Powder metallurgy processes – Powder metallurgy processes with heating or sintering – Liquid phase sintering
Reexamination Certificate
2000-05-31
2001-08-21
Mai, Ngoclan (Department: 1742)
Powder metallurgy processes
Powder metallurgy processes with heating or sintering
Liquid phase sintering
C419S039000
Reexamination Certificate
active
06277326
ABSTRACT:
CROSS REFERENCES TO RELATED APPLICATIONS
Not Applicable
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
Not Applicable
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to liquid phase sintering processes. More specifically, the present invention relates to a process for liquid phase sintering in an open air environment at standard temperatures and pressures.
2. Description of the Related Art
Sintering is a process that is primarily used to form alloy materials from a powder precursor mixture. Liquid phase sintering is a sintering process that liquefies one of the powders by heating the mixture to the melting temperature of the powder to be liquefied. Present techniques for liquid phase sintering of ternary alloys are performed in a hydrogen environment in order to reduce oxides thereby decreasing porosity and increasing the density.
An example of such a technique is disclosed in Bose, U.S. Pat. No. 5,863,492 for a Ternary Heavy Alloy Based On Tungsten-Nickel-Manganese which was originally filed in 1991. The Bose Patent discloses a process for manufacturing a kinetic energy penetrator at a sintering temperature of 1100° to 1400° C. in a dry hydrogen environment. The Bose Patent discloses densities that are 96% of the theoretical density.
Another example is Rezhets, U.S. Pat. No. 5,098,469 for a Powder Metal Process For Producing Multiphase Ni—Al—Ti Intermetallic Alloys, which was filed in 1991. The Rezhets Patent discloses a four step sintering process that includes degassing, reduction of NiO, homogenization and liquid phase sintering.
Yet another example is Kaufman, U.S. Pat. No. 4,092,223 for Copper, Coated, Iron-Carbon Eutectic Alloy Powders, which was filed in 1976. The Kaufman Patent discloses a pre-compaction, liquid phase sintering process that is performed in a hydrogen environment.
What is needed is a method to lower the processing cost of manufacturing a high density multiple component material that may be shaped for various applications.
BRIEF SUMMARY OF THE INVENTION
The present invention allows for liquid phase sintering in an open air environment and at standard atmospheric conditions. The present invention is able to accomplish this by using a multi-component material that includes an anti-oxidizing agent for the liquid phase sintering.
One aspect is a method for manufacturing a multiple component alloy through an open air liquid phase sintering process. The method includes introducing a multi-component powder/pellet mixture into a cavity on a body, and heating the multi-component powder/pellet mixture to a predetermined temperature for liquid phase sintering of the multi-component powder/pellet mixture. The predetermined temperature is above the melting temperature of one component of the multi-component powder/pellet mixture, and the process is conducted in an open air environment at standard pressure.
The multi-component powder/pellet mixture may be composed of a heavy metal component, an anti-oxidizing component and a metal binder component. One variation of the multi-component powder/pellet mixture may be composed of tungsten, copper and an anti-oxidizing component. The anti-oxidizing component may be containing alloy such as nickel-chrome, stainless steel or nickel superalloy. Preferably, the anti-oxidizing component is nickel chrome.
Having briefly described the present invention, the above and further objects, features and advantages thereof will be recognized by those skilled in the pertinent art from the following detailed description of the invention when taken in conjunction with the accompanying drawings.
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Deshmukh Uday V.
Vecchio Kenneth S.
Callaway Golf Company
Catania Michael A.
Mai Ngoclan
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