SE525660C2

SE525660C2 - Method for fixing metal foam to a metal plate

Info

Publication number: SE525660C2
Application number: SE0201788A
Authority: SE
Inventors: Lars Kaellman; Bernt Jaensson; Bjoern Seborn
Original assignee: Saab Ab
Priority date: 2002-06-12
Filing date: 2002-06-12
Publication date: 2005-03-29
Also published as: SE0201788D0; AU2003239010A1; SE0201788L; WO2003106091A1

Abstract

The invention concerns a method for fixing open-pore metal foam to a metal plate (2). In the method according to the invention, a metal plate (2) is chemically coated with a thin brazing filler metal coating (3), and a layer (1) of open-pore metal foam is applied against the coating (3) under pressure. Joining occurs via brazing in a furnace.

Description

IICI 0 O 0 0 00 0000 0 I 0 10 OO O UOUO IQ O 0 00 0 0 0 0 0 O I O I O I O O 00 000 0 II 0 0 0 0 O 0000 000 l 10 15 20 25 30 I . . . . 0' 00 _ 0 I 0 0 :oo ' 0 0 v n 0 n . f ° 0 I 0 0 0 . nu anwa oc Q. perforerad metallplåt 2. Den uppﬁnningsenliga metoden är framförallt lämplig vid fixering av ett s.k. öppenporigt metallskum. Detta kännetecknas av en mycket låg andel metall, i storleksordningen 5-10%, och tunna ligament som är känsliga för uppvärmning. IICI 0 O 0 0 00 0000 0 I 0 10 OO O UOUO IQ O 0 00 0 0 0 0 0 O I O I O I O O 00 000 0 II 0 0 0 0 O 0000 000 l 10 15 20 25 30 I. . . . 0 '00 _ 0 I 0 0: oo' 0 0 v n 0 n. f ° 0 I 0 0 0. nu anwa oc Q. perforated sheet metal 2. The method according to the invention is particularly suitable for fixing a so-called open-pored metal foam. This is characterized by a very low proportion of metal, in the order of 5-10%, and thin ligaments that are sensitive to heat.

Metallskumskiktet 1 fixeras mot plåten 2 genom hårdlödning. Metallplåten 2 har före montering mot metallskumskiktet 1 tillförts en beläggning 3 av lod med lämplig arbetstemperatur för konstruktionen i fråga. Lodet väljs så att det ger kontrollerad vätning utan att mer än nödvändigt sugas upp i skummet, vilket skulle kunna försämra funktionen hos den slutliga produkten. Beläggningen 3 utförs kemiskt eller på annat lämpligt sätt.The metal foam layer 1 is fixed to the plate 2 by brazing. Prior to mounting against the metal foam layer 1, the metal plate 2 has been coated with a solder 3 with a suitable working temperature for the construction in question. The solder is selected so that it provides controlled wetting without being more than necessary absorbed into the foam, which could impair the function of the final product. The coating 3 is carried out chemically or in another suitable way.

Beläggningen 3 ges en tjockleki storleksordningen 10-20 um Skiktet 1 av metallskum våtslipas för att erhålla en plan yta samt ge ligamenten i skiktet en oxidfri kontaktyta. Rengöring utförs med lämpligt lösningsmedel i ultraljudbad, varefter noggrann torkning sker.The coating 3 is given a thickness of the order of 10-20 μm. The layer 1 of metal foam is wet sanded to obtain a flat surface and to give the ligaments in the layer an oxide-free contact surface. Cleaning is performed with a suitable solvent in an ultrasonic bath, after which thorough drying takes place.

En keramisk platta placerad på skumskiktets yta avpassas med eventuell ytterligare vikt för att uppnå ett tryck som ger full anliggning under lödcykeln som utförs i vakuumugn alternativt skyddsgasugn. Tryck över lödfogen kan även upprättas med andra former av tyngder, mekaniskt med skruvförband eller genom vakuum i en så kallad retort.A ceramic plate placed on the surface of the foam layer is adapted with any additional weight to achieve a pressure that provides full abutment during the soldering cycle which is performed in a vacuum oven or shielding gas oven. Pressure over the solder joint can also be established with other forms of weights, mechanically with screw joints or by vacuum in a so-called retort.

Fixering av metallskumskiktet 1 utförs genom hårdlödning. Denna metod medger användning av lodmaterial med smältpunkt över 450 °C. Vid hårdlödning placeras plåt 2, skiktet 1 av metallskum och den mot skumskiktet vilande plattan i en ugn och upphettas till en temperatur som är högre än lodets smältpunkt, men lägre än metallskummets och plåtens 2 smältpunkter. Den valda temperaturen understiger smältpunkten för metallskummet väsentligt, vilket medför att det inte föreligger någon risk att ligament i metallskummet skadas vid uppvärmningen. Den sarnmanfogade konstruktionen kan därefter utnyttjas vid högtemperaturapplikationer.Fixing of the metal foam layer 1 is performed by brazing. This method allows the use of solder with a melting point above 450 ° C. In brazing, plate 2, the layer 1 of metal foam and the plate resting against the foam layer are placed in an oven and heated to a temperature higher than the melting point of the solder, but lower than the melting points of the metal foam and the plate 2. The selected temperature is significantly below the melting point of the metal foam, which means that there is no risk of ligaments in the metal foam being damaged during heating. The assembled structure can then be used in high temperature applications.

Den uppﬂnningsenliga metoden är särskilt fördelaktig vid infástning eller ﬁxering av ett skikt 1 av öppenporigt metallskum mot en metallplåt 2. Metoden kan naturligtvis även utnyttjas för fixering av slutenporigt metallskum.The method according to the invention is particularly advantageous when attaching or oxidizing a layer 1 of open-pore metal foam against a metal plate 2. The method can of course also be used for fixing closed-pore metal foam.

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Claims

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Method for eringxtering open-pored metal foam against a metal plate (2), characterized in that the metal plate (2) is chemically coated with a thin solder coating (3), the solder being selected so as to give controlled wetting without being more than necessary absorbed in the open-pore foam, that a layer (1) of open-pore metal foam is pressed against the solder coating (3) to full abutment and that joining is carried out by brazing in an oven.

Method according to claim 1, wherein the part of the layer (1) of metal foam facing the solder coating (3) is treated so that oxide-free contact surface is achieved.

A method according to claim 1, wherein the solder coating (3) is given a thickness of 10-20 μm.

Method according to claim 1 or 2, wherein a ceramic plate is allowed to abut against a surface facing away from the solder coating ring (3) on the layer (1) of metal foam, in order to apply it to the solder coating (3) under pressure.

The method of claim 4, wherein the ceramic plate is loaded with a weight.

A method according to any one of the preceding claims, wherein soldering is performed in a vacuum oven.

A method according to claims 1-4, wherein soldering is performed in a shielding gas furnace.

Method according to one of the preceding claims, wherein the metal plate (2) consists of a solid or perforated plate (2) of metal.