Zirconium-Doped Silicon Nitride Sintering for Lower Firing Energy
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for producing silicon nitride sintered bodies at high temperatures result in high energy consumption and carbon dioxide emissions, while attempts to reduce firing temperatures lead to insufficient strength for applications in wear-resistant members and semiconductor substrates.
Innovation Solution
Incorporating not less than 0.1 mass % and not more than 10 mass % of zirconium when converted to oxide into the silicon nitride sintered body, which forms a liquid phase at around 1,300° C, allowing for low-temperature firing of less than 1,650° C while maintaining high strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If high temperature firing (1600-2000°C) is used to produce silicon nitride sintered bodies, then high strength (≥700 MPa or ≥900 MPa) is achieved, but energy consumption and carbon dioxide emissions increase
Solution Approach 1:
The patent changes the chemical composition parameters by adding specific amounts of zirconium (0.1-10 mass%) and controlling the ratio of α-silicon nitride to β-silicon nitride crystal grains. This compositional parameter change enables the material to achieve high strength at lower firing temperatures (1200-1650°C), thus resolving the contradiction between strength and energy consumption
Solution Approach 2:
The patent creates a composite microstructure consisting of both α-silicon nitride and β-silicon nitride crystal grains in specific ratios, along with zirconium additions. This composite material approach allows the sintered body to achieve high strength at reduced firing temperatures, addressing the energy consumption issue while maintaining mechanical performance
2Use of energy by stationary object
If firing temperature is reduced to decrease energy consumption, then carbon dioxide emissions are reduced, but strength becomes insufficient (≈140 MPa at 1300-1375°C)
Solution Approach 1:
The patent modifies the chemical composition by adding zirconium (0.1-10 mass%) and controlling the crystal grain ratio, which fundamentally changes the sintering behavior of the material. This enables low-temperature sintering (1200-1650°C) to produce bodies with strength ≥600 MPa, resolving the contradiction between energy consumption and strength
Solution Approach 2:
The patent creates local structural optimization by controlling the distribution and ratio of α-silicon nitride and β-silicon nitride crystal grains, along with zirconium distribution. This local quality control ensures that even at lower temperatures, the material achieves sufficient strength for practical applications
3Use of energy by stationary object
If zirconium is added to enable low-temperature firing, then energy consumption is reduced, but manufacturing precision must be controlled to maintain strength ≥600 MPa
Solution Approach 1:
The patent establishes specific parameter ranges: zirconium content (0.1-10 mass%), α-silicon nitride to β-silicon nitride ratio (0.01 to 0.5), and firing temperature (1200-1650°C). These controlled parameter changes enable low-temperature firing while maintaining manufacturing precision and achieving strength ≥600 MPa, resolving the contradiction between energy consumption and manufacturing precision
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 approach enables the production of silicon nitride sintered bodies with a three-point bending strength of not less than 600 MPa and a dielectric strength of not less than 13 kV/mm, suitable for wear-resistant members and semiconductor substrates, while reducing energy consumption and environmental impact.
Implementation Method 1
Incorporating not less than 0.1 mass % and not more than 10 mass % of zirconium when converted to oxide into the silicon nitride sintered body, which forms a liquid phase at around 1,300° C, allowing for low-temperature firing of less than 1,650° C while maintaining high strength
Data Source
AI summary
A silicon nitride sintered body according to an embodiment includes not less than 0.1 mass % and not more than 10 mass % of zirconium when converted to oxide. In XRD analysis (2θ) of any cross section of the silicon nitride sintered body, 0.01≤I35.3/I27.0≤0.5 and 0≤I33.9/I27.0≤1.0 are satisfied; I35.3 is a maximum peak intensity detected at 35.3±0.2° based on α-silicon nitride crystal grains; I27.0 is a most intense peak detected at 27.0±0.2° based on β-silicon nitride crystal grains; and I33.9 is a most intense peak detected at 33.9±0.2° based on zirconium nitride.