阅读说明：本技术 WC-6Co-石墨自润滑硬质合金制备方法 (Preparation method of WC-6 Co-graphite self-lubricating hard alloy ) 是由 张建军 韦学龙 刘靠斌 梁炳亮 陈卫华 何文 欧阳晟 艾云龙 于 2020-07-09 设计创作，主要内容包括：本发明涉及一种WC-6Co-石墨自润滑硬质合金制备方法,WC-Co-石墨复合材料由高能球磨后细化的WC,纯Co粉和石墨球高能球磨混合形成,所得复合材料的石墨为石墨球在球磨时切削片,球磨介质为水或酒精,球磨混合一定时间后取出,并烘干、过筛以及造粒后使用一定压力的冷压成型和冷等静压。将压制好的胚体置于微波炉中烧结,采用一定的升温速率使得胚体达到一定温度后保温,烧结完毕后随炉冷却。本发明制备WC-6Co-石墨自润滑硬质合金制备方法,目的是为目的是为了增加WC-Co自润滑,从而提高硬质合金复合材料的磨损能力,本发明制备过程中无污染,低耗能,该高熵合金基复合材料可广泛应用于航空飞行器的高温结构件和耐腐蚀件,前景广阔。(The invention relates to a method for preparing WC-6 Co-graphite self-lubricating hard alloy, wherein a WC-Co-graphite composite material is formed by high-energy ball milling refined WC, pure Co powder and graphite spheres, the high-energy ball milling is carried out to mix, the graphite of the obtained composite material is cutting pieces of the graphite spheres during ball milling, a ball milling medium is water or alcohol, the graphite is taken out after ball milling and mixing for a certain time, and cold press molding and cold isostatic pressing are carried out after drying, sieving and granulation by using a certain pressure. And (3) sintering the pressed blank in a microwave oven, keeping the temperature of the blank after the blank reaches a certain temperature at a certain heating rate, and cooling the blank along with the oven after sintering. The invention discloses a preparation method of WC-6 Co-graphite self-lubricating hard alloy, aiming at increasing WC-Co self-lubricating so as to improve the wear capacity of a hard alloy composite material.)

1. A preparation method of WC-6 Co-graphite self-lubricating hard alloy is characterized by comprising the following specific steps:

(1) adding absolute ethyl alcohol into a ball milling tank by adopting a wet milling method, calculating WC fine powder and high-purity Co powder according to the proportion, and pouring the weighed raw materials and graphite balls into the ball milling tank;

(2) drying the ball-milled composite powder in a drying box, taking out graphite spheres, shaking the powder on the surfaces of the graphite spheres by using an ultrasonic cleaning machine, drying, weighing the mass of the graphite spheres, supplementing a proper amount of WC fine powder and high-purity Co powder according to a ratio, and mixing the powder;

(3) the obtained mixed powder is dried, sieved and granulated, and then is subjected to cold press molding and cold isostatic pressing under certain pressure. Placing the pressed blank in a microwave sintering furnace, and keeping the temperature of the blank after the blank reaches a certain temperature through a certain heating rate;

(4) through the steps, the WC-6 Co-graphite self-lubricating hard alloy with uniformly distributed graphite sheets can be obtained.

2. The method for preparing WC-6 Co-graphite self-lubricating hard alloy as recited in claim 1, wherein the graphite of the prepared sample is made of graphite ball cutting scraps in high-energy ball milling.

3. The method for preparing the WC-6 Co-graphite self-lubricating hard alloy as recited in claim 1, wherein the method comprises the following steps: the ball milling speed is 100-.

4. The method for preparing WC-6 Co-graphite self-lubricating hard alloy according to claim 1, wherein the method comprises the following steps: the sintering equipment is a microwave sintering furnace.

5. The method for preparing WC-6 Co-graphite self-lubricating hard alloy according to claim 1, wherein the method comprises the following steps: the heating rate is 5-20 ℃/min, the sintering temperature is 1400-1700 ℃, the heat preservation time is 15-60 min, and the sintering atmosphere is vacuum or argon atmosphere.

Technical Field

The invention relates to the technical field of metal ceramic composite material preparation, in particular to a preparation method of WC-6 Co-graphite self-lubricating hard alloy.

Background

The WC-based hard alloy and the pure WC hard alloy have high hardness and excellent wear resistance, oxidation resistance and corrosion resistance, but the melting point of WC reaches 2900 ℃, the fine non-bonding-phase WC hard alloy is obtained by the SPS sintering technology, and the hardness and the fracture toughness respectively reach 2600HV10 and 3-4 MPa.m^1/2The WC-Co hard alloy is the hard alloy which is most widely applied in recent decades, Co has excellent toughness and plasticity, the wettability between Co and WC is very good, and the WC can reach full compactness, meanwhile, compared with WC, the melting point of Co is lower (1475 ℃), liquid phase sintering can be realized at lower temperature, and the WC-Co hard alloy has higher hardness, moderate toughness and excellent comprehensive performance.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: graphite spheres are cut by the hard alloy spheres during high-energy ball milling to obtain flake graphite, so that the graphite is uniformly distributed in WC-Co, and the purpose is to increase WC-Co self-lubrication and improve the wear capacity of the hard alloy composite material. The hard alloy has the characteristics of high melting point, high strength, high hardness, high wear resistance and the like.

The technical scheme of the invention is as follows:

the invention relates to a method for preparing WC-6 Co-graphite self-lubricating hard alloy, which adopts a powder metallurgy-microwave sintering method for in-situ preparation and specifically comprises the following steps:

(1) the wet milling method adopted in the experiment is that absolute ethyl alcohol is added into a ball milling tank, WC fine powder and high-purity Co powder are calculated according to the proportion, and the weighed raw materials and graphite balls are poured into the ball milling tank together.

(2) Drying the ball-milled composite powder in a drying box, taking out the graphite spheres, shaking the powder on the surfaces of the graphite spheres by using an ultrasonic cleaning machine, drying, weighing the mass of the graphite spheres, supplementing a proper amount of WC fine powder and high-purity Co powder according to the proportion, and mixing the powder.

(3) The obtained mixed powder is dried, sieved and granulated, and then is subjected to cold press molding and cold isostatic pressing under certain pressure. And (3) placing the pressed blank in a microwave sintering furnace, and keeping the blank at a certain temperature through a certain heating rate.

(4) Through the steps, the WC-6 Co-graphite self-lubricating hard alloy with uniformly distributed graphite sheets can be obtained.

Preferably, the WC powder refined after ball milling accounts for WC fine powder, high-purity Co powder and graphite nodule according to the proportion.

Preferably, the graphite of the prepared sample is formed by cutting scraps of graphite spheres during high-energy ball milling.

Preferably, the ball milling speed is 100-.

Preferably, the sintering equipment is a microwave sintering furnace.

Preferably, the heating rate is 5-20 ℃/min, the sintering temperature is 1400-1700 ℃, the heat preservation time is 15-60 min, and the sintering atmosphere is vacuum or argon atmosphere.

The WC-Co hard alloy has higher hardness and moderate toughness and shows excellent comprehensive performance, and hard alloy materials with different hardness and toughness combinations can be prepared according to different use requirements by changing the proportion of hard phase WC and binder phase Co, changing the grain size and other parameters of the hard phase WC, and the invention uses the hard alloy balls to cut the graphite balls to obtain flake graphite when carrying out high-energy ball milling, so that the graphite is uniformly distributed in the WC-Co, the self-lubrication is increased, the wear resistance of the hard alloy composite material is improved, and the service life of a cutter is prolonged.

(1) The powder metallurgy-microwave sintering technology is adopted, so that the cost is reduced, no pollution is caused, and the heating speed is high.

(2) Graphite spheres are cut by hard alloy spheres during high-energy ball milling to obtain flake graphite, so that the graphite is uniformly distributed.

(3) The WC-6 Co-graphite self-lubricating hard alloy composite material prepared can ensure higher lubricity and prolong the service life of the composite material.

Drawings

FIG. 1 is an XRD pattern of a sample of a WC-6 Co-graphite self-lubricating cemented carbide composite prepared by microwave sintering of example 1;

FIG. 2 is a surface SEM image of a WC-6 Co-graphite self-lubricating cemented carbide composite material prepared by microwave sintering of example 1;

FIG. 3 is a friction coefficient chart of the WC-6 Co-graphite self-lubricating cemented carbide composite material prepared in situ by microwave sintering in example 1.

Detailed Description

The invention is explained in more detail below by means of specific embodiments and figures, but the following detailed description is only exemplary and not restrictive, and the technical features or combinations of technical features described in the embodiments should not be considered in isolation, but they can be combined with one another to achieve better technical features.