MgCuSb Contact Layer for MgAgSb Thermoelectric Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The Ag-rich environment in MgAgSb-based thermoelectric devices leads to the formation of Ag3Sb phase, causing performance deterioration and limiting the long-term stability of MgAgSb/Mg3Bi2 devices due to high contact resistance and thermal instability.
Innovation Solution
A preparation method involving high-energy ball milling to produce MgCuSb and MgCu0.1Ag0.87Sb0.99 nano-powders, which are used as contact materials, ensuring similar thermal expansion coefficients and forming a stable interface with low contact resistance, thereby enhancing thermal stability and ohmic contact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If Ag is selected as contact material for p-MgAgSb due to matched coefficient of thermal expansion, then thermal expansion compatibility is improved, but Ag3Sb phase is easily formed at Ag/MgAgSb interface under Ag-rich conditions, leading to performance deterioration
Solution Approach 1:
The patent introduces an intermediary layer of MgCuSb between the Ag-based contact material and the MgAgSb thermoelectric material. This intermediary layer prevents direct contact between Ag and MgAgSb, blocking the formation of Ag3Sb harmful phase while maintaining thermal expansion compatibility and electrical conductivity.
Solution Approach 2:
The patent employs composite contact materials with specific composition (MgCu0.1Ag0.87Sb0.99) that combine the benefits of Ag (thermal expansion matching) and MgCuSb (chemical stability). This composite structure prevents Ag3Sb formation while maintaining the desired thermal and electrical properties.
2Stability of the object's composition
If contact material is introduced on the surface of thermoelectric material to suppress elements diffusion and chemical reactions, then element diffusion suppression is improved, but contact resistance increases
Solution Approach 1:
The patent optimizes the compositional parameters of the contact material (MgCu0.1Ag0.87Sb0.99) to achieve a balance between diffusion suppression and low contact resistance. By adjusting the ratios of Mg, Cu, Ag, and Sb, the material maintains chemical stability while ensuring good electrical contact with the thermoelectric 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
The method achieves high thermal stability and low contact resistance, maintaining interface integrity and performance even after annealing at 280°C for 16 days, with a contact resistance below 1 μΩcm2, supporting long-term device stability and efficiency.
Implementation Method 1
placing the sealed ball mill tank into a high-energy ball mill machine for high-speed ball milling to obtain an MgCuSb nano-powder
Implementation Method 2
MgCuSb and MgAgSb (MgCu0.1Ag0.87Sb0.99) have similar thermal expansion coefficients, which can ensure an interface formed by both of them has a smaller thermal stress
Implementation Method 3
The prepared MgAgSb/MgCuSb interface still has good thermal stability after being annealed for 16 days at the temperature of 280° C. (553K)
Data Source
AI summary
The present disclosure provides a preparation method of a contact material with high thermal stability and low contact resistance based on an MgAgSb-based thermoelectric material and relates to the field of the contact materials preparation. The present disclosure aims to solve the problem of failure to achieve long-term stability for the MgAgSb/Mg3Bi2 device due to the fact that a contact material used by MgAgSb is Ag and MgAgSb may easily yield Ag3Sb in an Ag-rich environment at present. The method includes: at step 1, preparing MgCuSb nano-powder; at step 2, preparing MgCu0.1Ag0.87Sb0.99 nano-powder; at step 3, preparing MgCu0.1Ag0.87Sb0.99—Mg3.2Bi1.5Sb0.5 thermoelectric generation device. The present disclosure is applied to preparation of a contact material with high thermal stability and low contact resistance based on an MgAgSb-based thermoelectric material.