CN1199101A

CN1199101A - Method for preparation of ceramic/aluminium composite material

Info

Publication number: CN1199101A
Application number: CN 98101295
Authority: CN
Inventors: 冯涤; 韩光炜; 殷明
Original assignee: Central Iron and Steel Research Institute
Current assignee: Central Iron and Steel Research Institute
Priority date: 1998-04-21
Filing date: 1998-04-21
Publication date: 1998-11-18
Anticipated expiration: 2018-04-21
Also published as: CN1061695C

Abstract

A method for preparing co-continuous ceramic/aluminium composite material includes pre-preparing prefabricated ceramic work pieces with 3-D communicated holes, smelting Al alloy containing Mg and Si, immersing the prefabricated ceramic workpieces in molten alloy while introducing inertial gas for protection, heating to 760-1200 deg.C for 1-10 hr,taking the prefabricated ceramic workpieces out, and cooling, and features simple process and non-pressure calorizing.

Description

Method for manufacturing ceramic/aluminum co-continuous composite material

The invention belongs to the field of composite material preparation processes, and is particularly suitable for preparing ceramic/aluminum co-continuous composite materials.

The ceramic/aluminum co-continuous composite material has the high wear resistance, high rigidity and high corrosion resistance of ceramic; but also has good electric conduction and heat conduction performance, high toughness, high thermal shock resistance and low density. The composite material can be widely used for wear-resistant, corrosion-resistant, heat-resistant and expansion-resistant components in the electronic, automobile, aviation, chemical and metallurgical industries. Such as electronic packaging, automobile brake pads, cylinder liners, and parts resistant to mud corrosion.

It has been found that the introduction of a ductile metal phase into the ceramic material results in a substantial increase in toughness, and that toughening is best when the ductile metal is present in a network. The powder metallurgy process for preparing ceramic/metal composite material adopted in the prior art is difficult to ensure that metal and ceramic phases are distributed in a net shape, so that the optimal performance matching of the composite material can not be exerted. In addition, for large-size and complex-shaped components, the powder metallurgy process is difficult to prepare in a near net shape. In recent years, a process for preparing a ceramic/metal composite material by liquid metal infiltration is developed abroad. However, since the wettability of the liquid metal on the surface of the ceramic is low, external pressure is generally used to promote the penetration of the liquid metal into the ceramic particles or fibers to form a composite material. Such as vacuum infiltration processes (phil. trans. r.soc., a294(1980)151) and external pressure-promoted infiltration processes (j. mater. sci.20(1985) 85). However, this process is complicated and difficult to prepare near net shape of large-sized and complex-shaped members. In addition, the prepared composite material has the structure equivalent to that of a ceramic phase reinforced metal matrix composite material because the ceramic phase does not form a network, and does not have the performance of a co-continuous composite material.

The invention aims to provide a method for manufacturing a ceramic/aluminum co-continuous composite material, which has a simple process, can realize that non-pressure liquid aluminum automatically enters three-dimensional communication holes in a ceramic prefabricated member to form the co-continuous composite material, is not limited by the size and the shape of the ceramic prefabricated member, can be formed nearly in a final mode,and does not need subsequent processing.

In order to achieve the above object, the present invention employs a composition containing 0.0 to 10.0 wt% of Mg and 0.0 to 6.0 wt% of SiThe aluminum alloy is used for reducing the viscosity of liquid aluminum, so that the wettability of the liquid aluminum on the surface of the ceramic prefabricated member is increased. Meanwhile, the partial pressure of oxygen in the liquid aluminum is reduced by controlling the gas content of the inert gas or the non-oxidizing gas (argon, nitrogen, etc.) to further improve the wettability of the liquid aluminum. In addition, SiO is added into the ceramic prefabricated member₂Or oxidizing the SiC ceramic prefabricated part at high temperature to form SiO on the inner surface of the hole₂And (3) a membrane. After the ceramic prefabricated member is immersed in the liquid aluminum, the chemical reaction between the liquid and the solid interfaces is generated The speed of liquid aluminum infiltrating into the ceramic prefabricated member under the action of reaction pressure is increased, and the infiltration temperature is further reduced. Adding Mg and Si elements into liquid aluminum; controlling inert or non-oxidizing gas content and in liquidAnd introducing a complex phase chemical reaction into the solid interface, namely realizing the process of automatically permeating pressureless liquid aluminum into the ceramic prefabricated member at 760-1200 ℃ to form the co-continuous composite material.

Firstly, a blank of the ceramic prefabricated member is prepared by adopting the traditional slurry casting or cold pressing method. The density of the interconnected pores in the ceramic prefabricated member can be controlled by adjusting the granularity of ceramic powder, the adding amount of the binder and the pre-sintering temperature and time of a blank of theceramic prefabricated member. The ceramic preform may be made from industrial ceramic (e.g. 75, 95 industrial ceramic) slurry, common chemical ceramic slurry, Al₂O₃SiC or other ceramic powders. 0-20 vol.% SiO can be added to the slurry₂The sintering temperature of the ceramic prefabricated member is reduced to form a communicating hole, and the speed of liquid aluminum permeating into the ceramic prefabricated member is increased.

Combining the above principle and practical operation, the method of the invention is characterized in that: firstly, preparing a ceramic prefabricated member with three-dimensional communicated holes, then increasing the wettability of liquid aluminum on the surface of the ceramic prefabricated member and introducing a complex-phase chemical reaction on a liquid-solid interface to ensure that the liquid aluminum automatically enters the communicated holes in the ceramic prefabricated member under the action of capillary pressure and reaction pressure without pressurization, and forming a ceramic/aluminum co-continuous composite material after the liquid aluminum is cooled to room temperature, wherein the method comprises the following specific steps:

(1) preparing a ceramic preform with three-dimensional communicated holes;

the ceramic prefabricated member can be prepared by adopting a slurry pouring or cold pressing method,

wherein when the slurry casting method is adopted, the granularity of the ceramic powder is 0.2-60 mu m, the binder is clay slurry, PVA polyvinyl alcohol, resin aqueous solution or emulsion aqueous solution, and 0-20 vol% of fused SiO is added into the slurry₂(<30 mu m), preparing a blank, heating to 200-500 ℃, preserving heat for 1-3 hours to remove the adhesive after drying, heating to 1100-1500 ℃, preserving heat for 2-5 hours, and preparing a ceramic prefabricated part with three-dimensional communicated holes;

when cold pressing method is adopted, the granularity of the ceramic powder is 0.2-70 μm, and the adhesive is paraffin wax or PVAPolyvinyl alcohol, resin or latex, 0-20 vol% of molten SiO is added₂(<30 mu m), cold-pressing the mixture into a ceramic prefabricated blank under the pressure of 20-60Mpa after uniformly mixing, then preserving heat for 1-3 hours at the temperature of 200-500 ℃ for removing the adhesive, and then heating the blank to 1100-1500 ℃ for preserving heat for 2-5 hours to prepare a ceramic prefabricated part with three-dimensional communicated holes;

(2) putting an aluminum alloy containing 0.0-10.0 wt% of Mg and 0.0-6.0 wt% of Si into a graphite crucible, putting the graphite crucible into a stainless or heat-resistant steel sleeve capable of controlling the atmosphere, and simultaneously putting the graphite crucible into a box-type or well-type resistance heating furnace for heating;

(3) after the aluminum alloy is melted, the ceramic prefabricated part with the three-dimensional communicated holes prepared in the first step is immersed in aluminum liquid, then inert or non-oxidizing atmosphere (0-800cc/min) is introduced, the temperature of the aluminum liquid is raised to 760-1200 ℃, heat preservation is carried out for 1-10 hours, and finally the ceramic prefabricated part is taken out and cooled to room temperature, so that the ceramic/aluminum co-continuous composite material is obtained.

And then aging treatment of heat preservation at 150-200 ℃ for 2 hours can be carried out to further improve the performance of the connected aluminum network. The heat preservation time of the ceramic prefabricated member in the aluminum liquid can be determined according to the section size of the prefabricated member, the temperature of the liquid aluminum and the components of the aluminum liquid. The holding time is generally proportional to the square of the effective cross-sectional dimension of the ceramic preform and decreases linearly with increasing temperature.

Compared with the existing powder metallurgy process for preparing ceramic/metal composite materials, the composite material prepared by the invention has the toughening effect by virtue of a three-dimensional ductile metal network, and simultaneously does not lose the high rigidity, high wear resistance and high corrosion resistance of a ceramic material; meanwhile, the composite material has high electric conductivity and heat conductivity of metal. In addition, the components with complex shapes can be formed by slurry casting of ceramic preform blanks to approximate the final shape, and the powder metallurgy process has no such advantages. Compared with the process for promoting the liquid metal to permeate by external pressure, the process has simple operation and low cost, and can be used for preparing large-size components with complex shapes in a near net shape; and multiple components can be prepared at one time. The external pressure promotes the liquid metal to infiltrate the process and can only prepare the member with small size and simple shape; in addition, the cost is high and the operation is complex. In addition, in the composite material prepared by the traditional process for promoting the infiltration of the liquid metal by using external pressure, the metal and the ceramic phase do not form a co-continuous organizational structure, so the performance of the composite material is not as high as that of a ceramic/aluminum co-continuous composite material.

Examples

According to the manufacturing method of the ceramic/aluminum co-continuous composite material, 6 batches of tests are carried out, wherein the preparation process of the ceramic prefabricated member with the three-dimensional communicated holes is shown in the table 1, the prepared ceramic prefabricated member is immersed in aluminum alloy for aluminizing to obtain the ceramic/aluminum co-continuous composite material, the preparation process and the performance of the ceramic/aluminum co-continuous composite material are shown in the table 2, and experimental analysis shows that aluminum completely permeates the prefabricated member, the structure is uniform, and the fracture toughness is good.

TABLE 1 preparation Process of ceramic preform with three-dimensional connected pores

TABLE 2 preparation Process and Properties of ceramic/aluminum Co-continuous composites

Claims

1. A method for manufacturing a ceramic/aluminum co-continuous composite material is characterized by comprising the following steps: firstly, preparing a ceramic prefabricated member with three-dimensional communicated holes, then increasing the wettability of liquid aluminum on the surface of the ceramic prefabricated member and introducing a complex-phase chemical reaction on a liquid-solid interface to ensure that the liquid aluminum automatically enters the communicated holes in the ceramic prefabricated member under the action of capillary pressure and reaction pressure without pressurization, and forming a ceramic/aluminum co-continuous composite material after the liquid aluminum is cooled to room temperature, wherein the method comprises the following specific steps:

(1) preparing a ceramic prefabricated member with three-dimensional communicated holes;

the ceramic prefabricatedmember can be prepared by adopting a slurry pouring or cold pressing method,

wherein when the slurry pouring method is adopted, the granularity of the ceramic powder is 0.2-60 mu m, the binder is clay slurry, PVA (polyvinyl alcohol), resin aqueous solution or emulsion aqueous solution, and the clay slurry, the PVA polyvinyl alcohol, the resin aqueous solution or the emulsion aqueous solution are added into the slurryAdding 0-20 vol% molten (particle size<30 μm) SiO₂After drying, heating to 200-500 ℃, preserving heat for 1-3 hours, removing the adhesive, heating to 1100-1500 ℃, preserving heat for 2-5 hours, and preparing the ceramic prefabricated member with three-dimensional communicated holes;

when the cold pressing method is adopted, the granularity of the ceramic powder is 0.2-70 mu m, and the adhesive is paraffin, PVA polyvinyl alcohol, resin or latex. Adding 0-20 vol% of molten SiO₂(<30 mu m), cold-pressing the mixture into a ceramic prefabricated blank under the pressure of 20-60MPa after uniformly mixing, then preserving heat for 1-3 hours at the temperature of 200-500 ℃ for removing the adhesive, and then heating the blank to 1100-1500 ℃ for preserving heat for 2-5 hours to prepare the ceramic prefabricated part with three-dimensional communicated holes;

(3) after the aluminum alloy is melted, the ceramic prefabricated member with the three-dimensional communicated holes prepared in the first step is immersed in aluminum liquid, then inert or non-oxidizing atmosphere (0-800cc/min) is introduced, the temperature of the aluminum liquid is raised to 760-1200 ℃, heat preservation is carried out for 1-10 hours, and finally the ceramic prefabricated member is taken out and cooled to room temperature, so that the ceramic/aluminum co-continuous composite material is obtained.