Amorphous Alloy Ribbon Stack Crystallization by Two-Step End Heating
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Solution Overview
Problem
Existing methods for producing crystallized amorphous alloy ribbons are limited by low productivity due to the need to heat and crystallize each ribbon individually, which restricts the thickness of the ribbon stack and leads to inefficiencies in heat management.
Innovation Solution
A method involving a two-step heat treatment process, where a stack of amorphous alloy ribbons is first heated to a temperature below the crystallization start point, and then an end of the stack is heated to a temperature equal to or higher than the crystallization start point, allowing for efficient crystallization of the entire stack while managing heat dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If amorphous alloy ribbons are heated and crystallized one by one independently, then heat dissipation properties are improved and temperature rise is reduced, but productivity decreases
Solution Approach 1:
The patent applies segmentation by dividing the heating process into two distinct stages: a first heat treatment step that heats the entire stack to a temperature below the crystallization start temperature, and a second heat treatment step that selectively heats only one end of the stack to a temperature equal to or higher than the crystallization start temperature. This segmented approach allows controlled crystallization propagation while maintaining efficient heat dissipation, resolving the contradiction between temperature control and productivity.
2Productivity
If the thickness of the stack is increased to improve productivity, then more ribbons can be crystallized simultaneously, but heat dissipation becomes insufficient and temperature rises excessively
Solution Approach 1:
The patent applies preliminary action by performing the first heat treatment step before the second heat treatment step. The first heat treatment pre-heats the entire stack to a temperature close to but below the crystallization start temperature, preparing the material for subsequent crystallization. This preliminary heating reduces the temperature differential needed in the second step, enabling better heat dissipation control even in thicker stacks, thereby allowing increased productivity without excessive temperature rise.
3Productivity
If the entire stack is heated to the crystallization start temperature simultaneously, then crystallization can occur throughout the stack, but heat management becomes difficult and soft magnetic properties degrade
Solution Approach 1:
The patent applies local quality by creating a temperature gradient within the stack during the second heat treatment step. Only one end of the stack is heated to the crystallization start temperature or higher, while the rest of the stack remains at a lower temperature. This localized heating approach allows crystallization to propagate through the stack in a controlled manner, preventing excessive temperature rise and grain coarsening that would degrade soft magnetic properties, while still achieving complete crystallization of all ribbons.
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 method enables the high-productivity crystallization of amorphous alloy ribbons, allowing for thicker stacks and improved heat management, which helps maintain the soft magnetic properties of the ribbons.
Implementation Method 1
heating an end of the stack to a second temperature range equal to or higher than a crystallization start temperature... amount of heat that is applied to the stack when heating the end of the stack
Implementation Method 2
When amorphous alloy ribbons are crystallized into nanocrystalline alloy ribbons, heat is released by the crystallization reaction
Implementation Method 3
heat is released by the crystallization reaction
Data Source
AI summary
After a first heat treatment step, an ambient temperature of a stack is held so that the stack is kept in a temperature range that allows the stack to be crystallized by heating the end of the stack to a second temperature range in the second heat treatment step; and a following expression (1) is satisfied, where Q1 represents an amount of heat required to heat the stack to the first temperature range in the first heat treatment step, Q2 represents an amount of heat that is applied to the stack when heating the end of the stack to the second temperature range in the second heat treatment step, Q3 represents an amount of heat that is released during crystallization of the stack, and Q4 represents an amount of heat required to heat the entire stack to the crystallization start temperatureQ1+Q2+Q3>Q4 (1).