Silicon nitride-based ceramic ball and preparation method and application thereof
阅读说明：本技术 氮化硅基陶瓷球及其制备方法和应用 (Silicon nitride-based ceramic ball and preparation method and application thereof ) 是由 不公告发明人 于 2020-07-06 设计创作，主要内容包括：本发明公开了一种氮化硅基陶瓷球及其制备方法和应用,所述的氮化硅基陶瓷球为在氮化硅陶瓷球表面沉积一层碳化硅层。本发明的氮化硅基陶瓷球,与未沉积碳化硅层的氮化硅球相比,在强酸强碱且运动摩擦的状态下,不容易腐蚀失重,同时与强酸强碱环境接触的界面是致密的纯碳化硅,没有助烧剂,该氮化硅基陶瓷球具有更好的耐磨、耐腐蚀等性能,可应用于耐磨轴承领域应用。(The invention discloses a silicon nitride-based ceramic ball and a preparation method and application thereof. Compared with a silicon nitride ball without a deposited silicon carbide layer, the silicon nitride-based ceramic ball is not easy to corrode and lose weight under the conditions of strong acid, strong base and motion friction, and meanwhile, the interface in contact with the environment of strong acid, strong base is compact pure silicon carbide without a sintering aid, so that the silicon nitride-based ceramic ball has better wear resistance, corrosion resistance and the like, and can be applied to the field of wear-resistant bearings.)
1. The silicon nitride-based ceramic ball is characterized in that a silicon carbide layer is deposited on the surface of the silicon nitride-based ceramic ball.
2. The silicon nitride-based ceramic ball according to claim 1, wherein the diameter of the silicon nitride ceramic ball is 0.5 mm-20 mm, and the thickness of the silicon carbide layer is 10-200 μm.
3. The silicon nitride-based ceramic ball of claim 1, wherein the silicon nitride-based ceramic ball has a relative density of 95-99%, a surface hardness of 25-42 GPa, and a fracture toughness of 6-12 MPa-m1/2The bending strength is 800-1500 MPa.
4. The preparation method of the silicon nitride-based ceramic ball is characterized by comprising the following steps of:
s1: providing silicon nitride ceramic balls as cores;
s2: and depositing on the surface of the silicon nitride ceramic ball by adopting chemical vapor deposition to form a silicon carbide layer.
5. The method of claim 4The method for preparing silicon nitride-based ceramic balls is characterized in that the silicon nitride-based ceramic balls in the step S1 adopt Si powder as a raw material and ZrO powder as2As catalyst, with Al2O3-Re2O3Is used as a sintering aid, and the mixed material is dried to obtain Si-ZrO2-Al2O3-Re2O3Mixed powder, the mixed powder is pressed and molded, and then the mixed powder is subjected to nitridation and sintering processes to prepare Si3N4And (3) ceramic balls.
6. The method according to claim 5, wherein the Si-ZrO-Si ceramic balls are prepared by a method comprising290-95% to 5-10% by mass, and the Al2O3:Re2O3The mass fraction ratio of 1-99% to 99-1%, and the Si3N4And Al2O3-Re2O380-99% and 1-20% by mass.
7. The preparation method of the silicon nitride-based ceramic ball according to claim 5, wherein the nitriding process is carried out at 1300-1450 ℃ for 0.5-4 h in nitrogen atmosphere; the sintering process is characterized in that the temperature is maintained at 1700-1900 ℃ for 1-4 h, and the sintering atmosphere is nitrogen or argon.
8. The method as claimed in claim 4, wherein Si is used as the Si-nitride-based ceramic ball in step S13N4Powder is prepared by liquid phase sintering, and the liquid phase sintering auxiliary agent is Al2O3-Re2O3，Si3N4With Al2O3-Re2O380-99% by mass, 1-20% by mass, Al2O3:Re2O3The mass percentage ratio is 1-99% to 99-1%.
9. The method for preparing the silicon nitride-based ceramic ball according to claim 4, wherein the step S2 is specifically to adopt a chemical vapor deposition method to prepare the silicon carbide layer, add argon, hydrogen and methyltrichlorosilane into a reactor, and keep the temperature at 1300-1600 ℃ for 0.5-8 h.
10. Use of a silicon nitride based ceramic ball according to any of claims 1 to 3 in the field of wear resistant bearings.
Technical Field
The invention belongs to the technical field of ceramics, and particularly relates to a silicon nitride-based ceramic ball and a preparation method and application thereof.
Background
Silicon nitride (Si)3N4) As a structural material, the ceramic has excellent mechanical properties such as high hardness, wear resistance, high temperature resistance, high heat conductivity and the like, and has a very large development prospect in the field of structural members, particularly in the field of bearing balls. The traditional rolling bearing ball is a steel ball, but the degree of wear is large, a lubricant is needed, and the replacement is frequent; however, the silicon nitride ceramic not only has the characteristics, but also has the characteristics of low density, low friction coefficient and the like, and is an excellent candidate material for replacing steel balls as high-efficiency and high-performance rolling bearing balls.
At present, there are many techniques for using silicon nitride as ceramic bearing balls, such as preparing high performance silicon nitride ceramic balls by reaction sintering, or preparing gradient materials to realize high performance silicon nitride ceramic balls with hard surface and tough core. Although there are related technologies in the field of silicon nitride ceramic balls, one problem is generally ignored by the above technologies. Although the silicon nitride ceramic has the excellent performance, the performance of the silicon nitride ceramic is remarkably deteriorated by the additive for promoting the sintering of the silicon nitride ceramic, for example, the performance of the silicon nitride ceramic, such as high temperature resistance, corrosion resistance, wear resistance, thermal conductivity and the like, is remarkably reduced by the addition of the liquid phase additive, and particularly, the strong acid and strong alkali corrosion resistance is remarkably weakened; however, the preparation of high-density silicon nitride ceramics is difficult to realize without adding a liquid-phase sintering aid, and the silicon nitride ceramics cannot be applied as a structural member. The two conditions can not meet the application conditions in the field of ceramic bearing balls.
Based on the application potential of the silicon nitride bearing ball in the fields of aerospace aviation, chemical engineering, ocean, semiconductor industry and the like, a method which is easy to produce in batch is urgently needed to be developed, and the high-performance ceramic ball meeting the application environment of the ceramic bearing ball in the strong acid and strong alkali industry can be obtained on the premise of not influencing the performance of the silicon nitride ceramic.
Disclosure of Invention
Based on the silicon nitride-based ceramic ball, the invention provides a silicon nitride-based ceramic ball and a preparation method and application thereof, and the silicon nitride-based ceramic ball is applied to Si3N4On the basis of ceramic balls, continuously in Si3N4The silicon carbide coating is deposited on the surface of the ceramic ball to obtain the high wear-resistant and corrosion-resistant Si3N4And (3) ceramic balls.
The silicon nitride-based ceramic ball is characterized in that a silicon carbide layer is deposited on the surface of the silicon nitride-based ceramic ball.
According to the further scheme, the diameter of the silicon nitride ceramic ball is 0.5 mm-20 mm, and the thickness of the silicon carbide layer is 10-200 mu m.
In a further scheme, the relative density of the silicon nitride ceramic ball is 95-99%, the surface hardness is 25-42 GPa, and the fracture toughness is 6-12 MPa.m1/2With a bending strength of800～1500MPa。
In a further scheme, the density of the silicon nitride ceramic ball is more than 98%.
The technical scheme adopted by the invention is as follows: a preparation method of silicon nitride-based ceramic balls comprises the following steps:
s1: providing silicon nitride ceramic balls as cores;
s2: and depositing on the surface of the silicon nitride ceramic ball by adopting chemical vapor deposition to form a silicon carbide layer.
Further, the method further includes performing rough grinding and polishing on the silicon nitride ceramic balls between the steps S1 and S2.
In a further aspect, the silicon nitride ceramic balls in step S1 use Si powder as a raw material and ZrO2As catalyst, with Al2O3-Re2O3Is used as a sintering aid, and the mixed material is dried to obtain Si-ZrO2-Al2O3-Re2O3Mixed powder, the mixed powder is pressed and molded, and then the mixed powder is subjected to nitridation and sintering processes to prepare Si3N4And (3) ceramic balls.
Further, dry pressing and cold isostatic pressing are carried out on the mixed powder.
In a further aspect, the Si is ZrO290-95% to 5-10% by mass, and the Al2O3:Re2O3The mass fraction ratio of 1-99% to 99-1%, wherein the silicon nitride and the Al are2O3-Re2O380-99% and 1-20% by mass.
Further embodiment, the Re2O3Re of (2) is one of Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb or Lu.
In a further scheme, the purity of the Si powder is 95-100%, and the particle size is 1-10 mu m; ZrO (ZrO)2The purity of the powder is 95-100%, and the particle size is 1-10 mu m; al (Al)2O3The purity of the powder is 95-100%, and the particle size is 0.1-10 μm; re2O3The purity of the powder is 95-100%, and the particle size is 1-10 μm.
Further scheme, the Si-ZrO2-Al2O3-Re2O3The mixed powder is prepared by using ethanol as a solvent and Si3N4The balls are used as ball milling media, are mixed for 4-18 hours on a planetary ball mill, and are dried to obtain Si-ZrO2-Al2O3-Re2O3Mixing the powder.
In a further scheme, the nitriding process is carried out at 1300-1450 ℃ for 0.5-4 h, and the nitriding atmosphere is nitrogen; the sintering process is characterized in that the temperature is maintained at 1700-1900 ℃ for 1-4 h, and the sintering atmosphere is nitrogen or argon.
Further, in the step S1, the silicon nitride ceramic balls are Si3N4Powder is prepared by liquid phase sintering, and the liquid phase sintering auxiliary agent is Al2O3-Re2O3，Si3N4With Al2O3-Re2O380-99% by mass, 1-20% by mass, Al2O3:Re2O3The mass percentage ratio is 1-99% to 99-1%.
In a further scheme, Re is one of Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb or Lu.
In a further aspect, said Si3N4The purity of the powder is 95-100%, and the particle size is 1-10 mu m; al (Al)2O3The purity of the powder is 95-100%, and the particle size is 0.1-10 μm; re2O3The purity of the powder is 95-100%, and the particle size is 1-10 μm.
In a further scheme, the temperature of the liquid phase sintering is 1600-1900 ℃, the temperature is kept for 1-4 h, and the sintering atmosphere is nitrogen or argon.
In a further scheme, the step S2 is specifically to adopt a chemical vapor deposition method to prepare the silicon carbide layer, and argon, hydrogen and methyltrichlorosilane are added into a reactor, and the reaction temperature is 1300-1600 ℃ and the temperature is kept for 0.5-8 h.
Further, the volume ratio of the argon gas to the hydrogen gas is (1:1) - (1: 10).
In a further scheme, the volume ratio of the argon to the hydrogen is optimized to be 1: 3.
In a further scheme, the reaction temperature is 1550 ℃ and the temperature is kept for 1.5 h.
Further, argon/hydrogen mixed gas is used as protective gas, methyltrichlorosilane is provided in a gas carrying mode, and carrying gas is added into the reactor in a bubbling mode. The bubbling mode can ensure that the gas phase is highly dispersed in the liquid phase, increase the deposition contact area and improve the efficiency of mass transfer and heat transfer.
The application of the silicon nitride-based ceramic ball in the field of wear-resistant bearings.
Due to the application of the technical scheme, compared with the prior art, the invention has the following advantages:
1. compared with a silicon nitride ball without a deposited silicon carbide layer, the silicon nitride-based ceramic ball is not easy to corrode and lose weight under the conditions of strong acid, strong base and motion friction, and meanwhile, the interface in contact with the environment of strong acid, strong base is compact pure silicon carbide without a sintering aid, so that the silicon nitride-based ceramic ball has better wear resistance, corrosion resistance and the like, and can be applied to the field of wear-resistant bearings.
2. According to the silicon nitride-based ceramic ball, the difference of the thermal expansion coefficients of the silicon carbide and the silicon nitride is very small, so that the problem that a silicon carbide coating cracks in the cooling process is solved.
3. The silicon carbide layer obtained by the preparation method of the silicon nitride-based ceramic ball has high density, high purity, controllable thickness and high bonding strength with the silicon nitride ceramic ball.
4. According to the preparation method of the silicon nitride-based ceramic ball, silicon nitride can be prepared through liquid phase sintering, the bonding force of the junction of the surface of the silicon nitride-based ceramic ball and silicon carbide sintered through liquid phase sintering is strong, and the reliability of the silicon nitride-based ceramic ball is further improved.
5. The preparation method of the silicon nitride-based ceramic ball has low cost and high production efficiency, and meets the requirements of industrial application.
Detailed Description
In order to make the technical problems, technical solutions and advantageous effects to be solved by the present invention more clearly apparent, the present invention is further described in detail below with reference to the following embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.