High-Temperature Composite Bonding via Segmented Solder Layers
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Solution Overview
Problem
High-temperature rotary X-ray anodes face challenges in maintaining mechanical stability and preventing thermal ageing due to high thermal stresses and temperature gradients, while existing bonding methods struggle to withstand these conditions effectively.
Innovation Solution
A process involving a three-layer bonding solder layer, where a first Zr solder is used with an intermediate layer of Ta, Nb, or W, and a second solder with a lower melting point, such as Ti, Ti-based, or Zr-based, to join a non-metallic section to a metallic section like Mo or W-based alloys, preventing diffusion and thermal ageing by controlling soldering temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single high-melting-point solder is used to bond the non-metallic section to the metallic section, then the bond can withstand high temperatures, but the metallic section undergoes thermal ageing and loses mechanical strength
Solution Approach 1:
The bonding solder layer is segmented into three distinct sub-layers: a first sub-layer containing a high-melting-point solder (e.g., W-based) for high-temperature bond stability, a second sub-layer containing a low-melting-point solder (e.g., Mo-based) applied at lower temperature to prevent thermal ageing of the metallic section, and an intermediate sub-layer between them. This segmentation allows each layer to perform its specific function without compromising the other.
Solution Approach 2:
The invention changes the temperature parameter by applying the second low-melting-point solder layer at a temperature specifically controlled to be below the recrystallization temperature of the metallic section (e.g., below 1000°C for Mo, below 1500°C for W). This parameter change prevents thermal ageing while still achieving adequate bonding through the combined action of all three sub-layers.
2Ease of manufacture
If conventional single-layer soldering is used, then the process is simple, but the bond cannot withstand high temperature gradients and mechanical stresses
Solution Approach 1:
The bonding solder layer is constructed as a composite material system with three sub-layers, each having different chemical compositions and melting points. The first sub-layer (high-melting-point solder) provides high-temperature stability, the second sub-layer (low-melting-point solder) provides low-temperature bonding capability and stress accommodation, and the intermediate sub-layer facilitates the transition between them. This composite structure enables the bond to withstand high temperature gradients and mechanical stresses while maintaining manufacturing feasibility through a systematic two-step process.
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 ensures a strong, high-temperature-resistant bond that effectively dissipates stresses and prevents thermal ageing, maintaining the mechanical integrity and longevity of the composite body even at high temperatures and rotational speeds.
Implementation Method 1
a first Zr solder and an intermediate layer in this order, where the intermediate layer is formed to an extent of at least 90 atom % of at least one of the elements Ta (Ta: tantalum), Nb (Nb: niobium) and/or W
Implementation Method 2
heating of the first arrangement in a first soldering step in such a way that the Zr solder but not the intermediate layer melts
Implementation Method 3
heating of the first arrangement in a first soldering step in such a way that the Zr solder but not the intermediate layer melts
Data Source
AI summary
A high-temperature-resistant composite body is formed by joining over an area of a first, nonmetallic section via a bonding solder layer to a second, metallic section composed of Mo, an Mo-based alloy, W or a W-based alloy. A first arrangement composed of the first section, a first Zr solder and an intermediate layer is firstly soldered together in a first soldering step. A second arrangement of the resulting partial composite body, a second solder adjoining the intermediate layer and the second section is subsequently soldered together in a second soldering step. The intermediate layer at least 90 atom % of at least one of the elements Ta, Nb, W. The second solder is formed by precisely one material selected from Ti, Ti-based solder combination, V-based solder combination, Zr or Zr-based solder combination and it melts at a lower temperature than the first Zr solder in the second arrangement.