Lithium Silicate Glass Ceramic Low-Temperature Crystallization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional lithium disilicate glass ceramics require high temperatures for crystallization, consuming significant energy and necessitating the presence of alkali metal oxides like K2O, Na2O, and Al2O3 for the formation of the lithium disilicate crystal phase, which limits their production efficiency and flexibility for dental applications.
Innovation Solution
Lithium silicate glass ceramics incorporating monovalent metal oxides such as Rb2O and Cs2O, allowing for the formation of lithium disilicate as the main crystal phase at lower temperatures (around 700°C) without the need for K2O, Na2O, and Al2O3, thereby reducing energy consumption and expanding their suitability for dental restorations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by stationary object
If conventional lithium disilicate glass ceramics are used with K2O, Na2O, and Al2O3, then the lithium disilicate crystal phase can be formed, but high temperatures (>800°C) are required for crystallization, consuming significant energy
Solution Approach 1:
The patent changes the chemical composition parameters by substituting conventional alkali metal oxides (K2O, Na2O) and Al2O3 with monovalent metal oxides (Rb2O, Cs2O) in specific amounts (0.1-17.0 wt.%). This parameter change enables lithium disilicate crystallization at lower temperatures (600-750°C) while maintaining the desired crystal phase formation, thereby reducing energy consumption without sacrificing material properties
2Ease of manufacture
If conventional glass ceramics require K2O, Na2O, Al2O3, and BaO as essential components, then the lithium disilicate crystal phase can be produced, but the production process becomes more complex and less flexible
Solution Approach 1:
The patent extracts and removes unnecessary components (K2O, Na2O, Al2O3, BaO) from the conventional glass ceramic composition. By eliminating these traditionally essential components and replacing them with monovalent metal oxides (Rb2O, Cs2O), the formulation is simplified while maintaining the ability to produce lithium disilicate crystal phase, thereby increasing production flexibility and reducing compositional complexity
3Productivity
If high temperatures (>800°C) are used for crystallization, then lithium disilicate can be formed as main crystal phase, but the production efficiency decreases due to energy consumption and time requirements
Solution Approach 1:
The patent modifies the compositional parameters by incorporating monovalent metal oxides (Rb2O, Cs2O) in optimized amounts, which changes the crystallization behavior of the glass ceramic system. This parameter change enables efficient crystallization at lower temperatures (600-750°C) within reasonable time frames (5-30 minutes), significantly improving production efficiency while reducing energy consumption compared to conventional high-temperature processes
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution enables the production of lithium disilicate glass ceramics with enhanced mechanical and optical properties, achieving fracture toughness and biaxial flexural strength suitable for dental applications, while minimizing energy usage and eliminating the necessity for previously required components.
Implementation Method 1
They are prepared from corresponding nuclei-containing starting glasses which are heated to temperatures of from 850 to 870° C. for the crystallization of lithium disilicate
Implementation Method 2
A heat treatment is carried out at 870° C. for the formation of lithium disilicate
Data Source
AI summary
Lithium silicate glass ceramics and glasses comprising specific oxides of monovalent elements are described which crystallize at low temperatures and are suitable in particular as dental materials.