Method for preparing composite powder of nano tungsten carbide-coblt through direct reducition and carbonization

A composite powder and cobalt nanotechnology, which is applied in the field of direct reduction carbonization of tungsten carbide-cobalt nanocomposite powder, can solve the problems of high energy consumption, high cost, uneven mixing of WC and Co, and achieve simple and safe process control. The effect of broad utility

Inactive Publication Date: 2005-01-12
WUHAN UNIV OF TECH
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  • Abstract
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Problems solved by technology

[0010] Among them, methods (1), (2) are traditional methods for preparing ultrafine WC-Co cemented carbide powders, and these methods have disadvantages such as high carbonization temperature, high energy consumption, uneven mixing of WC and Co; method (3) is due to The use of organic polymer compounds and reducing agents has higher requirements for equipment, and it is more difficult to control product purity; methods (4) and (5) are methods for preparing nano-WC-Co composite powders developed in the past ten years, but The cost is high and the process control is difficult; the method (6) has the advantages of low cost and simple process, but due to the use of pure hydrogen atmosphere, the carbon content is not easy to control, and the effect of the reaction product water makes the carbonized particles easy to aggregate for a long time. Big

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  • Method for preparing composite powder of nano tungsten carbide-coblt through direct reducition and carbonization

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Comparison scheme
Effect test

Embodiment 1

[0040] Embodiment 1: ammonium metatungstate AMT ((NH 4 ) 6 (H 2 W 12 o 40 )·4H 2 O), hydrated cobalt nitrate Co(NO 3 ) 2 ·6H 2 The O raw material is miscible in distilled water according to the mass ratio of 2.34:1, and is made into composite oxide powder through spray pyrolysis. The composite powder and carbon powder were weighed according to the mass ratio W:C=23:6, Co:C=59:24, put into a ball mill for dry grinding for 120 hours (material: ball=1:2), and the obtained mixed powder was N 2 After carbonization at 950°C for 4 hours in a fixed bed under atmosphere, the temperature was lowered to 600°C, and H 2 Insulated for 4 hours for carbon washing, followed by N 2 It was cooled to room temperature in the atmosphere, thereby preparing WC-10Co composite powder.

Embodiment 2

[0041] Embodiment 2: ammonium paratungstate APT ((NH 4 ) 10 (H 2 W 12 o 42 )·4H 2 O), cobalt acetate hydrate Co(CH 3 COO) 2 4H 2 O, ammonium metavanadate NH 4 VO 3 The raw materials are miscible in distilled water according to the mass ratio of 132:11:1, spray-dried to make composite oxide powder, put it in a vacuum furnace at 200°C for 12 hours, and mix the composite powder and carbon powder according to the mass ratio W: C = 23: 6, Co: C = 59: 24, V: C = 51: 42 Weigh it, put it into a ball mill, and use ethanol as the wet grinding medium for wet grinding for 72 hours (material: ball: liquid = 1: 2:0.5), the powder obtained after drying was carbonized at 800°C for 6 hours in a rotary furnace under Ar atmosphere, cooled to 800°C, and CO 2 and CO mixed gas (CO accounted for 0.3vol%) insulation for 2 hours for carbon washing, followed by N 2 It was cooled to room temperature in the atmosphere, thereby preparing WC-3Co-0.5VC composite powder.

Embodiment 3

[0042] Example 3: 3CoWO 4 ·5WO 3 , cobalt chloride hydrate CoCl 2 ·6H 2 O, Chromium Chloride Hydrate CrCl 3 ·6H 2 O is miscible in distilled water at a weight ratio of 60:100:1, spray-dried to make a composite oxide powder, put it in a microwave oven and burn at 500°C for 0.5 hours, and then mix the composite powder and carbon powder according to the mass ratio W: C = 23: 6, Co: C = 59: 24, Cr: C = 59: 26 Weigh it, put it into a ball mill, and use acetone as the wet grinding medium for wet grinding for 60 hours (material: ball: liquid = 1: 20:10), the powder obtained after drying was in N 2 After carbonization at 800°C for 5 hours in a fluidized furnace under atmosphere, H 2 and CH 4 mixed gas (CH 4 accounted for 0.1vol%), kept in this atmosphere for 2 hours for carbon washing, and then cooled to room temperature in Ar atmosphere, thus producing WC-40Co-0.3Cr 3 C 2 Composite powder.

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Abstract

WC-CO nm composite powder is prepared by one of the three ways: 1. W-CO raw material, crystal depressor and carbon powder are mixed in proportion to be milled to mixed powder of the oxide and carbon 2. The W-CO raw material, crystal depressor are processed to oxide powder by a compound technology then to be mixed with carbon powder to be milled to a mixed powder of the oxide and carbon 3. W-CO raw material, crystal depressor and soluble carbon oxide powder with carbon by a compound technology which refers to spray pyrolytic decomposition, spray drying and spray burning. The nm WC-CO composite powder is got by putting the oxide powder in a reacting furnace, controlling temperature of recovery carburization and time and washing carbon temperature and time.

Description

technical field [0001] The invention relates to a method for preparing tungsten carbide-cobalt nano composite powder by direct reduction carbonization. Background technique [0002] Tungsten carbide-cobalt (WC-Co) cemented carbide with ultrafine / nano grains has the "double high" performance of high hardness and high strength. It is mainly used to make micro-drills for integrated circuit boards, printing needles for dot-matrix printers, overall hole processing tools, woodworking tools, precision molds, and tools for difficult-to-machine materials. The finer the grains of WC-based cemented carbide, the smaller the defects, the smaller the mean free path of the binder phase such as Co, and the higher the flexural strength and hardness. When other conditions are equal, the WC-based hard alloy Every property of hard alloys—hardness, elastic modulus, wear resistance, compressive strength, etc.—is enhanced as the average particle size of the hard comp...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22C1/05C22C29/08
Inventor 邵刚勤易忠来段兴龙谢济仁张卫丰李佳
Owner WUHAN UNIV OF TECH
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