Patent · US Expired

Method and device for controlling the electric current density across a workpiece during heat treatment in a plasma

US5717186A · kind A · utility

4Cited by

0References

5Claims

0Family size

Assignee

Ipsen Industries International GmbH · DE

Inventors

Hansjakob Drissen · Kleve, DE
Winfried Grafen · Duisburg, DE
Bernd Edenhofer · Kleve, DE

Key dates

Filing date	Jun 13, 1996
Grant date	Feb 10, 1998
Priority date	—
Expiry date	Jun 13, 2016

Classification

Technology area (CPC H)Electricity
CPC primaryH05H1/36
WIPO fieldMaterials, metallurgy
WIPO sectorChemistry

Abstract

In a method for controlling the electric current density across a workpiece in a furnace during heat treatment in a plasma an auxiliary electrode with a known surface area is introduced into the furnace. A batch of workpieces is then introduced into the furnace. First a plasma of a neutral gas is generated within the furnace. The total current within the furnace and the current within the auxiliary electrode are measured. The surface area of the workpieces is calculated according to the equation ##EQU1## The auxiliary electrode is then switched off and a material-transmitting plasma is generated. The nominal total electric current for controlling a desired nominal current density is then calculated according to the equation EQU I.sub.Gnominal =F.sub.CH .multidot.J.sub.nominal. The total current is measured in the furnace and is set to the nominal current value.

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.