Pulsed Current Sintering Device with Rotating Walls
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Solution Overview
Problem
Pulsed-current sintering of materials like diamond is challenging due to high compression, which prevents electrical discharges between grains, compromising the welding process and resulting product properties.
Innovation Solution
A pulsed-current sintering device with a sintering cell featuring two walls that rotate relative to each other, applying torsional stress to the material, allowing electrical discharges to occur even under high compression, enabling successful welding of diamond grains.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If high compression is applied to the material during pulsed-current sintering, then the density and mechanical properties of the sintered product are improved, but electrical discharges between grains cannot occur, compromising the welding process
Solution Approach 1:
The invention applies dynamic torsional stress through rotation of the pressing element during compression. This dynamic mechanical action creates relative motion between grains under high compression, generating electrical discharges that enable welding while maintaining high density. The rotation transforms a static compression problem into a dynamic solution where both high compression and electrical discharge coexist.
Solution Approach 2:
The rotation of the pressing element during compression creates mechanical vibration and shear motion within the compacted material. This vibration disrupts the grain contact interfaces under high pressure, allowing electrical discharges to initiate and propagate between grains, thereby enabling the welding process to occur even under high compression conditions.
2Strength
If high compression is applied to diamond material, then the hardness and density are improved, but the material degrades when heated at very high temperature, transforming into graphite
Solution Approach 1:
The invention uses periodic pulsed current instead of continuous heating. The pulsed nature of the current allows for brief, intense heating cycles that weld grains together without sustained exposure to temperatures that would cause diamond-to-graphite transformation. The periodic action limits total thermal exposure while achieving the necessary welding effect.
Solution Approach 2:
The invention replaces conventional thermal heating with electrical discharge heating through pulsed current. Instead of applying sustained high temperature that degrades diamond, the system uses electrical energy to create localized plasma and Joule heating at grain interfaces, achieving welding through electrical rather than thermal means. This substitution avoids the harmful thermal effects on diamond.
3Stress or pressure
If the walls are brought closer to apply high pressure, then the compression is improved, but the electrical discharges do not appear between grains
Solution Approach 1:
The invention introduces dynamic rotation of the pressing element during compression. This rotation creates shear motion and relative displacement between grains under high pressure, generating the conditions necessary for electrical discharge. The dynamic action transforms static compression into a process where electrical energy can be effectively utilized for welding.
Solution Approach 2:
The invention combines mechanical compression with electrical energy input in a hybrid process. The pressing element applies mechanical pressure while simultaneously electrical current is applied, creating a composite action where mechanical compression prepares the grain structure and electrical discharge provides the energy for welding. This composite approach enables both high pressure and electrical discharge to occur together.
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
Enables rapid and successful sintering of highly compressed materials like diamond without degrading their properties, achieving high-pressure sintering without compromising grain welding, thus improving the efficiency and effectiveness of the sintering process.
Implementation Method 1
The pulsed electric current causes the appearance of electrical discharges between the grains of the material. It is these electrical discharges that, by Joule effect, heat the material and thus allow the grains to be welded together
Implementation Method 2
The fact of relatively rotating the walls and bringing them closer to each other simultaneously makes it possible to apply the torsional stress to the material. This torsional stress makes it possible to move grains of this material away from each other
Data Source
AI summary
The present invention relates to a device (1) for sintering by pulsating current, the device (1) comprising: —a sintering cell (4) comprising two walls (14a, 14b) facing each other and defining between them a cavity (C) for receiving material to be sintered, —a press (2) arranged for moving one of the walls (14a, 14b) towards the other wall, so as to compress the material, when the material is received in the cavity (C), —means (10a, 10b) of rotating one of the walls (14a, 14b) relative to the other wall, so as to apply a torsional force to the material, when the material is compressed in the cavity (C).