The Research On Preparation And Properties Of Li-Si Dentistry Glass-ceramics

Li-Si microcrystalline glass is widely used in the field of dental dentistry repair because of its excellent performance.It has strong mechanical properties,thermal expansion coefficient and hardness matching with natural teeth,so it has become a hotspot in the field of dental restoration.At present,lithium disilicate as the main crystal phase of the dental restoration materials are mainly imported products,in order to meet the needs of domestic lithium disilicate dental prosthesis,this paper by matching nucleating agent,analysis of oxide composition,design the lithium disilicate glass-ceramics was prepared and modified by doping.In this paper,the basic composition of the mother glass was designed by analyzing the role of the oxide in the glass,and the basic composition of the maternal glass was designed by matching the lithium substrate,the nucleating agent and the functional oxide of the glass main body.By using XRD,DTA,SEM,IR the effects of P₂O₅/TiO₂/ZrO₂ ternary composite nucleating agent as effective nucleating agent for Li-Si glass were discussed.When the ratio of composite nucleating agent was 2.5?wt%?P₂O₅,2?wt%?TiO₂,1.5?wt%?ZrO₂ crystal crystallization and physical and chemical properties of more balanced.In this paper,corundum crucible and quartz crucible are selected as the object of analysis.When corundum crucible is used,the erosion is more serious and the ratio of raw materials is changed.The quartz crucible can meet the experimental conditions of molten glass.Will not pollute the raw materials.In order to obtain a more suitable combination of the composition of the glass oxide,the effect of the change of the oxide on the properties of the glass-ceramics was discussed by changing the silica-lithium ratio,introducing the intermediate oxide ZnO and introducing fluoride ions.When the heat treatment temperature is below 750?,the main crystal phase is lithium metasilicate,and when the heat treatment temperature is 750?or more,the main crystal phase is two,and the crystal phase of the glass lithium silicate;silicon lithium is relatively high,the crystallization of the main phase after heat treatment are lithium disilicate.Silicon lithium is relatively high with the silicon and lithium than the increase in glass density increases,thermal expansion coefficient decreases,reduce the degree of bending.Doped ZnO in glass-ceramics.The chemical stability of the crystallized glass is improved by hindering the diffusion of Na⁺ions.The chemical stability and flexural strength of the glass-ceramics were improved by Zn²⁺and F^-doping,and the thermal expansion coefficient of the glass-ceramics was adjusted to match the application requirements.In the glass-ceramics,F^-was introduced and passed through the F^-increasing the flexural strength of glass-ceramics by ion combination.In this paper,the effects of rare earth oxides on the crystallization behavior,high temperature viscosity,thermal expansion coefficient and mechanical properties of Li-Si glass-ceramics were investigated.The introduction of a small amount of Er₂O₃increases the glass transition temperature and crystallization temperature of the system glass-ceramics,which inhibits the occurrence of lithium metasilicate crystals.It does not change the species of the main crystal phase of the glass and the decrease of the thermal expansion coefficient.The damage of the Li-Si glass structure reduces the high temperature viscosity of the glass-ceramics.With the increase of the introduction amount,the high-temperature viscosity tends to decrease.When the amount of Er₂O₃ is 0.3%,the main crystal phase is Lithium disilicate system of the system of glass-ceramic to obtain the best microstructure,bending strength to a maximum of 310MPa.