In-situ titania reinforced alumina ceramic and method of making same

Abstract

The application relates to the technical field of alumina ceramic preparation, in particular to in-situ titanium oxide reinforced alumina ceramic and a preparation method thereof. Alumina and other oxides are mixed to obtain mixed powder, the mixed powder is dispersed into photocuring resin containing a dispersant, ball milling is carried out to obtain ceramic slurry; organic titanium is mechanically stirred and dispersed into the ceramic slurry to obtain ceramic slurry containing organic titanium; the ceramic slurry containing organic titanium is subjected to 3D printing to obtain a ceramic preform; the ceramic preform is subjected to debinding and sintering to obtain in-situ titanium oxide reinforced alumina ceramic. In the application, the organic titanium is dispersed in the 3D-printed ceramic slurry, and the organic titanium is decomposed into titanium oxide at high temperature in the process of ceramic debinding and sintering, so that the alumina is modified and toughened, the prepared alumina ceramic is uniform in titanium oxide distribution, and the material has great improvement in compactness and bending resistance.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of alumina ceramic preparation, and particularly relates to in-situ titanium oxide reinforced alumina ceramic and a preparation method thereof. BACKGROUND

[0002] Alumina ceramic is a kind of high-performance advanced ceramic material, which is known for high-temperature resistance, wear resistance and high cost performance. Compared with other precision ceramics, alumina ceramic has more competitive cost advantage while providing excellent performance. It can withstand high temperature of up to 1600 DEG C for a long time, and has excellent durability under high friction and high wear conditions, and is widely used in high-temperature industrial equipment, mechanical parts and chemical industry. However, due to its brittleness and poor toughness, its application and development are greatly limited.

[0003] How to toughen alumina ceramic is still a research hotspot. Toughening by using magnesium oxide, zirconium oxide, lanthanum oxide, titanium oxide and cerium oxide powder can improve the brittleness of alumina ceramic to some extent, but the density of the prepared ceramic is still far from the actual application requirements.

[0004] Alumina ceramic has high hardness and brittleness. The traditional subtractive manufacturing methods such as cutting, milling, drilling and drilling are used to manufacture complex structure ceramics, which has complex process, high cost, and is easy to cause product cracking or deformation.

[0005] In summary, it is necessary to develop a method for improving the density of ceramic and preventing alumina ceramic from cracking and deforming. SUMMARY

[0006] In view of the above problems of the prior art, the present application provides an in-situ titanium oxide reinforced alumina ceramic and a preparation method thereof. In the present application, organic titanium is dispersed in the 3D printed ceramic slurry, and the organic titanium is decomposed into titanium oxide at high temperature during the ceramic debinding and sintering process, so as to realize the toughening modification of alumina. In the alumina ceramic prepared by the present application, the titanium oxide is uniformly distributed, and the density and bending resistance of the ceramic material are greatly improved. The preparation method can prevent the alumina ceramic from cracking and deforming.

[0007] To solve the above technical problems, the present application adopts the following technical scheme:

[0008] A preparation method of in-situ titanium oxide reinforced alumina ceramic, comprising the following steps:

[0009] Mixing alumina and other oxides to obtain mixed powder, dispersing the mixed powder into photocuring resin containing dispersant, ball-milling mixing to obtain ceramic slurry for fully mixing; the other oxides are at least one of zirconium oxide, magnesium oxide and yttrium oxide powder; the alumina, zirconium oxide, magnesium oxide and yttrium oxide powder are important formula raw materials of alumina ceramic, and are important premise for realizing toughening modification of alumina;

[0010] Mechanically stirring and dispersing organic titanium into the ceramic slurry to obtain ceramic slurry containing organic titanium;

[0011] 3D printing the ceramic slurry containing organic titanium to obtain ceramic preform;

[0012] Debinding and sintering the ceramic preform to obtain in-situ titanium oxide reinforced alumina ceramic.

[0013] In the preferred embodiment of the present application, yttrium oxide and zirconium oxide are used simultaneously in the mixed powder, and the yttrium oxide functions to stabilize the zirconium oxide.

[0014] In the preferred embodiment of the present application, the volume fraction of the mixed powder in the photocuring resin containing dispersant is 40% to 55%. If the volume fraction is greater than 55% or less than 40%, the titanium oxide is unevenly distributed, and the density and bending resistance of the final ceramic material are significantly reduced.

[0015] In the preferred embodiment of the present application, the photocuring resin is an epoxy acrylate resin, and the mass percentage of the dispersant in the mixed powder is 5% to 15%. If the mass percentage is greater than 15% or less than 5%, the generated titanium oxide cannot be effectively dispersed.

[0016] In the preferred embodiment of the present application, the ball-milling mixing condition is 400 r / min ball-milling for 10 h.

[0017] In the preferred embodiment of the present application, the mechanical stirring condition is 400 r / min stirring for 2 h.

[0018] In the preferred embodiment of the present application, the organic titanium is diisopropyl titanate.

[0019] In the preferred embodiment of the present application, the mass percentage of the organic titanium in the ceramic slurry is 2%.

[0020] In the preferred embodiment of the present application, the layer thickness of 3D printing is set to 50 μm, and the exposure time is 2 s.

[0021] Further, in order to improve the density and bending resistance of the in-situ titanium oxide reinforced alumina ceramic, and to prevent cracking and deformation, the specific parameters of 3D printing are as follows: a digital mask device with a resolution of 1920*1080 pixels is used for exposure, a corresponding 3D model is imported into a DLP 3D printer through Tinkercad software, and slicing is performed by using PCLab software; the layer thickness is set to 50 mu m, and the exposure time is 2 s.

[0022] In the preferred embodiment of the present application, the debinding conditions are as follows: heating to 375 DEG C at a heating rate of 1 DEG C / min, holding for 30 min, then heating to 485 DEG C at a heating rate of 1 DEG C / min, holding for 30 min, then heating to 600 DEG C at a heating rate of 1 DEG C / min, holding for 30 min, then heating to 1000 DEG C at a heating rate of 5 DEG C / min without holding, and then cooling with the furnace, to complete the debinding and pre-sintering of the preform, and obtain the ceramic green body. The process uses a programmed heating method, which can simultaneously complete the debinding and pre-sintering operations, and plays an important role in preventing cracking and deformation of the alumina ceramic.

[0023] In the preferred embodiment of the present application, the sintering operation is as follows: the sintering conditions are as follows: heating to 1000 DEG C at a heating rate of 10 DEG C / min, heating to 1500 DEG C to 1700 DEG C at a heating rate of 1 DEG C / min, holding for 4 h, and then cooling with the furnace, to complete the sintering of the ceramic.

[0024] In the preferred embodiment of the present application, in the mixed powder, the mass percentage of zirconium oxide is 0% to 20%, the mass percentage of magnesium oxide is 0% to 0.5%, the mass percentage of yttrium oxide is 0% to 1%, and the mass percentage of aluminum oxide is the balance, and the total is 100%.

[0025] Another object of the present application is to provide an in-situ titanium oxide reinforced alumina ceramic prepared by the preparation method.

[0026] 3D printing is a new additive manufacturing technology developed in recent years, and has irreplaceable advantages in the preparation of complex ceramic structures. Currently, the 3D printing technologies applied to ceramics mainly include light solidification 3D printing technology and selective laser sintering (SLS) technology. The light solidification DLP-3D printing technology has significant advantages in precision, efficiency, cost and surface quality, and can realize high-quality and rapid prototyping.

[0027] Compared with the prior art, the present application has the following beneficial effects:

[0028] The application disperses organic titanium in a 3D-printed ceramic slurry. During the process of ceramic debinding and sintering, the organic titanium is decomposed into titanium oxide at high temperature, so as to realize the toughening modification of alumina. In the prepared alumina ceramic, the titanium oxide is uniformly distributed, and the material has great improvement in terms of compactness and bending resistance. In the early dispersion process, the organic titanium is uniformly dispersed in the epoxy acrylate resin by mechanical stirring, and can react with the acrylate resin in the photocuring process, so that uniform titanium oxide can be formed in the alumina matrix in the subsequent high-temperature debinding and sintering. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 SEM image of alumina ceramic particles prepared without adding titanium oxide in the control example 1.

[0030] Figure 2 In the figure, A is the SEM image of the in-situ titanium oxide reinforced alumina ceramic prepared in the embodiment 1 of the application, and B is the EDS image of each element of the alumina ceramic particles prepared in the embodiment 1 of the application.

[0031] Figure 3 XRD image of the in-situ titanium oxide reinforced alumina ceramic prepared in the embodiment 1 of the application. DETAILED DESCRIPTION

[0032] The technical solutions in the embodiments of the application will be described in detail below in combination with preferred embodiments and the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the application, rather than all the embodiments of the application. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the application.

[0033] It should be noted that all the professional terms used in the application are only for the purpose of describing the specific embodiments, and are not intended to limit the protection scope of the application. Unless otherwise specified, all the materials, reagents, instruments and equipment used in the following embodiments of the application can be purchased from the market or prepared by the existing method. In the following examples and experiments, the photocuring resin is an epoxy acrylate resin with a model number of 3H2T, which is purchased from Maixin New Material Technology (Gu'an) Co., Ltd. The dispersant has a model number of KOS110 and is purchased from Guangzhou Kangou International Trade Co., Ltd.

[0034] The terms involved in the application are described as follows:

[0035] 3D printing is the Chinese name of three-dimensional printing.

[0036] Titanium oxide is the abbreviation of titanium monoxide TiO.

[0037] Digital mask device, English abbreviation DMD.

[0038] SEM image is the Chinese name of scanning electron microscope image.

[0039] EDS image is the Chinese name of energy dispersive X-ray spectrum.

[0040] XRD image is the Chinese name of X-ray diffraction pattern.

[0041] Example 1

[0042] A method for preparing in-situ titanium oxide reinforced alumina ceramic, comprising the following steps:

[0043] (1) mixing alumina, zirconia, magnesium oxide and yttrium oxide powders to obtain a mixed powder; in the mixed powder, by mass percentage, zirconia is 20%, magnesium oxide is 0.5%, yttrium oxide is 1%, and alumina is the balance, totaling 100%.

[0044] Disperse the mixed powder into a photocurable resin containing a dispersant, ball mill at 400 r / min for 10 h to obtain a ceramic slurry, and the mass percentage of the dispersant in the mixed powder is 5%. The volume fraction of the mixed powder in the photocurable resin containing the dispersant is 40%.

[0045] Mechanically stir and disperse diisopropyl titanate bis(triethanolamine) into the ceramic slurry, and the mechanical stirring conditions are 400 r / min for 2 h to obtain a ceramic slurry containing organic titanium. The mass percentage of diisopropyl titanate bis(triethanolamine) in the ceramic slurry is 2%.

[0046] (2) Put the ceramic slurry containing organic titanium into a 3D printer for printing. The light source direction of the photocurable 3D printer used in the experiment is from top to bottom, and a digital mask device with a resolution of 1920x1080 pixels is used for exposure. The corresponding 3D model is imported into the DLP 3D printer through Tinkercad software, and slicing is performed using PCLab software, with a layer thickness of 50 μm and an exposure time of 2 s, to obtain a printed ceramic preform.

[0047] (3) Put the ceramic preform into a box-type resistance furnace, heat to 375℃ at a heating rate of 1℃ / min in air, heat to 485℃ at a heating rate of 1℃ / min after holding for 30 min, and continue to heat to 600℃ at a heating rate of 1℃ / min without holding, to complete the debinding and pre-sintering of the preform.

[0048] (4) Continue to heat to 1000℃ at a heating rate of 10℃ / min, heat to 1500℃ at a heating rate of 1℃ / min, and cool down with the furnace after holding for 4 h to complete the sintering of the ceramic, to obtain in-situ titanium oxide reinforced alumina ceramic.

[0049] The bending strength of the in-situ titanium oxide reinforced alumina ceramic is increased from 206.8 MPa of the control example 1 to 310.2 MPa, and the Vickers hardness is increased from 9.5 GPa to 19.3 GPa, which is more than doubled, indicating that the in-situ titanium oxide reinforced alumina ceramic prepared in this example is not prone to cracking and deformation.

[0050] Example 2

[0051] A method for preparing an in-situ titanium oxide reinforced alumina ceramic, comprising the following steps:

[0052] (1) mixing alumina and zirconia powders to obtain a mixed powder; in the mixed powder, the mass percentage of zirconia is 20%, and the mass percentage of alumina is the balance, with the total being 100%.

[0053] Disperse the mixed powder into a photocuring resin containing a dispersant, ball mill at 400 r / min for 10 h to obtain a ceramic slurry, and the mass percentage of the dispersant in the mixed powder is 10%. The volume fraction of the mixed powder in the photocuring resin containing the dispersant is 50%.

[0054] Mechanically stir diisopropyl titanate bis(triethanolamine) into the ceramic slurry, and the mechanical stirring conditions are 400 r / min for 2 h to obtain a ceramic slurry containing organic titanium. The mass percentage of diisopropyl titanate bis(triethanolamine) in the ceramic slurry is 2%.

[0055] (2) Put the ceramic slurry containing organic titanium into a 3D printer for printing. The light source direction of the photocuring 3D printer used in the experiment is from top to bottom, and a digital mask device with a resolution of 1920x1080 pixels is used for exposure. The corresponding 3D model is imported into the DLP 3D printer through Tinkercad software, and slicing is performed using PCLab software, with a layer thickness of 50 μm and an exposure time of 2 s to obtain a printed ceramic preform.

[0056] (3) Put the ceramic preform into a box-type resistance furnace, heat to 375℃ at a heating rate of 1℃ / min in air, heat to 485℃ at a heating rate of 1℃ / min after holding for 30 min, and continue to heat to 600℃ at a heating rate of 1℃ / min without holding, to complete the debinding and pre-sintering of the preform.

[0057] (4) Continue to heat to 1000℃ at a heating rate of 10℃ / min, heat to 1600℃ at a heating rate of 1℃ / min, and cool down with the furnace after holding for 4 h to complete the sintering of the ceramic, to obtain an in-situ titanium oxide reinforced alumina ceramic.

[0058] Example 3

[0059] A method for preparing an in-situ titania reinforced alumina ceramic, comprising the following steps:

[0060] (1) mixing alumina, magnesium oxide powders to obtain a mixed powder; in the mixed powder, by mass percentage, magnesium oxide is 0.5%, and alumina is the balance, totaling 100%.

[0061] Disperse the mixed powder into a photocuring resin containing a dispersant, ball mill at 400 r / min for 10 h to obtain a ceramic slurry, and the mass percentage of the dispersant in the mixed powder is 15%. The volume fraction of the mixed powder in the photocuring resin containing the dispersant is 55%.

[0062] Mechanically stir and disperse diisopropyl titanate bis(triethanolamine) into the ceramic slurry, and the mechanical stirring condition is stirring at 400 r / min for 2 h to obtain a ceramic slurry containing organic titanium. The mass percentage of diisopropyl titanate bis(triethanolamine) in the ceramic slurry is 2%.

[0063] (2) Put the ceramic slurry containing organic titanium into a 3D printer for printing. The light source direction of the photocuring 3D printer used in the experiment is from top to bottom, and a digital mask device with a resolution of 1920x1080 pixels is used for exposure. The corresponding 3D model is imported into the DLP 3D printer through Tinkercad software, and slicing is performed using PCLab software, with a layer thickness of 50 μm and an exposure time of 2 s, to obtain a printed ceramic preform.

[0064] (3) Put the ceramic preform into a box-type resistance furnace, heat to 375℃ at a heating rate of 1℃ / min in air, heat to 485℃ at a heating rate of 1℃ / min after holding for 30 min, and continue to heat to 600℃ at a heating rate of 1℃ / min without holding, to complete the debinding and pre-sintering of the preform.

[0065] (4) Continue to heat to 1000℃ at a heating rate of 10℃ / min, heat to 1700℃ at a heating rate of 1℃ / min, and hold for 4 h before cooling with the furnace, to complete the sintering of the ceramic, and obtain an in-situ titania reinforced alumina ceramic.

[0066] Comparative Example 1

[0067] A method for preparing an in-situ titania reinforced alumina ceramic, comprising the following steps:

[0068] (1) mixing alumina, zirconia, magnesium oxide and yttrium oxide powders to obtain a mixed powder; in the mixed powder, by mass percentage, zirconia is 20%, magnesium oxide is 0.5%, yttrium oxide is 1%, and alumina is the balance, totaling 100%.

[0069] The mixed powder is dispersed into a photocuring resin containing a dispersant, ball-milled at 400 r / min for 10 h to obtain a ceramic slurry, and the dispersant accounts for 5% of the mass percentage of the mixed powder in the photocuring resin containing the dispersant. The volume fraction of the mixed powder in the photocuring resin containing the dispersant is 40%.

[0070] (2) The ceramic slurry is placed into a 3D printer for printing. The light source direction of the photocuring 3D printer used in the experiment is from top to bottom, and a digital mask device with a resolution of 1920x1080 pixels is used for exposure. The corresponding 3D model is imported into the DLP 3D printer through Tinkercad software, and slicing is performed by using PCLab software, the layer thickness is set to 50 μm, and the exposure time is 2 s, to obtain the printed ceramic preform.

[0071] (3) The ceramic preform is placed into a box-type resistance furnace, heated to 375℃ at a heating rate of 1℃ / min in air, and then heated to 485℃ at a heating rate of 1℃ / min after being kept at 375℃ for 30 min, and then heated to 600℃ at a heating rate of 1℃ / min without keeping, to complete the debinding and pre-sintering of the preform.

[0072] (4) Continue to heat to 1000℃ at a heating rate of 10℃ / min, and then heat to 1500℃ at a heating rate of 1℃ / min, and then cool down with the furnace after keeping at 1500℃ for 4 h, to complete the sintering of the ceramic, and obtain the in-situ titania reinforced alumina ceramic.

[0073] Result analysis

[0074] Figure 1 is an SEM image of the alumina ceramic particles prepared in Comparative Example 1, Figure 2 , A is an SEM of the in-situ titania reinforced alumina ceramic prepared in Example 1 of the present application, and B is an EDS image of each element of the alumina ceramic particles prepared in Example 1 of the present application. From Figure 1 , it can be seen that the alumina, zirconia and yttria are still in the form of spherical particles, and are unevenly distributed, and the gap between the particles is large. From Figure 2 , it can be seen that with the addition of the organic titanium of the present application, the gap between the particles is reduced, and the density is increased. From the EDS image, it can be seen that the titania decomposed from the organic titanium is uniformly distributed.

[0075] Figure 3 is an XRD image of the alumina ceramic particles prepared in Example 1 of the present application. From the image, it can be seen that the sintered ceramic added with the organic body has a titania peak at 15.76°, and a ZrTiO4 peak generated by the high-temperature reaction of titania and zirconia at 30.64°. It is indicated that the organic titanium is decomposed into titania during the high-temperature debinding and sintering process, and part of the titania further reacts with zirconia. Figure 3XRD pattern of the control group of Comparative Example 1, i.e. without TiO addition, is shown in FIG. 1. Figure 3 0% TiO in FIG. 1.

[0076] It should be understood that the numerical ranges recited herein are intended to include all sub-ranges of the same numbers, as well as any numerical value within the range. Preferable embodiments of the application are described herein, including the best mode known to the inventors of practicing the application as of the time of the filing of this application. As such, the application should be understood to include every possible combination of the preferred embodiments described herein, including any numerical values within the ranges described herein. Although the application has been described in accordance with the embodiments shown, one of ordinary skill in the art will readily recognize that there could be variations to the embodiments and those variations would be within the spirit and scope of the application. Accordingly, many modifications can be made by one of ordinary skill in the art without departing from the spirit and scope of the application. Therefore, the appended claims encompass within their scope all such variations as fall within the scope of the claims. Any and all combinations of material elements, steps, and other features described herein fall within the scope of the application. Moreover, although expressed in language specific to software, the features of the present application are not limited to use in software implementations. Rather, the features of the present application can be applied to software, hardware, and / or firmware implementations.

[0077] Obviously, numerous modifications and variations of the present application are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the application can be practiced otherwise than as specifically described herein.

Claims

1. A method for producing an in-situ titania-reinforced alumina ceramic, characterized by, The method comprises the following steps: Mixing alumina and other oxides to obtain mixed powder, dispersing the mixed powder into photocuring resin containing dispersant, ball-milling to obtain ceramic slurry; the other oxides are at least one of zirconium oxide, magnesium oxide and yttrium oxide powder; Mechanically stirring and dispersing organic titanium into the ceramic slurry to obtain ceramic slurry containing organic titanium; 3D printing the ceramic slurry containing organic titanium to obtain ceramic preform; Debinding and sintering the ceramic preform to obtain in-situ titanium oxide reinforced alumina ceramic; The titanium oxide is titanium monoxide; The photocuring resin is epoxy acrylate resin; The organic titanium is diisopropyl titanate.

2. The method for producing in-situ titania-reinforced alumina ceramic according to claim 1, characterized by, The volume fraction of the mixed powder in the photocuring resin containing dispersant is 40%-55%.

3. The method for producing in-situ titania-reinforced alumina ceramic according to claim 1, characterized by, The mass percentage of the dispersant in the mixed powder is 5%-15%.

4. The method for in-situ titania reinforced alumina ceramic according to claim 1, characterized in that, The mass percentage of the organic titanium in the ceramic slurry is 2%.

5. The method of claim 1, wherein the in-situ titania reinforced alumina ceramic is prepared by the steps of: The layer thickness of 3D printing is set to 50μm, and the exposure time is 2s.

6. The method of claim 1, wherein the in-situ titania reinforced alumina ceramic is prepared by the steps of: The debinding conditions are as follows: heating at a rate of 1℃ / min to 375℃, keeping for 30min, then heating at a rate of 1℃ / min to 485℃, keeping for 30min, then heating at a rate of 1℃ / min to 600℃, keeping for 30min, then heating at a rate of 5℃ / min to 1000℃ without keeping, then furnace cooling, to complete the debinding and pre-sintering of the preform.

7. The method of claim 1, wherein the in-situ titania reinforced alumina ceramic is prepared by the steps of: The sintering conditions are as follows: heating at a rate of 10℃ / min to 1000℃, then heating at a rate of 1℃ / min to 1500℃-1700℃, keeping for 4h, then furnace cooling.

8. The method of claim 1, wherein the in-situ titania reinforced alumina ceramic is prepared by the steps of: a) providing a mixture of alumina and titania; b) forming the mixture into a green body; c) sintering the green body; and d) oxidizing the titania in the sintered green body. In the mixed powder, the mass percentage of zirconium oxide is 20%, the mass percentage of magnesium oxide is 0.5%, the mass percentage of yttrium oxide is 1%, and the mass percentage of alumina is the balance, and the total is 100%; Alternatively, in the mixed powder, the mass percentage of zirconium oxide is 20%, and the mass percentage of alumina is the balance, and the total is 100%; Alternatively, in the mixed powder, the mass percentage of magnesium oxide is 0.5%, and the mass percentage of alumina is the balance, and the total is 100%.

9. The method for preparing in-situ titanium dioxide-reinforced alumina ceramics according to claim 1, characterized in that, The ball-milling conditions are as follows: ball-milling at 400r / min for 10h.

10. An in-situ titanium oxide reinforced alumina ceramic prepared by the method of any one of claims 1-9.

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