Research And Preparation Of Low Melting Point Ceramic Materials

The sintering temperature of traditional ceramic materials is generally above 1200℃,which means that the sintering of traditional ceramics requires a lot of energy and requires very high production equipment,which is not suitable for future economic strategic development.And most ceramic materials have the disadvantage of large porosity and bulk specific gravity,low crushing strength and other performance disadvantages.Therefore,reducing the sintering temperature of ceramic materials and developing ceramic materials with excellent mechanical properties is a research hotspot of researchers in recent years.Zinc borosilicate low-melting glass system（ZnO-B₂O₃-SiO₂,abbreviated as ZBS）has the characteristics of low melting temperature,good thermal stability,excellent mechanical and electrical properties,and easy storage and processing,therefore,ZnO-B₂O₃-SiO₂ is a low-melting glass system with high research value.In this project,the low melting point glass of zinc borosilicate system is selected as the matrix,and MgO,Al₂O₃,TiO₂ and Bi₂O₃ are added as the composite components with ZBS low melting point glass.The ZnO-B₂O₃-SiO₂-MgO-Al₂O₃-TiO₂-Bi₂O₃ system low-melting glass/ceramic composites were designed and prepared by solid-state reaction method,and their structure and properties were studied.The main research contents are as follows:（1）Taking ZnO-B₂O₃-SiO₂low-melting glass as the matrix,adding MgO,Al₂O₃,TiO₂ and Bi₂O₃as components to form composite materials with ZBS low-melting glass.The effect of ZnO content on the structure and properties of ZBS low-melting glass/ceramic samples were explored by changing the content of ZnO in ZBS low-melting glass/ceramic composites.The characterization results of various modern research methods show that the preferred addition amount of ZnO content is in the range of 12%～25%mole fraction.ZBS low-melting glass/ceramic composite has the best performance and good mechanical properties.Its microhardness is 200～350 HV,its thermal expansion performance is between-70～-80*10^-6 K^-1,and its specific surface area is less than 1 m²/g.（2）Through various modern research methods and characterization methods,the influence of B₂O₃/SiO₂molar ratio on the structure and properties of ZBS low-melting glass/ceramic materials were studied.The experimental results show that the B/Si ratio has a significant effect on the glass network structure and crystal phase of ZBS low-melting glass/ceramic materials.The ZBS low-melting glass/ceramic material samples with higher B/Si ratio formed a new ZnB₄O₇ crystal phase after the sintering process at 650℃,and also maintained good mechanical properties.Its microhardness is maintained at 150～350 HV,its thermal expansion performance is between-80～-120*10^-6 K^-1,and its specific surface area is less than 1 m²/g.However,further increasing the B/Si ratio results in more severe shrinkage of the sample,which adversely affects its mechanical properties.（3）We explored the effect of Bi₂O₃ as a sintering aid on the structure and properties of ZBS low-melting glass/ceramic material samples.With the increase of Bi₂O₃ content in glass samples,the number of[BiO₃]and[BiO₆]units increase,which play an important role in the glass structure.The densification degree of ZBS low-melting glass/ceramic material samples is also deepened,and its mechanical properties remain good.However,the increase of Bi₂O₃content also means the increase of production cost.Considering its performance and cost comprehensively,the addition amount of Bi₂O₃ sintering aid is optimal in the range of 2%～5%mole fraction.The preparation process adopted in this study is simple,and the production cost of raw material formula is low.ZBS low-melting glass/ceramic material samples prepared by sintering at 650℃ have excellent comprehensive properties.It has the advantages of low sintering temperature,high strength,small specific surface area and good thermal shrinkage performance,and is expected to achieve large-scale industrial production.It is also used in the fields of environmental protection,energy and chemical industry,such as supporting catalyst carrier skeleton material,wastewater purification filter,thermal insulation material,packaging material,and has good application prospects.