WO2021196856A1 - 室温陶瓷烧结方法及陶瓷 - Google Patents

室温陶瓷烧结方法及陶瓷 Download PDF

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WO2021196856A1
WO2021196856A1 PCT/CN2021/074217 CN2021074217W WO2021196856A1 WO 2021196856 A1 WO2021196856 A1 WO 2021196856A1 CN 2021074217 W CN2021074217 W CN 2021074217W WO 2021196856 A1 WO2021196856 A1 WO 2021196856A1
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ceramic
green body
ceramic green
room temperature
sintering method
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PCT/CN2021/074217
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English (en)
French (fr)
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王希林
刘杰明
刘光华
贾志东
张若兵
王黎明
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清华大学深圳国际研究生院
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Publication of WO2021196856A1 publication Critical patent/WO2021196856A1/zh

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    • C04B35/01—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics
    • C04B35/453—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on zinc, tin, or bismuth oxides or solid solutions thereof with other oxides, e.g. zincates, stannates or bismuthates
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    • C04B2235/66—Specific sintering techniques, e.g. centrifugal sintering
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    • C04B2235/70—Aspects relating to sintered or melt-casted ceramic products
    • C04B2235/95—Products characterised by their size, e.g. microceramics

Definitions

  • This application relates to the technical field of ceramic material preparation, in particular to a room temperature ceramic sintering method and ceramics sintered using the room temperature ceramic sintering method.
  • Ceramic materials are now widely used in various high-tech industries. Due to its special physical and chemical properties, ceramic materials are usually not manufactured through mechanical processing or casting processes, but must be formed through powder molding and high-temperature sintering.
  • One of the main disadvantages of sintering is that it consumes a lot of energy, because the conventional sintering method requires high temperature and long time.
  • the flash sintering process applies a certain intensity electric field on the ceramic green body, so as to achieve the purpose of reducing the furnace temperature required for sintering and realizing the densification of the ceramic in a very short time.
  • most of the ceramic flash firing still requires a relatively high furnace temperature.
  • the present application provides a method for sintering ceramics at room temperature, so as to solve the above problems.
  • the present application also provides a ceramic sintered using the room temperature ceramic sintering method.
  • This application provides a room temperature ceramic sintering method, including the following steps:
  • the voltage is raised to a predetermined voltage value to cause the surface discharge or internal discharge of the water-containing ceramic green body, and the power supply is cut off after maintaining for a predetermined period of time, thereby obtaining the ceramic.
  • This application also provides a room temperature ceramic sintering method, including the following steps:
  • the voltage is raised to a predetermined voltage value to cause the liquid-containing ceramic green body to generate creeping discharge or internal discharge, and the power supply is cut off after maintaining for a predetermined period of time, thereby obtaining the ceramic.
  • the present application also provides a ceramic sintered using the room temperature ceramic sintering method, the crystal grain size of the ceramic is 500 nm-10 ⁇ m, and the density of the ceramic is greater than 90%.
  • the room temperature ceramic sintering method provided in this application realizes the sintering of ceramics at room temperature (0-30°C) by controlling the water content of the ceramic green body, which greatly reduces the furnace temperature and energy consumption required for ceramic sintering, thereby reducing a lot of Energy consumption.
  • the process flow of the room temperature ceramic sintering method in the present application is relatively simple, compared with the conventional flash sintering process, no additional heating device is required, and the method of controlling the moisture content of the ceramic green body is simple and easy to implement.
  • Fig. 1 is a flow chart of the preparation of ceramics provided by a preferred embodiment of the present application.
  • Fig. 2 is a schematic structural diagram of a device for absorbing moisture in a ceramic green body provided by a preferred embodiment of the present application.
  • Fig. 3 is a schematic diagram of the structure of a sintered ceramic device provided by a preferred embodiment of the present application.
  • Aqueous ceramic green body 20 Aqueous ceramic green body 20
  • a preferred embodiment of the present application provides a room temperature ceramic sintering method, which includes the following steps:
  • step S11 an original ceramic green body (not shown) is provided.
  • the ceramic powder is placed in a mold and pressed to form an original ceramic green body, and the prepared original ceramic green body is placed in an oven at a temperature of 110-150°C for drying for more than 15 minutes, and then immediately The mass of the dried original ceramic green body was weighed with a balance, and this weighing was recorded as the first weighing.
  • the shape of the original ceramic green body is at least one of a cylinder, a rectangular parallelepiped, and an I-shape. It is understandable that the shape of the original ceramic green body may also be other regular or irregular shapes. Specifically, the original ceramic green body may have any shape. In this embodiment, the shape of the original ceramic green body is an I-shape. Wherein, the material of the original ceramic green body may be zinc oxide.
  • the material of the electrode includes gold or conductive silver paste.
  • the material of the electrode may also be metals such as silver (Ag) and platinum (Pt) that are easily attached to the original ceramic green body.
  • the material of the electrode can also be other conductive metals.
  • the electrode may also be a metal sheet electrode.
  • Step S12 referring to FIG. 2, the original ceramic green body is placed in a closed container 10 containing water vapor, so that the original ceramic green body absorbs moisture, and a water-containing ceramic green body 20 is obtained.
  • the raw ceramic green body uniformly absorbs moisture in the moisture absorption device as shown in FIG. 2 to obtain the water-containing ceramic green body 20.
  • the moisture absorption device includes the airtight container 10 and a wire mesh 30 located in the airtight container 10.
  • the airtight container 10 is used to store water
  • the wire mesh 30 is used to store the original ceramic green body and the water-containing ceramic green body 20.
  • the airtight container 10 may be a beaker covered with a plastic wrap (not shown), and the material of the wire mesh 30 may be metal iron.
  • the beaker contains a certain amount of water
  • the wire mesh 30 is suspended on the surface of the water by a rope
  • the original ceramic green body is placed on the wire mesh 30, and the beaker is sealed with the plastic wrap
  • Heating the beaker causes the humidity in the beaker to continuously increase as the water evaporates until it is saturated, so that the original ceramic green body can uniformly absorb water.
  • step S13 the green hydrated ceramic body 20 is taken out of the airtight container 10, and both ends of the green hydrated ceramic body 20 are connected to a power source 40.
  • the water-containing ceramic green body 20 is taken out and the mass of the water-containing ceramic green body 20 is measured with a balance, and the weighing is recorded as the second weighing, and then the wires 50 are respectively wound On the two electrodes, the wire 50 is connected to the power source 40, so that the two electrodes are connected to the power source 40 respectively.
  • the moisture content of the water-containing ceramic green body 20 is calculated according to the mass of the second weighing and the mass of the first weighing. Wherein, the moisture content of the water-containing ceramic green body 20 is the percentage of the mass of the water-containing ceramic green body 20 that is increased after absorbing moisture in the original ceramic green body.
  • the moisture content of the green ceramic body containing water is controlled to be 3%-10%. If it is calculated that the moisture content of the green hydrated ceramic body is less than 3%, put it back into the airtight container 10 and absorb moisture appropriately to increase the moisture content of the green hydrated ceramic body 20; If the water content of the green ceramic body 20 is higher than 10%, proper heating is required to reduce the water content of the green ceramic body 20. Among them, it can be placed in an oven for heating.
  • the original ceramic green body can also be placed in a closed container containing water vapor, and the moisture content of the hydrated ceramic green body versus time can be measured to determine when to take out the hydrated ceramic Green body.
  • the research of this application found that if the water content of the water-containing ceramic green body 20 is lower than 3% or higher than 10%, the success rate of the experiment is relatively low, and the water-containing ceramic green body 20 may be broken or sintered. The ceramics cannot be densified.
  • the water content of zinc oxide ceramics is 2% to 7%
  • the water content of zirconia ceramics is 2% to 8%.
  • the specific moisture content required for sintering of a certain ceramic green body is subject to experiment.
  • the required criterion for judging the moisture content is that the sample (ie, the green ceramic body containing water) can generate internal discharge or creeping discharge when a high voltage is applied.
  • the wire 50 is a metal wire with a relatively high melting point.
  • the metal wire may include platinum wire.
  • the power supply 40 is a high-voltage power supply.
  • the power supply 40 may be a DC power supply or an AC power supply.
  • the power source 40 is an AC power source.
  • the use of AC power can make the final sintered ceramic grains have better uniformity. It is understandable that the power supply 40 may also be a square wave, pulse or other various forms of power supply.
  • the green hydrated ceramic body 20 when the green hydrated ceramic body 20 is connected to the power source 40, the green hydrated ceramic body 20 is suspended.
  • the wire 50 is fixed on the upper ends of the two fixing brackets 60 so that the green hydrated ceramic body 20 can be suspended between the two fixing brackets 60, and the two electrodes at both ends of the green hydrated ceramic body 20
  • the wires 50 are respectively connected to the power source 40, and the green ceramic hydrate 20 and the power source 40 form a closed loop through the wires 50.
  • the water-containing ceramic green body 20 can also be placed on an insulating ceramic plate.
  • step S14 the power source 40 is connected to apply a voltage to the green ceramic body 20 containing water.
  • step S15 the voltage is increased to a predetermined voltage value to cause the surface discharge or internal discharge of the green hydrated ceramic body 20 to be maintained for a predetermined period of time and then the power supply 40 is cut off to obtain the ceramic.
  • the voltage is increased to the predetermined voltage value at a rate of 0.1-5 kV/s.
  • the predetermined voltage value is 1-100 kV.
  • the predetermined voltage value is a variable value, and the predetermined voltage value is related to the length of the green ceramic embryo 20 containing water.
  • the field strength of the green ceramic body 10 with water is 5 kV/cm.
  • the current density flowing through the hydrated ceramic green body is 10-1000 mA/mm 2 .
  • the boost rate of the voltage and the current density flowing through the water-containing ceramic green body 20 may be different, and the specific values and ranges need to be verified by experiments.
  • raising the voltage to the predetermined voltage value is performed under the condition that the temperature is less than or equal to 30°C.
  • the present application also provides a room temperature ceramic sintering device used in the room temperature ceramic sintering method for sintering the green ceramic body 20 containing water.
  • the room temperature ceramic sintering device includes a power source 40, a wire 50 and two fixing brackets 60.
  • the wire 50 is fixed on the upper ends of the two fixing brackets 60 so that the green hydrated ceramic body 20 can be suspended between the two fixing brackets 60, and the two electrodes at both ends of the green hydrated ceramic body 20 pass through
  • the wire 50 is connected to the power source 40, and the green ceramic hydrate 20 and the power source 40 form a closed loop through the wire 50.
  • the above description only takes water as an example, that is, the sintering of ceramics at room temperature is achieved by controlling the water content of the ceramic green body.
  • the water described above can be expanded into other liquids.
  • the sintering of ceramics at room temperature can be achieved by controlling the amount of the liquid contained in the ceramic green body.
  • the specific amount of the liquid is subject to experimental data.
  • the liquid may be a volatile liquid.
  • the volatile liquid may be methanol, ethanol, and the like.
  • the application also provides a ceramic sintered using the room temperature ceramic sintering method.
  • a green zinc oxide ceramic body with an I-shaped shape is placed in a beaker as shown in FIG. 2 and placed for about 20 hours.
  • the moisture content of the obtained green ceramic body reaches 4.32%.
  • the middle part of the I-shaped ceramic green body has a thickness of 1.7 mm, a length of 21 mm, and a width of 3.3 mm.
  • the second step is to wind wires on both ends of the green hydrated ceramic body, connect the wires to an AC power source, and fix the wires on a fixed support to make the green hydrated ceramic body hang in the air.
  • the third step is to switch on the power supply, and then quickly increase the voltage at a rate of 1kV/s until the voltage across the hydrated ceramic green body suddenly drops, and the current flowing through the hydrated ceramic green body suddenly rises, maintaining the voltage and current No change, the power supply is disconnected after 1 minute to complete the sintering.
  • the shape of the ceramic green body in the first step is a cylinder with a diameter of 3mm and a length of 22mm. When placed in a beaker for about 36 hours, the moisture content of the obtained green ceramic body reaches 6.12%. .
  • a DC power supply is used.
  • Example 1 The difference from Example 1 is that in the first step, the ceramic green body is placed in a beaker for about 20 hours, and the moisture content of the obtained hydrated ceramic green body reaches 1%.
  • Example 2 The difference from Example 1 is that in the first step, the ceramic green body is dried at a high temperature (120°C), and the moisture content of the obtained hydrated ceramic green body reaches 0%, and the ceramic green body is not placed in the beaker. .
  • the sintered ceramics of Example 1-2 and Comparative Example 1-2 were tested by the Archimedes drainage method.
  • the calculation results showed that the density of the sintered ceramics of Example 1 was 94%, and the density of the sintered ceramics of Example 2 Is 95%.
  • the ceramic in Comparative Example 1 only had creeping discharge, and although there were electric traces on the surface, the overall sintering did not occur.
  • the calculated density of the ceramic was only 70%.
  • the ceramic in Comparative Example 2 only had creeping discharge, and although there were electric traces on the surface, the overall sintering did not occur.
  • the calculated density of the ceramic was 60%, which was unchanged from that before sintering.
  • the density of ceramics sintered by the room temperature ceramic sintering method provided in the present application can be as high as 90%, and no obvious defects such as cracks appear.
  • the room temperature ceramic sintering method provided by the present application realizes the sintering of ceramics at room temperature by controlling the water content of the ceramic green body, which greatly reduces the furnace temperature and energy consumption required for ceramic sintering, thereby reducing a large amount of energy consumption.
  • the process flow of the room temperature ceramic sintering method in the present application is relatively simple, compared with the conventional flash sintering process, no additional heating device is required, and the method of controlling the moisture content of the ceramic green body is simple and easy to implement.

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Abstract

一种室温陶瓷烧结方法，包括以下步骤：提供原始陶瓷生坯；将所述原始陶瓷生坯放置于含有水蒸气的密闭容器中，使所述原始陶瓷生坯吸收水分，得到含水陶瓷生坯；将所述含水陶瓷生坯从所述密闭容器中取出，并将所述含水陶瓷生坯的两端连接电源；连通所述电源以向所述含水陶瓷生坯施加电压；以及升高所述电压至一预定电压值，使所述含水陶瓷生坯发生沿面放电或内部放电，维持一预定时间段后切断所述电源，从而得到所述陶瓷。该室温陶瓷烧结方法能够在室温下烧结陶瓷。还提供一种所述的室温陶瓷烧结方法烧结的陶瓷。

Description

室温陶瓷烧结方法及陶瓷 技术领域
本申请涉及陶瓷材料制备技术领域，尤其涉及一种室温陶瓷烧结方法以及应用所述的室温陶瓷烧结方法烧结的陶瓷。
背景技术
人类使用陶瓷材料的历史已有数千年，从最早的陶器到现在功能多样的陶瓷材料与器件，陶瓷材料如今被广泛应用于各个高技术行业。由于其特殊的物理、化学性能，陶瓷材料通常不能通过机械加工或铸造工艺来制造，而是要通过粉末成型和高温烧结而成。烧结的主要缺点之一就是需要消耗大量能源，因为常规烧结方法需要很高的温度和较长的时间。
闪烧工艺通过在陶瓷生坯上施加一定强度的电场，从而达到降低烧结所需炉温并在极短的时间内实现陶瓷致密化的目的。但是，大多数的陶瓷闪烧仍然需要比较高的炉温。
发明内容
有鉴于此，本申请提供一种能够实现陶瓷在室温下烧结的方法，从而解决以上问题。
另，本申请还提供一种应用该室温陶瓷烧结方法烧结的陶瓷。
本申请提供一种室温陶瓷烧结方法，包括以下步骤：
提供原始陶瓷生坯；
将所述原始陶瓷生坯放置于含有水蒸气的密闭容器中，使所述原始陶瓷生坯吸收水分，得到含水陶瓷生坯；
将所述含水陶瓷生坯从所述密闭容器中取出，并将所述含水陶瓷生坯的两端连接电源；
连通所述电源以向所述含水陶瓷生坯施加电压；以及
升高所述电压至一预定电压值，使所述含水陶瓷生坯发生沿面放电或内部放电，维持一预定时间段后切断所述电源，从而得到所述陶瓷。
本申请还提供一种室温陶瓷烧结方法，包括以下步骤：
提供原始陶瓷生坯；
将所述原始陶瓷生坯放置于含有液体的密闭容器中，将所述液体蒸发以使所述原始陶瓷生坯吸收所述液体，得到含液体陶瓷生坯；
将所述含液体陶瓷生坯从所述密闭容器中取出，并将所述含液体陶瓷生坯的两端连接电源；
连通所述电源以向所述含液体陶瓷生坯施加电压；以及
升高所述电压至一预定电压值，使所述含液体陶瓷生坯发生沿面放电或内部放电，维持一预定时间段后切断所述电源，从而得到所述陶瓷。
本申请还提供一种应用所述的室温陶瓷烧结方法烧结的陶瓷，所述陶瓷的晶粒粒径为500nm-10μm，所述陶瓷的致密度大于90％。
本申请提供的所述室温陶瓷烧结方法通过控制陶瓷生坯的含水量实现陶瓷在室温(0-30℃)下的烧结，大幅降低了陶瓷烧结所需的炉温与能耗，从而减少了大量的能耗。同时，本申请中的所述室温陶瓷烧结方法工艺流程较为简单，与常规的闪烧工艺相比，不需要额外的加热装置，并且控制陶瓷生坯含水率的方法简便易行。
附图说明
图1是本申请较佳实施例提供的陶瓷的制备流程图。
图2是本申请较佳实施例提供的陶瓷生坯吸收水分装置的结构示意图。
图3是本申请较佳实施例提供的烧结陶瓷的装置结构示意图。
主要元件符号说明
密闭容器                        10
含水陶瓷生坯                    20
丝网                            30
电源                            40
导线                            50
固定支架                        60
如下具体实施方式将结合上述附图进一步说明本申请。
具体实施方式
下面将结合本申请实施例中的附图，对本申请实施例中的技术方案进行清楚、完整地描述，显然，所描述的实施例仅仅是本申请一部分实施例，而不是全部的实施例。基于本申请中的实施例，本领域普通技术人员在没有作出创造性劳动前提下所获得的所有其他实施例，都属于本申请保护的范围。
除非另有定义，本文所使用的所有的技术和科学术语与属于本申请的技术领域的技术人员通常理解的含义相同。本文中在本申请的说明书中所使用的术语只是为了描述具体的实施例的目的，不是旨在于限制本申请。
为能进一步阐述本申请达成预定目的所采取的技术手段及功效，以下结合附图及较佳实施方式，对本申请作出如下详细说明。
请参阅图1及图2，本申请较佳实施方式提供一种室温陶瓷烧结方法，包括以下步骤：
步骤S11，提供原始陶瓷生坯(图未示)。
具体地，将陶瓷粉体放入模具中压制，制成原始陶瓷生坯，并将制成的所述原始陶瓷生坯放入温度为110～150℃的烘箱中烘干15分钟以上，而后立即用天平称量干燥后的所述原始陶瓷生坯的质量，并将此次称重记为第一次 称重。
其中，所述原始陶瓷生坯的形状为圆柱体、长方体以及工字型中的至少一种。可以理解的，所述原始陶瓷生坯的形状也可为其他规则或不规则的形状。具体地，所述原始陶瓷生坯可为任意形状。在本实施方式中，所述原始陶瓷生坯的形状为工字型。其中，所述原始陶瓷生坯的材质可为氧化锌。
在本实施方式中，在提供所述原始陶瓷生坯之后，并在干燥所述原始陶瓷生坯之前，还需要在所述原始陶瓷生坯的两端分别喷形成电极(图未示)。其中，所述电极的材质包括金或导电银浆。所述电极的材质还可为容易与所述原始陶瓷生坯贴合的银(Ag)以及铂(Pt)等金属。此外，所述电极的材质还可为其他导电的金属。在其他实施方式中，所述电极还可为金属片电极。
步骤S12，请参阅图2，将所述原始陶瓷生坯放置于含有水蒸气的密闭容器10中，使所述原始陶瓷生坯吸收水分，得到含水陶瓷生坯20。
其中，所述原始陶瓷生坯在如图2所示的吸收水分装置中均匀吸收水分，得到所述含水陶瓷生坯20。在本实施方式中，所述吸收水分装置包括所述密闭容器10以及位于所述密闭容器10内的丝网30。所述密闭容器10用于存放水，所述丝网30用于存放所述原始陶瓷生坯以及所述含水陶瓷生坯20。其中，所述密闭容器10可为覆盖有保鲜膜(图未示)的烧杯，所述丝网30的材质可为金属铁。具体地，所述烧杯内装有一定量的水，所述丝网30利用绳子悬在水面上面，所述原始陶瓷生坯放在所述丝网30上，用所述保鲜膜将所述烧杯密封，加热所述烧杯使得所述烧杯内的湿度随着水的蒸发不断升高直至饱和，进而使得所述原始陶瓷生坯能够均匀的吸收水分。
步骤S13，将所述含水陶瓷生坯20从所述密闭容器10中取出，并将所述含水陶瓷生坯20的两端连接电源40。
具体地，经过一段时间后将所述含水陶瓷生坯20取出后用天平测量所述含水陶瓷生坯20的质量，并将此次称重记为第二次称重，然后用导线50分别缠绕在两个所述电极上，并将所述导线50与电源40连接，以使两个所述 电极分别与所述电源40相连。
根据第二次称重的质量和第一次称重的质量计算出所述含水陶瓷生坯20的含水率。其中，所述含水陶瓷生坯20的含水率为所述含水陶瓷生坯20吸收水分后增加的质量占所述原始陶瓷生坯的百分比。
在本实施方式中，控制所述含水陶瓷生坯的含水率为3％～10％。若计算得出所述含水陶瓷生坯的含水率低于3％，则放回所述密闭容器10中再适当的吸收水分以增加所述含水陶瓷生坯20的含水率；若计算得出所述含水陶瓷生坯20的含水率高于10％，则适当的加热以降低所述含水陶瓷生坯20的含水率。其中，可放在烘箱中进行加热。
可以理解的，在陶瓷烧结之前，还可将原始陶瓷生坯放置在含有水蒸气的密闭容器中，并测定含水陶瓷生坯的含水率与时间的关系曲线，以确定何时取出所述含水陶瓷生坯。
其中，本申请研究发现，如果所述含水陶瓷生坯20的含水率低于3％或高于10％，则实验的成功率相对较低，可能会出现所述含水陶瓷生坯20断裂或者烧结的陶瓷无法致密化的情况。
需要说明的是，不同陶瓷体系(即不同材质的陶瓷生坯)需要的含水率是不同的。如氧化锌陶瓷的含水率为2％-7％，氧化锆陶瓷的含水率为2％-8％。具体某种陶瓷生坯烧结需要的含水率以实验为准，判断含水率需要的标准是该含水率下，样品(即含水陶瓷生坯)在施加高电压时能发生内部放电或沿面放电。
其中，所述导线50为熔点较高的金属导线。具体地，所述金属导线可包括铂丝。在本实施方式中，所述电源40为高压电源。所述电源40可为直流电源，也可为交流电源。优选地，所述电源40为交流电源。使用交流电源可使最终烧结得到的陶瓷晶粒具有较好的均匀性。可以理解的，所述电源40还可以为方波、脉冲或其他各种形式的电源。
如图3所示，在本实施方式中，当所述含水陶瓷生坯20连通所述电源 40时，所述含水陶瓷生坯20悬空设置。具体地，所述导线50固定在两个固定支架60的上端以使得所述含水陶瓷生坯20能够在两个固定支架60之间悬空，所述含水陶瓷生坯20两端的两个所述电极通过所述导线50分别与所述电源40连接，且所述含水陶瓷生坯20与所述电源40通过所述导线50形成一个闭合的回路。在其他实施方式中，所述含水陶瓷生坯20还可放置于绝缘陶瓷板上。
步骤S14，连通所述电源40以向所述含水陶瓷生坯20施加电压。
步骤S15，升高所述电压至一预定电压值，使所述含水陶瓷生坯20发生沿面放电或内部放电，维持一预定时间段后切断所述电源40，从而得到所述陶瓷。
具体地，以0.1-5kV/s的速率升高所述电压至所述预定电压值。其中，所述预定电压值为1-100kV。其中，所述预定电压值为一个变化值，所述预定电压值与所述含水陶瓷生胚20的长度有关。升高所述电压至所述预定电压值后，所述含水陶瓷生坯10的场强大致为5kV/cm。在升高所述电压至所述预定电压值时，流经所述含水陶瓷生坯的电流密度为10-1000mA/mm 2。当流经所述含水陶瓷生坯20的电流突然增大以及所述含水陶瓷生坯20两端的电压陡降时，即可判断所述含水陶瓷生坯20发生沿面放电或内部放电，从而实现所述含水陶瓷生坯20的快速致密化。
可以理解的，在不同的陶瓷体系中，所述电压的升压速率以及流经所述含水陶瓷生坯20的电流密度可不相同，具体数值和范围需要实验验证。
其中，升高所述电压至所述预定电压值在温度小于或等于30℃的条件下进行。
如图3所示，本申请还提供一种应用所述的室温陶瓷烧结方法使用的室温陶瓷烧结装置，用于烧结含水陶瓷生坯20。所述室温陶瓷烧结装置包括电源40、导线50以及两个固定支架60。其中，所述导线50固定在两个固定支架60的上端以使得所述含水陶瓷生坯20能够在两个固定支架60之间悬空， 所述含水陶瓷生坯20两端的两个所述电极通过所述导线50与所述电源40连接，且所述含水陶瓷生坯20与所述电源40通过所述导线50形成一个闭合的回路。
可以理解的，上述仅仅以水为例进行说明，即通过控制陶瓷生坯的含水量实现陶瓷在室温下的烧结，在其他实施方式中，上述描述的水可扩大到其他液体中。即可通过控制陶瓷生坯的含所述液体的量实现陶瓷在室温下的烧结。具体含所述液体的量以实验数据为准。其中，所述液体可为挥发性液体。具体地，所述挥发性液体可为甲醇以及乙醇等。
本申请还提供一种应用所述的室温陶瓷烧结方法烧结的陶瓷。
下面通过实施例及对比例对本申请进行具体说明。
实施例1
第一步、将一形状为工字型形状的氧化锌陶瓷生坯放入如图2所示的烧杯中放置约20小时后，得到的含水陶瓷生坯的含水率达到4.32％。其中，工字型陶瓷生坯的中间部分厚度为1.7mm，长度为21mm，宽度为3.3mm。
第二步、在所述含水陶瓷生坯的两端缠绕上导线，并将所述导线与交流电源相连，且将所述导线固定在固定支架上以使所述含水陶瓷生坯悬空。
第三步、接通电源，之后迅速以1kV/s的速率升高电压，直到所述含水陶瓷生坯两端的电压突然下降、流经所述含水陶瓷生坯的电流突然上升，保持电压、电流不变，1分钟后断开所述电源，完成烧结。
实施例2
与实施例1不同的是：第一步中陶瓷生坯的形状为圆柱体，其中，直径为3mm，长度为22mm，在烧杯中放置约36h，得到的含水陶瓷生坯的含水率达到6.12％。第二步中采用直流电源。
对比例1
与实施例1不同的是：第一步中将陶瓷生坯在烧杯中放置约20小时，得到的含水陶瓷生坯的含水率达到1％。
对比例2
与实施例1不同的是：第一步中将陶瓷生坯在高温(120℃)条件下烘干，得到的含水陶瓷生坯的含水率达到0％，并不将陶瓷生胚放置在烧杯中。
利用阿基米德排水法对实施例1-2以及对比例1-2烧结的陶瓷进行测试，计算结果显示实施例1烧结的陶瓷的致密度为94％，实施例2烧结的陶瓷的致密度为95％。对比例1中的陶瓷由于仅发生了沿面放电，表面虽有电痕，但没有发生整体烧结，计算得到的陶瓷的致密度仅为70％。对比例2中的陶瓷由于仅发生了沿面放电，表面虽有电痕，但没有发生整体烧结，计算得到的陶瓷的致密度为60％，与未烧结之前相比无变化。
通过本申请提供的所述室温陶瓷烧结方法烧结的陶瓷致密度可高达90％以上，并未出现明显的裂纹等缺陷。
本申请提供的所述室温陶瓷烧结方法通过控制陶瓷生坯的含水量实现陶瓷在室温下的烧结，大幅降低了陶瓷烧结所需的炉温与能耗，从而减少了大量的能耗。同时，本申请中的所述室温陶瓷烧结方法工艺流程较为简单，与常规的闪烧工艺相比，不需要额外的加热装置，并且控制陶瓷生坯含水率的方法简便易行。
以上说明仅仅是对本申请一种优化的具体实施方式，但在实际的应用过程中不能仅仅局限于这种实施方式。对本领域的普通技术人员来说，根据本申请的技术构思做出的其他变形和改变，都应该属于本申请的保护范围。

Claims (10)

  1. 一种室温陶瓷烧结方法，其特征在于，包括以下步骤：
    提供原始陶瓷生坯；
    将所述原始陶瓷生坯放置于含有水蒸气的密闭容器中，使所述原始陶瓷生坯吸收水分，得到含水陶瓷生坯；
    将所述含水陶瓷生坯从所述密闭容器中取出，并将所述含水陶瓷生坯的两端连接电源；
    连通所述电源以向所述含水陶瓷生坯施加电压；以及
    升高所述电压至一预定电压值，使所述含水陶瓷生坯发生沿面放电或内部放电，维持一预定时间段后切断所述电源，从而得到所述陶瓷。
  2. 如权利要求1所述的室温陶瓷烧结方法，其特征在于，所述含水陶瓷生坯的含水率为3％～10％。
  3. 如权利要求1所述的室温陶瓷烧结方法，其特征在于，升高所述电压至所述预定电压值的速率为0.1-5kV/s。
  4. 如权利要求1所述的室温陶瓷烧结方法，其特征在于，所述预定电压值为1-100kV。
  5. 如权利要求1所述的室温陶瓷烧结方法，其特征在于，升高所述电压至所述预定电压值时，流经所述含水陶瓷生坯的电流密度为10-1000mA/mm 2。
  6. 如权利要求1所述的室温陶瓷烧结方法，其特征在于，升高所述电压至所述预定电压值发生的温度小于或等于30℃。
  7. 如权利要求1所述的室温陶瓷烧结方法，其特征在于，在将所述原始陶瓷生坯放置于含有水蒸气的所述密闭容器中之前，还包括：
    在所述原始陶瓷生坯的两端分别形成电极，其中，所述电源连接于所述电极。
  8. 一种室温陶瓷烧结方法，其特征在于，包括以下步骤：
    提供原始陶瓷生坯；
    将所述原始陶瓷生坯放置于含有液体的密闭容器中，将所述液体蒸发以使所述原始陶瓷生坯吸收所述液体，得到含液体陶瓷生坯；
    将所述含液体陶瓷生坯从所述密闭容器中取出，并将所述含液体陶瓷生坯的两端连接电源；
    连通所述电源以向所述含液体陶瓷生坯施加电压；以及
    升高所述电压至一预定电压值，使所述含液体陶瓷生坯发生沿面放电或内部放电，维持一预定时间段后切断所述电源，从而得到所述陶瓷。
  9. 如权利要求8所述的室温陶瓷烧结方法，其特征在于，所述液体包括甲醇以及乙醇中的至少一种。
  10. 一种应用如权利要求1至9中任一项所述的室温陶瓷烧结方法烧结的陶瓷，所述陶瓷的晶粒粒径为500nm-10μm，所述陶瓷的致密度大于90％。
PCT/CN2021/074217 2020-04-03 2021-01-28 室温陶瓷烧结方法及陶瓷 WO2021196856A1 (zh)

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