Spinel Light-Transmitting Window Material Pore Control
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Solution Overview
Problem
Conventional spinel light-transmitting window materials suffer from high light scattering factors due to pores, which affect their optical and mechanical properties, necessitating a reduction in pore size and density to enhance performance in advanced applications.
Innovation Solution
The development of a spinel sintered body light-transmitting window material with pores limited to a maximum diameter of 100 μm and fewer than 2 pores per cubic centimeter, achieved through controlled sintering processes to maintain a relative density of 95-96% after primary sintering and 99.8% after secondary sintering, along with the use of high-purity spinel powder to minimize impurities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional sintering processes are used, then production efficiency is maintained, but light scattering factors increase due to large pores
Solution Approach 1:
The invention applies parameter changes by implementing a two-stage sintering process with specific temperature and time parameters. Primary sintering is conducted at 1500-1900°C for 1-5 hours to achieve 95-96% relative density, followed by secondary sintering at 1500-2000°C under 5-300 MPa pressure for 1-5 hours to achieve 99.8% relative density. These controlled parameter changes eliminate large pores while maintaining production efficiency.
2Object-affected harmful factors
If pore density is reduced to improve light transmission, then light scattering factors decrease, but mechanical strength may be compromised
Solution Approach 1:
The invention resolves this contradiction through precise parameter control in the sintering process. By maintaining relative density at 95-96% after primary sintering and 99.8% after secondary sintering, the process eliminates harmful large pores (>100 μm) while preserving mechanical strength through optimal densification without excessive pore elimination that would create stress concentrations.
Solution Approach 2:
The invention uses high-purity spinel powder (≥99.9% purity) as the base material, which inherently provides both good mechanical strength and optical properties. The controlled pore structure in the sintered body creates a composite-like architecture where minimal pores remain to maintain strength while large scattering centers are eliminated.
3Object-affected harmful factors
If high-purity spinel powder is used, then light scattering from impurities is reduced, but manufacturing cost increases
Solution Approach 1:
The invention addresses this contradiction by using high-purity spinel powder (≥99.9% purity) as the raw material. This high purity level eliminates light scattering from impurities while the optimized sintering parameters (temperature, pressure, time) ensure efficient processing that minimizes overall manufacturing cost despite the premium raw material.
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
This approach significantly reduces light scattering, improves mechanical strength, and stabilizes the product, making it suitable for high-temperature and high-pressure environments, such as semiconductor production and infrared detection.
Implementation Method 1
pores, which are contained in the spinel sintered body composing a light-transmitting window material, act as optical defects of the light-transmitting window material and cause an increase in light scattering factor
Implementation Method 2
a primary sintering step of sintering the spinel molded body at normal pressure or less or in a vacuum at a temperature in the range of 1500 to 1900° C.; and a secondary sintering step of sintering the spinel molded body after the primary sintering step at an ambient pressure of 5 to 300 MPa at a temperature in the range of 1500 to 2000° C.
Data Source
AI summary
To provide a light-transmitting window material made of a spinel sintered body, wherein the largest diameter of pores contained in the light-transmitting window material is not more than 100 μm, and the number of pores having a largest diameter of not less than 10 μm is not more than 2.0 per 1 cm3 of the light-transmitting window material, and wherein light scattering factors are further reduced, and a method for producing a spinel light-transmitting window material including the steps of preparing a spinel molded body; a primary sintering step of sintering the spinel molded body at normal pressure or less or in a vacuum at a temperature in the range of 1500 to 1900° C.; and a secondary sintering step of sintering the spinel molded body under pressure at a temperature in the range of 1500 to 2000° C., wherein the relative density of the spinel molded body after the primary sintering step is 95 to 96% and the relative density of the spinel molded body after the secondary sintering step is 99.8% or more.