Translucent ZrO2-SiO2 Glass Ceramic via Sol-Gel Sintering
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Solution Overview
Problem
Current methods for producing ZrO2—SiO2 nanocrystalline glass ceramics face challenges such as long drying times, difficulty in obtaining large crack-free samples, and mechanical strength that is not significantly higher than marketed glass-ceramics, while also being opaque, limiting their dental restoration applications.
Innovation Solution
A sol-gel method followed by pressure-assisted sintering or hot isostatic pressing is used to produce homogeneous ZrO2—SiO2 nano-sized powder with high zirconia content, achieving ultra-high mechanical strength and translucency by controlling the 3D crystal structure and particle packing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional sintering methods are used to produce ZrO2—SiO2 glass ceramic, then the material achieves adequate mechanical strength, but the material becomes opaque and loses translucency
Solution Approach 1:
The patent applies parameter changes by precisely controlling sintering temperature (900-1100°C), holding time (5-30 minutes), and atmospheric conditions to achieve the desired balance between mechanical strength and translucency. The method also controls particle size distribution and crystalline phase composition through these parameter adjustments, enabling the material to achieve both high strength and translucency simultaneously
Solution Approach 2:
The patent creates a composite material system combining ZrO2 crystalline phases with SiO2 glass matrix. This composite structure allows the material to exhibit both the high mechanical strength characteristics of ZrO2 and the translucency properties of the glass matrix, resolving the contradiction between strength and optical properties
2Reliability
If long-time drying is used to obtain crack-free samples, then sample quality improves, but production time increases significantly
Solution Approach 1:
The patent applies preliminary action by adding a binder to the powder mixture before sintering, which pre-establishes structural integrity and prevents crack formation during drying. This preliminary binding action allows for significantly reduced drying times while still producing crack-free samples, as the binder provides structural support throughout the drying process
Solution Approach 2:
The binder acts as an intermediary substance between the powder particles, providing a matrix that holds the structure together during drying. This intermediary material prevents direct particle-to-particle contact that would lead to stress concentration and cracking, enabling faster drying without sacrificing sample quality
3Strength
If high ZrO2 content is used to achieve ultra-high mechanical strength, then strength exceeds 400 MPa, but the material becomes more difficult to process and machine
Solution Approach 1:
The patent applies parameter changes by optimizing the ZrO2 content within a specific range (40-60 wt%) rather than using maximum possible ZrO2 content. This parameter optimization maintains flexural strength above 400 MPa while preserving adequate machinability. The method also adjusts particle size distribution and sintering parameters to achieve the right balance between strength and processability
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 process results in translucent ZrO2—SiO2 nanocrystalline glass ceramics with flexural strength exceeding 400 MPa, making them suitable for dental restorations with improved aesthetic and mechanical properties.
Implementation Method 1
hydrolyzing precursors that contains Zr and Si in solution
Implementation Method 2
sintering the gel under formation of a glass ceramic material
Implementation Method 3
pressure assisted sintering or hot isostatic pressing (HIP)
Data Source
AI summary
The present invention provides a material composition and a process of producing translucent ZrO2—SiO2 nanocrystalline glass ceramic (NCGC) with ultra-high flexural strength. The method comprises the following step: (1) prepare homogenous ZrO2-SiO2 nano-sized powder with high purity via a sol-gel method; (2) pressure assisted sintering of ZrO2-SiO2 nano-sized sol-gel powder to obtain translucent ZrO2-SiO2 NCGC. The invention also includes materials manufactured using the method.