CN-121976079-A - Low-cost preparation method of WC-Co alloy

Abstract

The invention discloses a low-cost preparation method of WC-Co alloy, and belongs to the technical field of hard alloy. The method comprises the steps of wet grinding, mixing and drying tungsten carbide powder and cobalt powder to obtain mixed powder, dispersing the mixed powder in an additive aqueous solution to prepare WC-Co water-based slurry with the solid phase content of 89-92 wt%, printing and forming the obtained slurry by adopting a direct-writing type 3D printer at room temperature to obtain a WC-Co composite material green body, degreasing and sintering the green body to obtain the WC-Co alloy. The invention adopts a water-based system, has low consumption of dispersing agent and environmental protection, the prepared slurry has high solid content and good rheological property, is suitable for direct-writing 3D printing, the density of the obtained WC-Co alloy is more than 98 percent, the Vickers hardness is higher than 1800HV 30 , and the invention has simple process, low equipment and raw material cost, can realize the efficient forming of WC-Co alloy components with complex shapes, and has good application prospect in the field of carbide additive manufacturing.

Inventors

• LU YINGWEI
• LI XIAOFEI

Assignees

• 合肥工业大学

Dates

Publication Date

20260505

Application Date

20260309

Claims (6)

1. 1. A low cost method for preparing WC-Co alloy comprising the steps of: (1) Preparing WC-Co water-based slurry, namely wet-milling and mixing tungsten carbide powder and cobalt powder, drying to obtain mixed powder, dispersing the mixed powder in an additive water solution to prepare WC-Co water-based slurry with the solid phase content of 89-92 wt%, wherein the additive water solution is a mixed water solution of ammonium citrate and polyethylene glycol, the mass ratio of the ammonium citrate to the polyethylene glycol is 1-5:1, and the total mass percentage of the ammonium citrate to the polyethylene glycol in the WC-Co water-based slurry is 1-1.2 wt%; (2) 3D printing and forming, namely printing and forming the WC-Co water-based slurry prepared in the step (1) by using a direct-writing type 3D printer at room temperature to obtain a WC-Co composite material green body with a required shape; (3) Degreasing and sintering, namely degreasing and sintering the WC-Co composite material green body to obtain the WC-Co alloy.
2. 2. The method for preparing the WC-Co alloy with low cost according to claim 1, wherein in the step (1), the mass percentage of the tungsten carbide powder to the cobalt powder is 80% -96%, and the mass percentage is 20% -4%.
3. 3. The method for preparing WC-Co alloy at low cost according to claim 1, wherein in the step (1), absolute ethyl alcohol is used as a medium for wet milling, and the wet milling mixing time is 10-12 hours.
4. 4. The method for preparing WC-Co alloy at low cost according to claim 1, wherein in the step (1), the drying temperature is 60-80 ℃ and the drying time is 8-10 hours.
5. 5. The method of manufacturing a WC-Co alloy at low cost according to claim 1, wherein in the step (1), the mixed powder is dispersed in the aqueous additive solution at room temperature.
6. 6. A WC-Co alloy, characterized in that it is produced by the low-cost production method of a WC-Co alloy as set forth in any one of claims 1 to 6.

Description

Low-cost preparation method of WC-Co alloy Technical Field The invention relates to the field of hard alloy, in particular to a low-cost preparation method of WC-Co alloy. Background The hard alloy has excellent mechanical property and wear resistance, and is widely applied to a plurality of fields such as machining, mining, aerospace and the like. The traditional hard alloy forming process is developed and mature, but when the parts with complex structures are prepared, the problems of high mold design and manufacturing cost, complex subsequent precision machining procedures, great difficulty, serious material waste and the like exist, and the requirements of high-efficiency and low-cost preparation of complex components are difficult to meet. The rise of additive manufacturing technology provides a new path for preparing complex hard alloy components, can realize the direct forming without a mould, and effectively solves the defects of the traditional forming process. At present, additive manufacturing of WC-Co alloy is mainly divided into two types of technical routes, namely a powder melting technology based on hot forming, wherein the technology has the defects of rapid cooling and rapid heating in the forming process, a large temperature gradient, easy introduction of brittle phases, pores, cracks and the like in a formed part, influences the quality of products, and meanwhile, the technology has the advantages of large equipment investment, high energy consumption, low powder utilization rate and further increases the preparation cost. The other is a forming-degreasing-sintering technology based on cold forming, wherein the direct writing forming process is an important development direction of WC-Co alloy additive manufacturing because powder spreading is not needed, the equipment structure is relatively simple, the cost is low, and a high-density hard alloy product can be prepared after subsequent degreasing and sintering treatment. The core difficulty of the technology is that the slurry meeting the requirements of direct writing forming is prepared, and the forming precision and the subsequent sintering quality can be ensured only by simultaneously having high solid phase content, good stability and proper fluidity. At present, most of the sizing agents adopted in the forming-degreasing-sintering technology are organic solvent systems, and the sizing agents have the problems of high toxicity, pungent smell, unfriendly environment and the like, and the organic solvents have high cost and are not beneficial to large-scale production. In order to solve the problems, related research is turned to the development of water-based slurry, but in order to optimize rheological property of the existing water-based slurry, more than 1.9wt% of dispersing agent is generally required to be added, so that the slurry preparation cost is still high, low-cost large-scale preparation of WC-Co alloy is difficult to realize, and popularization and application of the technology are limited. Disclosure of Invention The invention aims to overcome the defects of WC-Co alloy preparation and slurry preparation in the prior art, provides a low-cost preparation method of WC-Co alloy, aims to obtain WC-Co water-based slurry with good rheological property and high solid content (more than or equal to 89 wt%) and simultaneously realizes high-efficiency and low-cost preparation of WC-Co alloy, and ensures that the WC-Co alloy obtained after 3D printing, forming and sintering has excellent compactness and hardness. The invention adopts the following technical scheme for realizing the purpose: A low cost method for preparing WC-Co alloy, comprising the following steps: (1) Preparing WC-Co water-based slurry, namely wet-milling and mixing tungsten carbide powder and cobalt powder, and drying to obtain mixed powder, dispersing the mixed powder in an additive aqueous solution, and preparing the WC-Co water-based slurry with the solid phase content of 89-92 wt%; (2) 3D printing and forming, namely printing and forming the WC-Co water-based slurry prepared in the step (1) by using a direct-writing type 3D printer at room temperature to obtain a WC-Co composite material green body with a required shape; (3) Degreasing and sintering, namely degreasing and sintering the WC-Co composite material green body to obtain the WC-Co alloy. In the step (1), the mass percentage of the tungsten carbide powder and the cobalt powder is 80-96% and 20-4% as a preferable scheme. In the step (1), absolute ethyl alcohol is used as a medium for wet grinding, and the wet grinding mixing time is 10-12 hours. In the step (1), the drying temperature is 60-80 ℃ and the drying time is 8-10 hours. As a preferable scheme, the additive aqueous solution in the step (1) is a mixed aqueous solution of Ammonium Citrate (AC) and polyethylene glycol (PEG), wherein the mass ratio of the ammonium citrate to the polyethylene glycol is 1-5:1, and the total mass percentage of t