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Multi-field coupling flash sintering system based on induction heating

An induction heating and flash technology, applied in the field of powder metallurgy, which can solve the problems of incompleteness, damage, sample contamination and debinding, etc.

Active Publication Date: 2020-10-23
UNIV OF SCI & TECH BEIJING
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

And because there is usually no mold support in the traditional flash sintering device, the ceramic green body needs to be mixed with a binder (usually organic matter such as polyvinyl alcohol) and pre-fired at about 500°C for a certain period of time (1~2h) to remove the binder and form a certain The intergranular sintered neck to obtain a certain strength, otherwise it is easy to be damaged during the connection of electrodes or other experimental preparations
However, the above pretreatment process usually leads to problems such as sample contamination (incomplete debinding, diffusion of conductive paste) and grain growth, which instead complicates the process and makes it impossible to take full advantage of the flash sintering technology.

Method used

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  • Multi-field coupling flash sintering system based on induction heating
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  • Multi-field coupling flash sintering system based on induction heating

Examples

Experimental program
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Effect test

Embodiment 1

[0057] This implementation is ceria (CeO 2 ) The flash sintering of ceramics uses an induction heating module, a temperature measurement and temperature control module, and a DC power supply. figure 2 is a typical flash sintering curve based on the present invention, image 3 It is a photo of the sample after flash sintering, with a diameter of 6 mm and a thickness of 1 mm. When the critical electric field is 100V / cm, the maximum current density is 10A / cm 2 Under the condition of 16s, the sudden change of current and voltage begins to appear, and the power reaches the peak value within a few seconds, that is, the flash sintering phenomenon of oxide ceramics occurs. After flash sintering at 740℃ for 3min, 5min and 7min, the microstructure is as follows Figure 4 As shown, it shows a very dense state, the original powder particle boundaries are straightened, the particles are closely connected, there is almost no residual porosity, and the grains only grow slightly. Measure...

Embodiment 2

[0059] This embodiment is the flash sintering of Al-12Si alloy, which adopts a pressurized module and a high-voltage pulse power supply, and utilizes the characteristics of instantaneous discharge of the high-voltage pulse power supply to realize flash sintering of metal materials. About 0.7g of Al-12Si powder was loaded into a mold with a diameter of 6mm, and it was discharged and sintered under the conditions of uniaxial pressure of 550MPa, voltage of 7000V, and capacitance of 90μF. It reached 99% density in less than 1s. The sample photo and Microstructure such as Figure 6 As shown, compared with the casting alloy of the same composition, its hardness is more than doubled (about 64HV for the casting alloy and >130HV for the flash sintered sample).

Embodiment 3

[0061] This embodiment is flash sintering of high-speed steel titanium carbide composite material (titanium carbide content 30wt.%), using a pressurized module and a high-power DC pulse power supply. About 1.2g of powder is put into a mold with a diameter of 6mm on the outer steel sleeve of the inner alumina tube. Under the conditions of voltage 3V, current 500A, frequency 30000HZ, and continuous pressure, sinter for about 12s, and obtain 96% density and average hardness. It is a sample of 1100HV, the sample photo and microstructure are as follows Figure 7 shown.

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Abstract

The invention relates to a multi-field coupled flash sintering system based on induction heating, which belongs to the technical field of powder metallurgy. The system includes an induction heating module, a pressurization module, a temperature measurement module, a temperature control module, a power supply module, a mold and electrodes. The invention provides a new flash sintering technology based on induction heating, short process and multi-field coupling, which has the advantages of high power utilization rate, simple operation, low cost, convenient pressurization, rapid temperature rise, and sinterable materials Features such as wide range.

Description

technical field [0001] The invention belongs to the technical field of powder metallurgy, in particular to a multi-field coupled flash sintering system based on induction heating. [0002] technical background [0003] With the development of new powder metallurgy technology, various types of field-assisted sintering methods have been applied to the preparation of advanced materials in key fields such as military industry and aerospace. Numerous studies have shown that field-assisted sintering methods can produce higher levels of densification at lower temperatures in shorter times than conventional techniques, and that materials prepared using these methods have superior properties. Among the many field-assisted methods, spark plasma sintering and microwave sintering technology are the most commercialized. A large number of related researches and patents have shown that these two methods can complete various metals and metal substrates in a shorter time and at a lower temper...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B22F3/00B22F3/105C04B35/01C04B35/50C04B35/56C04B35/64
CPCC04B35/01C04B35/50C04B35/5626C04B35/64B22F3/105B22F3/003B22F2003/1053
Inventor 张新房梁艺涵
Owner UNIV OF SCI & TECH BEIJING