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CN-121974723-A - Zirconia regenerated by glass powder infiltration and preparation method thereof

CN121974723ACN 121974723 ACN121974723 ACN 121974723ACN-121974723-A

Abstract

The invention relates to the technical field of biological ceramics, in particular to a method for preparing zirconium oxide by utilizing glass powder permeation regeneration. The method is characterized in that the presintered porous blank is subjected to alkali solution activation and acid catalysis silica-boron sol and alkali silicate-boric acid solution sequential vacuum infiltration treatment so as to form a silica-boron transition phase on the surface of a pore wall/microcrack in situ, and the wettability and interface bonding strength of the subsequent borosilicate glass powder slurry are enhanced. And filling of relative pores of the glass and healing of microcracks are realized by optimizing the formula of the glass powder and the step heating sintering process. The obtained material has high compactness, excellent bending strength and fracture toughness, and is suitable for high-performance scenes such as dental restoration and the like.

Inventors

  • WANG ZHIHUAN
  • LIU YIJING
  • HU WEIYU
  • Chen Siri
  • GUO HUAN

Assignees

  • 湖南泽尔顿新材料有限公司

Dates

Publication Date
20260505
Application Date
20260409

Claims (10)

  1. 1. The preparation method of the zirconia by utilizing the glass powder infiltration regeneration is characterized by comprising the following steps: (1) Mixing the regenerated zirconia powder, the polyvinyl alcohol solution and the polystyrene latex microsphere aqueous dispersion, drying and granulating to obtain granulated powder, forming the granulated powder to obtain a green body, and presintering to obtain a presintered porous blank; (2) Sequentially performing alkali solution activation treatment, acid catalysis silica-boron sol vacuum infiltration treatment and alkali silicate-boric acid solution vacuum infiltration treatment on the presintered porous blank, and performing heat treatment to form a silica-boron transition phase on the pore wall and/or the micro-crack surface of the presintered porous blank; (3) Placing the blank body treated in the step (2) into glass powder infiltration slurry containing borosilicate glass powder for vacuum infiltration to obtain a glass powder-containing blank body; (4) Sintering the glass powder-containing blank to soften and adhere the glass phase, filling and healing pores and/or microcracks, and obtaining regenerated zirconia permeated by the glass powder; The acid-catalyzed silica-boron sol in the step (2) is prepared by mixing 30-40 parts by mass of deionized water with 80-92 parts by mass of absolute ethyl alcohol, adding 3-6 parts by mass of 65wt% nitric acid solution, then dropwise adding 90-110 parts by mass of tetraethoxysilane, stirring for 25-40min, adding 10-16 parts by mass of boric acid, stirring for 2-2.5h at 40 ℃, and sealing and aging for 8-16h at room temperature to obtain the acid-catalyzed silica-boron sol; The alkaline silicate-boric acid solution in the step (2) is prepared by adding 20-35 parts by mass of sodium metasilicate into 240-260 parts by mass of deionized water for dissolution, adding 8-12 parts by mass of boric acid, stirring, adding 8-12 parts by mass of 28wt% ammonia water, and adding deionized water to 300 parts by mass of the total mass to obtain the alkaline silicate-boric acid solution.
  2. 2. The method for preparing regenerated zirconia by glass frit infiltration according to claim 1, wherein the polyvinyl alcohol solution in the step (1) is a polyvinyl alcohol 1788 aqueous solution with a concentration of 5wt%, the polystyrene latex microsphere aqueous dispersion has a concentration of 10wt%, and the mass ratio of the regenerated zirconia powder, the polyvinyl alcohol solution and the polystyrene latex microsphere aqueous dispersion is 150:100:10-40.
  3. 3. The method for preparing the regenerated zirconia by utilizing glass powder infiltration according to claim 1, wherein the regenerated zirconia powder in the step (1) is prepared from dental presintered zirconia block processing leftover materials through cleaning, pickling, ball milling, sieving and drying, wherein the pickling is carried out by adopting pickling liquid prepared from citric acid monohydrate and deionized water, filtering and rinsing after stirring and soaking at 60 ℃, drying, carrying out wet milling by adopting absolute ethyl alcohol as a dispersion medium, and drying the slurry after passing through a 200-mesh screen to obtain the regenerated zirconia powder.
  4. 4. The method for producing a regenerated zirconia by infiltration with glass frit according to claim 1, wherein the molding in the step (1) is a unidirectional press at a pressing pressure of 120 to 160MPa and a holding pressure of 60s, and the presintering comprises heating to 400 ℃ at 2 ℃ per minute and holding the temperature for 2 hours, heating to 1200 to 1280 ℃ at 5 ℃ per minute and holding the temperature for 0.5 to 1.5 hours, and then cooling in a furnace.
  5. 5. The method for producing a porous zirconia by infiltration of glass frit according to claim 1, wherein in the alkali solution activation treatment in the step (2), the alkali solution is an aqueous sodium hydroxide solution, and the activation treatment comprises immersing the pre-sintered porous green body in the alkali solution, standing at 55 to 65 ℃ for 5 to 15 minutes, taking out, rinsing and drying.
  6. 6. The method for preparing the regenerated zirconia by glass frit infiltration according to claim 1, wherein the vacuum infiltration treatment of the acid catalyzed silica-boron sol in the step (2) comprises immersing the green body in the acid catalyzed silica-boron sol, vacuumizing to a vacuum degree of-80+/-10 kPa and keeping the vacuum degree for 3-6min, returning to normal pressure, continuing to soak for 15-30min, repeating vacuumizing-returning to normal pressure circulation for 0-2 times, wherein the vacuum infiltration treatment of the alkali silicate-boric acid solution comprises immersing the green body in the alkali silicate-boric acid solution, vacuumizing to a vacuum degree of-80+/-10 kPa and keeping the vacuum degree for 2-5min, returning to normal pressure, continuing to soak for 15-30min, and heating to 550-650 ℃ at 2 ℃ per min, keeping the temperature for 0.5-1.5h, and cooling in a furnace.
  7. 7. The method for preparing the regenerated zirconia by glass frit infiltration according to claim 1, wherein the borosilicate glass frit in the step (3) is prepared by mixing 95-110 parts by mass of silicon dioxide powder, 60-85 parts by mass of boric acid, 30-50 parts by mass of sodium metasilicate, 5-15 parts by mass of potassium carbonate, 8-15 parts by mass of calcium carbonate and 2-8 parts by mass of alumina, melting, maintaining the melting temperature at 1200-1280 ℃, maintaining the temperature for 60-100min, quenching the molten glass to obtain glass frit, drying, performing wet ball milling in absolute ethyl alcohol for 12-36h, drying and sieving with a 300-600 mesh sieve to obtain borosilicate glass frit, and the glass frit infiltration slurry is prepared by adding 120-180 parts by mass of borosilicate glass frit into 80-150 parts by mass of absolute ethyl alcohol and 20-60 parts by mass of deionized water as dispersion media, adding 1-3 parts by mass of sodium polyacrylate and 1788-3 parts by mass of polyvinyl alcohol, and stirring for 20-60 min.
  8. 8. The method for producing a regenerated zirconia by infiltration with glass frit according to claim 1, wherein the vacuum infiltration in the step (3) comprises immersing the green body in the glass frit infiltration slurry, evacuating to a vacuum level of-80.+ -.10 kPa for 3-6min, returning to normal pressure for soaking for 15-30min, taking out, and drying.
  9. 9. The method for producing a regenerated zirconia by infiltration with glass frit according to claim 1, wherein the firing in step (4) comprises heating to 380-450 ℃ at 2 ℃ per minute and keeping the temperature for 0.5-1.5 hours, heating to 760-820 ℃ at 5 ℃ per minute and keeping the temperature for 20-50 minutes, heating to 880-930 ℃ at 5 ℃ per minute and keeping the temperature for 10-30 minutes, and finally cooling to room temperature with a furnace.
  10. 10. A method for producing a zirconia by infiltration of glass frit, characterized in that the method is used for producing a zirconia by infiltration of glass frit according to any one of claims 1 to 9.

Description

Zirconia regenerated by glass powder infiltration and preparation method thereof Technical Field The invention relates to the technical field of biological ceramics, in particular to a method for regenerating zirconia by utilizing glass powder permeation and a preparation method thereof. Background The regenerated zirconia is taken as an important direction of recycling resources, and has wide application potential in the fields of dental restoration, wear-resistant parts and the like. However, the current mainstream regeneration treatment mode is mostly dependent on a simple process route of re-pressing and re-sintering or re-sintering after secondary crushing, and the method can realize powder recycling and simultaneously hardly avoid the problem of introducing foreign matters. For example, environmental contaminants or precursor residues are prone to mixing into the powder during collection, crushing and reprocessing, thereby forming amorphous or heterogeneous inclusions after sintering, disrupting the chemical uniformity of the zirconia matrix. Further, since the morphology and size distribution of the reclaimed powder are easy to change after multiple treatments, the ideal particle stacking state is difficult to recover by simple mechanical pressing, and the partial densification shortage or stress concentration area exists in the green body. In the sintering stage, the defects can be developed into macropores or microcracks, and particularly when the temperature rise at high rate or the heat preservation time is insufficient, the residual porosity is obviously increased, so that the bulk density of the material is reduced, and the defects become a preferential path for crack propagation. In addition, the grain boundary structure of the regenerated zirconia tends to be unstable due to the history of heat, and the risk of abnormal growth of crystal grains or phase change induced microstrain in the secondary sintering process is increased, so that the fluctuation of mechanical properties is aggravated. It is noted that the above problems are particularly prominent in the field of dental restorations and the like that require high precision machining and long-term service. For example, if there are voids or weak interfaces inside the crown-bridge prosthesis during cutting, edge chipping is liable to occur, whereas under masticatory load, cracks initiate and propagate from the defect, leading to early failure. While the prior art attempts to improve performance by adjusting the sintering temperature or adding sintering aids, often at the expense of translucency or chemical stability, and fails to address the problem of batch-to-batch consistency at all. Therefore, developing a method for modifying regenerated zirconia, which can achieve high densification, interface stability and batch reliability, becomes a bottleneck to be broken through in the field. Disclosure of Invention In view of the above, the present invention aims to provide a method for preparing regenerated zirconia by infiltration of glass frit, so as to solve the problems that the existing method for preparing regenerated zirconia is easy to introduce impurities, out-of-control grain composition and residual pores during the reprocessing process, resulting in significantly reduced flexural strength and fracture toughness of the material, poor batch-to-batch stability, and difficulty in meeting the severe requirements of applications such as dental crown and bridge on high reliability. Based on the above object, the present invention provides a method for preparing regenerated zirconia by infiltration of glass frit, comprising the steps of: (1) Mixing the regenerated zirconia powder, the polyvinyl alcohol solution and the polystyrene latex microsphere aqueous dispersion, drying and granulating to obtain granulated powder, forming the granulated powder to obtain a green body, and pre-sintering to obtain the presintered porous green body. (2) Sequentially performing alkali solution activation treatment, acid catalysis silica-boron sol vacuum infiltration treatment and alkali silicate-boric acid solution vacuum infiltration treatment on the presintered porous blank, and performing heat treatment to form a silica-boron transition phase on the pore wall and/or the micro-crack surface of the presintered porous blank; (3) Placing the blank body treated in the step (2) into glass powder infiltration slurry containing borosilicate glass powder for vacuum infiltration to obtain a glass powder-containing blank body; (4) Sintering the glass powder-containing blank body to soften and adhere the glass phase, filling and healing pores and/or microcracks, and obtaining the regenerated zirconia by using the glass powder infiltration. Preferably, the acid-catalyzed silica-boron sol in the step (2) is prepared by mixing 30-40 parts by mass of deionized water with 80-92 parts by mass of absolute ethyl alcohol, adding 3-6 parts by mass of 65wt% nitric acid soluti