Electrode with emissive element having conductive portions

Details Electrode with emissive element having conductive portions Electrode with emissive element having conductive portions

1998-09-10

2000-05-23

Walberg, Teresa

Electric heating

Metal heating

By arc

21912151, B23K 900

Patent

active

06066827&

ABSTRACT:
The invention relates to an emissive element for supporting an electric arc in a plasma arc torch using an oxygen gas to create the plasma. The element includes a body having a front face for supporting the electric arc which is defined by at least two distinct components formed from different materials. The first component is an emissive material having a low work function for readily emitting electrons in support of the arc and being reactive with the oxygen plasma gas to form an oxide during an operation of the torch. The oxide forms an electrically resistive layer on the front face of the body upon cooling subsequent to the operation of the torch. Hafnium is a preferred material for the first component. The second component comprises a conductive material having an electrical conductivity greater than the oxide layer for supporting the arc during the initiation of a subsequent torch operation at least until the oxide reaches an operating temperature. Silver and copper are preferred materials for the second component. The conductive material provides a conductive path which allows the arc to be supported thereon until the oxide layer reaches an operating temperature, thereby preventing thermal cracking and removal of the oxide layer. Accordingly, electrode start erosion is reduced.

REFERENCES:
patent: 3086103 (1963-04-01), Hackman et al.
patent: 3198932 (1965-08-01), Weatherly
patent: 3597649 (1971-08-01), Bykhovsky et al.
patent: 3639161 (1972-02-01), Trattner
patent: 3930139 (1975-12-01), Bykhovsky et al.
patent: 4229873 (1980-10-01), Bykhovsky et al.
patent: 4304984 (1981-12-01), Bolotnikov et al.
patent: 4392047 (1983-07-01), Bykhovsky et al.
patent: 4766349 (1988-08-01), Johansson et al.
patent: 5023425 (1991-06-01), Severance, Jr.
patent: 5083005 (1992-01-01), Degrigny
patent: 5124525 (1992-06-01), Severance, Jr. et al.
patent: 5200594 (1993-04-01), Okada et al.
patent: 5451739 (1995-09-01), Nemchinsky et al.
patent: 5660743 (1997-08-01), Nemchinsky
patent: 5676864 (1997-10-01), Walters
patent: 5767478 (1998-06-01), Walters
patent: 5951888 (1999-09-01), Oakley

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