Sintering method of titanium oxide ceramic with static dissipation function

Abstract

The invention relates to the technical field of titanium oxide ceramics, in particular to a sintering method of titanium oxide ceramics with a static dissipation function. The preparation method at least comprises the following steps: carrying out vacuum sintering on a titanium dioxide ceramic body in a gradient heating manner, and cooling to obtain the titanium dioxide ceramic. According to the titanium oxide ceramic sintering method provided by the invention, vacuum gradient heating sintering is adopted, the preparation process is simple, the cost is low, the process is controllable, and the titanium oxide electrostatic dissipation ceramic prepared by the method has high density, low volume resistivity and relatively high mechanical performance.

Description

Technical Field

[0001] The invention relates to the technical field of titanium oxide ceramics, and in particular to a sintering method of titanium oxide ceramics with static dissipation function. Background Art

[0002] With the rapid development of semiconductor manufacturing technology, the role of static elimination in the production process has become increasingly prominent. As we all know, semiconductor production is mostly carried out in a dust-free environment. The characteristics of this environment are low air humidity. In addition, the role of high-efficiency air filtration system and warm pass filtration system can effectively remove ions in the air, so that the air in the clean room has good insulation properties. At the same time, most of the materials used in the clean room have large energy level differences. Therefore, when static electricity is generated in the clean room, it is difficult to dissipate in a short time.

[0003] In view of the serious threat posed by static electricity to semiconductor devices, many anti-static materials have been designed as electrostatic discharge dissipation jigs. These materials designed for anti-static dissipation can quickly release the static electricity generated during the semiconductor production process with their excellent conductive properties. Generally speaking, the volume resistivity of such materials is generally required to be 10 -4 -10 6 Ω·cm. In structural parts applications, common static dissipative ceramics include alumina ceramics, zirconia ceramics, silicon carbide ceramics and titanium oxide ceramics. Among them, titanium oxide ceramics are regarded as high-quality static dissipative ceramic matrices due to their affordable price, simple preparation and excellent mechanical properties. Most of the titanium oxide materials with static dissipative functions widely circulated on the market are Magneli phase titanium oxide ceramics. Currently, the main methods for preparing Magneli phase titanium oxide ceramics include H 2 reduction method, C reduction method and Ti reduction method. However, H 2 The reduction method involves flammable and explosive gases, and their use and transportation require high vigilance and safety. 2 The high cost of carbon also pushes up the production cost of Magneli titanium oxide ceramics. The C reduction method will leave C materials that are difficult to remove in the ceramics. If used in the field of semiconductor equipment, it may bring the risk of particle contamination to semiconductor devices. The Ti reduction method also has the problem of introducing difficult-to-remove Ti particles and increasing production costs.

[0004] For example, Chinese patent CN109761599A discloses a method for preparing and applying Magneli phase titania conductive ceramics, which uses metallic zinc to reduce nano-titanium oxide to obtain Magneli phase titania conductive ceramics. The Magneli phase titania conductive ceramics can be applied to zinc-nickel batteries without complicated post-processing steps, greatly saving production costs. However, after sintering, the Magneli phase titania ceramics have many pores, and are often accompanied by various problems such as low density and poor mechanical properties. Summary of the invention

[0005] In order to solve the problems in the prior art, the present invention provides a sintering method of titanium oxide ceramics with electrostatic dissipation function, which at least comprises the following steps: vacuum sintering and cooling the titanium dioxide ceramic body in a gradient heating manner to obtain the titanium dioxide ceramic body.

[0006] In one embodiment, the crystal form of the titanium dioxide includes any one of rutile type and anatase type.

[0007] In a preferred embodiment, the crystal form of the titanium dioxide includes rutile.

[0008] In one embodiment, the vacuum sintering pressure is ≤10 -3 Pa.

[0009] In a preferred embodiment, the vacuum sintering pressure is 10 -3 Pa.

[0010] The applicant of the present invention has found through a lot of creative research that when rutile phase titanium dioxide is used, the final sintered titanium oxide ceramic has better mechanical properties. It is speculated that the unit lattice of rutile phase titanium dioxide is composed of two titanium dioxide molecules, and its unit lattice is smaller and more compact, with greater stability and relative density, and therefore has a higher refractive index and dielectric constant and lower thermal conductivity. At the same time, sintering with rutile phase can avoid the problem of abnormal growth of grain size caused by phase conversion during the sintering process, thereby ensuring that the fired ceramic has better mechanical properties.

[0011] In one embodiment, the gradient temperature increase comprises:

[0012] The first gradient temperature is room temperature to 770°C, the second gradient temperature is 770 to 980°C, and the third gradient temperature is 980 to 1220°C.

[0013] In one embodiment, the heating rate of the first gradient temperature is 80° C. / h.

[0014] In one embodiment, the heating rate of the second gradient temperature is 60-80°C / h, and can be 60°C / h, 70°C / h, or 80°C / h.

[0015] In a preferred embodiment, the heating rate of the second gradient temperature is 70° C. / h.

[0016] In one embodiment, the heating rate of the third gradient temperature is 30-50°C / h, and can be 30°C / h, 40°C / h, or 50°C / h.

[0017] In a preferred embodiment, the heating rate of the third gradient temperature is 40° C. / h.

[0018] In one embodiment, the first gradient temperature is raised to 770° C., kept warm for 4 to 5 hours, and then a second gradient temperature is raised.

[0019] In a preferred embodiment, the first gradient temperature is raised to 770° C., kept warm for 4 hours, and then a second gradient temperature is raised.

[0020] In one embodiment, the second gradient temperature is raised to 980° C., kept for 4 to 5 hours, and then the third gradient temperature is raised.

[0021] In a preferred embodiment, the second gradient temperature is raised to 980° C., kept for 4 hours, and then the third gradient temperature is raised.

[0022] In one embodiment, the third gradient temperature is raised to 1220° C. and kept warm for 3 to 4 hours.

[0023] In a preferred embodiment, the third gradient temperature is raised to 1220° C. and kept warm for 3 hours.

[0024] In one embodiment, the sintering method includes: placing a titanium dioxide ceramic body in a vacuum furnace for gradient temperature vacuum sintering, wherein the first gradient temperature is room temperature to 770°C, the heating rate is 80°C / h, and the temperature is kept for 4 hours; the second gradient temperature is 770 to 980°C, the heating rate is 70°C / h, and the temperature is kept for 4 hours; the third gradient temperature is 980 to 1220°C, the heating rate is 40°C / h, and the temperature is kept for 3 hours, and then the ceramic body is cooled to room temperature in the furnace.

[0025] Beneficial Effects

[0026] 1. The sintering method of titanium oxide ceramics provided by the present invention adopts vacuum gradient temperature sintering, which is conducive to removing adsorbed gas, promoting the shrinkage of ceramics at different stages, and reducing the sintering temperature and energy consumption. The product sintered by the method provided by the present invention has both good electrical conductivity and good mechanical properties.

[0027] 2. The present invention uses rutile phase titanium dioxide for sintering, which can avoid the problem of abnormal growth of grain size caused by phase conversion during the sintering process, thereby ensuring that the fired ceramic has better mechanical properties.

[0028] 3. The present invention adopts a specific vacuum gradient temperature rise sintering. Compared with the reducing atmosphere sintering, the rate of oxygen vacancies generation in the vacuum gradient temperature rise sintering is greatly reduced, and the grain size of the product can be well controlled.

[0029] 4. The sintering method of titanium oxide ceramics provided by the present invention has a simple preparation process, low cost and controllable process. The titanium oxide electrostatic dissipative ceramics prepared by this method have high density, low volume resistivity and high mechanical properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1-9 They are the physical pictures of Example 1 and Comparative Examples 1-8 respectively.

[0031] Figure 10-18 They are SEM images of Example 1 and Comparative Examples 1-8 respectively. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with the examples and drawings. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. The experimental methods for which specific conditions are not specified in the examples are carried out under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used that do not specify the manufacturer are all conventional products that can be purchased commercially.

[0033] Example 1

[0034] This embodiment provides a sintering method of titanium oxide ceramics with electrostatic dissipation function provided by the present invention, comprising the following steps: placing a titanium dioxide ceramic body in a vacuum furnace for gradient temperature rising vacuum sintering, wherein the first gradient temperature is room temperature to 770°C, the heating rate is 80°C / h, and the temperature is kept for 4 hours; the second gradient temperature is 770 to 980°C, the heating rate is 70°C / h, and the temperature is kept for 4 hours; the third gradient temperature is 980 to 1220°C, the heating rate is 40°C / h, and after keeping warm for 3 hours, the ceramic body is cooled to room temperature with the furnace.

[0035] The crystal form of the titanium dioxide is rutile.

[0036] The vacuum sintering pressure is 10 -3 Pa.

[0037] Figure 1 This is a physical diagram of Example 1; Fig.10 This is the SEM picture of Example 1.

[0038] Comparative Example 1

[0039] The comparative example provides a sintering method of titanium oxide ceramics, comprising the following steps: placing a titanium dioxide ceramic body in a vacuum furnace for gradient temperature rising vacuum sintering, wherein the first gradient temperature is room temperature to 770°C, the heating rate is 80°C / h, and the temperature is kept for 4 hours; the second gradient temperature is 770 to 980°C, the heating rate is 70°C / h, and the temperature is kept for 4 hours; the third gradient temperature is 980 to 1220°C, the heating rate is 40°C / h, and the temperature is kept for 3 hours, and then the titanium dioxide ceramic body is cooled to room temperature with the furnace to obtain the product.

[0040] The crystal form of the titanium dioxide is rutile.

[0041] The pressure of the vacuum sintering is 10Pa.

[0042] Figure 2 This is a physical diagram of Comparative Example 1; Fig.11 This is the SEM image of Comparative Example 1.

[0043] Comparative Example 2

[0044] The comparative example provides a sintering method of titanium oxide ceramics, comprising the following steps: placing a titanium dioxide ceramic body in a vacuum furnace for gradient temperature rising vacuum sintering, wherein the first gradient temperature is room temperature to 770°C, the heating rate is 80°C / h, and the temperature is kept for 4 hours; the second gradient temperature is 770 to 980°C, the heating rate is 70°C / h, and the temperature is kept for 4 hours; the third gradient temperature is 980 to 1220°C, the heating rate is 40°C / h, and the temperature is kept for 3 hours, and then the titanium dioxide ceramic body is cooled to room temperature with the furnace to obtain the product.

[0045] The crystal form of the titanium dioxide is rutile.

[0046] The pressure of the vacuum sintering is 25 KPa.

[0047] Figure 3 This is a physical diagram of Comparative Example 2; Fig.12 This is the SEM image of Comparative Example 2.

[0048] Comparative Example 3

[0049] This comparative example provides a sintering method for titanium oxide ceramics, comprising the following steps: placing a titanium dioxide ceramic body in a normal pressure sintering furnace for gradient temperature sintering, continuously introducing air into the furnace during the sintering process, with an air intake rate of 20 L / min and a furnace pressure of 100 KPa.

[0050] The first gradient temperature is room temperature to 770°C, the heating rate is 80°C / h, and the temperature is kept for 4 hours; the second gradient temperature is 770 to 980°C, the heating rate is 70°C / h, and the temperature is kept for 4 hours; the third gradient temperature is 980 to 1220°C, the heating rate is 40°C / h, and after keeping for 3 hours, it is cooled to room temperature with the furnace.

[0051] The crystal form of the titanium dioxide is rutile.

[0052] Figure 4 This is a physical diagram of Comparative Example 3; Fig.13 This is the SEM image of Comparative Example 3.

[0053] Comparative Example 4

[0054] The present comparative example provides a sintering method for titanium dioxide ceramics, comprising the following steps: placing a titanium dioxide ceramic body in a vacuum furnace for gradient temperature sintering, and continuously introducing 5% H into the furnace during the sintering process. 2 / Ar mixed gas (H 2 content 5%), the air intake rate is 20L / min, and the pressure in the furnace is 100Kpa.

[0055] The first gradient temperature is room temperature to 770°C, the heating rate is 80°C / h, and the temperature is kept for 4 hours; the second gradient temperature is 770 to 980°C, the heating rate is 70°C / h, and the temperature is kept for 4 hours; the third gradient temperature is 980 to 1220°C, the heating rate is 40°C / h, and after keeping for 3 hours, it is cooled to room temperature with the furnace.

[0056] The crystal form of the titanium dioxide is rutile.

[0057] Figure 5 This is a physical diagram of Comparative Example 4; Fig.14 This is the SEM image of Comparative Example 4.

[0058] Comparative Example 5

[0059] The comparative example provides a sintering method for titanium oxide ceramics, comprising the following steps: placing a titanium dioxide ceramic body in a vacuum furnace for gradient temperature rising vacuum sintering, wherein the first gradient temperature is room temperature to 770°C, the heating rate is 80°C / h, and the temperature is kept for 4 hours; the second gradient temperature is 770 to 980°C, the heating rate is 50°C / h, and the temperature is kept for 4 hours; the third gradient temperature is 980 to 1220°C, the heating rate is 40°C / h, and the temperature is kept for 3 hours, and then the titanium dioxide ceramic body is cooled to room temperature with the furnace to obtain the product.

[0060] The crystal form of the titanium dioxide is rutile.

[0061] The vacuum sintering pressure is 10 -3 Pa.

[0062] Figure 6 This is a physical diagram of Comparative Example 5; Fig.15 This is the SEM image of Comparative Example 5.

[0063] Comparative Example 6

[0064] The comparative example provides a sintering method of titanium oxide ceramics, comprising the following steps: placing a titanium dioxide ceramic body in a vacuum furnace for gradient temperature rising vacuum sintering, wherein the first gradient temperature is room temperature to 770°C, the heating rate is 80°C / h, and the temperature is kept for 4 hours; the second gradient temperature is 770 to 980°C, the heating rate is 90°C / h, and the temperature is kept for 4 hours; the third gradient temperature is 980 to 1220°C, the heating rate is 40°C / h, and the temperature is kept for 3 hours, and then the titanium dioxide ceramic body is cooled to room temperature with the furnace.

[0065] The crystal form of the titanium dioxide is rutile.

[0066] The vacuum sintering pressure is 10 -3 Pa.

[0067] Figure 7 This is a physical diagram of Comparative Example 6; Fig.16 This is the SEM image of Comparative Example 6.

[0068] Comparative Example 7

[0069] The comparative example provides a sintering method for titanium oxide ceramics, comprising the following steps: placing a titanium dioxide ceramic body in a vacuum furnace for gradient temperature rising vacuum sintering, wherein the first gradient temperature is room temperature to 770°C, the heating rate is 80°C / h, and the temperature is kept for 4 hours; the second gradient temperature is 770 to 980°C, the heating rate is 70°C / h, and the temperature is kept for 4 hours; the third gradient temperature is 980 to 1220°C, the heating rate is 20°C / h, and after keeping the temperature for 3 hours, the ceramic body is cooled to room temperature in the furnace to obtain the product.

[0070] The crystal form of the titanium dioxide is rutile.

[0071] The vacuum sintering pressure is 10 -3 Pa.

[0072] Figure 8 This is a physical diagram of Comparative Example 7; Fig.17 This is the SEM image of Comparative Example 7.

[0073] Comparative Example 8

[0074] The comparative example provides a sintering method of titanium oxide ceramics, comprising the following steps: placing a titanium dioxide ceramic body in a vacuum furnace for gradient temperature rising vacuum sintering, wherein the first gradient temperature is room temperature to 770°C, the heating rate is 80°C / h, and the temperature is kept for 4 hours; the second gradient temperature is 770 to 980°C, the heating rate is 70°C / h, and the temperature is kept for 4 hours; the third gradient temperature is 980 to 1220°C, the heating rate is 60°C / h, and after keeping the temperature for 3 hours, the ceramic body is cooled to room temperature in the furnace to obtain the product.

[0075] The crystal form of the titanium dioxide is rutile.

[0076] The vacuum sintering pressure is 10 -3 Pa.

[0077] Fig. 9 This is a physical diagram of Comparative Example 8; Fig.18 This is the SEM image of Comparative Example 8.

[0078] Performance Testing

[0079] The volume resistivity, density and three-point bending strength of the titanium oxide ceramics prepared in each embodiment and comparative example were tested.

[0080] The volume resistivity was tested by the four-probe method, with a sample size of 50×50×2 mm. The test instrument was Mitsubishi Chemical MCP-700 low impedance analyzer. The reference test standard was GB / T 1551-2009.

[0081] The density of the product is measured using the Archimedes drainage method. The sample is a sintered product and the size is not specified. The reference test standard is ASTM C20.

[0082] The three-point bending strength was tested using a universal testing machine with a sample size of 3×4×45 mm and the reference test standard was ASTM C1161.

[0083] The test results are shown in Table 1.

[0084] When sintered in an oxygen atmosphere, oxygen vacancies sufficient to make the product conductive cannot be generated, and the excessive volume resistivity limits its application in static dissipative ceramics.

[0085] When sintering is carried out in a reducing atmosphere, the amount and speed of oxygen vacancies are difficult to control, the grain size of the product tends to grow abnormally, and the mechanical properties deteriorate rapidly;

[0086] In addition, lowering or increasing the heating rate of the gradient temperature will result in the inability to effectively discharge the internal pores of the product or an increase in the pores and defects within the crystal, resulting in deterioration of the mechanical properties of the product or even cracking.

[0087] Table 1

[0088]

[0089]

Claims

1. A method for sintering titanium oxide ceramics with electrostatic dissipation function, characterized in that: At least the following steps are included: The titanium dioxide ceramic green body is vacuum sintered and cooled by a gradient temperature increase method to obtain the product.

2. The sintering method of titanium oxide ceramics with electrostatic dissipation function according to claim 1, characterized in that: The crystal form of the titanium dioxide includes any one of rutile type and anatase type.

3. The sintering method of titanium oxide ceramics with static dissipation function according to claim 2, characterized in that: The vacuum sintering pressure is 10 -3 Pa.

4. The sintering method of titanium oxide ceramics with static dissipation function according to claim 1, characterized in that: The gradient heating includes: The first gradient temperature is room temperature to 770°C, the second gradient temperature is 770 to 980°C, and the third gradient temperature is 980 to 1220°C.

5. The sintering method of titanium oxide ceramics with static dissipation function according to claim 4, characterized in that: The heating rate of the first gradient temperature is 80° C. / h.

6. The sintering method of titanium oxide ceramics with static dissipation function according to claim 4, characterized in that: The heating rate of the second gradient temperature is 60-80° C. / h.

7. The sintering method of titanium oxide ceramics with static dissipation function according to claim 4, characterized in that: The heating rate of the third gradient temperature is 30-50° C. / h.

8. The sintering method of titanium oxide ceramics with static dissipation function according to claim 4, characterized in that: The first gradient temperature is raised to 770° C., kept at this temperature for 4 to 5 hours, and then a second gradient temperature is raised.

9. The sintering method of titanium oxide ceramics with static dissipation function according to claim 8, characterized in that: The second gradient temperature is raised to 980° C., kept at this temperature for 4 to 5 hours, and then the third gradient temperature is raised.

10. The sintering method of titanium oxide ceramics with static dissipation function according to claim 9, characterized in that: The third gradient temperature is raised to 1220° C. and kept warm for 3 to 4 hours.

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