Study On The Preparation Of Negative Temperature Coefficient Thermal Ceramic Resistors And Properties By Hydrothermal Method

Currently,most of the general-purpose NTC heat-sensitive materials are prepared by a conventional ceramic process through processes such as batching,molding,and sintering.However,in recent years,electronic devices have gradually become lighter,smaller,and thinner,which has higher requirements on electrical and thermal performance of NTC thermistors.In this paper,the solid phase method and the hydrothermal method are combined to combine the oxides of the heat-sensitive ceramic raw materials by solid phase method,and the mixed mixture is treated by hydrothermal method.The effect of hydrothermal treatment on the particle size,morphology and uniformity of the powder was investigated,and the effect of the powder on the properties of the ceramic was observed.The details are as follows:(1)The binary,ternary and quaternary heat-sensitive ceramic powders were first mixed by solid phase ball milling,and after orthogonal hydrothermal treatment,the particle size of the powder was significantly reduced by laser particle size analyzer and SEM observation.(2)Further exploration of the preparation time of hydrothermal and the preparation temperature of hydrothermal heat can be clearly observed by hydrothermal treatment of Mn-Ni-Al-Cu quaternary powder without ball milling,as the hydrothermal time Prolonged,the average particle size of the powder is first decreased and then increased.As the temperature of the water heat rises,the particle size increases significantly.(3)The powder of Mn-Ni-Al-Cu quaternary orthogonal analysis was prepared into ceramics to investigate the effect of sintering temperature change on its properties.The effect of sintering temperature on electrical properties can be seen.The change in sintering temperature has little effect on the mixing of hydrothermal treatment than the solid phase ball milling alone.(4)The powders of Mn-Ni-Al-Cu quaternary thermal ceramic powder treated with different hydrothermal time were prepared into ceramics to investigate their effects on electrical properties.It can be obtained that the powder treated by hydrothermal treatment is made into ceramic,and its electrical property stability is better than that of solid phase ball milling,and the stability of R25 and B value is greatly improved.The Mn-Ni-Al-Cu quaternary thermal ceramic powder is treated with different hydrothermal temperatures.With the hydrothermal preparation temperature from 160 °C to 240 °C,the R25 standard deviation can be increased from 1.70 to 3.78,and the R25 standard of the solid phase method.The deviation is 4.55.The thermal ceramic powder is treated with different hydrothermal time.As the hydrothermal preparation time increases from 1h to 7h,the R25 standard deviation can be reduced from 5.96 to 0.93.When the time reaches 9h,the R25 standard deviation increases and reaches 1.00.The R25 standard deviation of the solid phase method is 4.55.