Search

CN-121990835-A - Diamond/silicon carbide biphase homogeneous suspension slurry and preparation method thereof

CN121990835ACN 121990835 ACN121990835 ACN 121990835ACN-121990835-A

Abstract

The invention relates to the technical field of ceramic composite material preparation, in particular to diamond/silicon carbide biphase homogeneous suspension slurry and a preparation method thereof. The method comprises the steps of setting the total volume fraction of diamond and silicon carbide in slurry and the volume ratio of the diamond to the silicon carbide according to requirements, preparing water-based suspension according to the set total volume fraction and the volume ratio, measuring Zeta potential of the suspension at different pH values, recording the pH value corresponding to the maximum Zeta potential absolute value as an optimal pH value A, selecting a dispersing agent according to the optimal pH value A, adding the dispersing agent into the suspension, determining the optimal adding amount of the dispersing agent by taking the approach to the optimal pH value A as a standard, mixing diamond particles, silicon carbide particles, deionized water and the dispersing agent in proportion, and carrying out dispersion treatment to obtain the diamond/silicon carbide biphase homogeneous suspension slurry. The method has the advantages that the proportion and distribution of the two phases can be accurately regulated and controlled, the slurry has low viscosity and good stability, and the method is suitable for various forming processes.

Inventors

  • ZHU WANLI
  • ZHANG GE
  • BAO JIANXUN
  • CUI CONGCONG
  • GUO CONGHUI

Assignees

  • 中国科学院长春光学精密机械与物理研究所

Dates

Publication Date
20260508
Application Date
20260324

Claims (9)

  1. 1. The preparation method of the diamond/silicon carbide biphase homogeneous suspension slurry is characterized by comprising the following steps: s1, setting the total volume fraction of diamond and silicon carbide in slurry and the volume ratio of diamond to silicon carbide according to requirements; S2, preparing a water-based suspension according to a set total volume fraction and a set volume ratio, measuring Zeta potentials of the water-based suspension under different pH values, and recording the pH value corresponding to the maximum Zeta potential absolute value as an optimal pH value A; S3, selecting a dispersing agent according to the optimal pH value A, adding the dispersing agent into the suspension, and determining the optimal adding amount of the dispersing agent by taking the system pH value approaching the optimal pH value A as a standard; S4, mixing the diamond particles, the silicon carbide particles and deionized water with the dispersing agent determined in the step S3 in proportion, and performing dispersion treatment to obtain the diamond/silicon carbide biphase homogeneous suspension slurry.
  2. 2. The method of preparing a dual-phase homogeneous suspension slurry of diamond and silicon carbide according to claim 1, wherein the total volume fraction of diamond and silicon carbide in the step S1 is 20-70% and the volume ratio of diamond to silicon carbide is 0.1-10.
  3. 3. The method of preparing a dual-phase homogeneous suspension slurry of diamond and silicon carbide according to claim 1, wherein the particle size of the diamond and the silicon carbide is 0.5-100 μm.
  4. 4. The method of preparing a dual-phase homogeneous suspension slurry of diamond and silicon carbide according to claim 3, wherein in said step S1, said diamond and said silicon carbide are hydroxylated by using a silane coupling agent.
  5. 5. The method for preparing a dual-phase homogeneous suspension slurry of diamond/silicon carbide according to claim 1, wherein in the step S3, the dispersant is classified into an acidic dispersant and an alkaline dispersant according to the pH value A; when the optimal pH value A is less than 7, the acid dispersing agent is at least one selected from polyacrylic acid, citric acid, tartaric acid, polymethacrylic acid and polyacrylic acid-maleic anhydride copolymer; When the optimal pH value A is more than 7, the alkaline dispersing agent is at least one selected from tetramethylammonium hydroxide, polyethyleneimine, ammonium polyacrylate, polyethylene glycol, polyvinylpyrrolidone, sodium hydroxide, potassium hydroxide and ammonia water.
  6. 6. The method of preparing a dual-phase homogeneous suspension slurry of diamond/silicon carbide according to claim 1, wherein in the step S4, the dispersion treatment comprises pre-stirring and ball-milling dispersion; The rotation speed of the pre-stirring is 300-500 r/min, and the time is 0.1-0.5 h; The ball milling and dispersing time is 3-12 hours.
  7. 7. The method of preparing a dual-phase homogeneous suspension slurry of diamond/silicon carbide as claimed in claim 1, wherein in the step S4, a molding aid is added according to molding requirements during mixing, and the molding aid comprises at least one of a binder, a plasticizer and a defoaming agent.
  8. 8. A diamond/silicon carbide dual-phase homogeneous suspension slurry is characterized in that the slurry is prepared by adopting the preparation method of the diamond/silicon carbide dual-phase homogeneous suspension slurry in claim 1.
  9. 9. The method of preparing a ceramic composite preform using a diamond/silicon carbide dual phase homogeneous suspension slurry according to claim 9, wherein the slurry is prepared into a green body by slip casting, tape casting, press filtration, 3D printing, or surface coating.

Description

Diamond/silicon carbide biphase homogeneous suspension slurry and preparation method thereof Technical Field The invention relates to the technical field of ceramic composite material preparation, in particular to diamond/silicon carbide biphase homogeneous suspension slurry and a preparation method thereof. Background The diamond/silicon carbide composite material has high specific stiffness and excellent thermal stability, and has become an ideal material in the fields of precision instruments, optical elements, semiconductor equipment and the like. The main stream preparation process is a two-step method of 'preform forming and silicon infiltration densification', wherein wet forming (such as grouting, casting and the like) is suitable for preparing a blank body with complex shape and high uniformity, but the key point is to obtain ceramic suspension with high solid content, low viscosity and good stability. The prior art has focused on the preparation of single phase silicon carbide or diamond suspensions. For example, publication No. CN105645968A, publication No. 2016, 6/8, entitled "preparation method of high-Performance slurry of ultrafine silicon carbide powder" discloses a preparation method of ultrafine silicon carbide slurry with a solid content of 51-55% and a viscosity of 0.01-0.5 Pa.s, publication No. CN111484330A, publication No. 2020, 4/8, entitled "preparation method of diamond-enhanced silicon carbide substrate and electronic product" discloses a preparation method of diamond-cast slurry with a viscosity of about 8000 mPa.s, and diamond-enhanced silicon carbide substrate is obtained by reactive infiltration of silicon. When preparing the diamond/silicon carbide dual-phase composite material, one common process route is to prepare a preform of diamond (containing other carbon sources) first, then densify by silicon infiltration, and react the silicon with the diamond and other carbon sources during the infiltration process to generate a silicon carbide phase, thereby obtaining the diamond/silicon carbide composite material. Although the method is widely applied, the specific structure and content of the silicon carbide phase in the composite material are mainly determined by silicon-carbon reaction in the infiltration process, the accurate regulation and control of the two-phase proportion in the slurry stage are difficult, and the real 'two-phase uniform composite' cannot be realized. Because of large difference of surface properties of diamond and silicon carbide particles, selective agglomeration or phase separation easily occurs in a water-based medium, so that slurry has poor uniformity, high viscosity and insufficient stability. The dispersion scheme of simply superposing two single-phase slurries cannot realize the cooperative stabilization of the two-phase particles, and is difficult to simultaneously meet the process requirements of high solid content and low viscosity. Disclosure of Invention The invention aims to solve the problems and provides a diamond/silicon carbide dual-phase homogeneous suspension slurry and a preparation method thereof. The first aim of the invention is to provide a preparation method of diamond/silicon carbide biphase homogeneous suspension slurry, which comprises the following steps: s1, setting the total volume fraction of diamond and silicon carbide in slurry and the volume ratio of diamond to silicon carbide according to requirements; S2, preparing a water-based suspension according to a set total volume fraction and a set volume ratio, measuring Zeta potentials of the water-based suspension under different pH values, and recording the pH value corresponding to the maximum Zeta potential absolute value as an optimal pH value A; S3, selecting a dispersing agent according to the optimal pH value A, adding the dispersing agent into the suspension, and determining the optimal adding amount of the dispersing agent by taking the system pH value approaching the optimal pH value A as a standard; S4, mixing the diamond particles, the silicon carbide particles and deionized water with the dispersing agent determined in the step S3 in proportion, and performing dispersion treatment to obtain the diamond/silicon carbide biphase homogeneous suspension slurry. Preferably, in the step S1, the total volume fraction of diamond and silicon carbide is 20-70%, and the volume ratio of diamond to silicon carbide is 0.1-10. Preferably, the particle sizes of the diamond and the silicon carbide are 0.5-100 μm. Preferably, in step S1, the diamond and the silicon carbide are subjected to hydroxylation treatment using a silane coupling agent. Preferably, in step S3, the dispersant is classified into an acidic dispersant and a basic dispersant according to the acid-base property of the optimum pH value a; when the optimal pH value A is less than 7, the acid dispersing agent is at least one selected from polyacrylic acid, citric acid, tartaric acid, polymethacrylic acid and polyac