Metal facing porcelain powder and preparation method thereof, metal facing porcelain

Abstract

This application discloses a metal facing porcelain powder, a preparation method thereof, and a metal facing porcelain, thereby improving the yield rate of metal porcelain teeth. The metal facing porcelain powder is a microcrystalline glass containing a main crystal phase of barium metaborate (BaB2O4) and a secondary crystal phase of barium silicate (Ba2Si3O8). By precipitating two crystals of barium metaborate and barium silicate, the microcrystalline glass has a high thermal expansion coefficient, thereby matching the thermal expansion coefficient of the cobalt-chromium alloy substrate. The thermal expansion coefficient of the metal facing porcelain is 12.5×10 ‑6 ℃ ‑1 ~13.5×10 ‑6 ℃ ‑1 (Room temperature ~ 500℃), porcelain baking temperature is 720℃ ~ 750℃.

Description

Technical Field

[0001] The present application relates to the technical field of medical dental materials, and in particular to a metal facing porcelain powder and a preparation method thereof, and a metal facing porcelain. Background Art

[0002] Metal porcelain teeth are very common in clinical use, and one type of metal porcelain teeth is based on cobalt-chromium alloy. Cobalt-chromium alloy as a base material mainly provides mechanical properties, and then the veneer powder is coated on it and provides aesthetic properties after the porcelain is fused. The thermal expansion coefficient of cobalt-chromium alloy is generally 13.8×10 -6 ℃ -1 ~15.2×10 -6 ℃ -1 (Room temperature ~ 500℃), so the thermal expansion coefficient of the facing porcelain is required to be 12.5×10 -6 ℃ -1 ~14.0×10 -6 ℃ -1 (Room temperature ~ 500℃), which is slightly lower than the thermal expansion coefficient of cobalt-chromium alloy, can form compressive stress in the facing porcelain body and improve the strength of the facing porcelain.

[0003] At present, leucite glass-ceramic is used for metal facing porcelain. Since leucite crystal has a high thermal expansion coefficient (20.0×10 -6 ℃ -1 ~25.0×10 -6 ℃ -1 , room temperature to 500°C), so the thermal expansion coefficient of leucite glass-ceramics can meet the requirements of metal facing porcelain. However, the base glass of leucite glass-ceramics is SiO2-Al2O3-K2O, which has a very high melting point, is extremely difficult to melt, and is very energy-intensive. Furthermore, the firing temperature of leucite glass-ceramics typically reaches 920°C, which can easily reduce the yield rate. Summary of the Invention

[0004] The purpose of this application is to provide a metal facing porcelain powder and its preparation method, and metal facing porcelain. The base glass corresponding to the metal facing porcelain powder is easier to melt and can be melted well at 1300°C, and the metal facing porcelain powder can be baked at 720°C to 750°C, thereby improving the yield rate of metal porcelain teeth.

[0005] In the first aspect, the present application provides a metal facing porcelain powder for facing the metal base of a denture, characterized in that the main crystal phase of the microcrystalline glass is barium metaborate (BaB2O4) crystal, and the secondary crystal phase is barium silica (Ba2Si3O8) crystal, and its thermal expansion coefficient is 12.5×10 -6 ℃ -1 ~13.5×10 -6 ℃-1 (Room temperature ~ 500℃), porcelain baking temperature is 720℃ ~ 750℃.

[0006] In a possible implementation, the base glass of the metal facing porcelain is composed of the following components in terms of weight percentage:

[0007]

[0008] The sum of the weight percentages of the components in the base glass is 100%; wherein, the BaO is introduced in the form of raw material BaCO3.

[0009] In a second aspect, the present application provides a method for preparing a metal finishing porcelain powder, for preparing the metal finishing porcelain powder according to claim 1 or 2, characterized in that the method comprises the following steps:

[0010] SiO2, BaCO3, B2O3, La2O3, Y2O3 and ZrO2 are mixed according to weight percentage, and the mixture is ball-milled;

[0011] Melting the product obtained after ball milling, and then quenching it with water to obtain the basic glass;

[0012] The base glass is dried and then ball-milled into a powder of 300-500 mesh, and then the base glass powder is heat-treated to obtain a micro-ceramic glass powder containing barium metaborate and barium silica crystals;

[0013] The microcrystalline glass powder containing barium metaborate and barium silica crystals is ball-milled and then sieved to obtain a powder with a mesh size of 300 to 500, thereby obtaining the metal facing porcelain powder.

[0014] In a possible implementation, the temperature of heat-treating the basic glass powder is 780°C to 820°C.

[0015] In the third aspect, the present application provides a metal facing porcelain, which is made by baking the metal facing porcelain powder described in the first aspect.

[0016] Compared to existing technologies, the glass-ceramics provided in this application have the following advantages: the base glass of this application can be melted well at 1300°C and has very low viscosity. In contrast, traditional SiO2-Al2O3-K2O glass requires high temperatures above 1650°C to ensure melting quality. In addition, the glass-ceramics produced in this application have a firing temperature of 720°C to 750°C, which is lower than the firing temperature of most metal facing porcelains. This low firing temperature helps improve the yield rate of metal porcelain teeth. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1This is the XRD pattern of the metal finishing porcelain powder in the embodiment of this application;

[0018] Figure 2 This is a flow chart of the method for preparing metal finishing porcelain powder provided in an embodiment of the present application. DETAILED DESCRIPTION

[0019] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0020] The metal facing porcelain powder provided in this application is a kind of microcrystalline glass, which is composed of barium metaborate crystals, barium silica crystals and glass matrix. Its thermal expansion coefficient can reach 12.5×10 -6 ℃ -1 ~13.5×10 -6 ℃ -1 (Room temperature to 500°C), fully meeting the thermal expansion coefficient requirements of cobalt-chromium alloys for veneer porcelain. Because the present invention utilizes the low-melting-temperature BaO-B2O3-SiO2 system, the glass exhibits high melting quality at 1300°C, significantly reducing energy consumption. Furthermore, the resulting metal veneer porcelain can be successfully fired at temperatures between 720°C and 750°C, significantly improving the yield rate of metal porcelain-fused-to-metal teeth.

[0021] The base glass of the metal facing porcelain powder is composed of the following components in terms of weight percentage:

[0022]

[0023] The sum of the weight percentages of the components in the base glass is 100%, wherein BaO is introduced in the form of raw material BaCO3.

[0024] Since cobalt-chromium alloy has a high thermal expansion coefficient (13.8×10 -6 ℃ -1 ~15.2×10 -6 ℃ -1 , room temperature ~ 500 ℃), so the metal facing porcelain is required to have a high thermal expansion coefficient (12.5×10 -6 ℃ -1 ~14.0×10 -6 ℃ -1, room temperature ~ 500 ℃) to prevent the facing porcelain from falling off the metal substrate. The pure glass phase cannot meet the thermal expansion coefficient requirements of metal facing porcelain, so it is necessary to precipitate crystals with high thermal expansion coefficients in the glass phase and meet the requirements of high thermal expansion coefficients by manufacturing microcrystalline glass. From the BaO-B2O3-SiO2 ternary phase diagram, the composition of the metal facing porcelain powder of this application is in the BaB2O4 and Ba2Si3O8 phase region. Barium metaborate crystals (BaB2O4) have a very high thermal expansion coefficient (α c =36×10 -6 ℃ -1 ), barium silicate crystal (Ba2Si3O8) also has a high thermal expansion coefficient (12.6×10 -6 ℃ -1 ), so the precipitation of these two crystal phases helps to improve the thermal expansion coefficient of metal finishing porcelain powder.

[0025] The following is a combination of Table 1 and the attached Figure 1 The technical solution of this application is further illustrated through specific implementation methods.

[0026] The base glass prepared in Example 1 is composed of six components: SiO2, BaO, B2O3, La2O3, Y2O3, and ZrO2, and the total weight percentage of each component is 100%. This application achieves the technical effect of glass-ceramics containing barium metaborate crystals and barium silicate crystals through the coordinated cooperation of these components. Specifically, SiO2, BaO, and B2O3 are added to precipitate barium metaborate crystals and barium silicate crystals, while La2O3, Y2O3, and ZrO2 are added to adjust the viscosity of the glass.

[0027] In the specific preparation process, according to the weight percentage of each glass component in the embodiment listed in Table 1, analytically pure SiO2, BaCO3, B2O3, La2O3, Y2O3, and ZrO2 were weighed, thoroughly mixed and ground in a planetary ball mill, and then taken out and dried. The resulting powder after drying was placed in a platinum alloy crucible, placed in a box-type resistance furnace, heated to 1300°C in an air atmosphere, and melted at this temperature for 2 hours. The melt was then poured into water at 1300°C and quenched to obtain a base glass block. After drying, the base glass block was ball-milled into a powder of 300-500 mesh. The base glass powder was then heat-treated to obtain a micro-ceramic glass powder containing barium metaborate and barium silica crystals. The micro-ceramic glass powder containing barium metaborate and barium silica crystals was ball-milled and sieved to obtain a powder of 300-500 mesh, which can be used as dental metal veneer porcelain.

[0028] Figure 1 This is the XRD diagram of the microcrystalline glass obtained in Example 1. It can be seen from the figure that the microcrystalline glass contains barium metaborate crystal phase and barium silica crystal phase.

[0029] Table 1 Basic glass composition (weight percentage)

[0030]

[0031] The present invention also provides a method for preparing a metal finishing porcelain powder, the method comprising the following steps:

[0032] 201. SiO2, BaCO3, B2O3, La2O3, Y2O3 and ZrO2 are mixed according to weight percentage, and the mixture is ball-milled.

[0033] 202. The product obtained after ball milling is melted and then water quenched to obtain basic glass.

[0034] 203. The base glass is dried and then ball-milled into a powder of 300-500 meshes, and then the base glass powder is heat-treated to obtain a microcrystalline glass powder containing barium metaborate and barium silica crystals.

[0035] 204. The microcrystalline glass powder containing barium metaborate and barium silica crystals is ball-milled and then sieved to obtain a powder of 300-500 mesh to obtain a metal facing porcelain powder.

[0036] In a possible implementation, the temperature for heat treating the basic glass powder is 780°C to 820°C.

[0037] The embodiment of the present application also provides a metal facing porcelain, which is prepared by using the above metal facing porcelain powder through porcelain baking.

[0038] Although the present application has been illustrated and described using specific embodiments, it should be appreciated that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Those skilled in the art should understand that the technical solutions described in the above embodiments may be modified, or some or all of the technical features therein may be replaced by equivalents, without departing from the spirit and scope of the present application. These modifications or replacements do not deviate from the essence of the corresponding technical solutions within the scope of the technical solutions of the embodiments of the present application. Therefore, this means that all such replacements and modifications within the scope of the present application are included in the appended claims.

Claims

1. A metal facing porcelain powder for facing the metal base of a denture, wherein the metal facing porcelain powder is prepared from glass-ceramics, characterized in that: The main crystalline phase of the glass-ceramics is BaB2O4 crystal, and the secondary crystalline phase is Ba2Si3O8 crystal. The thermal expansion coefficient of the glass-ceramics at room temperature to 500°C is 12.5×10 -6 ℃ -1 ~13.5×10 -6 ℃ -1 , the porcelain temperature is 720℃~750℃; The base glass of the glass-ceramics is composed of the following components in terms of weight percentage: SiO2 13%~15% BaO 59%~61% B2O3 19%~21% La2O3 0%~2% Y2O30%~2% ZrO2 0%~2% The sum of the weight percentages of the components in the base glass is 100%; wherein, BaO is introduced in the form of raw material BaCO3.

2. A method for preparing a metal finishing porcelain powder, for preparing the metal finishing porcelain powder according to claim 1, characterized in that: The method comprises the following steps: SiO2, BaCO3, B2O3, La2O3, Y2O3 and ZrO2 are mixed according to weight percentage, and the mixture is ball-milled; Melting the product obtained after ball milling, and then quenching it with water to obtain the basic glass; The base glass is dried and then ball-milled into a powder of 300-500 mesh, and then the base glass powder is heat-treated to obtain a micro-ceramic glass powder containing BaB2O4 crystals and Ba2Si3O8 crystals; The microcrystalline glass powder containing BaB2O4 crystals and Ba2Si3O8 crystals is ball-milled and then sieved to obtain a powder with a mesh size of 300 to 500, thereby obtaining the metal facing porcelain powder.

3. The method for preparing metal finishing porcelain powder according to claim 2, wherein: The temperature for heat treating the powder of the base glass is 780° C. to 820° C.

4. A metal facing porcelain, characterized in that: The metal facing porcelain is made by baking the metal facing porcelain powder as claimed in claim 1.

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