Joint Manufacturing Method Using Pre-Sintering Layer
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Solution Overview
Problem
Conventional joint manufacturing methods face issues with peeling between the joining material and objects due to volatile matter, leading to insufficient joining at high temperatures and potential aggregation of sinterable particles, which affects the reliability of the joint.
Innovation Solution
A joint manufacturing method that involves increasing the temperature of the laminate from a first temperature to a second temperature while applying pressure, thereby preventing rapid volatilization of organic components and promoting a densely sintered structure, using a heat-joining sheet with a pre-sintering layer containing metal fine particles and a low-boiling binder, and controlling the atmosphere to inhibit volatile matter generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the objects to be joined are joined while being pressurized at high temperature (250°C), then the joining strength is improved, but the organic component and coating material rapidly volatilize causing aggregation of sinterable particles and insufficient joining
Solution Approach 1:
The patent applies preliminary action by conducting a preliminary firing step at a lower temperature (100°C for 10 minutes) before the main firing step. This preliminary treatment removes some volatile components gradually, preventing their rapid volatilization during the subsequent high-temperature main firing step (350°C for 5 minutes), thereby maintaining particle dispersion and ensuring reliable joining.
Solution Approach 2:
The patent employs periodic action by dividing the heating process into distinct stages: a preliminary firing step followed by a main firing step. This staged approach allows controlled removal of volatile components in periods, preventing sudden aggregation of sinterable particles while achieving the necessary joining strength through the main firing step.
2Object-affected harmful factors
If the objects to be joined are joined in a pressureless state, then damage to the object to be joined is reduced, but peeling occurs between the joining material and object due to volatile matter causing insufficient joining at high temperature
Solution Approach 1:
The preliminary firing step at 100°C for 10 minutes serves to gradually remove volatile components from the joining material before the high-temperature main firing step. This preliminary action prevents sudden volatile matter generation that would cause peeling, enabling strong joining without requiring excessive pressure that could damage the objects.
Solution Approach 2:
The patent changes the temperature parameter in stages, first holding at a low temperature (100°C) for preliminary firing, then increasing to a higher temperature (350°C) for main firing. This parameter change strategy allows controlled volatile matter removal while achieving the necessary joining strength, balancing object protection with joint quality.
3Ease of manufacture
If a paste-like joining material is used, then the joining process can be performed, but additional coating step and drying step are required increasing the step time
Solution Approach 1:
The patent changes the physical state parameter of the joining material from a paste-like form to a sheet form. This parameter change eliminates the need for coating and drying steps, as the sheet material can be directly positioned and fired. The material transformation maintains ease of application while significantly reducing process time.
Solution Approach 2:
The patent replaces the mechanical coating process (applying paste material) with a simpler positioning process (placing sheet material). This substitution eliminates the need for coating equipment and drying time, streamlining the manufacturing process while maintaining the ability to apply the joining material effectively.
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 effectively suppresses peeling and ensures high joining reliability at high temperatures by maintaining the dispersion of sinterable particles and preventing coarse voids in the sintered layer, resulting in a stronger and more reliable joint.
Implementation Method 1
the pre-sintering layer is a layer which is subjected to sintering; increasing the temperature of the laminate from a first temperature to a second temperature
Implementation Method 2
The first temperature is a temperature at which an organic component contained in the pre-sintering layer is decreased by 10% by weight when the pre-sintering layer is subjected to thermogravimetric measurement
Implementation Method 3
there is a probability that the volatilization of an organic component and a coating material of sinterable particles (for example, metal particles) contained in a joining material causes insufficient joining
Data Source
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AI summary
Provided is a joint manufacturing method including: a step A of preparing a laminate (10) in which two objects to be joined are temporarily adhered with a heat-joining sheet (40) including a pre-sintering layer interposed between the two objects to be joined; a step B of increasing a temperature of the laminate from a temperature equal to or lower than a first temperature defined below to a second temperature; and a step C of holding the temperature of the laminate in a predetermined range after the step B, in which the laminate is pressurized during at least a part of the step B and at least a part of the step C. The first temperature is a temperature at which an organic component contained in the pre-sintering layer is decreased by 10% by weight when the pre-sintering layer is subjected to thermogravimetric measurement.