Process for the preparation of a titania modification layer on the surface of zirconia based on chemical precipitation-thermal treatment, products and uses

Abstract

The application discloses a method for preparing a titanium dioxide modification layer on the surface of zirconia based on chemical precipitation-heat treatment, which comprises the following steps: (1) uniformly mixing titanium sulfate, urea and water to obtain a precursor solution; (2) placing zirconia ceramics in the precursor solution and heating to a boiling state for a period of time; and (3) taking out the zirconia ceramics and preparing a titanium dioxide modification layer on the surface of the zirconia after heat treatment. The method disclosed by the application can prepare a titanium dioxide layer with stronger chemical activity and no harm to human body on the surface of zirconia, improve the chemical activity and hydrophilicity of the surface of zirconia, and be more conducive to the adhesion and growth of bone cells on the surface of zirconia implant, so as to promote the further application of zirconia in the field of implant.

Description

Technical Field

[0001] This invention relates to the technical field of zirconia ceramic surface modification, and more particularly to a method, product, and application for preparing a titanium dioxide modified layer on a zirconia surface based on chemical precipitation-thermal treatment. Background Technology

[0002] Titanium is currently the most widely used implant material, possessing advantages such as superior mechanical properties, corrosion resistance, ease of processing, good biocompatibility, and good osseointegration. Pure titanium and Ti-6Al-4V are commonly used in clinical implants. However, numerous studies have demonstrated that titanium's corrosion resistance and lifespan can decrease in the complex environment of the human oral cavity. Furthermore, the electrostatic effects of the metal and the allergic inflammation caused by the release of titanium nanoparticles can both pose threats to oral health.

[0003] Compared to titanium, zirconia (ZrO2) possesses superior chemical and biological stability, corrosion resistance, and non-toxicity, while also exhibiting excellent mechanical properties, meeting the requirements for long-term use and adaptation to the complex oral environment. Since the 1970s and 80s, zirconia (ZrO2) has been widely used as a bio-inert ceramic in the field of dental prosthetics, commonly used in the manufacture of crowns, veneers, and other restorations. Yttrium-stabilized tetragonal zirconia is the most commonly used type. However, due to its extreme stability, zirconia is difficult to modify surface to meet the biocompatibility and osseointegration requirements of implants.

[0004] Currently, the concepts and techniques for commonly used surface modification methods for implants mainly originate from the modification of metal implants. These include clinically common physical methods such as sandblasting, and chemical methods such as in-situ injection of active groups and ions into the surface for oxidation. However, the former easily creates microcracks on the zirconia surface, while the latter has minimal effect on the modification of the extremely chemically inert zirconia. Other modification techniques, such as laser treatment, ion implantation, biomimetic deposition, and biological modification, either have limited osteogenic effects, insignificant modification effects, weak binding with zirconia, or potential adverse side effects, and all fail to achieve the desired modification results. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention discloses a method for constructing a titanium dioxide modification layer on the surface of a zirconia implant. This method can prepare a titanium dioxide layer with stronger chemical activity and no toxicity to the human body on the zirconia surface, thereby improving the chemical activity and hydrophilicity of the zirconia surface and making it more conducive to the adhesion and growth of bone cells on the zirconia implant surface, thus promoting the further application of zirconia in the field of implants.

[0006] The specific technical solution is as follows:

[0007] A method for preparing a titanium dioxide modified layer on a zirconium oxide surface based on chemical precipitation-thermal treatment includes:

[0008] (1) Mix titanium sulfate, urea and water evenly to obtain a precursor fluid;

[0009] (2) Place the zirconia ceramic in the precursor liquid and heat it to boiling state for a period of time;

[0010] (3) The zirconia ceramic is taken out and heat-treated to prepare a titanium dioxide modified layer on the zirconia surface.

[0011] This invention constructs a titanium dioxide modified layer in situ on the surface of zirconium oxide using a chemical precipitation-thermal treatment method. By controlling the concentration and ratio of components in the precursor fluid, the morphology and coverage of the titanium dioxide layer can be controlled, thereby enabling the preparation of a titanium dioxide layer that is tightly bonded to the zirconium oxide substrate on the zirconium oxide surface.

[0012] In fact, due to the chemical inertness of zirconium oxide, it is quite difficult to successfully prepare titanium dioxide films on its surface. The inventors tried to use conventional methods to prepare titanium dioxide films, such as using tetrabutyl titanate as a titanium source for hydrolysis to prepare titanium dioxide films; or directly using titanium dioxide powder as raw material, dispersing it in a solvent and then coating it on the zirconium oxide surface. However, they were unable to successfully prepare a titanium dioxide modified layer on the zirconium oxide surface.

[0013] Replacing urea with stronger alkaline sodium hydroxide or ammonia will also prevent the successful deposition of titanium dioxide films on the zirconium oxide surface.

[0014] Experiments revealed that when the precursor solution prepared from titanium sulfate and urea is heated to boiling, the urea decomposes to produce carbon dioxide and ammonia, which react with titanium ions in the solution to generate titanium dioxide. This produces a large amount of white colloidal titanium dioxide precipitate explosively within a very short time, depositing a thin film of titanium dioxide on the zirconium oxide surface. Heat treatment allows the titanium dioxide film to further crystallize and grow, bonding tightly with the zirconium oxide substrate.

[0015] In step (1):

[0016] Preferably, the molar ratio of titanium sulfate to urea is 1:(4-10);

[0017] Experiments revealed that when the ratio of titanium sulfate to urea was greater than 1:4, the resulting titanium dioxide particles could not completely and uniformly cover the zirconium oxide surface, resulting in exposed, uncovered zirconium oxide areas. However, with increasing urea content, the nanoparticle size showed a slight increasing trend. This is likely because the reaction rate of urea's thermal decomposition to produce carbon dioxide and ammonia is key to controlling the entire chemical precipitation process. Higher urea content leads to more, smaller, and more active titanium dioxide clusters generated during the same timeframe, making them easier to sinter and grow under the same heat treatment conditions, resulting in larger particle sizes. However, excessively high urea concentrations do not promote complete particle film coverage, leading to reagent waste and increased costs. Therefore, a further optimized molar ratio of titanium sulfate to urea is 1:(4–6).

[0018] Preferably, the concentration of titanium sulfate in the precursor fluid is 0.3–1.0 mol / L.

[0019] Experiments revealed that when the titanium sulfate concentration was less than 0.3 mol / L, the resulting titanium dioxide particles could not form a film covering the zirconium oxide surface, and the exposed zirconium oxide area was much larger than the area of ​​the titanium dioxide layer.

[0020] Further optimization yielded a titanium sulfate concentration of 0.3–0.6 mol / L in the precursor solution. A titanium sulfate concentration of 0.6 mol / L was sufficient to successfully prepare a titanium dioxide modified layer, but further increases in concentration did not promote the preparation and film formation of titanium dioxide, easily leading to reagent waste and ineffective cost input.

[0021] In step (2):

[0022] Preferably, the mixture is heated to boiling and held for 5 to 30 minutes; more preferably, it is held for 10 to 20 minutes.

[0023] In step (3):

[0024] Preferably, the heat treatment is performed at a temperature of 800–1000°C, a holding time of 10–60 min, and a heating rate of 10–20°C / min.

[0025] Further optimization is achieved by using a heat treatment temperature of 850–950°C.

[0026] The present invention also discloses zirconium oxide with a titanium dioxide modified layer on its surface prepared according to the above method.

[0027] The prepared titanium dioxide layer is a layer of nanoparticles uniformly distributed on the surface of zirconium oxide. The main morphology is nanoparticles with a size of about 30-70 nm, accompanied by a small number of agglomerated nanospheres composed of nanoparticles with a size of 250-500 nm and a layer thickness of about 100 nm.

[0028] The present invention also discloses the application of the zirconium oxide with a titanium dioxide modified layer on its surface in the field of bio-implant materials.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] This invention discloses a method for constructing a titanium dioxide modified layer on a zirconium oxide surface. A titanium dioxide nanoparticle film is prepared on the zirconium oxide surface by chemical precipitation-thermal treatment. The morphology and coverage of the titanium dioxide layer are controlled by adjusting the concentration and ratio of raw materials in the precursor fluid. Finally, a titanium dioxide layer with tight bonding with the substrate, complete coverage, and uniform morphology is prepared on the zirconium oxide surface.

[0031] This invention provides a titanium dioxide-modified layer on the surface of zirconia, approximately 100 nm thick, composed of nanoparticles with a diameter of 30–70 nm, accompanied by a small number of nanospheres (approximately 250–500 nm in size) formed by the aggregation of nanoparticles. The titanium dioxide layer is tightly bonded to the zirconia substrate. Compared to zirconia particles with a diameter of 300–800 nm, the smaller titanium dioxide particles effectively increase the specific surface area of ​​the zirconia surface, providing more adsorption sites for proteins and other nutrients and signaling factors after zirconia implantation. The construction of the titanium dioxide layer improves the hydrophilicity of the zirconia surface, which is beneficial to the adhesion and growth of osteoblasts after implantation. Titanium dioxide is non-toxic to the human body, and titanium dioxide modification has already been applied in the field of titanium metal implants. In summary, the titanium dioxide-modified layer can promote the adsorption of biological factors such as proteins, which helps the adhesion and growth of early osteoblasts after implantation, thereby effectively improving the biocompatibility of zirconia ceramics and promoting the in-depth application of zirconia ceramics in the field of implants. Attached Figure Description

[0032] Figure 1 Here is a SEM image of the zirconia ceramic surface before heat treatment in Example 1;

[0033] Figure 2 XRD pattern (a), planar SEM image (b), and cross-sectional SEM image (c) of the titanium dioxide modified layer on the zirconium oxide surface prepared in Example 1;

[0034] Figure 3 Images showing the apparent contact angles of the titanium dioxide-modified zirconia surface prepared in Example 1 and the unmodified zirconia.

[0035] Figure 4 SEM image of the titanium dioxide modified layer on the zirconium oxide surface prepared in Example 3;

[0036] Figure 5Here is a SEM image of the titanium dioxide modified layer on the zirconium oxide surface prepared in Example 4;

[0037] Figure 6 SEM image of the titanium dioxide modified layer on the zirconium oxide surface prepared in Example 5;

[0038] Figure 7 SEM image of the titanium dioxide modified layer on the zirconium oxide surface prepared in Example 6;

[0039] Figure 8 SEM image of the product prepared in Comparative Example 1;

[0040] Figure 9 SEM image of the product prepared in Comparative Example 2;

[0041] Figure 10 SEM image of the product prepared in Comparative Example 3;

[0042] Figure 11 SEM image of the product prepared in Comparative Example 4;

[0043] Figure 12 SEM image of the product prepared in Comparative Example 5. Detailed Implementation

[0044] The present invention will be described in further detail below with reference to embodiments and comparative examples, but the implementation of the present invention is not limited thereto.

[0045] Example 1

[0046] 1) A precursor solution with a titanium sulfate concentration of 0.3 mol / L was prepared by dissolving titanium sulfate and urea in deionized water at a molar ratio of 1:4.

[0047] 2) Place the zirconia ceramic in the precursor liquid prepared in step 1), heat the precursor liquid to boiling and maintain for 10 min;

[0048] 3) Remove the zirconia ceramic from the precursor liquid after boiling and cooling to room temperature, place it in a muffle furnace, heat it from room temperature to 900℃ at a rate of 15℃ / min, hold it at that temperature for 30min, and then cool it with the furnace to obtain zirconia ceramic with a titanium dioxide modification layer on the surface.

[0049] Figure 1 The image shown is an SEM image of the zirconia ceramic surface before heat treatment in this embodiment. It is observed that a nearly transparent titanium dioxide layer is deposited on the zirconia surface at this time. This layer is gel-like and has no particle texture. Through this titanium dioxide layer, zirconia particles of hundreds of nanometers in the substrate can be clearly observed.

[0050] Figure 2In Figure (a), the XRD pattern of the sample prepared in this embodiment is shown. It is observed that the phase of the sample is titanium dioxide composed of zirconium oxide and anatase, indicating the formation and presence of titanium dioxide.

[0051] Figure 2 (b) is a planar SEM image of the sample prepared in this embodiment. It was observed that the titanium dioxide layer is relatively dense under microscopic conditions, without obvious defects, and is composed of irregular nanoparticles with a particle size of about 30 to 50 nm. The particles are closely adjacent to each other and tend to form necks through sintering. In addition, there are a small number of nanospheres formed by the aggregation of nanoparticles on the film, with a size in the range of 250 to 350 nm.

[0052] Figure 2 Image (c) shows a cross-sectional SEM image of the sample prepared in this embodiment. It is observed that the titanium dioxide layer is approximately 100 nm thick and is tightly bonded to the zirconium oxide particles of its substrate material.

[0053] Figure 3 The images show the apparent contact angles of the sample prepared in this embodiment and the unmodified zirconia. It was observed that the apparent contact angle of the zirconia sample modified with a titanium dioxide layer (32.8°) was smaller than that of the unmodified zirconia sample (71.8°), indicating that the titanium dioxide modification layer can significantly improve the hydrophilicity of the zirconia surface, which is conducive to cell adhesion and proliferation.

[0054] Example 2

[0055] The preparation process is basically the same as in Example 1, except for step 1):

[0056] Replace the concentration of titanium sulfate in the precursor fluid with 0.4 mol / L.

[0057] Characterized by SEM, XRD and apparent contact angle, the phase composition and apparent contact angle of the zirconium oxide coated with the titanium dioxide modification layer were basically the same as those in Example 1.

[0058] Example 3

[0059] The preparation process is basically the same as in Example 1, except for step 1):

[0060] Replace the concentration of titanium sulfate in the precursor fluid with 0.6 mol / L.

[0061] Figure 4 The SEM images of the samples prepared in this embodiment show that the morphology of the titanium dioxide modified layer is similar to that in Example 1.

[0062] XRD and apparent contact angle characterization showed that the phase composition and apparent contact angle of the zirconium oxide coated with the titanium dioxide modification layer were basically the same as those in Example 1.

[0063] Example 4

[0064] The preparation process is basically the same as in Example 1, except for step 1):

[0065] The molar ratio of titanium sulfate and urea was changed to 1:5, and the concentration of titanium sulfate in the precursor fluid was 0.3 mol / L.

[0066] Figure 5 The SEM images of the samples prepared in this embodiment show that the morphology of the titanium dioxide modified film is similar to that in Example 1, but the particle size of the nanoparticles is slightly larger, about 30-60 nm. This may be because the reaction rate of carbon dioxide and ammonia produced by the thermal decomposition of urea controls the entire chemical precipitation process. As the urea content increases, more titanium dioxide is chemically precipitated in the same time period, the colloidal size is smaller, and the activity is stronger. After heat treatment, it is easier for sintering growth between crystal particles to occur.

[0067] XRD and apparent contact angle characterization showed that the phase composition and apparent contact angle of the zirconium oxide coated with the titanium dioxide modification layer were basically the same as those in Example 1.

[0068] Example 5

[0069] The preparation process is basically the same as in Example 1, except for step 1):

[0070] The molar ratio of titanium sulfate and urea was changed to 1:6, and the concentration of titanium sulfate in the precursor fluid was 0.3 mol / L.

[0071] Figure 6 The SEM images of the samples prepared in this embodiment show that the morphology of the titanium dioxide modified film is similar to that in Example 1, but the particle size of the nanoparticles is slightly larger, about 30-70 nm. This is because with the further increase of urea content, more titanium dioxide is produced by chemical precipitation in the same time, the rate is faster, and the colloidal size is smaller. The more active titanium dioxide colloid is more likely to sinter and grow faster during the heat treatment process, forming nanoparticles with larger particle size.

[0072] XRD and apparent contact angle characterization showed that the phase composition and apparent contact angle of the zirconium oxide coated with the titanium dioxide modification layer were basically the same as those in Example 1.

[0073] Example 6

[0074] The preparation process is basically the same as in Example 1, except for step 2):

[0075] Replace the boiling time with 20 minutes.

[0076] Figure 7The SEM images of the samples prepared in this embodiment show that the morphology of the titanium dioxide modified film is similar to that in Example 1, but the number of nanospheres is slightly increased and their size is also slightly larger. The nanospheres are composed of nanoparticles with a size of about 250-500 nm. This is because the longer heating and boiling time will cause some nanoparticles to self-aggregate, settle, and further grow to reduce surface energy.

[0077] Example 7

[0078] The preparation process is basically the same as in Example 1, except for step 3):

[0079] Replace the heat treatment temperature with 850℃.

[0080] Characterized by SEM, XRD and apparent contact angle, the phase and apparent contact angle of the titanium dioxide-modified zirconium oxide were basically the same as those in Example 1.

[0081] Example 8

[0082] The preparation process is basically the same as in Example 1, with the only difference being:

[0083] Replace the heat treatment temperature in step 3) with 950℃.

[0084] Characterized by SEM, XRD and apparent contact angle, the phase composition and apparent contact angle of the zirconium oxide coated with the titanium dioxide modification layer were basically the same as those in Example 1.

[0085] Example 9

[0086] The preparation process is basically the same as in Example 1, except for step 3):

[0087] Replace the heating rate of the heat treatment with 10℃ / min.

[0088] Characterized by SEM, XRD and apparent contact angle, the phase composition and apparent contact angle of the zirconium oxide coated with the titanium dioxide modification layer were basically the same as those in Example 1.

[0089] Example 10

[0090] The preparation process is basically the same as in Example 1, except for step 3):

[0091] Replace the heating rate of the heat treatment with 20℃ / min.

[0092] Characterized by SEM, XRD and apparent contact angle, the phase composition and apparent contact angle of the zirconium oxide coated with the titanium dioxide modification layer were basically the same as those in Example 1.

[0093] Example 11

[0094] The preparation process is basically the same as in Example 1, except for step 3):

[0095] Replace the heat treatment holding time with 10 minutes.

[0096] Characterized by SEM, XRD and apparent contact angle, the phase composition and apparent contact angle of the zirconium oxide coated with the titanium dioxide modification layer were basically the same as those in Example 1.

[0097] Example 12

[0098] The preparation process is basically the same as in Example 1, except for step 3):

[0099] Replace the heat treatment holding time with 60 minutes.

[0100] Characterized by SEM, XRD and apparent contact angle, the phase composition and apparent contact angle of the zirconium oxide coated with the titanium dioxide modification layer were basically the same as those in Example 1.

[0101] Comparative Example 1

[0102] The preparation process is basically the same as in Example 1, except for step 1):

[0103] Replace the urea with an equal molar amount of NaOH.

[0104] Figure 8 The SEM image of the sample prepared in this comparative example shows that only a small number of titanium dioxide nanoparticles and nanosheets are coated on the surface of some zirconium oxide particles, and they do not completely cover the zirconium oxide substrate to form a uniform film. This indicates that the bonding force between the titanium dioxide prepared by this method and the zirconium oxide substrate is weak and cannot form a modification layer.

[0105] Comparative Example 2

[0106] The preparation process is basically the same as in Example 1, except that in step (1), titanium sulfate is replaced with an equimolar amount of tetrabutyl titanate.

[0107] Figure 9 The SEM image of the sample prepared in this comparative example shows that nano-bulbs with a size of about 1 μm are scattered on the surface of the zirconia substrate, while a large amount of zirconia substrate is exposed. This indicates that the titanium dioxide prepared by this method cannot form a uniform modification layer that completely covers the zirconia surface.

[0108] Comparative Example 3

[0109] (1) Mix 0.5g of titanium dioxide powder with 5mL of anhydrous ethanol to prepare titanium dioxide slurry, and coat it on the surface of zirconium oxide.

[0110] (2) Place the coated zirconia ceramic in a muffle furnace and heat it from room temperature to 900°C at a rate of 15°C / min. Hold it at that temperature for 30 min and then cool it with the furnace.

[0111] Figure 10 The SEM image of the sample prepared in this comparative example shows that a small number of 300-600 nm nanoparticle aggregates are dispersed on the surface of the zirconia substrate, and a uniform and completely covering modification layer cannot be formed on the zirconia surface.

[0112] Comparative Example 4

[0113] The preparation process is basically the same as in Example 1, except for step 1):

[0114] Replace the concentration of titanium sulfate in the precursor fluid with 0.2 mol / L.

[0115] Figure 11 The SEM images of the comparative sample show that titanium dioxide exists as irregular nanoparticles with a size of 100-600 nm, dispersed on the zirconium oxide surface. It cannot form a film and does not form a tight and uniform bond with the zirconium oxide substrate, exposing a large amount of the zirconium oxide substrate.

[0116] Comparative Example 5

[0117] The preparation process is basically the same as in Example 1, except for step 1):

[0118] The molar ratio of titanium sulfate and urea was changed to 1:3, and the concentration of titanium sulfate in the precursor fluid was 0.3 mol / L.

[0119] Figure 12 The SEM image of the sample prepared in this comparative example shows that titanium dioxide exists in the form of nanoparticles with a particle size of 30-50 nm, covering the surface of zirconium oxide to form a film, which is tightly bonded to the zirconium oxide substrate. However, under the microscopic level, a large number of irregularly shaped cracks and vacancies are clearly visible in the titanium dioxide film, exposing the zirconium oxide substrate.

[0120] The above-described embodiments are preferred embodiments, but the scope of protection of the present invention is not limited thereto. Those skilled in the art can easily understand the spirit of the present invention based on the above embodiments and make different extensions and variations, but as long as they do not depart from the spirit of the present invention, they are all within the scope of protection of the present invention.

Claims

1. A zirconium oxide with a titanium dioxide-modified surface, characterized in that, The titanium dioxide modification layer prepared on the zirconium oxide surface is a layer of nanoparticles evenly distributed on the zirconium oxide surface. The main morphology is nanoparticles with a size of 30~70nm, accompanied by a small number of agglomerated nanospheres composed of nanoparticles with a size of 250~500nm. The method for preparing the zirconium oxide with a titanium dioxide modification layer on its surface includes: (1) Titanium sulfate, urea and water are mixed evenly to obtain a precursor fluid; The molar ratio of titanium sulfate to urea is 1:(4~10). The concentration of titanium sulfate in the precursor fluid is 0.3~1.0 mol / L; (2) Place the zirconium oxide ceramic in the precursor fluid and heat it to boiling state for a period of time; Heat to boiling and maintain for 5-30 minutes; (3) The zirconia ceramic is taken out and heat-treated to prepare a titanium dioxide modification layer on the zirconia surface; The heat treatment is performed at a temperature of 800~1000℃ for a holding time of 10~60 min. The heating rate of the heat treatment is 10~20℃ / min.

2. The zirconium oxide with a titanium dioxide-modified surface according to claim 1, characterized in that, In step (1): The molar ratio of titanium sulfate to urea is 1:(4~6). The concentration of titanium sulfate in the precursor fluid is 0.3~0.6 mol / L.

3. The zirconium oxide with a titanium dioxide modification layer on its surface according to claim 2, characterized in that, In step (2): Heat to boiling and maintain for 10-20 minutes.

4. The zirconium oxide with a titanium dioxide modification layer on its surface according to claim 3, characterized in that, In step (3): The heat treatment is performed at a temperature of 850~950℃.

5. The application of zirconium oxide with a titanium dioxide-modified surface as described in any one of claims 1 to 4 in the field of biological implant materials.

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