Pre-treated carbon based composite material for molten metal
OwnerC. Edward Eckertinventor
Life of this patent
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Abstract
An improved shaft suitable for use in the treatment of molten aluminum including pumping or fluxing employing an impeller, comprised of a shaft material comprised of a carbon or graphite surface treated to provide a reacted surface and a refractory layer provided to cover the reacted surface of the shaft. The refractory layer is resistant to attack by the molten metal. The refractory layer and the carbon or graphite material have a coefficient of thermal expansion less than 5.times.10.sup.-6 in/in/.degree. F., the refractory layer has a ratio of coefficient of thermal expansion in the range of 5:1 to 1:5.
Claims36
An improved shaft suitable for use in the treatment of molten aluminum, comprised of:
- (a) a shaft comprised of a carbon or graphite material, said shaft treated at a temperature of at least 1000.degree. F. for a time sufficient to provide a reacted surface thereon;
- and
- (b) a refractory layer comprised of consolidated particles applied to said reacted surface of said shaft, the refractory layer resistant to attack by said molten metal, said refractory layer and said carbon or graphite material having a coefficient of thermal expansion less than 5.times.10.sup.-6 in/in/.degree. F., said refractory layer and said carbon or graphite material having a ratio of coefficient of thermal expansion in the range of 5:1 to 1:5.
An improved shaft for use in the treatment of molten aluminum comprised of:
- (a) a carbonaceous material, said shaft being circular in cross section, said shaft treated at a temperature sufficiently high to provide a reacted surface thereon;
- (b) a refractory layer thermally applied to said reacted surface of said shaft, the refractory layer selected from one of the group consisting of Al.sub.2 O.sub.3, ZrO.sub.2, Y.sub.2 O.sub.3, stabilized ZrO.sub.2, Al.sub.2 O.sub.3 --TiO.sub.2 and MgO--ZrO.sub.2, the carbonaceous material having a coefficient of thermal expansion of less than 5.times.10.sup.-6 in/in/.degree. F., said refractory layer and said carbonaceous material having a ratio of coefficient of thermal expansion in the range of 5:1 to 1:5, the refractory having pores;
- and
- (c) a sealant applied to said pores to prevent intrusion of said pores.
A method for processing a body of molten aluminum using an impeller, the method comprising the steps of:
- (a) providing a body of molten aluminum having a surface;
- (b) projecting an impeller on a shaft into said body through said surface, said shaft comprised of:
- (i) a carbonaceous material having an outside surface and having a coefficient of thermal expansion of less than 5.times.10.sup.-6 in/in/.degree. F., said shaft treated in a range of about 1000.degree. to 2800.degree. F. for a time sufficient to provide an oxidized surface thereon;
- and
- (ii) a refractory coating thermally applied to said oxidized surface, said refractory coating having a coefficient of thermal expansion of less than 5.times.10.sup.-6 in/in/.degree. F., said refractory coating extending above and below said surface to protect said shaft against wear and oxidation degradation at said surface;
- and
- (c) processing said body by rotating said impeller in an uni-directional mode or bi-directional mode.
An improved composite suitable for use in contacting molten aluminum, the composite comprised of:
- (a) a base layer of a carbonaceous material having a coefficient of thermal expansion of less than 5.times.10.sup.-6 in/in/.degree. F., said base layer treated at a temperature of at least 1000.degree. F. for a time sufficient to oxidize a surface of said base layer;
- (b) a refractory layer having a coefficient of thermal expansion of less than 5.times.10.sup.-6 in/in/.degree. F. bonded to said surface, the refractory layer resistant to attack by said molten aluminum, said refractory layer and said carbonaceous material having a ratio of coefficient of thermal expansion in the range of 5:1 to 1:5.
An improved composite suitable for use in contacting molten aluminum having improved resistance to degradation at the molten aluminum surface, the composite comprised of:
- (a) a base layer of carbonaceous material having a coefficient of thermal expansion of less than 5.times.10.sup.-6 in/in/.degree. F., said base layer treated at a temperature of at least 1000.degree. F. for a time sufficient to oxidize a surface of said base layer;
- and
- (b) a refractory layer having a coefficient of thermal expansion of less than 5.times.10.sup.-6 in/in/.degree. F. thermally applied to said surface, the refractory layer selected from one of the group consisting of Al.sub.2 O.sub.3, ZrO.sub.2, Y.sub.2 O.sub.3, stabilized ZrO.sub.2, Al.sub.2 O.sub.3 --TiO.sub.2 and MgO--ZrO.sub.2, said refractory layer and said carbonaceous material having a ratio of coefficient of thermal expansion in the range of 5:1 to 1:5, the refractory having pores, said pores sealed to prevent intrusion of said pores by vapors.
Dependencies are inferred from the claim text.