U.S. patent application number 10/168011 was filed with the patent office on 2003-04-24 for method of handling liquid non-ferrous metals with refractory material.
Invention is credited to Olsson, Jan-Olof, Popilowski, Chet, Sundberg, Mats.
Application Number | 20030075251 10/168011 |
Document ID | / |
Family ID | 20418206 |
Filed Date | 2003-04-24 |
United States Patent
Application |
20030075251 |
Kind Code |
A1 |
Sundberg, Mats ; et
al. |
April 24, 2003 |
Method of handling liquid non-ferrous metals with refractory
material
Abstract
A method of handling liquid non-ferrous metals in which the
liquid metal is treated while coming into contact with a solid
refractory material. The invention is characterised in that the
solid material is Ti.sub.3SiC.sub.2. According to one preferred
embodiment, the liquid material is aluminium or aluminium
alloys.
Inventors: |
Sundberg, Mats; (US)
; Olsson, Jan-Olof; (Hallstahammar, SE) ;
Popilowski, Chet; (Washington, CT) |
Correspondence
Address: |
ALFRED J MANGELS
4729 CORNELL ROAD
CINCINNATI
OH
452412433
|
Family ID: |
20418206 |
Appl. No.: |
10/168011 |
Filed: |
October 16, 2002 |
PCT Filed: |
December 18, 2000 |
PCT NO: |
PCT/SE00/02572 |
Current U.S.
Class: |
148/688 ;
266/280; 266/44; 501/99 |
Current CPC
Class: |
C04B 35/5615
20130101 |
Class at
Publication: |
148/688 ; 501/99;
266/44; 266/280 |
International
Class: |
C21C 005/44 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 20, 1999 |
SE |
9904670-8 |
Claims
1. A method of handling liquid non-ferrous metals, in which the
liquid metal is treated while coming into contact with a solid
refractory material, characterised in that the solid material is
Ti.sub.3SiC.sub.2.
2. A method according to claim 1, characterised in that the liquid
material is aluminium or aluminium alloys.
3. A method according to claim 1 or 2, characterised in that the
liquid material is magnesium or magnesium alloys.
4. A method according to claim 1 or 2, characterised in that said
treatment includes melting, retaining, transporting, filtering or
casting the liquid material.
Description
[0001] The present invention relates to a method of handling liquid
non-ferrous metals, and more specifically to the solid material
with which the liquid material comes into contact.
[0002] There is a need for refractory material that can resist the
aggressive conditions that occur when the material comes into
contact with liquid non-ferrous metals, such as aluminium. Among
other things, this need is due to the increasing use of aluminium
in vehicle parts, such as chassis and cast engine parts. Material
that shall be used in direct contact with liquid aluminium must
possess good corrosion properties and good erosion properties and
also have a high resistance to oxidation at high temperatures and
against thermal shocks, and shall also have high impact resistance
and high strength and hardness. The material shall also be capable
of being easily worked into complex shapes at a competitive
cost.
[0003] The aluminium industry uses at present silicon aluminium
oxynitride, SIALON, despite its high manufacturing costs. One
drawback with SIALON, however, is that it is brittle and therefore
expensive to work.
[0004] SiC and Si3N4 are materials that have also been evaluated in
contact with liquid aluminium. It was found that Si dissolved into
liquid aluminium in both cases. Si3N4 was found to have the best
resistance to corrosion when produced by hot isostatic pressing
(HIP) of reaction-bound Si3N4 (HIPRBSN).
[0005] A dense protective layer was formed from AIN. SiC has been
found to have low corrosion resistance when the material is
manufactured by using silicon metal as a binding phase.
Brittleness, difficulties in mechanical working, poor resistance
against thermal shocks, low impact resistance, and reactions with
liquid aluminium are among the drawbacks exhibited by SiC when used
with liquid aluminium.
[0006] Generally speaking, the high affinity of Al to Si and the
high solubility of Si in Al normally results in Si dissolving in
liquid aluminium.
[0007] Some metallic materials, such as cast iron, have normally
been used in conjunction with liquid aluminium, because these
metals are inexpensive, have high mechanical strength and resist
thermal shocks. Cast iron protective pipes, however, are wetted by
liquid aluminium, resulting in dissolving of the material with
subsequent contamination of the melt with undesirable iron
particles.
[0008] The aforesaid problems are solved by the present
invention.
[0009] The present invention thus relates to a method of handling
liquid non-ferrous metals, in which the liquid metal is treated as
it comes into contact with a solid refractory material, said method
being characterised in that the solid material is
Ti.sub.3SiC.sub.2.
[0010] It has surprisingly and unexpectedly been found that this
material is stable in liquid aluminium. It has been found that when
in contact with liquid aluminium there is formed on the surface of
the material a reaction zone which produces a layer that passivates
the outer surface of said material and which prevents chemical
corrosion in all essentials.
[0011] The material has therefore been found excellent in respect
of handling liquid aluminium and aluminium alloys.
[0012] The material Ti.sub.3SiC.sub.2 has a unique combination of
properties that render it suitable for high temperature
applications. It has very good working properties, which enable
complicated shapes to be produced. The material is also insensitive
to thermal shocks. Ti.sub.3SiC.sub.2 is also a material that has
high impact resistance and an equilibrium temperature between
brittle and tough material of about 1200.degree. C. The thermal
conductivity of the material is about 37 W/mK at room temperature.
The material can be produced by conventional methods of producing
ceramic materials, such as extrusion, cold isostatic pressing
(CIPing), casting and packing by pressureless sintering, or by hot
isostatic pressing (HIP). Minor fractions of TiC, SiC and
TiSi.sub.2 may be present in the finished material. The above
mentioned treatment of the liquid material includes melting,
retaining, such as when alloying, transportation, filtration, such
as when degassing and purifying the material, or casting of the
liquid material.
[0013] Aluminium has been mentioned above. According to a preferred
embodiment, the liquid material is magnesium or magnesium alloys
instead.
[0014] It is also conceivable to use successfully said material for
other metals or metal alloys that have a relatively low melting
point. Zinc, copper, tin and lead or their alloys are primarily
intended in this respect.
[0015] The present invention is therefore not restricted to liquid
material in the form of aluminium or magnesium, but can be applied
with respect to other materials in which the material
Ti.sub.3SiC.sub.2 is stable.
[0016] It will therefore be understood that the present invention
is not restricted to the aforedescribed embodiments thereof but
variations can be made within the scope of the accompanying
Claims.
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