LSAM Ceramic Interconnect for Oxygen Sensor Sealing
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Solution Overview
Problem
Conventional oxygen partial pressure measurement systems face challenges in achieving reliable and durable gas-tight seals at high temperatures, leading to reduced accuracy and response time due to the use of platinum electrodes with yttrium-stabilized tetragonal zirconia polycrystal (YTZP) cylinders, where glass seals are unreliable.
Innovation Solution
The use of lanthanum/strontium/aluminum/manganese/oxide (LSAM) compounds as electrically conducting ceramic interconnects, which form a gas-tight seal with YTZP and have a compatible thermal expansion coefficient, allowing for reliable electrical conductivity and mechanical stability at high temperatures through plastic deformation bonding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If platinum electrodes are used with YTZP cylinders for oxygen partial pressure measurement, then electrical conductivity for signal measurement is achieved, but gas-tight sealing reliability deteriorates due to incompatible thermal expansion coefficients
Solution Approach 1:
The patent modifies the material composition parameters by introducing aluminum doping into the lanthanum strontium manganese oxide system, creating LSAM with specific compositional ratios (La0.8Sr0.2Al0.1Mn0.9O3) to achieve compatible thermal expansion coefficients with YTZP while maintaining electrical conductivity
Solution Approach 2:
The patent creates a composite ceramic interconnect material combining lanthanum, strontium, aluminum, and manganese oxides in specific proportions to achieve both gas-tight sealing and electrical conductivity functions simultaneously, eliminating the need for separate sealing agents
2Reliability
If glass seals are used to seal platinum electrodes to housing, then gas-tight sealing is achieved, but durability and reliability deteriorate at high temperatures
Solution Approach 1:
The patent replaces the traditional glass seal approach with a ceramic interconnect material that is chemically stable and durable at high temperatures, eliminating the need for separate sealing agents and providing long-term reliability in harsh thermal environments
Solution Approach 2:
The patent changes the material phase from glass to ceramic by using aluminum-doped lanthanum strontium manganese oxide, which provides superior thermal stability and chemical durability while maintaining gas-tight sealing properties
3Stability of the object's composition
If aluminum is added to LaxSryMnO3 to create LSAM, then chemical stability in reactions with YTZP is improved, but manufacturing complexity increases
Solution Approach 1:
The patent optimizes the compositional parameters by controlling the aluminum doping level at 10 at% and establishing specific stoichiometric ratios among La, Sr, Al, and Mn elements to achieve the desired chemical stability while maintaining manufacturability through conventional ceramic processing
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 LSAM compound enables stable and accurate oxygen partial pressure measurements by forming a durable, gas-tight seal between the ceramic electrode and the system housing, eliminating the need for secondary sealing agents and improving the response time and accuracy of oxygen sensors.
Implementation Method 1
The LSAM conductor is joined to the YTZP by plastic deformation at temperatures between about 1250°-1350° C. at stresses of approximately 10-50 MPa
Implementation Method 2
a conducting ceramic material for use as an electron carrier for signal measurement in an oxygen sensor system
Implementation Method 3
providing a compatible thermal expansion coefficient between LSAM and YTZP
Data Source
AI summary
A method and an article of an electrically conductive ceramic interconnect bonded to a compatible ceramic housing for an oxygen partial pressure sensor system. The interconnect includes a LaxSryAlzMn1−zO3 (LSAM) having a stoichiometry enabling good electrical conductivity at high temperatures and the LSAM also bonded to a yttria stabilized zirconia forming a stable and durable seal.