Zirconium oxide composite powder, molded body, pre-sintered body, sintered body, method for producing same, and dental prosthesis

Abstract

The invention provides zirconium oxide composite powder, a molded body, a pre-sintered body, a sintered body, a manufacturing method of the molded body, a manufacturing method of the sintered body and a dental restoration. The zirconium oxide composite powder is composed of secondary particles, the secondary particles are formed by agglomeration of a plurality of primary particles, the performance of the secondary particles meets the range of a parameter D defined by the following relational expression: D = [D (3, 2) / D (4, 3)] * F, 0.5 g / s < = D < = 2 g / s, in the formula, D (3, 2) is the area average particle size of the primary particles, and the value range of D (3, 2) is 0.1 [mu] m-0. 5 [mu] m; d (4, 3) is the volume average particle size of the primary particles, and the value range of D (4, 3) is 0.2 [mu] m-0. 8 [mu] m; f is the outflow rate measured by the powder through a standard Hall flowmeter funnel with the inner diameter of 2.5 mm under the action of gravity, and the value range of F is 1g / s-2g / s. According to the scheme provided by the invention, the sintering time can be greatly shortened while the zirconia sintered body prepared by sintering the zirconia composite powder has excellent mechanical strength and light transmission, and rapid sintering of the dental restoration is realized.

Description

Technical Field

[0001] This invention relates to the field of biomedical materials technology, specifically to a zirconia composite powder, a molded body, a pre-fired body, a sintered body, a manufacturing method thereof, and a dental prosthesis. Background Technology

[0002] Zirconia sintered bodies have been widely used in dental materials such as dental restorations in recent years. These dental restorations are mostly manufactured by the following process: pressing zirconia particles to form zirconia shaped bodies with desired shapes such as discs or prisms, then pre-firing them to form pre-fired bodies (blanks), cutting (grinding) them into the shape of the target dental restoration, and then sintering them.

[0003] Currently, mainstream dental restorations on the market require sintering for 10-20 hours, consuming as much as 30-50 kWh / kg of energy. Due to this extended time, patients often need to make multiple trips to the hospital, resulting in significant time waste. Furthermore, the prolonged high-temperature exposure and excessively long sintering time increase process instability, making zirconia grains prone to non-uniform growth, leading to excessively large local grain sizes or residual pores, thus reducing the material's mechanical strength. Summary of the Invention

[0004] The purpose of this invention is to provide a zirconia composite powder, a molded body, a pre-fired body, a sintered body, a manufacturing method thereof, and a dental prosthesis, so as to ensure that the zirconia composite powder has high fluidity and bulk density, and to sinter it into a zirconia sintered body. While ensuring that the zirconia sintered body has excellent mechanical strength and light transmittance, the sintering time can be significantly shortened, achieving rapid sintering.

[0005] To achieve the above objectives, the present invention provides the following technical solution: A zirconia composite powder, wherein the powder is composed of secondary particles, which are formed by the agglomeration of multiple primary particles, and its properties satisfy the range of parameter D defined by the following relationship: D = [D(3,2) / D(4,3)]×F, 0.5 g / s ≤ D ≤ 2 g / s, where D(3,2) is the area average particle size of the primary particles, which ranges from 0.1 μm to 0.5 μm; D(4,3) is the volume average particle size of the primary particles, which ranges from 0.2 μm to 0.8 μm; and F is the outflow rate of the powder measured by a standard Hall flowmeter funnel with an inner diameter of 2.5 mm under gravity, which ranges from 1 g / s to 2 g / s.

[0006] To achieve the above objectives, the present invention also provides the following technical solution: A zirconia shaped body formed by pressurizing the above-mentioned zirconia composite powder, wherein the zirconia shaped body has a porosity of 30-50%.

[0007] To achieve the above objectives, the present invention also provides the following technical solution: A method for manufacturing zirconia molded bodies includes a step of pressurizing the zirconia composite powder under a pressure of 60 MPa to 240 MPa.

[0008] To achieve the above objectives, the present invention also provides the following technical solution: A zirconia pre-sintered body is prepared by pre-sintering the above-mentioned zirconia shaped body, wherein the porosity of the zirconia pre-sintered body is 30-50%.

[0009] To achieve the above objectives, the present invention also provides the following technical solution: A method for manufacturing a zirconia pre-fired body includes a step of pre-firing the zirconia shaped body at 800°C to 1100°C.

[0010] To achieve the above objectives, the present invention also provides the following technical solution: A zirconia sintered body is made by fully sintering the above-mentioned zirconia shaped body or by fully sintering the above-mentioned zirconia pre-sintered body.

[0011] To achieve the above objectives, the present invention also provides the following technical solution: A method for manufacturing a zirconia sintered body includes a step of sintering the zirconia shaped body or the zirconia pre-sintered body under normal pressure at 1400°C to 1600°C.

[0012] To achieve the above objectives, the present invention also provides the following technical solution: A dental prosthesis is made by fully sintering the aforementioned zirconia molded body or by fully sintering the aforementioned zirconia pre-fired body.

[0013] To achieve the above objectives, the present invention also provides the following technical solution: A method for manufacturing a dental prosthesis includes a step of sintering the zirconia molded body or the zirconia pre-sintered body at atmospheric pressure and at 1400°C to 1600°C.

[0014] Optionally, the sintering time is less than 1 hour.

[0015] Further optionally, the sintering time is less than 30 minutes.

[0016] To achieve the above objectives, the present invention also provides the following technical solution: The use of the above-mentioned zirconia composite powder, the above-mentioned zirconia shaped body, or the above-mentioned zirconia pre-fired body in the preparation of dental restorations.

[0017] Other applicable fields will become apparent from the description provided in this invention.

[0018] The descriptions and specific examples in the invention summary are intended to be illustrative only and are not intended to limit the scope of the invention.

[0019] Compared with the prior art, the technical solution provided by the present invention has the following beneficial effects: The zirconia powder, molded body, pre-fired body, sintered body, manufacturing method and dental restoration provided by the present invention can ensure that the zirconia composite powder has high fluidity and bulk density, and the number of contact points between particles increases, thereby promoting mass transfer behavior during sintering. The zirconia sintered body is made from it, which can significantly shorten the sintering time while ensuring that the zirconia sintered body has excellent mechanical strength and light transmittance. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other solutions can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a flowchart illustrating a method for preparing zirconia composite powder according to an embodiment of the present invention. Detailed Implementation

[0022] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. It should be understood that the specific embodiments described herein are only for illustration and explanation of the present invention and are not intended to limit the present invention.

[0023] Any specific numerical values ​​disclosed herein (including the endpoints of numerical ranges) are not limited to their exact values, but should be understood to also include values ​​close to the exact value, such as all possible values ​​within ±5% of the exact value. Furthermore, with respect to the disclosed numerical ranges, one or more new numerical ranges can be obtained by arbitrarily combining the endpoint values ​​of the range, the endpoint values ​​with specific point values ​​within the range, and the specific point values ​​themselves; these new numerical ranges should also be considered as specifically disclosed herein.

[0024] The terminology used in this invention is for the purpose of describing specific exemplary embodiments only and is not intended to be limiting. Unless the context clearly indicates otherwise, the singular forms “a,” “an,” and “the” as used herein are intended to include the plural forms as well. The terms “comprising,” “including,” “containing,” and “having” are inclusive and thus describe the presence of said features, elements, compositions, steps, integers, operations, and / or components, but do not exclude the presence or inclusion of one or more other features, integers, steps, operations, elements, components, and / or sets thereof. Although the open-ended term “comprising” should be understood as a non-limiting term used to describe and claim the various embodiments described in this invention, in some aspects it may instead be understood as a more restrictive and limiting term, such as “consisting of” or “essentially composed of.” Thus, for any given embodiment describing a composition, material, component, element, feature, integer, operation, and / or process step, the invention also particularly includes embodiments consisting of or substantially consisting of such compositions, materials, components, elements, features, integers, operations, and / or process steps. In the case of “consisting of…”, the alternative embodiments exclude any additional compositions, materials, components, elements, features, integers, operations and / or process steps. In the case of “essentially composed of…”, any additional compositions, materials, components, elements, features, integers, operations and / or process steps that substantially affect the essential and novel characteristics are excluded from such embodiments. However, any compositions, materials, components, elements, features, integers, operations and / or process steps that do not substantially affect the essential and novel characteristics may be included in the embodiments.

[0025] Any method steps, processes, and operations described in this invention should not be construed as necessarily requiring them to be performed in the specific order discussed or shown, unless explicitly specified. It should also be understood that, unless otherwise stated, additional or alternative steps may be used.

[0026] In this invention, except where expressly stated, any matters or issues not mentioned are directly applicable to those known in the art without any modification. Furthermore, any embodiment described in this invention can be freely combined with one or more other embodiments described in this invention, and the resulting technical solutions or concepts are considered part of the original disclosure or original record of this invention, and should not be regarded as new content not disclosed or anticipated by this invention, unless those skilled in the art consider the combination to be clearly unreasonable.

[0027] Unless otherwise stated, the terms used herein have the same meaning as commonly understood by those skilled in the art, and if a term is defined herein and its definition differs from the common understanding in the art, the definition herein shall prevail.

[0028] Unless otherwise stated, when % is mentioned in this document, it refers to wt%.

[0029] It is worth noting that the "rapid sintering" described in this invention specification means that when the zirconia composite powder, shaped body (green body), and pre-sintered body provided by this invention are sintered into a sintered body, the sintering time is significantly shortened compared to the sintering time of traditional sintering methods, while ensuring that the overall performance of the sintered body meets the application requirements.

[0030] It is worth noting that in this invention, "shaped body" refers to a shaped body obtained by forming zirconia composite powder as the main raw material through a pressure forming process, which has not progressed to the pre-sintered or sintered state. That is, the zirconia shaped body is distinguished from the zirconia pre-sintered body and zirconia sintered body in that it is not fired after being formed into a shaped body.

[0031] It is worth noting that the terms "molded body" and "green body" used in this invention specification are interchangeable in specific contexts.

[0032] It is worth noting that in this invention, "pre-fired body" refers to the precursor (intermediate product) of zirconia sintered body, which is the state in which zirconia particles (powder) are not completely sintered (pre-fired state).

[0033] It is worth noting that in this invention, "sintered body" refers to a substance in which zirconium oxide particles (powder) have progressed to the sintered state.

[0034] It is worth noting that "D(3,2)" as described in this invention specification refers to the average particle size based on surface area. Specifically, it refers to the particle size corresponding to the ratio of the total volume of all particles in the zirconia composite powder to its total surface area, reflecting the particle size per unit surface area of ​​the zirconia composite powder. D(3,2) is also known as the Sauter average diameter, which is the average particle size weighted by the particle surface area. The formula for calculating D(3,2) is D(3,2)=(∑n i d i 3 ) / (∑n i d i 2 ), where d i It is the particle size (diameter) of a single particle, n i The particle size (diameter) is d i The number of particles.

[0035] It is worth noting that "D(4,3)" as described in this invention specification refers to the volume-weighted average particle size of the zirconium oxide composite powder, or the average particle size with particle volume as the weight, also known as "volume-average particle size" or "DeBrouckere average diameter". The formula for calculating D(4,3) is D(4,3)=(∑ni d i 4 ) / (∑n i d i 3 ), where d i It is the particle size (diameter) of a single particle, n i The particle size (diameter) is d i The number of particles; since molecules are d 4 The denominator is d 3 The volume weight of large particles is amplified, so a small number of large particles will significantly increase D(4,3), while a large number of small particles have a limited effect on decreasing D(4,3); D(4,3) focuses more on reflecting the contribution of large particles. D(4,3) is the volume-weighted average particle size, and its size is positively correlated with the actual particle size of the powder, but it is not equivalent to the diameter of a specific particle. Rather, it is a statistical description of the entire powder system. The larger D(4,3) is, the more significant the volume contribution of "large particles" in the powder, and the overall powder is coarser; the smaller D(4,3) is, the more dominant the volume contribution of "small particles" in the powder, and the overall powder is finer. D(4,3) is an average particle size that "biased towards large particles," and its size directly reflects the degree of volume dominance of "large particles" in the powder.

[0036] Generally, D(3,2) is used to consider small particles, and D(4,3) is used to consider large particles.

[0037] The following examples illustrate this: Powder sample A has a particle size distribution characteristic of "mostly 1μm, a small amount of 50μm", so its D(4,3) is significantly greater than 1μm and close to 10~20μm; Powder sample B has a particle size distribution characteristic of "mostly 1μm, no large particles", so its D(4,3)≈1μm; Powder sample C has a particle size distribution characteristic of "mostly 10μm, a small amount of 1μm", so its D(4,3)≈10μm.

[0038] The engineering significance of D(3,2) and D(4,3) is as follows: If D(4,3) is large, it indicates that the powder particle size is relatively coarse; if D(4,3) is small, it indicates that the powder particle size is relatively fine; if D(4,3) is much larger than D(3,2), it indicates that the powder particle size distribution is relatively wide and there are significant large particles; if D(4,3)≈D(3,2), it indicates that the powder particle size distribution is relatively narrow and the particle distribution is relatively uniform.

[0039] It is worth noting that the particle sizes D(3,2), D(4,3), and D1 of the present invention are... V 50 was tested using a Malvern laser particle size analyzer at a refractive index of 2.19, D2 V50 was tested using a Horiba laser particle size analyzer at a refractive index of 2.19, while F and loose density were measured using a Hall flow meter.

[0040] First aspect This invention provides a zirconia composite powder composed of secondary particles formed by the agglomeration of multiple primary particles. The secondary particles' properties satisfy the following relationship, defined by the parameter D: D = [D(3,2) / D(4,3)] × F, 0.5 ≤ D ≤ 2, where D(3,2) is the area-average particle size of the primary particles; D(4,3) is the volume-average particle size of the primary particles; and F is the outflow rate of the powder measured by a standard Hall flowmeter funnel with an inner diameter of 2.5 mm under gravity. This method ensures that the primary particles of the zirconia composite powder have more regular shapes and more uniform dispersion, resulting in higher flowability and bulk density. The increased contact points between primary particles promote mass transfer during sintering. Sintering this powder into a zirconia sintered body significantly shortens the sintering time while maintaining excellent mechanical strength and light transmittance, achieving rapid sintering.

[0041] In some embodiments of the present invention, D(3,2) is 0.1 μm to 0.5 μm. Understandably, D(3,2) can take any value or a range of any two of the following: 0.10 μm, 0.12 μm, 0.18 μm, 0.21 μm, 0.25 μm, 0.26 μm, 0.30 μm, 0.33 μm, 0.36 μm, 0.40 μm, 0.41 μm, 0.42 μm, 0.48 μm, 0.5 μm. Since the D(3,2) metric indicates that small particles contribute more significantly, a D(3,2) that is too large results in low sintering activity, making rapid sintering difficult. Conversely, a D(3,2) that is too small leads to particle aggregation. This results in high resistance to primary particle migration, causing secondary particles to break easily. Furthermore, a D(3,2) that is too small leads to excessively high sintering activity, making abnormally large particles prone to appear during sintering. Consequently, the sintered body exhibits significantly reduced strength and transparency after rapid sintering. When the primary particle size D(3,2) of the zirconia composite powder meets this range, the particles exhibit better dispersibility and moderate sintering activity, ensuring that the sintered body maintains excellent strength and transparency even during rapid sintering.

[0042] In some embodiments of the present invention, D(4,3) is 0.2μm to 0.8μm. Understandably, D(4,3) can take any value or a range of any two of the following: 0.20μm, 0.22μm, 0.25μm, 0.27μm, 0.29μm, 0.30μm, 0.33μm, 0.39μm, 0.40μm, 0.41μm, 0.42μm, 0.48μm, 0.50μm, 0.56μm, 0.58μm, 0.60μm, 0.67μm, 0.70μm, 0.78μm, 0.79μm, 0.80μm. D(4,3) is an average particle size that favors larger particles. If D(4,3) is too large, the powder has low sintering activity, uneven particle size distribution, and poor powder flowability. If D(4,3) is too small, the particles are prone to agglomeration, and the agglomerates contain a large number of closed or open pores. These pores remain after sintering, leading to a decrease in the density of the sintered body and affecting its strength. When the primary particle size D(4,3) of the zirconia composite powder meets this value range, it can ensure that the size and content of large particles in the powder are controlled within a small range, resulting in a more uniform particle size distribution. This ensures that the sintered body has excellent strength while sintering rapidly.

[0043] In some embodiments of the present invention, F is 1 g / s to 2 g / s. Understandably, F can be 1.00 g / s, 1.01 g / s, 1.09 g / s, 1.18 g / s, 1.23 g / s, 1.37 g / s, 1.38 g / s, 1.43 g / s, 1.52 g / s, 1.53 g / s, 1.68 g / s, 1.76 g / s, 1.93 g / s, 2.00 g / s, or any value between them, or any combination of both. F represents the flowability of the powder per unit time. When F is too low, loose particle packing and high porosity easily occur, leading to a decrease in the density of the green body for sintering, thus making rapid sintering impossible. When F is too high, secondary particles are prone to separation during the preparation of the sintered body, resulting in uneven density of the green body for sintering, decreased strength of the sintered body, and local shrinkage differences, deformation, or cracking, seriously affecting practical applications. When the F of the zirconia composite powder meets this value range, it can ensure that the sintered body has sufficient strength and can achieve rapid sintering.

[0044] It is worth noting that D(3,2) and D(4,3) have the same unit. When the unit of D(3,2) is μm, the unit of D(4,3) is also μm. When the unit of D(3,2) is nm, the unit of D(4,3) is also nm. Therefore, D(3,2) / D(4,3) is a ratio, and the unit of D is the same as the unit of F.

[0045] D = [D(3,2) / D(4,3)] × F, where D value correlates the primary and secondary particles of the zirconia composite powder. If D satisfies the range of 0.5 g / s ≤ D ≤ 2 g / s, the primary particles of the zirconia composite powder are regularly shaped and uniformly dispersed. Simultaneously, the secondary particles formed by the agglomeration of primary particles have fewer defects and better flowability, ensuring the acquisition of high-density green bodies for sintering and achieving rapid sintering. If D is too large, there may be extremely irregular primary particles or excessively high powder flowability, leading to numerous defects in the green bodies for sintering and significantly deteriorating the strength and transparency of the sintered body. If D is too small, the primary particle distribution is wider, the powder flowability deteriorates, the density of the green bodies for sintering decreases, and the contact between particles is reduced, affecting mass transfer behavior during sintering. This necessitates a longer time or higher temperature to achieve densification, making rapid sintering impossible.

[0046] In some embodiments of the present invention, the median particle size D1 of the primary particles V 50 represents the median particle size D1 of the primary particles of the zirconia composite powder, which is 0.1 μm to 0.5 μm. V Within this range, 50 allows for control of the overall particle size of the powder to be finer, further enhancing the density of the sintered body. Understandably, D1 V 50 can take values ​​of 0.10μm, 0.11μm, 0.14μm, 0.19μm, 0.21μm, 0.25μm, 0.27μm, 0.30μm, 0.33μm, 0.35μm, 0.40μm, 0.41μm, 0.44μm, 0.45μm, 0.47μm, 0.5μm, and any value between them or any combination of two.

[0047] In some embodiments of the present invention, the specific surface area of ​​the primary particles is 7 m². 2 / g ~18m 2 / g, understandably, the specific surface area of ​​the primary particles can be taken as 7m². 2 / g、8m 2 / g、9m 2 / g, 10m 2 / g、11m 2 / g、12m 2 / g、13m 2 / g、14m 2 / g, 15m 2 / g, 16m 2 / g、17m 2 / g、18m 2 / g and any values ​​between them or a range consisting of any two of them.

[0048] In some embodiments of the present invention, the loose packing density of the powder is 1 g / cm³ to 1.5 g / cm³. Understandably, the loose packing density of the powder can be 1 g / cm³, 1.1 g / cm³, 1.2 g / cm³, 1.3 g / cm³, 1.4 g / cm³, 1.5 g / cm³, or any value between them, or any combination thereof. Loose packing density = powder mass / container volume. The loose packing density of the present invention is calculated using a Hall effect flow meter to measure the mass of powder that flows naturally into a 25 ml container.

[0049] In some embodiments of the present invention, the median particle size of the secondary particles is D2. V 50 is 40μm~80μm, and the median particle size of the secondary particles can be 40μm, 42μm, 45μm, 48μm, 50μm, 53μm, 55μm, 60μm, 63μm, 64μm, 70μm, 71μm, 76μm, 78μm, 80μm, and any value between them or any combination of two.

[0050] In some embodiments of the present invention, the zirconia composite powder contains zirconia and a stabilizer capable of inhibiting the zirconia phase transformation, preferably yttrium oxide. In some optional embodiments, the zirconia composite powder contains 3 mol% to 5 mol% yttrium oxide relative to the total molar amount of zirconia and yttrium oxide. Understandably, based on the total molar amount of zirconia and yttrium oxide, the powder contains 3 mol%, 3.5 mol%, 4 mol%, 4.5 mol%, or 5 mol% yttrium oxide. The content of the stabilizer in the zirconia composite powder of the present invention can be determined by, for example, inductively coupled plasma (ICP) luminescence spectrophotometry, fluorescence X-ray analysis, etc.

[0051] Of course, solutions obtained by understanding stabilizers as other conventional stabilizers besides yttrium oxide are also included in this invention.

[0052] In some embodiments of the present invention, the zirconia composite powder further contains a densification-promoting sintering aid. Examples of such sintering aids include alumina, titanium dioxide, magnesium oxide, zinc oxide, gallium oxide, calcium oxide, and sodium oxide, as well as combinations thereof. In some optional embodiments, the zirconia composite powder contains 0 to 0.5 wt% of the sintering aid based on the total weight of the powder; understandably, the powder contains 0.1 wt%, 0.15 wt%, 0.2 wt%, 0.25 wt%, 0.3 wt%, 0.35 wt%, 0.4 wt%, 0.45 wt%, or 0.5 wt% of the sintering aid based on the total weight of the zirconia composite powder. The content of the sintering aid in the zirconia composite powder of the present invention can be determined by, for example, inductively coupled plasma (ICP) luminescence spectrophotometry, fluorescence X-ray analysis, etc. It should be noted that the sintering aid will affect the pH value of the slurry during the preparation of the slurry described later, thereby affecting the values ​​of D(4.3), D(3.2) and F.

[0053] In some embodiments of the present invention, the zirconia composite powder further comprises a colorant. The type of colorant is not particularly limited, and known pigments commonly used for coloring ceramics, known dental liquid colorants, etc., can be used. Examples of such colorants include compounds containing metallic elements. Examples of metallic elements include Er, Fe, Tb, Pr, Mn, Co, Nd, etc. The colorant may contain one of these metallic elements alone, or it may contain two or more. Examples of compounds include oxides, hydroxides, acetates, nitrates, etc., of the aforementioned metallic elements. The content of colorant is not particularly limited and can be appropriately adjusted according to the type of colorant and the intended use of zirconia composite powder. From the viewpoint of being preferably used as a dental restoration, the zirconia composite powder contains 0 to 2 wt% colorant based on the total weight of the zirconia composite powder, for example, 0.1 wt%, 0.2 wt%, 0.4 wt%, 0.6 wt%, 0.8 wt%, 1.0 wt%, 1.2 wt%, 1.4 wt%, 1.6 wt%, 1.8 wt%, and 2 wt%.

[0054] The secondary particles of this invention are formed by the aggregation of multiple primary particles. The aggregation is a controllable soft aggregation achieved through binders and granulation processes (such as spray granulation or pressure granulation), mainly based on adhesive action and capillary forces, while avoiding hard aggregation inherent in the powder (such as van der Waals forces, electrostatic interactions) or mainly based on chemical bonding (such as hydrogen bonds), which can lead to large pores, cracks or abnormal grain growth in the sintered body.

[0055] In some embodiments of the present invention, the secondary particles are secondary particles formed by spray granulation of primary particles, wherein the primary particles in the secondary particles are physically connected and interlocked with each other.

[0056] In some embodiments of the present invention, the powder further comprises a binder at a weight of 0-4 wt% based on the total weight of the powder. Understandably, based on the total weight of the zirconia composite powder, the powder comprises 0.1 wt%, 0.5 wt%, 1.0 wt%, 1.5 wt%, 2.0 wt%, 2.5 wt%, 3.0 wt%, 3.5 wt%, or 4.0 wt% of binder. Examples of binders include, for instance, polyvinyl alcohol, polyethylene glycol, polyacrylic acid, ammonium polyacrylate, and polymethyl methacrylate, as well as combinations thereof.

[0057] Second aspect This invention provides a method for preparing the above-mentioned zirconia composite powder, comprising the following steps: S10 provides a slurry containing primary zirconium oxide particles; and S20, the above-mentioned primary zirconium oxide particles are dried to form secondary particles.

[0058] The method for preparing the zirconia primary particles in the slurry containing zirconia primary particles is not particularly limited. For example, a break-down process can be used to pulverize coarse particles to achieve micronization; a building-up process can be used to synthesize particles from atoms and / or ions using nucleation and growth processes; a building-up process is preferred.

[0059] In some embodiments of the present invention, step S10 includes: S11, amorphous zirconium oxide was synthesized through a construction process; S12, calcining the amorphous zirconium oxide to obtain crystalline zirconium oxide; and S13, the crystalline zirconia is added to a dispersion medium and dispersed to obtain the slurry containing zirconia primary particles.

[0060] Examples of construction processes include hydrothermal synthesis, coprecipitation, solid-phase synthesis, and sol-gel synthesis.

[0061] As a zirconium source in the construction process, nitrates, acetates, chlorides, alkoxides, etc. can be used. Specifically, zirconium dichloride, zirconium acetate, zirconium oxynitrate, etc. can be used.

[0062] The above-described construction processes can all be carried out using specific operating procedures known to those skilled in the art, and the process parameters are not particularly limited, with the goal of obtaining high-purity and finely regular particles. However, it should be noted that the above construction processes should avoid agglomeration.

[0063] Furthermore, in order to achieve the yttrium oxide content in the zirconia composite powder within the aforementioned range, yttrium oxide can be incorporated into the primary zirconia particles during manufacturing. For example, yttrium oxide can be dissolved in the primary zirconia particles. As a yttrium source, nitrates, acetates, chlorides, alkoxides, etc., can be used; specifically, yttrium chloride, yttrium acetate, and yttrium nitrate can be used.

[0064] In some embodiments of the present invention, in step S12, the calcination temperature is 900℃~1200℃, for example, it can also be 950℃, 1000℃ or 1500℃. If the calcination temperature is too high, it will cause particle agglomeration; if the calcination temperature is too low, it will result in a smaller D(3.2). A calcination temperature within this range is more conducive to forming primary particles with regular shape, uniform dispersion, and suitable size, thereby achieving rapid sintering.

[0065] In step S20, the secondary particles are preferably obtained by spray drying the slurry containing the primary zirconium oxide particles. Spray drying can agglomerate the primary particles into secondary particles.

[0066] The dispersion medium can be water or an organic solvent other than water, such as ethanol, acetone, or tetrahydrofuran. The amount of dispersion medium used is not particularly limited and can be any amount known in the art.

[0067] The above-mentioned dispersion treatment can be implemented by mechanical means, such as using a roller mill, colloid mill, high-pressure jet disperser, ultrasonic disperser, ball mill, or sand mill, or by heat and pressure-based dispersion treatments such as reflux treatment or hydrothermal treatment. Each treatment may employ only one method, or two or more methods.

[0068] In some embodiments of the present invention, the dispersion treatment is carried out using a sand mill with a milling speed of 400 r / min to 1500 r / min, for example, it can also be 500 r / min, 600 r / min, 700 r / min, 800 r / min, 1000 r / min or 1200 r / min. A milling speed within this range can avoid D(3.2) being too small, D50 being too large, and the powder activity being too low, thus ensuring that the sintered body obtained by rapid sintering has better performance.

[0069] In some embodiments of the present invention, the dispersion treatment is carried out using a ball mill at a speed of 300 r / min to 500 r / min, for example, 320 r / min, 350 r / min, 380 r / min, 400 r / min, 420 r / min, 450 r / min, or 480 r / min. Within this range, the ball milling speed avoids excessively small D(3.2), excessively large D50, and excessively low powder activity, ensuring that the sintered body obtained by rapid sintering has better performance.

[0070] When the zirconia composite powder contains a binder, this binder can be included in the slurry containing primary zirconia particles. In this case, the binder is mixed with the slurry containing primary zirconia particles in a liquid state such as a solution or dispersion.

[0071] In some embodiments of the present invention, step S13 further includes adding an adhesive to the slurry containing the primary zirconium oxide particles. It should be noted that the adhesive can be added before or after the dispersion treatment.

[0072] When the zirconia composite powder contains a sintering aid and / or colorant, the slurry containing primary zirconia particles may also contain such a sintering aid and / or colorant. In this case, the sintering aid and / or colorant are preferably mixed with the slurry containing primary zirconia particles in liquid form, such as a solution or dispersion.

[0073] In some embodiments of the present invention, step S13 further includes adding a sintering aid and / or a colorant to the slurry containing the zirconia primary particles. It is understood that the sintering aid and / or colorant may be added before or after the dispersion treatment.

[0074] In some embodiments of the present invention, the slurry containing zirconia primary particles may further contain one or more of the following components in addition to sintering aids, colorants, and binders: dispersants, emulsifiers, defoamers, pH adjusters, lubricants, etc. By including these other components (especially dispersants, defoamers, pH adjusters, etc.) in addition to the binder, particle aggregation can sometimes be suppressed during drying, resulting in a denser zirconia sintered body. These components can be added before or after the dispersion treatment.

[0075] Please see Figure 1 In some embodiments of the present invention, the method for preparing zirconium oxide composite powder includes the following steps: S11, amorphous zirconium oxide was synthesized through a construction process; S12, the amorphous zirconium oxide is calcined to obtain crystalline zirconium oxide; S131, the crystalline zirconium oxide is added to a dispersion medium and processed by a ball mill or sand mill to obtain a slurry containing primary zirconium oxide particles: and S21, an adhesive is added to the slurry containing primary zirconium oxide particles, and the primary particles are agglomerated to form secondary particles by spray drying.

[0076] In some embodiments of the present invention, the spray inlet temperature of the spray dryer is 150°C to 250°C, for example, it can also be 160°C, 180°C, 200°C, 220°C or 240°C.

[0077] In some embodiments of the present invention, the spray outlet temperature of the spray dryer is 150°C to 250°C, for example, 160°C, 180°C, 200°C, 220°C or 240°C.

[0078] In some embodiments of the present invention, the spray speed of the spray drying is 5000 r / min to 10000 r / min, for example, it can also be 6000 r / min, 7000 r / min, 8000 r / min or 9000 r / min.

[0079] Third aspect The present invention provides a zirconia molded body formed by pressurizing the above-mentioned zirconia composite powder.

[0080] Understandably, in addition to containing zirconium oxide, the zirconia molded body of the present invention may also contain one or more of stabilizers, sintering aids, colorants, and binders when the zirconium oxide composite powder contains zirconium oxide. Specific examples of these components can be found in the foregoing section and will not be repeated here. The content of these components in the zirconia molded body is also consistent with that in the zirconium oxide composite powder.

[0081] The porosity of the zirconia molded body obtained by mercury intrusion porosimetry of the present invention is 30-50%.

[0082] The density of the zirconia molded body of the present invention is not particularly limited and varies depending on the manufacturing method of the zirconia molded body, etc. However, from the perspective of obtaining a dense zirconia sintered body, the density is preferably 3.0 g / cm³. 3 The above, more preferably 3.2 g / cm³ 3 The above is further optimized to be 3.4 g / cm³. 3 That's all. There is no specific upper limit to this density; for example, it could be set to 6.0 g / cm³. 3 Therefore, it can be set to 5.8 g / cm³. 3 the following.

[0083] The shape of the zirconia molded body of the present invention is not particularly limited, and can be made into a desired shape according to the application. However, considering the processability when obtaining a zirconia pre-sintered body for use as a blank for manufacturing dental materials such as dental repairs, a disc shape or a prism shape (cubic parallelepiped shape) is preferred. Furthermore, the zirconia molded body can be a single-layer structure or a multi-layer structure. By making it into a multi-layer structure, the final zirconia sintered body can be made into a multi-layer structure, and its physical properties such as light transmittance can be locally modified.

[0084] Fourth aspect The present invention provides a method for manufacturing a zirconia shaped body, which includes a step of pressurizing the zirconia composite powder under a pressure of 60MPa to 240MPa.

[0085] Fifth aspect The present invention provides a zirconia pre-sintered body made by pre-sintering the above-mentioned zirconia shaped body.

[0086] The porosity of the zirconia pre-fired body of the present invention, as determined by mercury intrusion porosimetry, is 30-50%. The pre-fired body has higher strength than the molded body and can be machined, but residual pores remain after debinding.

[0087] The density of the zirconia pre-fired body of the present invention is not particularly limited, but is preferably 3.0 g / cm³. 3 ~6.0g / cm 3 More preferably 3.2 g / cm³ 3 ~5.8g / cm 3 .

[0088] Understandably, the zirconia pre-sintered body of the present invention contains, in addition to zirconia, one or more of stabilizers, sintering aids, and colorants. The adhesive is preferably removed by combustion during sintering, but residues are possible. The amount of adhesive residue in the zirconia pre-sintered body of the present invention is such that it does not affect the light transmittance of the final sintered body. The content of the other components may be slightly reduced during the sintering process, but this is negligible.

[0089] Sixth aspect The present invention provides a method for manufacturing the above-mentioned zirconia pre-fired body, which includes a step of pre-firing the zirconia shaped body at 800°C to 1100°C.

[0090] It should be noted that the pre-fired body can be further processed and shaped to obtain the final sintered body shape for practical applications.

[0091] Seventh aspect The present invention provides a zirconia sintered body made by fully sintering the zirconia shaped body or by fully sintering the zirconia pre-sintered body.

[0092] Understandably, the zirconia sintered body of the present invention contains, in addition to zirconia, one or more of stabilizers, sintering aids, and colorants. The adhesive is preferably removed by combustion during sintering, but residues are possible. The amount of adhesive residue in the zirconia sintered body of the present invention is such that it does not affect its light transmittance. The content of the other components may be slightly reduced during the sintering process, but this is negligible.

[0093] In some embodiments of the present invention, the zirconia sintered body satisfies at least one of the following conditions (1) to (3): (1) The relative density of the zirconia sintered body is greater than 99%, and the relative density is the ratio of the actual density to the theoretical density of the zirconia sintered body: (2) The three-point bending strength of the zirconia sintered body is >800MPa; (3) The light transmittance of the zirconia sintered body is >40%, and the total transmittance of the zirconia sintered body is measured by a spectrophotometer in the 360-750nm band through a 10mm aperture when the thickness of the zirconia sintered body is 1mm.

[0094] Eighth aspect The present invention provides a method for manufacturing a zirconia sintered body, comprising: sintering the zirconia shaped body or the zirconia pre-sintered body under normal pressure and at 1400°C to 1600°C.

[0095] In some preferred embodiments of the present invention, the sintering time is less than 1 hour, and more preferably less than 30 minutes.

[0096] Ninth aspect The present invention provides a dental prosthesis made by fully sintering the zirconia molded body or by fully sintering the zirconia pre-sintered body.

[0097] Tenth aspect The present invention provides a method for manufacturing a dental prosthesis, comprising: sintering the zirconia molded body or the zirconia pre-sintered body under normal pressure and at 1400°C to 1600°C.

[0098] In some preferred embodiments of the present invention, the sintering time is less than 1 hour, and more preferably less than 30 minutes.

[0099] Eleventh aspect This invention provides the use of the zirconia composite powder, the zirconia shaped body, or the zirconia pre-fired body in the preparation of dental restorations.

[0100] Example To better understand the present invention, the following description, in conjunction with embodiments, further illustrates the present invention. However, the scope of protection of the present invention is not limited to the scope of the embodiments.

[0101] In the following examples, unless otherwise specified, all experimental instruments and raw materials involved are commercially available products or can be prepared by known methods. Experimental methods not specifying particular conditions in the examples were performed under conventional conditions, such as those described in literature, books, or methods recommended by the manufacturer.

[0102] In the following examples and comparative examples, the zirconia particles, zirconia composite powder, zirconia molded body, zirconia pre-fired body, and zirconia sintered body are all zirconia containing yttrium oxide stabilized.

[0103] Example 1 1. Zirconia composite powder (1) Amorphous zirconium oxide was prepared by hydrothermal synthesis of zirconium source and yttrium source at a synthesis temperature of 120℃ and a synthesis time of 48h.

[0104] (2) Amorphous zirconium oxide is calcined at a temperature of 1050℃ to obtain crystalline zirconium oxide (yttrium oxide is dissolved in zirconium oxide).

[0105] (3) Add crystalline zirconia to the dispersion medium and use ball milling at 400 r / min to obtain a slurry containing 4 mol% yttrium oxide, wherein the primary particle size D(3.2) of the zirconia particles is 0.33 and D(4.3) is 0.56.

[0106] (4) Add 1 wt% polyethylene glycol as an adhesive to the slurry in step (3), and then send the prepared slurry into the spray drying tower. The spray inlet temperature is 160℃, the spray outlet temperature is 180℃, and the rotation speed is 6500 r / min to prepare zirconia composite powder.

[0107] 2. Zirconia molded body The zirconia composite powder obtained in step 1 was subjected to 120 MPa pressure molding to obtain a zirconia shaped body.

[0108] 3. Zirconia pre-sintered body The zirconia shaped body obtained in step 2 is pre-fired at a temperature of 1000℃ to obtain a zirconia pre-fired body.

[0109] 4. Dental restorations The pre-sintered body obtained in step 3 was sintered at the highest sintering temperature of 1550℃ for 1 hour to obtain a zirconia sintered body, i.e. a dental restoration, with a relative sintering density of 99.3%.

[0110] Example 2 This embodiment is basically the same as embodiment 1, except that: Step (2) The calcination temperature is 1000℃; In step (3), the primary particle size of zirconium oxide is 0.18 for D(3.2) and 0.39 for D(4.3).

[0111] The zirconia shaped body and pre-sintered body of Example 2 were obtained by the same preparation method as in Example 1; the pre-sintered body was sintered at the highest sintering temperature of 1550°C for 45 min to obtain the sintered body with a relative sintering density of 99.5%.

[0112] Example 3 This embodiment is basically the same as method embodiment 1, except that: Add 0.15wt% ZnO as a sintering aid; In step (3), the primary particle size of zirconia is D(3.2) 0.26 and D(4.3) 0.29.

[0113] The zirconia shaped body and pre-sintered body of Example 3 were obtained in the same manner as in Example 1; the pre-sintered body was sintered at the highest sintering temperature of 1450°C for 20 min to obtain the sintered body with a relative sintering density of 99.5%.

[0114] Example 4 This embodiment is basically the same as method embodiment 1, except that: Amorphous zirconium oxide was prepared by coprecipitation method, with ammonia water as the precipitant. The coprecipitate was obtained by adding a mixed aqueous solution of zirconium salt and stabilizer salt dropwise at room temperature. Step (2) The calcination temperature is 900℃; In step (3), the ball milling speed is 360 r / min, and the primary particle size of zirconia is D(3.2) 0.21 and D(4.3) 0.2.

[0115] The zirconia shaped body and pre-sintered body of Example 4 were obtained in the same manner as in Example 1; the pre-sintered body was sintered at the highest sintering temperature of 1550°C for 30 min to obtain the sintered body with a relative sintering density of 99.2%.

[0116] Example 5 This embodiment is basically the same as method embodiment 1, except that: Step (2) The calcination temperature is 950℃; Step (3) The primary particle size of zirconium oxide is 0.12 for D(3.2) and 0.27 for D(4.3), and it contains 5 mol% yttrium oxide.

[0117] The zirconia shaped body and pre-sintered body of Example 5 were obtained in the same manner as in Example 1; the pre-sintered body was sintered at the highest sintering temperature of 1400°C for 20 min to obtain the sintered body with a relative sintering density of 99.6%.

[0118] Example 6 This embodiment is basically the same as method embodiment 1, except that: Add 0.3wt% CaO as a sintering aid and 0.05wt% iron oxide as a colorant; Step (3) The primary particle size of zirconium oxide is 0.25 for D(3.2) and 0.40 for D(4.3), and it contains 5 mol% yttrium oxide.

[0119] The zirconia molded body and the pre-sintered body of Example 6 were obtained in the same manner as in Example 1; the pre-sintered body was sintered at the highest sintering temperature of 1450°C for 1 hour to obtain the sintered body with a relative sintering density of 99.4%.

[0120] Example 7 This embodiment is basically the same as method embodiment 1, except that: Add 0.001 wt% manganese oxide as a colorant. Step (3) The primary particle size of zirconium oxide is 0.42 for D(3.2) and 0.58 for D(4.3), and it contains 5 mol% yttrium oxide.

[0121] The zirconia molded body and the pre-sintered body of Example 7 were obtained in the same manner as in Example 1; the pre-sintered body was sintered at a maximum sintering temperature of 1500°C for 20 minutes to obtain a sintered body with a relative sintering density of 99.1%.

[0122] Example 8 This embodiment is basically the same as method embodiment 1, except that: Step (1) The synthesis temperature is 150℃ and the synthesis time is 18h; Step (3) The primary particle size of zirconium oxide is 0.41 for D(3.2) and 0.78 for D(4.3), and it contains 3 mol% yttrium oxide.

[0123] The zirconia molded body and the pre-sintered body of Example 8 were obtained in the same manner as in Example 1; the pre-sintered body was sintered at a maximum sintering temperature of 1600°C for 45 minutes to obtain a sintered body with a relative sintering density of 99.4%.

[0124] Example 9 This embodiment is basically the same as method embodiment 1, except that: Step (3) The ball milling speed is 800 r / min, the primary particle size of zirconium oxide is D(3.2) 0.36, D(4.3) 0.67, and it contains 3 mol% yttrium oxide.

[0125] The zirconia shaped body and pre-sintered body of Example 9 were obtained in the same manner as in Example 1; the pre-sintered body was sintered at the highest sintering temperature of 1550°C for 30 min to obtain the sintered body with a relative sintering density of 99.6%.

[0126] Example 10 This embodiment is basically the same as method embodiment 1, except that: Step (2) The calcination temperature is 1200℃; Step (3) The primary particle size of zirconium oxide is 0.40 for D(3.2) and 0.79 for D(4.3), and it contains 3 mol% yttrium chloride.

[0127] The zirconia shaped body and pre-sintered body of Example 10 were obtained in the same manner as in Example 1; the pre-sintered body was sintered at the highest sintering temperature of 1500°C for 1 hour to obtain the sintered body with a relative sintering density of 99.5%.

[0128] Example 11 This embodiment is basically the same as method embodiment 1, except that: Ammonium polyacrylate is used as an adhesive.

[0129] The zirconia shaped body and pre-sintered body of Example 11 were obtained in the same manner as in Example 1; the pre-sintered body was sintered at a maximum sintering temperature of 1500°C for 45 minutes to obtain the sintered body with a relative sintering density of 99.4%.

[0130] Example 12 This embodiment is basically the same as method embodiment 1, except that: Step (4) The spray inlet temperature is 200℃, the spray outlet temperature is 200℃, and the rotation speed is 8000r / min.

[0131] The zirconia molded body and the pre-sintered body of Example 12 were obtained in the same manner as in Example 1; the pre-sintered body was sintered at a maximum sintering temperature of 1480°C for 45 minutes to obtain a sintered body with a relative sintering density of 99.3%.

[0132] Comparative Example 1 This comparative example is basically the same as the method example 1, except that: Step (2) The calcination temperature is 1250℃; In step (3), the primary particle size of zirconium oxide is 0.48 for D(3.2) and 0.85 for D(4.3).

[0133] Zirconia molded body and pre-sintered body of Comparative Example 1 were obtained in the same manner as in Example 1. The pre-sintered body was sintered at the highest sintering temperature of 1600°C for 1 hour. After sintering, it did not form porcelain and had a noticeable powdery texture, making it impossible to test its performance.

[0134] Comparative Example 2 This comparative example is basically the same as the method example 1, except that: Step (2) The calcination temperature is 850℃; In step (3), the primary particle size of zirconium oxide is D(3.2) 0.08 and D(4.3) 0.21.

[0135] Zirconia shaped body and pre-sintered body of Comparative Example 2 were obtained in the same manner as in Example 1; the pre-sintered body was sintered at the highest sintering temperature of 1600°C for 1 hour to obtain the sintered body with a relative sintering density of 97.9%.

[0136] Comparative Example 3 This comparative example is basically the same as the method example 1, except that: In step (3), the ball milling speed is 240 r / min, and the primary particle size of zirconia is D(3.2) 0.45 and D(4.3) 0.77.

[0137] Zirconia molded body and pre-sintered body of Comparative Example 3 were obtained in the same manner as in Example 1; the pre-sintered body was sintered at the highest sintering temperature of 1600°C for 3 hours to obtain the sintered body, which had a relative sintering density of 96.3%, was not dense, and its performance could not be tested.

[0138] Comparative Example 4 This comparative example is basically the same as the method example 1, except that: LiF was added as a sintering aid; The slurry has a pH of 9 and is viscous. In step (3), the primary particle size of zirconium oxide is 0.23 for D(3.2) and 0.65 for D(4.3).

[0139] The zirconia shaped body and the pre-sintered body of Comparative Example 4 were obtained in the same manner as in Example 1; the pre-sintered body was sintered at the highest sintering temperature of 1600°C for 1 hour to obtain the sintered body with a relative sintering density of 98.1%.

[0140] Comparative Example 5 This comparative example is basically the same as the method example 1, except that: Replace the adhesive with ammonia; The zirconia shaped body and the pre-sintered body of Comparative Example 5 were obtained in the same manner as in Example 1; the pre-sintered body was sintered at the highest sintering temperature of 1600°C for 1 hour to obtain the sintered body with a relative sintering density of 97.1%.

[0141] Comparative Example 6 This comparative example is basically the same as the method example 1, except that: Step (4) The spray inlet temperature is 280℃ and the outlet temperature is 260℃. The zirconia molded body and the pre-sintered body of Comparative Example 6 were obtained in the same manner as in Example 1. The pre-sintered body was sintered at the highest sintering temperature of 1600°C for 1 hour to obtain the sintered body with a relative sintering density of 99.0%. The ceramic warped and its performance could not be tested.

[0142] Comparative Example 7 This comparative example is basically the same as the method example 1, except that: Add 0.1wt% SiO2 as a sintering aid; Step (3) reduces the shearing efficiency of the grinding balls, and the primary particle size of zirconia D(3.2) is 0.55 and D(4.3) is 0.87.

[0143] The zirconia shaped body and the pre-sintered body of Comparative Example 7 were obtained in the same manner as in Example 1; the pre-sintered body was sintered at the highest sintering temperature of 1600°C for 3 hours to obtain the sintered body with a relative sintering density of 98.9%.

[0144] Comparative Example 8 This comparative example is basically the same as the method example 1, except that: Zirconium source was dissolved in a low-melting-point salt and thoroughly mixed using the molten salt method. The mixture was reacted at 1000℃ to obtain plate-like crystals. The product was cooled, washed to remove impurities, and dried to prepare plate-like zirconia, resulting in zirconia with a primary particle size D(3.2) of 0.43 and D(4.3) of 0.35.

[0145] Zirconia molded body and pre-sintered body of Comparative Example 8 were obtained in the same manner as in Example 1; the pre-sintered body was sintered at the highest sintering temperature of 1600°C for 1 hour to obtain the sintered body, which had a relative sintering density of 95.7%, was not dense, and its performance could not be tested.

[0146] The materials prepared in the above embodiments and comparative examples were tested using the following methods, and the test results are listed in Tables 1 and 2 below: 1. D(3,2), D(4,3), D1 V 50 was tested using a Malvern laser particle size analyzer at a refractive index of 2.19, D2 V50 were tested using a Horiba laser particle size analyzer at a refractive index of 2.19.

[0147] 2. F (powder flow rate) is calculated using a Hall effect flow meter, taking the powder to flow through a 2.5mm orifice. F = powder mass / flow time.

[0148] 3. Loose packing density is calculated using a Hall effect flow meter, based on the mass of powder that flows naturally into a 25ml container. Loose packing density = powder mass / container volume.

[0149] 4. The density of the molded body was obtained through calculation, ρ 成形 =m / V.

[0150] 5. The density of the pre-fired body was obtained through calculation, ρ 预烧 =m / V.

[0151] 6. The relative density of the sintered body was measured using a density balance and obtained based on Archimedes' principle.

[0152] 7. The strength of the sintered body was tested using a universal testing machine, specifically the three-point bending strength of a zirconia composite with a width and thickness of 4*1.2.

[0153] 8. The permeability of the sintered body was measured using a spectrophotometer. The total transmittance of a 1 mm thick zirconia composite was measured through a 10 mm aperture in the 360-750 nm wavelength range.

[0154] Table 1

[0155] Table 2

[0156] As can be seen from Tables 1 and 2, by comparing Examples 1-12 and Comparative Examples 1-8, the zirconia composite powder, shaped body, pre-sintered body and sintered body provided by the present invention have better performance and can achieve rapid sintering.

[0157] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims. Furthermore, specific examples have been used in the specification to illustrate the principles and implementation methods of the present invention. The above description of the embodiments is only for the purpose of helping to understand the method and core ideas of the present invention, and the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A zirconium oxide composite powder, characterized in that, The powder is composed of secondary particles, which are formed by the aggregation of multiple primary particles. Its properties satisfy the range of parameter D defined by the following relationship: D = [D(3,2) / D(4,3)]×F, 0.5 g / s ≤ D ≤ 2 g / s, In the formula, D(3,2) is the average particle size of the primary particles, which ranges from 0.1 μm to 0.5 μm. D(4,3) is the volume average particle size of the primary particles, and its value ranges from 0.2 μm to 0.8 μm; F is the outflow rate of the powder measured by a standard Hall flow meter funnel with an inner diameter of 2.5 mm under the action of gravity, and its value ranges from 1 g / s to 2 g / s.

2. The zirconium oxide composite powder according to claim 1, characterized in that, The median particle size D1 of the primary particles V 50 is 0.1μm ~ 0.5μm.

3. The zirconium oxide composite powder according to claim 1, characterized in that, The specific surface area of ​​the primary particles is 7m². 2 / g ~18m 2 / g.

4. The zirconium oxide composite powder according to claim 1, characterized in that, The loose packing density of the powder is 1 g / cm³ to 1.5 g / cm³.

5. The zirconium oxide composite powder according to claim 1, characterized in that, The median particle size of the secondary particles is D2. V 50 represents 40μm~80μm.

6. The zirconium oxide composite powder according to any one of claims 1 to 5, characterized in that, The powder contains 3 mol% to 5 mol% of yttrium oxide relative to the total molar amount of zirconium oxide and yttrium oxide.

7. The zirconium oxide composite powder according to any one of claims 1 to 5, characterized in that, The powder also contains a sintering aid at a weight of 0-0.5 wt% based on the total weight of the powder. Optionally, the sintering aid includes one or more of alumina, titanium dioxide, magnesium oxide, zinc oxide, gallium oxide, calcium oxide, and sodium oxide.

8. The zirconium oxide composite powder according to any one of claims 1 to 5, characterized in that, The powder also contains 0-2 wt% colorant based on the total weight of the powder. Optionally, the colorant is a compound containing one or more elements selected from Er, Fe, Tb, Pr, Mn, Co, and Nd.

9. The zirconium oxide composite powder according to any one of claims 1 to 5, characterized in that, The powder contains a binder at a weight of 0-4 wt% based on the total weight of the powder. Optionally, the adhesive includes one or more of polyvinyl alcohol, polyethylene glycol, polyacrylic acid, ammonium polyacrylate, and polymethyl methacrylate.

10. A zirconia molded body formed by pressurizing the zirconia composite powder according to any one of claims 1 to 9, characterized in that, The porosity of the zirconia shaped body is 30-50%.

11. A method for manufacturing a zirconia molded article, comprising: The process of pressurizing and forming the zirconia composite powder according to any one of claims 1 to 9 under a pressure of 60 MPa to 240 MPa.

12. A zirconia pre-sintered body prepared by pre-sintering the zirconia shaped body according to claim 10, characterized in that, The porosity of the zirconia pre-sintered body is 30-50%.

13. A method for manufacturing a zirconia pre-fired body, comprising: The process of pre-firing the zirconia molded body according to claim 10 at 800°C to 1100°C.

14. A zirconia sintered body made by fully sintering the zirconia shaped body of claim 10 or by fully sintering the zirconia pre-sintered body of claim 12.

15. The zirconia sintered body according to claim 14, characterized in that, The zirconia sintered body satisfies at least one of the following conditions (1) to (3): (1) The relative density of the zirconia sintered body is greater than 99%, and the relative density is the ratio of the actual density to the theoretical density of the zirconia sintered body; (2) The three-point bending strength of the zirconia sintered body is >800MPa; (3) The light transmittance of the zirconia sintered body is >40%, and the light transmittance is the total transmittance measured by a spectrophotometer in the 360-750nm band through a 10mm aperture when the thickness of the zirconia sintered body is 1mm.

16. A method for manufacturing a zirconia sintered body, comprising: The process of sintering the zirconia shaped body according to claim 10 or the zirconia pre-sintered body according to claim 12 under normal pressure and at 1400°C to 1600°C.

17. The method for manufacturing a zirconia sintered body according to claim 18, characterized in that, The sintering time is less than 1 hour, preferably less than 30 minutes.

18. A dental prosthesis, characterized in that, It is prepared by fully sintering the zirconia shaped body according to claim 10 or by fully sintering the zirconia pre-sintered body according to claim 12.

19. A method for manufacturing a dental prosthesis, comprising: The process of sintering the zirconia shaped body according to claim 10 or the zirconia pre-sintered body according to claim 12 under normal pressure and at 1400°C to 1600°C; Optionally, the sintering time is less than 1 hour; Further optionally, the sintering time is less than 30 minutes.

20. Use of the zirconia composite powder according to any one of claims 1 to 9, the zirconia shaped body according to claim 10, or the zirconia pre-fired body according to claim 12 in the preparation of dental restorations.

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