Simulation And Experimental Study On Sintering Process Of Borosilicate Glass Ceramics

Borosilicate glass-ceramic is one of the commonly used materials in LTCC,which can be used in aerospace,laser,nuclear engineering and optoelectronics.Sintering is an important process in the preparation and application of borosilicate glass ceramics,but the problems of warpage,deformation and uneven shrinkage in the sintering process limit its application.With the development of computer simulation technology,the simulation technology represented by finite element shows great advantages in thermal analysis with its better calculation efficiency and accuracy,which provides a powerful means to solve the problems in the sintering process of borosilicate glass ceramics.Based on the analysis of the sintering mechanism of ceramic materials,the effects of heating rate,sintering temperature,cooling mode,thickness and aspect ratio of green body on the sintering of borosilicate glass ceramics were analyzed by ANSYS software,and the borosilicate ceramic green body was prepared for sintering experiment.The results of finite element analysis and experimental study show that sintering process parameters and green body structure parameters affect the quality of green body sintering by affecting the size and distribution of internal stress of support(1)The results of thermal analysis show that the faster the heating rate is,the more uneven the temperature field distribution is and the greater the maximum stress is.The results of sintering experiments show that the shrinkage of ceramic body in three directions is more uniform when the heating rate is 1℃/min.(2)The results show that the distribution of temperature field is similar under different sintering temperatures(800℃,850℃,900℃),but the thermal stress and deformation increase with the increase of sintering temperature.The experimental results show that the shrinkage of ceramic body is 850℃>900℃>800℃ under different sintering temperature,and the sintering temperature is the key factor affecting the density of borosilicate glass-ceramic body.(3)Cooling rate will greatly affect the temperature and stress distribution in ceramic body.The larger the temperature gradient in natural cooling(air cooling)ceramic body is,the greater the stress will be,which will lead to serious warping deformation and even cracking.(4)The ceramic structure parameters also have great influence on the temperature and stress distribution in the green body during sintering.The larger the ceramic thickness is,the worse the uniformity of temperature field is,and the greater the internal stress is.The temperature gradient increases with the increase of aspect ratio.The results of sintering experiment show that when the aspect ratio is 1,the shrinkage in the direction of length and width is basically the same.With the increase of the aspect ratio,the shrinkage in the direction of length and width increases,which is prone to warping and cracking.This study shows that the simulation of sintering process of borosilicate glass ceramics based on finite element method can clarify the influence of relevant parameters on sintering quality,realize the optimization of process parameters,and provide a reference for solving the application of ceramic materials.