CN1179474A

CN1179474A - Process for preparing adjustable foam size foamed aluminium

Info

Publication number: CN1179474A
Application number: CN 96117125
Authority: CN
Inventors: 韩福生; 朱震刚; 刘长松
Original assignee: INST OF SOLID PHYSICS CHINESE
Current assignee: INST OF SOLID PHYSICS CHINESE; Institute of Solid State Physics ISSP of CAS
Priority date: 1996-10-10
Filing date: 1996-10-10
Publication date: 1998-04-22
Anticipated expiration: 2016-10-10
Also published as: CN1058058C

Abstract

A process for preparing pore size regulatable foamed aluminium includes such technological steps as smelting metal aluminium and its alloy to be foamed, covering it with thickening agent (aluminium) or used foamed aluminium, heeping temp constant, stirring, addition of foaming agent, stirring, keeping temp at 600-700 deg. C, and colling to obtain foamed aluminium with uniform porous structure. The pore size can be regulated by changing the amount of thickening agent and controlling the preheating temp.

Description

The preparation method of adjustable foam size foamed aluminium

The present invention relates to the preparation method of metal foamed aluminium.

Foamed aluminium is a kind of porous matter metallic substance that comprises countless bubbles, and it is little to have density, and premium properties such as sound-absorbing, fire-retardant, energy-absorbing is the type material that the utmost point has application prospect.

Up to the present, the manufacture method that people study the foamed aluminium of more and tool application prospect is a foam melt method, and the main preparation process of this method is: aluminium (fine aluminium or aluminium alloy) is melted, add tackifier, stir tackify, (metal hydride is as TiH to add whipping agent again ₂, ZrH ₂, HfH ₂Deng), whipping agent decomposes releasing hydrogen gas forms bubble in viscous melt, just obtain foamed aluminium after the cooled and solidified.

A homogeneity that important indicator is bore hole size and shape of foamed aluminium structure quality.And to obtain uniform pore structure, the tackified finish in the flux foaming process is the most key.Because viscosity is low excessively, can make subsequently the whipping agent that adds decompose the gas that produces and very easily escape, and bubble is easy to assemble in process of growth and grows up, form pore not of uniform size; And viscosity is too high, then makes whipping agent homodisperse difficulty in melt.Therefore, controlling suitable viscosity, is the important assurance that obtains even pore structure.The researchist has used multiple tackifier and tackify method for this reason, as uses the gas tackify, and gases used is O ₂, Ar, N ₂, air, water etc.; The powder tackify is as MnO ₂, Mg, Ca, Al ₂O ₃Deng.But these tackify methods all have the following disadvantages:

1. required equipment is numerous and diverse.During as usefulness gas tackify, need Ignitable gas devices, gas transmission pipeline etc.;

2. easily cause foaming metal to pollute.Because of used whipping agent substantially not with the foaming metal alloying, but stay in the foamed metal, and its add-on is all bigger with the form of various inclusiones, be 0.2-8.0% as the add-on of Ca, this performance to foamed metal will have a negative impact;

3. because of viscosity increases soon, very high to technological process control requirement, be difficult for reaching;

4. used tackifier cost is higher;

5. used active tackifier such as Mg, Ca etc., easy oxidizing fire has polluted Working environment in whipping process.

The object of the invention provides a kind of above-mentioned shortcoming that can overcome, and safety, cheap, effectively tackifier and tackify method are with the foamed aluminium aperture that these tackifier and tackify method are prepared adjustable, and good uniformity.

The present invention is as tackifier with aluminium bits or waste foam aluminium.

The inventive method is, at first will treat foaming metal aluminium and alloy melting thereof, and in liquidus temperature Tm+20～40 ℃ insulation, again tackifier aluminium bits or waste foam aluminium are covered on it, the add-on of tackifier is 30～60% of total amounts, insulation 10～30min stirs stirring velocity 500～800rpm again; Add whipping agent 0.5～2.0%TiH after stirring again ₂Or ZrH ₂Deng.Speed with 1500～2300rpm stirs 20～60s again, at 600～700 ℃ of insulation 60～300s, takes out postcooling and promptly obtain the uniform foamed aluminium of pore structure from stove.

Theoretical foundation of the present invention is: the viscosity of liquid metal results from the internal friction between particle, when becoming uneven multiphase system if any the solid phase particle of some amount in the liquid, even will make internal friction increase viscosity increases, solid rate is high more, viscosity is just big more, when solid-state aluminium bits with waste foam aluminium joins in the melt and after stirring, the increase of solid phase particle just forms the bigger rheology melt of viscosity in the melt.Therefore, the viscosity of melt can be controlled by add-on and the soaking time of adjusting aluminium bits and waste foam aluminium.For this reason, the prepared foamed aluminium of the inventive method aperture is adjustable, and good uniformity.

Advantage of the present invention is:

1. used tackifier are consistent with matrix metal, can not pollute;

2. low production cost can make full use of waste foam aluminium, and this part aluminium is difficult to the remelting recovery;

3. tackify speed is convenient to control, and the heat-up time or the add-on that only need to change tackifier can realize;

4. there are not burning, smog and peculiar smell, environmentally safe when operating;

5. adjustable, the good uniformity in foamed aluminium aperture that makes.

In a word, the inventive method is simple, and easily row does not need huge equipment, and prepared foamed aluminium aperture is adjustable, and good uniformity is the preparation method who has the foamed aluminium of practical value and application prospect.

Embodiment:

1. with cast aluminium alloy (ZL104),, be cooled to 660～685 ℃ again, add waste foam aluminium (foaming) and account for 20～30% of total amount, stir 30s, add whipping agent Al with 500～800rpm speed with ZL104 660～700 ℃ of fusings ₂O ₃: TiH ₂=(1.0～2.0): 1, with the speed stirring 30s of 1500～2300rpm,, from stove, to take out cooling and promptly obtain foamed aluminium at 650～675 ℃ of insulation 120s, its porosity is 74%, the aperture is 2.8mm.

Claims

1. preparation method who prepares adjustable foam size foamed aluminium with foam melt method, it is characterized in that, to treat foaming metal aluminium and alloy melting thereof earlier, and in liquidus temperature Tm+20～40 ℃ insulation, again tackifier aluminium bits are covered on it, insulation 10～30min, speed with 500～800rpm stirs again, add whipping agent after waiting to stir, speed with 1500～2300rpm stirs 20～60s again, at 600～700 ℃ of insulation 60～300s, take out postcooling and promptly obtain the adjustable and uniform foamed aluminium of pore structure at last.

2. the method for claim 1 is characterized in that, tackifier can also be waste foam aluminium, and its add-on is 30～60% of a total amount.

3. the method for claim 1 is characterized in that, whipping agent can be used TiH ₂, ZrH ₂, HfH ₂Deng, its add-on is 0.5～2.0% of a total amount.

4. the method for claim 1 is characterized in that, can adjust melt viscosity by the add-on of adjusting tackifier, can also adjust tackify speed by the preheating temperature of adjusting tackifier, thereby the acquisition aperture is adjustable, the foamed aluminium of good uniformity.