphology.