阅读说明：本技术 一种稀土氧化物强化钨铜基复合材料的制备方法 (Preparation method of rare earth oxide reinforced tungsten-copper-based composite material ) 是由 吴玉程 傅义毅 罗来马 刘家琴 昝祥 朱晓勇 于 2021-08-16 设计创作，主要内容包括：本发明公开了一种稀土氧化物强化钨铜基复合材料的制备方法,包括：将钨酸盐、可溶性稀土盐和草酸溶于水中,再滴加油酸三乙醇胺,加热搅拌至溶液完全蒸发得到前驱体；将前驱体在氢气气氛中进行两步还原；将所得还原产物进行压制,然后置于氢气气氛中烧结；检测所得烧结产物的致密度,将铜置于烧结产物表面在氢气气氛中进行熔渗得到稀土氧化物强化钨铜基复合材料。本发明采用湿化学法掺入的Y-(2)O-(3)使得还原后的W晶粒在烧结骨架过程中较细小,降低烧结活化能,在较低温度下获得孔隙率较小的骨架；同时Y-(2)O-(3)阻碍了晶界扩散,使得W晶粒不会过度长大而破坏骨架多孔结构,为后续获得低铜含量、均匀致密的复合材料奠定了基础。(The invention discloses a preparation method of a rare earth oxide reinforced tungsten-copper-based composite material, which comprises the following steps: dissolving tungstate, soluble rare earth salt and oxalic acid in water, dropwise adding triethanolamine oleate, heating and stirring until the solution is completely evaporated to obtain a precursor; carrying out two-step reduction on the precursor in a hydrogen atmosphere; pressing the obtained reduction product, and then sintering in a hydrogen atmosphere; and detecting the density of the obtained sintered product, and putting copper on the surface of the sintered product to perform infiltration in a hydrogen atmosphere to obtain the rare earth oxide reinforced tungsten-copper-based composite material. The invention adopts a wet chemical method to dope Y 2 O 3 So that the reduced W crystal grains are finer in the process of sintering the framework, and the sintering activity is reducedEnergy conversion, namely obtaining a framework with low porosity at a lower temperature; at the same time Y 2 O 3 The grain boundary diffusion is hindered, so that W grains do not excessively grow to damage the porous structure of the framework, and a foundation is laid for obtaining a uniform and compact composite material with low copper content subsequently.)

1. The preparation method of the rare earth oxide reinforced tungsten-copper-based composite material is characterized by comprising the following steps of:

step 1, dissolving tungstate, soluble rare earth salt and oxalic acid in water, then dropwise adding triethanolamine oleate, and heating and stirring until the solution is completely evaporated to obtain a precursor;

2, carrying out two-step reduction on the precursor in a hydrogen atmosphere;

step 3, pressing the reduction product obtained in the step 2, and then sintering in a hydrogen atmosphere;

step 4, detecting the density of the sintered product obtained in the step 3, and putting copper on the surface of the sintered product to perform infiltration in a hydrogen atmosphere to obtain a rare earth oxide reinforced tungsten-copper-based composite material; the infiltration temperature is 1350-.

2. The method for preparing a rare earth oxide reinforced tungsten-copper-based composite material according to claim 1, wherein in the step 1, the tungstate is ammonium metatungstate, ammonium paratungstate or ammonium tungstate, and the soluble rare earth salt is a nitrate, oxalate, carbonate, chloride or sulfate of at least one of yttrium, lanthanum and cerium.

3. The method for preparing the rare earth oxide reinforced tungsten-copper-based composite material according to claim 1, wherein in the step 1, the tungstate is ammonium metatungstate, the soluble rare earth salt is yttrium nitrate hexahydrate, the oxalic acid is oxalic acid dihydrate, and the mass ratio of the yttrium nitrate hexahydrate, the oxalic acid dihydrate, triethanolamine oleate to the ammonium metatungstate is 1.2-1.4: 38-40: 5.5-6.5: 100.

4. the method for preparing the rare earth oxide reinforced tungsten-copper-based composite material according to claim 1, wherein the specific operation of the two-step reduction in the step 2 is as follows: heating to 550 ℃ and 600 ℃, and preserving the heat for 50-60 minutes; the temperature is continuously increased to 750 ℃ and 800 ℃, the temperature is maintained for 110 minutes and 120 minutes, and the temperature is reduced to the room temperature.

5. The method for preparing the rare earth oxide reinforced tungsten-copper-based composite material according to claim 1, wherein in the step 3, the sintering is performed as follows: raising the temperature to 1380-1450 ℃, preserving the temperature for 120-130min, and then cooling to room temperature.

Technical Field

The invention relates to the technical field of tungsten-copper-based composite materials, in particular to a preparation method of a rare earth oxide reinforced tungsten-copper-based composite material.

Background

Today, as modern industry develops at a high speed, electronic packaging materials realize protection of chips, CPUs (central processing units) and large-scale circuits, the packaging materials can protect components from physical damage and corrosion of harmful gases, and meanwhile, high thermal conductivity ensures heat dissipation of electronic elements. Because the electronic packaging material plays a role in heat dissipation and matrix protection, it is critical to improve the thermal conductivity and hardness of the electronic packaging material, and secondly, in order to prevent the stress generated between the packaging material and the matrix due to too large difference of expansion coefficients during operation, the thermal expansion coefficient of the packaging material is also required correspondingly.

The tungsten-copper composite material integrates the high strength and low thermal expansion of tungsten and the high thermal conductivity of copper, so that the tungsten-copper composite material has better electronic packaging comprehensive performance, and the effect of controlling the thermal expansion coefficient of the tungsten-copper composite material can be achieved by changing the copper amount. However, the tungsten-copper composite material still has some problems in application, namely, the wettability of the tungsten-copper composite material is poor, so that the compactness of the composite material is difficult to improve.

Disclosure of Invention

The invention aims to solve the defects in the prior art and provides a preparation method of a rare earth oxide reinforced tungsten-copper-based composite material. The invention adopts a wet chemical method to prepare W-Y₂O₃Preparing W-Cu-Y by sintering composite powder and infiltrating copper into skeleton₂O₃A composite material. Y incorporated by wet-chemical methods₂O₃The reduced W crystal grains are finer in the process of sintering the framework, the sintering activation energy is reduced, and the framework with lower porosity is obtained at lower temperature; at the same time Y₂O₃The grain boundary diffusion is hindered, so that W grains do not excessively grow to damage the porous structure of the framework, and a foundation is laid for obtaining a uniform and compact composite material with low copper content subsequently.

The invention provides a preparation method of a rare earth oxide reinforced tungsten-copper-based composite material, which comprises the following steps:

step 1: precursor preparation

Respectively mixing ammonium metatungstate (AMT, Aladdin, purity is more than or equal to 99.95%), yttrium nitrate (Y (NO3)₃·6H₂O, Aladdin with purity not less than 99.5 percent) and oxalic acid (C)₂H₂O₄·2H₂O, analytical grade) was dissolved in deionized water to make a solution; mixing the above solutions, and adding triethanolamine oleate (C) dropwise₁₆H₂₂N₄O₃And the purity is 99 percent), heating and stirring are carried out until the solution is completely evaporated, the obtained precipitate is a precursor, and the precursor is placed in a vacuum drying oven to be dried and then taken out.

(NH₄)₆H₂W₁₂O₄₀＝6NH₄++2H⁺+W₁₂O₄₀ ^8- (1)

2Y³⁺+2H⁺+W₁₂O₄₀ ^8-＝9WO₃↓+Y₂(WO₄)₃↓+H₂O (2)

(NH₄)₆H₂W₁₂O₄₀·xH₂O+2Y(NO₃)₃→6NH₃↑+6HNO₃↑+9WO₃·mH₂O↓+Y₂(WO₄)₃·nH₂O↓+H₂O (3)

The invention adopts ammonium metatungstate as a tungsten source, yttrium nitrate as an yttrium source, oxalic acid as a precipitator and triethanolamine oleate as a dispersant, and the above reaction is carried out in a mixed solution.

The solubility of ammonium metatungstate in water is high, which is beneficial to the generation of liquid phase reaction; yttrium nitrate reaction product HNO₃The material is volatile, and N as an impurity is easier to remove than S and the like; oxalic acid providing hydrogen ions to promote Y in solution³⁺Reaction precipitation, and meanwhile, the danger of oxalic acid is low; the triethanolamine oleate serving as a nonionic surfactant has strong stability in acidic and alkaline media and excellent dispersing performance, and can ensure that Y generated in a mixed solution₂(WO4)₃The suspension particles are dispersed and distributed, so that the reduced composite powder is more uniform.

In the step 1, the addition amounts of yttrium nitrate, oxalic acid and triethanolamine oleate are respectively 1.2-1.4%, 38-40% and 6% of the mass of ammonium metatungstate.

Step 2: reduction of

Fully grinding the precursor obtained in the step 1 in a mortar, and then putting the ground precursor into a tube furnace to perform two-step reduction under a hydrogen atmosphere: firstly, the temperature is raised to 550-600 ℃, the temperature is preserved for 50-60 minutes, then the temperature is raised to 750-800 ℃, the temperature is preserved for 110-120 minutes, and finally the temperature is reduced to room temperature, wherein the purity of hydrogen is more than or equal to 99.999 percent in the reduction process.

Y in the precursor powder₂(WO₄)₃And residual oxalic acid is thermally decomposed during the temperature rise to generate WO₃、H₂O、CO₂The higher the reduction temperature is, the more the tungsten oxide and the water vapor can be promoted to form volatile hydrate, and the tungsten powder particles and the low-valence tungsten oxide are reduced on the surfaces of the reduced tungsten powder particles and the low-valence tungsten oxide, so that the original particles are coarse, and the lower reduction temperature is needed for preparing the fine tungsten powder particles; at the same time due to WO₃Has volatility of WO₂Large, first stage reduction (WO)₃→WO₂) Using a lower reduction temperature, followed by reduction in a second stage (WO)₂→ W) higher reduction temperatures were used.

And step 3: sintering

Reducing the W-Y obtained in the step 2₂O₃Pressing the composite powder into a green body by a steel die, and then placing the green body in a tube furnace in H₂Raising the temperature to 1380-1450 ℃ in the atmosphere, preserving the heat at 1380-1450 ℃ for 120-130min, and then cooling to room temperature to obtain the framework with certain density.

Because the superfine W powder has large specific surface area, a large amount of impurity gas molecules are adsorbed on the surface of the superfine W powder, and the superfine W powder is used for preventing the superfine W powder from producing the internal components of the porous tungsten framework in the sintering processWithout influence, using H₂And sintering in the atmosphere.

And 4, step 4: infiltration by infiltration

Measuring the density of the framework obtained in the step 3, placing Cu with corresponding mass on the framework for infiltration, wherein the infiltration process is carried out in a hydrogen atmosphere of a tubular furnace, the temperature is firstly increased to 1350-₂O₃A composite material.

The research shows that the rare earth oxide can refine grains and strengthen the material. When the invention adopts the infiltration method to prepare the rare earth oxide doped tungsten-copper composite material, Y₂O₃The particles prevent W framework grains from becoming coarse and blocking pores, so that the Cu liquid is ensured to permeate into the framework under the action of developed capillary, and the composite material obtains higher density and uniform tissue structure.

The invention has the beneficial effects that:

the wet chemical method of the invention is used for preparing W-Y₂O₃Precursor of Y³⁺Uniformly dispersing in tungsten compound, reducing, sintering, and infiltrating to obtain W-Cu-Y₂O₃In the composite material, Y₂O₃The tungsten-copper composite material is uniformly distributed at the tungsten matrix and the tungsten-copper crystal boundary, so that the crystal boundary movement is hindered, the thermal expansion coefficient of the composite material is reduced, and the density of the composite material is improved.

With W-10Cu-Y₂O₃For example, the compactness can reach more than 99 percent, and the thermal conductivity reaches 199W/(m.K), which is better than that of commercial W-10Cu (the thermal conductivity is about 180W/(m.K)).

Drawings

FIG. 1 shows W-10Cu-Y obtained in example 1₂O₃Electron microscope scanning of the composite fracture.

FIG. 2 shows W-10Cu-Y obtained in example 1₂O₃Thermal conductivity profile of the composite.

FIG. 3 shows W-10Cu-Y obtained in example 1₂O₃Graph of coefficient of thermal expansion of the composite material.

Detailed Description

The present invention will be further illustrated with reference to the following specific examples.

Example 1

The preparation method of the rare earth oxide reinforced W-Cu based composite material in the embodiment is as follows:

1. precursor preparation

Respectively mixing ammonium metatungstate (AMT, Aladdin, purity is more than or equal to 99.95%) and yttrium nitrate (Y (NO)₃)₃·6H₂O, Aladdin with purity not less than 99.5 percent) and oxalic acid (C)₂H₂O₄·2H₂O, analytical grade) was dissolved in deionized water to make a solution. Mixing the above solutions, and adding triethanolamine oleate (C) dropwise₁₆H₂₂N₄O₃Purity 99%), heating and stirring until the solution is completely evaporated.

Wherein the addition amounts of yttrium nitrate, oxalic acid and triethanolamine oleate are respectively 1.2%, 38% and 6% of the mass of ammonium metatungstate.

2. Reduction of

And (3) fully grinding the precursor dried in the step (1) in a mortar, then putting the ground precursor into a tube furnace, and carrying out two-step reduction in a hydrogen atmosphere, wherein the hydrogen purity is more than or equal to 99.999%. In the reduction process, firstly, the temperature is raised to 600 ℃, and the temperature is kept for 60 minutes; then the temperature is raised to 800 ℃ and the temperature is kept for 120 minutes.

3. Sintering

Reducing the W-Y obtained in the step 2₂O₃Pressing the composite powder into a green body by a steel die, and then placing the green body in a tube furnace in H₂Raising the temperature to 1380 ℃ in the atmosphere, sintering at 1380 ℃ for 120min, and then cooling to room temperature to obtain the skeleton with certain density.

4. Infiltration by infiltration

Measuring the density of the skeleton obtained in the step 3, putting Cu with corresponding mass on the skeleton for infiltration, wherein the infiltration process is carried out in a tubular furnace under hydrogen atmosphere, firstly, the temperature is increased to 1350 ℃, the infiltration is carried out for 120min at 1350 ℃, and then, the temperature is reduced to room temperature to obtain compact W-10Cu-Y₂O₃A composite material.

The W-10Cu-Y obtained in this example was used₂O₃The fracture of the composite material was subjected to electron microscope scanning, and the result is shown in fig. 1. As can be seen from fig. 1: obtained W-10Cu-Y₂O₃The composite material is compact, has no pores, and has a continuous and uniform Cu network wrapping W grains inside, and Y₂O₃The particles are distributed inside the W grains and at the grain boundaries.

W-10Cu-Y obtained according to this example₂O₃The thermal conductivity of the composite material at different temperatures was plotted as a thermal conductivity curve, as shown in figure 2. As can be seen from fig. 2: w-10Cu-Y₂O₃The thermal conductivity of the composite material at normal temperature is 199W/(m.K), which is better than that of commercial W-10Cu (the thermal conductivity is about 180W/(m.K)).

W-10Cu-Y obtained according to this example₂O₃The coefficient of thermal expansion of the composite material at different temperatures is plotted as shown in figure 3. As can be seen from fig. 3: with increasing temperature, W-10Cu-Y₂O₃The coefficient of expansion of the composite decreased first and then increased, while the average linear expansion coefficient at 25-300 ℃ was about 5.0 ppm/deg.C, which is better than commercial W-10Cu (average linear expansion coefficient about 6.1 ppm/deg.C).

Example 2

The preparation method of the rare earth oxide reinforced W-Cu based composite material in the embodiment is as follows:

1. precursor preparation

Respectively mixing ammonium metatungstate (AMT, Aladdin, purity is more than or equal to 99.95%) and yttrium nitrate (Y (NO)₃)₃·6H₂O, Aladdin with purity not less than 99.5 percent) and oxalic acid (C)₂H₂O₄·2H₂O, analytical grade) was dissolved in deionized water to make a solution. Mixing the above solutions, and adding triethanolamine oleate (C) dropwise₁₆H₂₂N₄O₃Purity of 99 percent) and heating and stirring until the solution is completely evaporated, wherein the addition amounts of yttrium nitrate, oxalic acid and triethanolamine oleate are respectively 1.3 percent, 39 percent and 6 percent of the mass of the ammonium metatungstate.

2. Reduction of

And (3) fully grinding the precursor dried in the step (1) in a mortar, then putting the ground precursor into a tube furnace, and carrying out two-step reduction in a hydrogen atmosphere, wherein the hydrogen purity is more than or equal to 99.999%. In the reduction process, firstly, the temperature is raised to 580 ℃, and the temperature is kept for 55 minutes; the temperature was then raised to 780 ℃ and held for 115 minutes.

3. Sintering

The W-Y reduced in the step 2₂O₃Pressing the composite powder into a green body by a steel die, and then placing the green body in a tube furnace in H₂Raising the temperature to 1400 ℃ in the atmosphere, preserving the heat at 1400 ℃ for 125min, and then reducing the temperature to room temperature to obtain the skeleton with certain density.

4. Infiltration by infiltration

And (4) measuring the density of the framework obtained in the step (3), and putting Cu with corresponding mass on the framework for infiltration, wherein the infiltration process is carried out in the hydrogen atmosphere of the tube furnace. The temperature is increased to 1360 ℃, infiltration is carried out for 125min at 1360 ℃, and then the temperature is reduced to the room temperature, thus obtaining compact W-9Cu-Y₂O₃A composite material.

W-9Cu-Y obtained in this example₂O₃The thermal conductivity of the composite material is 188W/(m.K).

Example 3

The preparation method of the rare earth oxide reinforced W-Cu based composite material in the embodiment is as follows:

1. precursor preparation

Respectively mixing ammonium metatungstate (AMT, Aladdin, purity is more than or equal to 99.95%) and yttrium nitrate (Y (NO)₃)₃·6H₂O, Aladdin with purity not less than 99.5 percent) and oxalic acid (C)₂H₂O₄·2H₂O, analytical grade) was dissolved in deionized water to make a solution. Mixing the above solutions, and adding triethanolamine oleate (C) dropwise₁₆H₂₂N₄O₃Purity of 99 percent) and heating and stirring until the solution is completely evaporated, wherein the addition amounts of yttrium nitrate, oxalic acid and triethanolamine oleate are respectively 1.4 percent, 40 percent and 6 percent of the mass of the ammonium metatungstate.

2. Reduction of

And (3) fully grinding the precursor dried in the step (1) in a mortar, then putting the ground precursor into a tube furnace, and carrying out two-step reduction in a hydrogen atmosphere, wherein the hydrogen purity is more than or equal to 99.999%. In the reduction process, firstly, the temperature is raised to 550 ℃, and the temperature is kept for 50 minutes; the temperature was then raised to 750 ℃ and held for 110 minutes.

3. Sintering

Reacting the W-Y reduced in step 2₂O₃Pressing the composite powder into a green body by a steel die, and then placing the green body in a tube furnace in H₂Raising the temperature to 1450 ℃ in the atmosphere, preserving the heat for 130min at 1450 ℃, and then reducing the temperature to room temperature to obtain the framework with certain density.

4. Infiltration by infiltration

Measuring the density of the skeleton obtained in the step 3, putting Cu with corresponding mass on the skeleton for infiltration, wherein the infiltration process is carried out in a tubular furnace hydrogen atmosphere, firstly raising the temperature to 1370 ℃, carrying out infiltration for 130min at 1370 ℃, and then reducing the temperature to room temperature to obtain compact W-7Cu-Y₂O₃A composite material.

W-7Cu-Y obtained in this example₂O₃The thermal conductivity of the composite material is 184W/(m.K).

The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art should be considered to be within the technical scope of the present invention, and the technical solutions and the inventive concepts thereof according to the present invention should be equivalent or changed within the scope of the present invention.