Pressure-assisted induction heating vacuum atmosphere flash sintering device

Abstract

The invention relates to the field of new material preparation, and provides a pressure-assisted induction heating vacuum atmosphere flash sintering device. The pressure-assisted induction heating vacuum atmosphere flash sintering device comprises a furnace body, a pressure system, a flash sintering system, an induction heating system, a cooling system and a vacuum system. The pressure system comprises an upper pressing head and a movable lower pressing head. An upper electrode and a lower electrode are arranged on the end portions of the upper pressing head and the lower pressing head correspondingly and provide pressure for flash sintering samples. The flash sintering system provides a flash sintering circuit. The induction heating system provides heating and heat preservation. The furnace body is cooled by the cooling system. The furnace body is vacuumized by the vacuum system. The inherent defects in a traditional flash sintering technology are overcome, flash sintering power sources can be flexibly selected according to the electrical properties of materials obtained after flash sintering to cause thermal runaway, thus, the density level and microstructures of the samples arefinely adjusted and controlled to the maximum degree, and the device has universality for metal and ceramic materials; and pressure assisting of the flash sintering process can be easily achieved, andnew preparation means can be provided for the research field.

Description

technical field

[0001] The invention relates to the technical field of new material preparation, in particular to a pressure-assisted induction heating vacuum atmosphere flash sintering device. Background technique

[0002] Since flash sintering (or called flash sintering or flash firing) was proposed in 2010, it has been applied to a variety of materials, including ionic conductors such as yttria-stabilized zirconia (YSZ) and gadolinium-doped ceria (GDC). ); semiconductors, such as zinc oxide (ZnO) and silicon carbide (SiC); and certain types of electronic conductors and insulators, such as Co 2 MnO 4 , strontium titanate (SrTiO 3 ) and alumina (Al 2 o 3 ). Compared with the conventional sintering process, the most obvious advantage of flash sintering is that it greatly reduces the time, temperature and energy required for ceramic densification, which means that it has great significance and application prospects in terms of industrial and environmental benefits. [0...

Examples

Embodiment 1

[0049] This example is pressure assisted flash sintering of commercial ZnO powder. The induction heating preheating temperature is set to 770°C, the pressure is 26MPa, and the sample diameter is 6.4mm. The flash power supply uses a low-power pulsed DC power supply, the initial electric field strength is about 80V / cm, the frequency is 1000Hz, and the pulse width is 128μs. In this embodiment, the flash current is set to 0A (that is, the flash power supply is not turned on), and the temperature is kept at the preheating temperature and constant pressure for 30s. The photo of the appearance of the sample and the microstructure are as follows: Figure 5 As shown in (a), the density is 71.1%, and the grain size is 130.1nm.

Embodiment 2

[0051] This example is pressure assisted flash sintering of commercial ZnO powder. The induction heating preheating temperature is set to 770°C, the pressure is 26MPa, and the sample diameter is 6.4mm. The flash power supply uses a low-power pulsed DC power supply, the initial electric field strength is about 80V / cm, the frequency is 1000Hz, and the pulse width is 128μs. In this embodiment, the flash current is set to 50A, the power is turned on at the preheating temperature and constant pressure, and it is turned off immediately after 30s. The photos of the appearance of the sample and the microstructure are as follows: Figure 5 As shown in (b), the density is 77.3%, and the grain size is 200.7nm.

Embodiment 3

[0053]This example is pressure assisted flash sintering of commercial ZnO powder. The induction heating preheating temperature is set to 770°C, the pressure is 26MPa, and the sample diameter is 6.4mm. The flash power supply uses a low-power pulsed DC power supply, the initial electric field strength is about 80V / cm, the frequency is 1000Hz, and the pulse width is 128μs. In this embodiment, the flash current is set to 100A, the power is turned on at the preheating temperature and constant pressure, and it is turned off immediately after 30s. The appearance photos and microstructure of the sample are as follows: Figure 5 As shown in (c), the density is 91.9%, and the grain size is 687.5nm.

technical field

[0001] The invention relates to the technical field of new material preparation, in particular to a pressure-assisted induction heating vacuum atmosphere flash sintering device. Background technique

[0002] Since flash sintering (or called flash sintering or flash firing) was proposed in 2010, it has been applied to a variety of materials, including ionic conductors such as yttria-stabilized zirconia (YSZ) and gadolinium-doped ceria (GDC). ); semiconductors, such as zinc oxide (ZnO) and silicon carbide (SiC); and certain types of electronic conductors and insulators, such as Co 2 MnO 4 , strontium titanate (SrTiO 3 ) and alumina (Al 2 o 3 ). Compared with the conventional sintering process, the most obvious advantage of flash sintering is that it greatly reduces the time, temperature and energy required for ceramic densification, which means that it has great significance and application prospects in terms of industrial and environmental benefits. [0...

Examples

Embodiment 1

[0049] This example is pressure assisted flash sintering of commercial ZnO powder. The induction heating preheating temperature is set to 770°C, the pressure is 26MPa, and the sample diameter is 6.4mm. The flash power supply uses a low-power pulsed DC power supply, the initial electric field strength is about 80V / cm, the frequency is 1000Hz, and the pulse width is 128μs. In this embodiment, the flash current is set to 0A (that is, the flash power supply is not turned on), and the temperature is kept at the preheating temperature and constant pressure for 30s. The photo of the appearance of the sample and the microstructure are as follows: Figure 5 As shown in (a), the density is 71.1%, and the grain size is 130.1nm.

Embodiment 2

[0051] This example is pressure assisted flash sintering of commercial ZnO powder. The induction heating preheating temperature is set to 770°C, the pressure is 26MPa, and the sample diameter is 6.4mm. The flash power supply uses a low-power pulsed DC power supply, the initial electric field strength is about 80V / cm, the frequency is 1000Hz, and the pulse width is 128μs. In this embodiment, the flash current is set to 50A, the power is turned on at the preheating temperature and constant pressure, and it is turned off immediately after 30s. The photos of the appearance of the sample and the microstructure are as follows: Figure 5 As shown in (b), the density is 77.3%, and the grain size is 200.7nm.

Embodiment 3

[0053]This example is pressure assisted flash sintering of commercial ZnO powder. The induction heating preheating temperature is set to 770°C, the pressure is 26MPa, and the sample diameter is 6.4mm. The flash power supply uses a low-power pulsed DC power supply, the initial electric field strength is about 80V / cm, the frequency is 1000Hz, and the pulse width is 128μs. In this embodiment, the flash current is set to 100A, the power is turned on at the preheating temperature and constant pressure, and it is turned off immediately after 30s. The appearance photos and microstructure of the sample are as follows: Figure 5 As shown in (c), the density is 91.9%, and the grain size is 687.5nm.

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