Preparation method for Cu-based composite material based on negative thermal expansion particles

Abstract

The invention relates to a preparation method for a Cu-based composite material based on negative thermal expansion particles. The preparation method is characterized by comprising: carrying out ball milling on raw material powders such as Sc2W3O12 powder and Cu powder according to different ratios, taking out the ball milling tank to dry after completing the ball milling, placing the raw material powders into a mortar to grind so as to obtain mixed powder, filling the mixed powder into a mold, carrying out vibratory compaction, placing the mold on an oil hydraulic press, pressurizing, maintaining the pressure, relieving the pressure, taking the sample out from the mold, sintering by using a vacuum tubular furnace, vacuumizing, then introducing Ar / H2 mixed gas into the furnace so as to be adopted as the protective gas, sintering for 1-4 h at a temperature of 500-900 DEG C, and cooling along with the furnace. According to the present invention, the negative thermal expansion material Sc2W3O12 powder particles are creatively introduced as the composite phase for improving the copper thermal expansion coefficient to regulate the thermal expansion performance of the composite material, such that the method is novel, the preparation process is simple, and the practicality is strong.

Description

technical field [0001] The invention belongs to the technical field of composite functional materials. The negative thermal expansion powder material Sc with stable structure and no pressure phase transition at high temperature has been obtained in the early stage. 2 W 3 o 12 On the basis of Cu-based Sc prepared by powder metallurgy 2 W 3 o 12 composite material. Background technique [0002] With the development of science and technology, higher and higher requirements are put forward for material properties; taking electronic packaging materials as an example, metal Cu has been widely used due to its high thermal conductivity, high electrical conductivity and good processability. However, due to semiconductor The packaging density of integrated circuits is increasing, requiring packaging materials not only to have sufficient strength and rigidity to support and protect the chip, but also to have a low coefficient of thermal expansion (CTE), making it compatible with c...

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Problems solved by technology

[0002] With the development of science and technology, higher and higher requirements are put forward for material properties; taking electronic packaging materials as an example, metal Cu has been widely used due to its high thermal conductivity, high electrical conductivity and good processability. However, due to semiconductor The packaging density of integrated circuits is increasing, requiring packaging materials not only to have sufficient strength and rigidity to support and protect the chip, but also to have a low coefficient of thermal expansion (CTE), making it compatible with chips such as Si or GaAs. It needs to be matched with each other, and it must have a high thermal conductivity, which can dissipate the heat generated by the semiconductor chip in time, so the research and development of low-expansion copper-based composite materials has always been a hot research direction; a series of low-expansion copper-based composite materials have been developed at home and abroad. The composite research of positive thermal expansion materials such as W, Mo, SiC, diamond and other powders and Cu and Al has made some progress one after another. The American SCM company composited W, Mo and Cu. Although it maintains a high thermal conductivity, the CTE Values ​​are still above 10.0×10 -6 / K; In the 1990s, Texas Instruments of the United States developed a composite material called Cuvar with controllable expansion and high thermal conductivity. Adding low-expansion alloy Invar to Cu, the CTE value was reduced to 0.4×10 -6 / K, but the thermal conductivity is very low, only 11.0W / m·K; later, the researchers combined carbon fiber with Cu, but due to the anisotropy of carbon fiber properties, the composite material has a high performance in the parallel direction and vertical direction of carbon fiber. The difference is very large; in recent years, high volume ratio SiC particle reinforced Cu composites have been widely studied, which have high thermal conductivity and adjustable low expansion characteristics, but due to the SiC particle volume fraction as high as 55%, making the preparation difficult and It is difficult to ensure the uniform dispersion of particles, and the resulting composite material is brittle and hard, and it is difficult to achieve secondary machining; in 2002, the United States and Japan successively proposed a copper-diamond composite material called Dymalloy, due to the excellent thermal conductivity of diamond , the thermal conductivity of the composite material at 25-200°C is as high as 600.0 W / m·K, and the CTE is 5.5-6.5×10 -6 / K, but the filling amount of diamond is also as high as 55%, and the interface thermal resistance and molding process become the bottleneck restricting the development of this material; in order to reduce the thermal expansion coefficient of the metal matrix, a sufficient amount of low-expansion powder must be added, and the composite powder The composite powder Addition will inevitably sacrifice part of the thermal conductivity of the metal matrix and reduce its machinability. Coordinating and solving this contradiction has become a research hotspot in this direction. How to achieve low expansion, high thermal conductivity, and Performance stability and processability are the key issues to solve the practical application of this type of material; the discovery of negative thermal expansion materials provides the possibility to solve such problems. Verdon and Dunand of the Massachusetts Institute of Technology envisage the use of Cu's high thermal conductivity and ZrW 2 o 8 The negative thermal expansion (NTE) characteristics of the development of low-expansion or even zero-expansion Cu-based composite materials, it was found that due to ZrW 2 o 8 Extremely narrow stable range (1378~1560K) and pressure phase transition at lower pressure (0.2GPa), ZrW occurs in composite materials obtained by vacuum sintering or hot isostatic pressing 2 o 8 If the NTE particles with stable structure at high temperature and no pressure phase transition are used as the composite phase, Cu-based composite materials with low expansion and high thermal conductivity can be obtained, Sc 2 W 3 o 12 The material not only has good negative thermal expansion performance (-6~-11×10 -6 / K), and the structure is stable at high temperature, there is no phase transition and no decomposition from room temperature to 1200 ° C, although there is a pressure phase transition, but the required pressure is relatively high (2.7G); therefore, the present invention uses Sc 2 W 3 o 12 Based on powder materials, powder metallurgy is used to realize the design, preparation and performance control of low thermal expansion copper matrix composites

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