Process for preparing a metal body having a hermetic seal

Details Process for preparing a metal body having a hermetic seal Process for preparing a metal body having a hermetic seal

2000-02-07

2001-05-08

Jenkins, Daniel (Department: 1742)

Stock material or miscellaneous articles

All metal or with adjacent metals

Having metal particles

C419S006000, C419S054000, C428S548000

Reexamination Certificate

active

06228508

ABSTRACT:

TECHNICAL FIELD OF THE INVENTION
The invention is in the field of metal powder molding, and pertains more specifically to a method for preparing a metal body via metal powder molding techniques.
BACKGROUND OF THE INVENTION
It is known to make metal objects by means of metal powder molding techniques. In accordance with such techniques, a mixture of metal powder and a resinous binder is molded into a green body, typically by injection molding. The green body is then chemically or thermally debound, and is then sintered at a temperature near the melting temperature of the metal powder. Upon sintering of the green body, the metal powder particles fuse together to form a metal body. Numerous metal powder molding materials and techniques are known in the art, and such are exemplified in U.S. Pat. No. 5,401,292 (Japka), entitled “Carbonyl Iron Powder Premix Composition” and in U.S. Pat. No. 4,971,755 (Kawano et al.), entitled “Method for Preparing Powder Metallurgical Sintered Product.”
When forming hollow metal objects using metal powder molding techniques, it is typical to mold two green halves or component parts of the metal object separately, and to then place these two component parts into contact with one another under pressure prior to debinding and sintering. One problem with known metal powder molding techniques is that it is difficult and often impossible to attain a hermetic seal between the two molded component parts in the metal body. Thus, it is not presently commercially practicable to fabricate hermetically sealed hollow metal bodies, such as pressure vessels and fluid flow nozzles, using known metal powder molding techniques. The present invention is addressed to this drawback in the metal powder molding art.
SUMMARY OF THE INVENTION
The present invention is based on the surprising discovery that a hermetic seal may be obtained between two component parts of a metal powder molded body if the parts are ultrasonically welded to one another while still in the green state. While it is not intended to limit the invention to a particular theory of operation, it is believed that the ultrasonic welding causes a more intimate mixing of the metal powder and binder materials in the component parts, such that upon sintering a more uniform and intimate metal bond is formed between the two component parts than would be obtained absent the ultrasonic welding step. This bond, it is believed, results in a hermetic seal in the metal body in the region of the ultrasonic weld.
In accordance with the invention, a process for preparing a metal body is provided. The process includes the steps of providing first and second component parts each comprising a molded metal powder material and being in the green state, the first component part having an ultrasonic energy director surface; ultrasonically welding the first component part to the second component part to form a green assembly with an ultrasonic weld along its energy director surface; debinding the green assembly; and sintering the debound green assembly to form a metal body. The metal body thus formed will be hermetically sealed along the ultrasonic weld. Preferably, the component parts have mutually-engaging bonding surfaces that further define a green bonding area upon formation of the ultrasonic weld between the component parts. This green bonding area preferably is greater than the area of the ultrasonic weld, to thereby provide a union in the metal body that is strong relative to the union in the region of the weld. The invention also encompasses a metal body prepared in accordance with the foregoing process.
These and other features of the invention will be exemplified in the following drawings, in which:


REFERENCES:
patent: 4191654 (1980-03-01), Larson
patent: 4364783 (1982-12-01), Theodore et al.
patent: 4971755 (1990-11-01), Kawano et al.
patent: 5401292 (1995-03-01), Japka

Affiliated with

Also associated with

Rating

Process for preparing a metal body having a hermetic seal does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Process for preparing a metal body having a hermetic seal, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Process for preparing a metal body having a hermetic seal will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2565388