Method for producing high metal powder content aluminum composite body, method for preparing preform, and high metal powder content aluminum composite body

A method for producing a high metal powder content aluminum composite body, the method comprising:

• a preform preparation step for obtaining a metal powder molded body (preform) having a high metal content ratio;
• and
• an aluminum or aluminum alloy impregnation step of impregnating the obtained preform with molten aluminum or a molten aluminum alloy, or causing molten aluminum or a molten aluminum alloy to infiltrate into the obtained preform, wherein
• in the preform preparation step, two or more metal powder materials each having a different average particle size are selected from metal powder materials having an average particle size of 1 μm or larger and 200 μm or smaller (excluding powder materials of a Mg powder, an AlMg powder, a ZnMg powder, a ZnAl powder, and a Mg2Si powder) to use the two or more metal powder materials as metal raw materials for the preform, molding is performed using a mixture obtained by adding one or more powders selected from the group consisting of a Mg powder, an AlMg powder, a ZnMg powder, a ZnAl powder, and a Mg2Si powder in an amount within a range of 0.2 to 5 parts by mass based on 100 parts by mass of the metal raw materials, and further adding and mixing an organic/inorganic binder being at least any one selected from the group consisting of a silicone resin, a Si alkoxide, and an Al alkoxide, which are in a liquid form or in a state of having been made into a liquid form, and a resultant molded product is calcined at a temperature of 300° C. or higher and 500° C. or lower, and thereby an organic substance in the molded product is removed and an inorganic substance functions as an inorganic binder to obtain a metal powder molded body having a content ratio (volume content ratio) of the metal raw materials of 55 v % or more, and
• in the aluminum or aluminum alloy impregnation step, aluminum or an aluminum alloy is caused to infiltrate without pressurization in a nitrogen atmosphere into the metal powder molded body obtained in the preform preparation step.

A preform preparation method for obtaining a metal powder molded body (preform) which is used in obtaining a high metal powder content aluminum composite body metal by impregnating the preform with molten aluminum or a molten aluminum alloy at a high pressure and has a high metal powder content ratio, wherein

• two or more metal powder materials each having a different average particle size, the metal powder materials containing at least a metal powder A having an average particle size of 10 μm or smaller, a metal powder B having an average particle size of 40 μm or larger and containing at least 3% of the metal powder A and 50% or more of the metal powder B in the total amount of the metal powders on a mass basis, are selected from metal powder materials having an average particle size of 1 μm or larger and 200 μm or smaller to use the two or more metal powder materials as metal raw materials for the preform, molding is performed using a mixture obtained by adding and mixing an organic/inorganic binder being at least any one selected from the group consisting of a silicone resin, a Si alkoxide, and an Al alkoxide, which are in a liquid form or in a state of having been made into a liquid form, into the metal raw materials, and a resultant molded product is calcined at a temperature of 300° C. or higher and 800° C. or lower, thereby obtaining a metal powder molded body having a content ratio (volume content ratio) of the metal raw materials of 55 v % or more.

A preform preparation method for obtaining a metal powder molded body (preform) which is used in obtaining a high metal powder content aluminum composite body metal by causing molten aluminum or a molten aluminum alloy to infiltrate without pressurization in a nitrogen atmosphere into the preform and has a high metal powder content ratio, wherein

• two or more metal powder materials each having a different average particle size, the metal powder materials containing at least a metal powder A having an average particle size of 10 μm or smaller, a metal powder B having an average particle size of 40 μm or larger and containing at least 3% of the metal powder A and 50% or more of the metal powder B in a total amount of the metal powders on a mass basis, are selected from metal powder materials having an average particle size of 1 μm or larger and 200 μm or smaller (excluding powder materials of a Mg powder, an AlMg powder, a ZnMg powder, a ZnAl powder, and a Mg2Si powder) to use the two or more metal powder materials as metal raw materials for the preform, molding is performed using a mixture obtained by adding one or more powders selected from the group consisting of a Mg powder, an AlMg powder, a ZnMg powder, a ZnAl powder, and a Mg2Si powder in an amount within a range of 0.2 to 5 parts by mass based on 100 parts by mass of the metal raw materials, and further adding and mixing an organic/inorganic binder being at least any one selected from the group consisting of a silicone resin, a Si alkoxide, and an Al alkoxide, which are in a liquid form or in a state of having been made into a liquid form, and a resultant molded product is calcined at a temperature of 300° C. or higher and 500° C. or lower, thereby obtaining a metal powder molded body having a content ratio (volume content ratio) of the metal raw materials of 55 v % or more.