Method for melting and evaporating a solid in a vapor deposition coating system

Abstract

Apparatuses and methods for use in vacuum vapor deposition coating provide for simpler, economical and continuous operation. A system and method for continuously melting and evaporating a solid material for forming a coating vapor includes the use of a separate melting crucible and evaporating crucible. A system and method for energizing the evaporative solids to form a plasma which includes first and second electrodes and a device for selectively switching polarity between the first and second electrodes to avoid coating vapor deposition on the electrodes. Another a system and method for energizing the evaporative solids to form a plasma which includes an electric arc discharge apparatus with a cathodic and an anodic part. A continuously fed electrode is disclosed for continuous vaporization of electrode members in an electric arc discharge. An apparatus and method provides for measurement of the rate of evaporation from an evaporator and the degree of ionization in a vapor deposition coating system. Lastly, a system is disclosed for in-situ cleaning of vaporizable deposits for cleaning of the enclosure of the vacuum vapor deposition system.

1 . A system for continuously melting and evaporating a solid material comprising: 
 a melting crucible for receiving and melting the solid material to form molten material; and    an evaporating crucible for evaporating the molten material, the evaporating crucible connected to the melting crucible in flow communication with the melting crucible for receiving the molten material from the melting crucible and having an opening for releasing vapor as the molten material evaporates.    
     
     
         2 . A melting and evaporating system as in  claim 1  wherein the melting crucible has an opening for receiving the solid material and the melting and evaporating system further comprises a feeder for feeding the solid material into the melting crucible as the molten material evaporates.  
     
     
         3 . A melting and evaporating system as in  claim 2  wherein the feeder automatically feeds the solid material into the melting crucible as the molten material evaporates.  
     
     
         4 . A melting and evaporating system as in  claim 3  wherein the feeder feeds the solid material into the melting crucible so as to maintain the molten material in the evaporating crucible at a substantially constant level during evaporation of the molten material.  
     
     
         5 . A melting and evaporating system as in  claim 1  further comprising: 
 a melting crucible heater for heating the melting crucible to a first temperature and melting the solid material in the melting crucible; and  
 an evaporating crucible heater for heating the evaporating crucible and the molten material in the evaporating crucible to a second temperature different then the first temperature for evaporating the molten material.  
 
     
     
         6 . A melting and evaporating system as in  claim 5  wherein the evaporating crucible heater is controllable independently of the melting crucible heater.  
     
     
         7 . A melting and evaporating system as in  claim 1  wherein the evaporating crucible is arranged so that the molten material is maintained at a substantially constant level in the evaporating crucible during evaporation of the molten material.  
     
     
         8 . A melting and evaporating system as in  claim 1  wherein the evaporating crucible is a conduit which is arranged so that the molten material flows from the melting crucible through the conduit to the vapor releasing opening in the evaporating crucible.  
     
     
         9 . A melting and evaporating system as in  claim 1  wherein the melting crucible and evaporating crucible are arranged so that the melting crucible holds the molten material at a first hydraulic level and the evaporating crucible holds molten material at a second hydraulic level which is the same as the first hydraulic level.  
     
     
         10 . A melting and evaporating system as in  claim 9  wherein the melting crucible and evaporating crucible are arranged side-by-side and the evaporating crucible is a conduit which is arranged so that the molten material flows from the melting crucible through the conduit to the vapor releasing opening in the evaporating crucible.  
     
     
         11 . A melting and evaporating system as in  claim 9  further comprising a level monitor for monitoring the level of solid material and molten material in the melting crucible.  
     
     
         12 . A melting and evaporating system as in  claim 1  wherein the melting crucible and evaporating crucible are arranged so that the melting crucible holds the molten material at a first level and the evaporating crucible holds molten material at a second level which is above the first level and the evaporating crucible draws the molten material from the melting crucible, through the evaporating crucible, to the vapor releasing opening via capillary action.  
     
     
         13 . A melting and evaporating system as in  claim 11  wherein the evaporating crucible is a conduit which is at least partially disposed in the melting crucible so that the molten material flows from the melting crucible through the conduit to the vapor releasing opening in the evaporating crucible.  
     
     
         14 . A melting and evaporating system as in  claim 1  wherein the melting crucible and evaporating crucible are arranged so that the melting crucible holds the molten material at a first level and the evaporating crucible holds molten material at a second level which is above the first level and the evaporating crucible draws the molten material from the melting crucible, through the evaporating crucible, to the vapor releasing opening via thermal syphonic force.  
     
     
         15 . A melting and evaporating system as in  claim 14  wherein: 
 the evaporating crucible is a conduit which is at least partially disposed in the melting crucible, has an upper portion extending above the level of solid and molten material in the melting crucible to the vapor releasing opening, so that the molten material flows from the melting crucible through the conduit to the vapor releasing opening in the evaporating crucible; and  
 the melting and evaporating system further comprises:  
 a melting crucible heater for heating the melting crucible to a first temperature and melting the solid material in the melting crucible; and  
 an evaporating crucible heater for heating the evaporating crucible and the molten material in the evaporating crucible proximate the vapor releasing opening to a second temperature different then the first temperature for evaporating the molten material.  
 
     
     
         16 . A melting and evaporating system as in  claim 1  wherein the melting crucible is larger than the evaporating crucible.  
     
     
         17 . A melting and evaporating system as in  claim 1  further comprising a heat shield covering at least a portion of the melting crucible.  
     
     
         18 . A melting and evaporating system as in  claim 1  further comprising a plurality of evaporating crucibles for evaporating the molten material, the evaporating crucibles each connected to the melting crucible in flow communication with the melting crucible for receiving the molten material from the melting crucible and each having an opening for releasing vapor as the molten material evaporates.  
     
     
         19 . A vacuum vapor deposition coating system comprising: 
 a vacuum cell capable of maintaining a vacuum within the vacuum cell; and    the melting and evaporating system of  claim 1  disposed within the vacuum cell.    
     
     
         20 . A method for melting and evaporating a solid material comprising the steps of: 
 melting the solid material in a melting crucible to form molten material;    flowing the molten material from the melting crucible into an evaporating crucible connected to the melting crucible;    evaporating the molten material in the evaporating crucible to form a vapor; and    releasing the vapor from the evaporating crucible.    
     
     
         21 . A method as in  claim 20  further comprising feeding the solid material into the evaporating crucible as the molten material evaporates.  
     
     
         22 . A method as in  claim 21  wherein the feeding step comprises automatically feeding the solid material into the melting crucible as the molten material evaporates.  
     
     
         23 . A method as in  claim 22  wherein the feeding step further comprises feeding the solid material into the melting crucible so as to maintain the molten material in the evaporating crucible at a substantially constant level during evaporation of the molten material.  
     
     
         24 . A method as in  claim 1  further comprising the steps of: 
 heating the melting crucible to a first temperature to melt the solid material in the melting crucible; and  
 heating the evaporating crucible and the molten material in the evaporating crucible to a second temperature different then the first temperature to evaporate the molten material.  
 
     
     
         25 . A method as in  claim 20  further comprising maintaining the molten material at a substantially constant level in the evaporating crucible during evaporation of the molten material.  
     
     
         26 . A method as in  claim 20  further comprising holding the molten material at a first hydraulic level in the melting crucible and holding the molten material at a second hydraulic level in the evaporating crucible, the first hydraulic level being the same as the second hydraulic level.  
     
     
         27 . A method as in  claim 26  further comprising monitoring the level of solid material and molten material in the melting crucible.  
     
     
         28 . A method as in  claim 20  wherein the flowing step comprises drawing the molten material from the melting crucible, through the evaporating crucible, to a vapor releasing opening in the evaporating crucible via capillary action.  
     
     
         29 . A method as in  claim 1  wherein the flowing step comprises drawing the molten material from the melting crucible, through the evaporating crucible, to a vapor releasing opening in the evaporating crucible via thermal syphonic force.  
     
     
         30 . A system for continuously melting and evaporating a solid material comprising: 
 a pivotable melting crucible for receiving and melting the solid material to form molten material; and    an evaporating crucible, positioned below the melting crucible, for evaporating the molten material,    wherein the melting crucible is selectively pivotable between an upright position in which the melting crucible receives and melts the solid material, and alternatively, a tilted position in which the melting crucible pours the molten material in the evaporating crucible.    
     
     
         31 . A melting and evaporating system as in  claim 30  further comprising a conduit for receiving the molten material from the melting crucible in the tilted position and delivering the molten material to the evaporating crucible.  
     
     
         32 . A melting-and evaporating system as in  claim 30  wherein the melting crucible has an opening for receiving the solid material and the melting and evaporating system further comprises a feeder for feeding the solid material into the melting crucible as the molten material evaporates.  
     
     
         33 . A melting and evaporating system as in  claim 32  wherein the feeder automatically feeds the solid material into the melting crucible as the molten material evaporates.  
     
     
         34 . A melting and evaporating system as in  claim 30  wherein the melting crucible includes a spout for pouring the molten material into the evaporating crucible.  
     
     
         35 . A melting and evaporating system as in  claim 34  wherein the melting crucible further includes a pouring sieve to prevent solid material from passing into the evaporating crucible with the molten material.  
     
     
         36 . A method for continuously melting and evaporating a solid material comprising: 
 (a) melting the solid material in a melting crucible in an upright position to form molten material; and    (b) pivoting the melting crucible from the upright position to a tilted position and pouring the molten material in an evaporating crucible positioned below the melting crucible;    (c) evaporating the molten material from the evaporating crucible;    (d) pivoting the melting crucible from the tilted position to the upright position; and    (e) repeating steps a-d.    
     
     
         37 . A method as in  claim 36  wherein the melting crucible has an opening for receiving the solid material and the method further comprises feeding the solid material into the melting crucible as the molten material evaporates.  
     
     
         38 . A method as in  claim 37  wherein the feeder automatically feeds the solid material into the melting crucible as the molten material evaporates.  
     
     
         39 . A system for continuously melting and evaporating a solid material comprising: 
 a melting crucible for receiving and melting the solid material to form molten material;    an electrically conductive evaporating member disposed in the melting crucible for evaporating the molten material; and    an electric power supply for supplying electric power to the evaporating member such that the power supply, the evaporating member, the molten material and the melting crucible form an electric circuit, the power supply supplying sufficient power to heat the evaporating member and evaporate at least a portion of the molten material which contacts the evaporating member.    
     
     
         40 . A melting and evaporating system as in  claim 39  further comprising a heater for initially melting at least a portion of the solid material so that the molten portion of the solid material can complete the electric circuit and the evaporating member becomes capable of heating, melting and evaporating the solid material.  
     
     
         41 . A melting and evaporating system as in  claim 39  wherein the evaporating member is disposed in the melting crucible so that at least a portion of the evaporating member extends above the molten material in the melting crucible, and the molten material is drawn up the portion of the evaporating member by electromagnetic forces generated by the electric circuit and evaporated by heat from the portion of the evaporating member.  
     
     
         42 . A melting and evaporating system as in  claim 39  wherein the evaporating member is a rod.  
     
     
         43 . A melting and evaporating system as in  claim 39  wherein the melting crucible has an opening for receiving the solid material and the melting and evaporating system further comprises a feeder for feeding the solid material into the melting crucible as the molten material evaporates.  
     
     
         44 . A melting and evaporating system as in  claim 43  wherein the feeder automatically feeds the solid material into the melting crucible as the molten material evaporates.  
     
     
         45 . A melting and evaporating system as in  claim 39  wherein the heater is an electric arc discharge apparatus.  
     
     
         46 . A method for continuously melting and evaporating a solid material comprising: 
 filling a melting crucible with the solid material;    placing an electrically conductive evaporating member in the melting crucible;    melting at least a portion of the solid material to form molten material; and    supplying electric power supply to the evaporating member such that the power supply, the evaporating member, the molten material and the melting crucible form an electric circuit, the power supply supplying sufficient power to heat the evaporating member and evaporate at least a portion of the molten material which contacts the evaporating member.    
     
     
         47 . A method as in  claim 46  wherein the evaporating member is placed in the melting crucible so that at least a portion of the evaporating member extends above the molten material in the melting crucible, and the molten material is drawn up the portion of the evaporating member by electromagnetic forces generated by the electric circuit and evaporated by heat from the portion of the evaporating member extending above the molten material.  
     
     
         48 . A method as in  claim 46  wherein the evaporating member is a rod.  
     
     
         49 . A method as in  claim 46  wherein the melting crucible has an opening for receiving the solid material and the method further comprises feeding the solid material into the melting crucible as the molten material evaporates.  
     
     
         50 . A method as in  claim 49  wherein the feeder automatically feeds the solid material into the melting crucible as the molten material evaporates.  
     
     
         51 . A method as in  claim 46  wherein the heater is an electric arc discharge apparatus.  
     
     
         52 . A vapor deposition coating system comprising: 
 a vacuum cell capable of maintaining a vacuum within the vacuum cell;    a source of coating vapor disposed in the vacuum cell;    a first electrode disposed in the vacuum cell;    a second electrode disposed in the vacuum cell so that there is a gap between the first and second electrodes and coating vapor passes through the gap when the source of coating vapor produces coating vapor;    an electric power supply for supplying electric power to the first and second electrodes so that the first and second electrodes become oppositely charged and create an electric arc discharge between the first and second electrodes; and    a switch connecting the power supply to the first and second electrodes for selectively switching polarity between the first and second electrodes.    
     
     
         53 . A coating system as in  claim 52  wherein: 
 the switch is a first switch;  
 the first and second electrodes form a first pair of electrodes;  
 the coating system further comprises a second pair of electrodes including a third electrode and a fourth electrode spaced from one another so that there is a gap between the third and fourth electrodes and coating vapor passes through the gap when the source of coating vapor produces coating vapor;  
 the electric power supply supplies electric power to the third and fourth electrodes so that the third and fourth electrodes become oppositely charged and create an electric arc discharge between the third and fourth electrodes; and  
 a second switch connecting the power supply to the third and fourth electrodes for selectively switching polarity between the third and fourth electrodes, wherein the first and second switches are phased so that whenever one of the first and second pairs of electrodes is switching polarity, another of the first and second pairs of electrodes has an electric arc discharge therebetween.  
 
     
     
         54 . A coating system as in  claim 52  wherein the switch is capable of automatically and repeatedly switching the polarity between the first and second electrodes.  
     
     
         55 . A coating system as in  claim 52  wherein the electric arc discharge is capable of ionizing the coating vapor in the gap and forming a plasma.  
     
     
         56 . A coating system as in  claim 52  wherein the source of coating vapor is an evaporator for melting and vaporizing a solid material.  
     
     
         57 . A coating system as in  claim 52  wherein the source of coating vapor comprises a plurality of evaporators for melting and vaporizing a plurality of different solid materials.  
     
     
         58 . A coating system as in  claim 52  wherein the first and second electrodes comprise an electrode material which significantly erodes during the electric arc discharge when negatively charged.  
     
     
         59 . A coating system as in  claim 58  wherein the electrode material of the first electrode is different from the electrode material of the second electrode.  
     
     
         60 . A coating system as in  claim 52  wherein the switch is capable of switching the polarity of the first and second electrodes with sufficient frequency to prevent insulating deposits on the electrodes from interrupting the electric arc discharge between the first and second electrodes.  
     
     
         61 . A coating system as in  claim 52  wherein the power supply for the first and second electrodes is controllable independently from power supplied to the coating vapor source.  
     
     
         62 . A method for ionizing a coating vapor in a vapor deposition coating system comprising the steps of: 
 forming a vacuum within a vacuum cell;    supplying a coating vapor in the vacuum cell;    passing the coating vapor through a gap between a first electrode disposed in the vacuum cell and a second electrode disposed in the vacuum cell;    supplying electric power to the first and second electrodes so that the first and second electrodes become oppositely charged and create an electric arc discharge between the first and second electrodes; and    switching polarity between the first and second electrodes while the electric power is supplied to the first and second electrodes.    
     
     
         63 . A method as in  claim 62  wherein the switching step comprises automatically and repeatedly switching the polarity between the first and second electrodes.  
     
     
         64 . A method as in  claim 62  wherein the electric power supply is a DC power supply.  
     
     
         65 . A method as in  claim 62  wherein the electric arc discharge ionizes the coating vapor in the gap and forms a plasma.  
     
     
         66 . A method as in  claim 62  wherein the step of forming the coating vapor comprises melting and vaporizing a solid material.  
     
     
         67 . A method as in  claim 62  wherein the step of forming the coating vapor comprises melting and vaporizing a plurality of different solid materials.  
     
     
         68 . A method as in  claim 62  wherein the first and second electrodes comprise an electrode material which, when negatively charged, vaporizes during the electric arc discharge.  
     
     
         69 . A method as in  claim 68  wherein the electrode material of the first electrode is different from the electrode material of the second electrode.  
     
     
         70 . A method as in  claim 62  wherein the switching step comprises switching the polarity of the first and second electrodes with sufficient frequency to prevent insulating deposits on the electrodes from interrupting the electric arc discharge between the first and second electrodes.  
     
     
         71 . A vapor deposition coating system comprising: 
 a vacuum cell capable of maintaining a vacuum within the vacuum cell;    a source of coating vapor disposed in the vacuum cell;    an electric arc discharge apparatus disposed in the vacuum cell, the electric arc discharge apparatus comprising a cathode, an anodic hood at least partially covering the cathode, and an electrical insulating material connecting the cathode to the anodic hood, the cathode and the anodic hood arranged to form an ionization chamber and the anodic hood having a plasma discharge opening for discharging plasma from the electric arc discharge apparatus; and    an electric power supply for supplying electric power to the electric arc discharge apparatus so that when the electric power supply supplies electric power to the electric arc discharge apparatus, the cathode becomes negatively charged and the anodic hood becomes positively charged so that (a) an electric arc discharge is created between the cathode and the anodic hood in the ionization chamber, (b) the cathode emits electrons and ionizes the coating vapor in the vacuum cell by the source of coating vapor, (c) the cathode vaporizes and forms an ionized cathode vapor within the ionization chamber, and (d) the ionized cathode vapor is emitted from the discharge opening of the anodic hood and mixes with the coating vapor.    
     
     
         72 . A coating system as in claim;  71  further comprising an ignitor for igniting the electric arc discharge in the ionization chamber.  
     
     
         73 . A coating system as in  claim 72  wherein the ignitor includes a electrically conductive element connected to the anodic hood and the power supply and a mechanism for selectively connecting the electrically conductive element to the cathode to ignite the electric arc discharge apparatus, and alternatively, disconnecting the electrically conductive element from the cathode.  
     
     
         74 . A coating system as in  claim 71  wherein the insulating material comprises a sleeve, the cathode comprises a metallic disk disposed in the sleeve, the insulating material comprises a sleeve and the anodic hood tapers from the sleeve to the discharge opening.  
     
     
         75 . A coating system as in  claim 71  wherein the electric power supply is a DC power supply.  
     
     
         76 . A coating system as in  claim 71  wherein the source of coating vapor is an evaporator for melting and vaporizing a solid material.  
     
     
         77 . A coating system as in  claim 71  wherein the source of coating vapor comprises a plurality of evaporators for melting and vaporizing a plurality of different solid materials.  
     
     
         78 . A coating system as in  claim 71  wherein the cathode comprises an electrode material which vaporizes during the electric arc discharge.  
     
     
         79 . A coating system as in  claim 78  wherein the electrode material of the cathode has a composition different from the coating vapor composition.  
     
     
         80 . A coating system as in  claim 71  wherein the power supply for the electric arc discharge apparatus is controllable independently from power supplied to the coating vapor source.  
     
     
         81 . A coating system as in  claim 71  wherein the anodic hood has an interior surface and shields the interior surface and the cathode from the coating vapor.  
     
     
         82 . A method for ionizing a coating vapor in a vapor deposition coating system comprising the steps of: 
 forming a vacuum within a vacuum cell;    supplying a coating vapor in the vacuum cell;    passing the coating vapor adjacent an electric arc discharge apparatus disposed in the vacuum cell, the electric arc discharge apparatus comprising a cathode, an anodic hood at least partially covering the cathode, and an electrical insulating material connecting the cathode to the anodic hood, the cathode and the anodic hood arranged to form an ionization chamber and the anodic hood having a plasma discharge opening;    and    supplying electric power to the electric arc discharge apparatus so that the cathode becomes negatively charged and the anodic hood becomes positively charged so that (a) an electric arc discharge is created between the cathode and the anodic hood in the ionization chamber, (b) the cathode emits electrons and ionizes the coating vapor in the vacuum cell by the source of coating vapor, (c) the cathode vaporizes and forms an ionized cathode vapor within the ionization chamber, and (d) the ionized cathode vapor is emitted from the discharge opening of the anodic hood and mixes with the coating vapor.    
     
     
         83 . A method as in  claim 82  further comprising the step of igniting the electric arc discharge in the ionization chamber.  
     
     
         84 . A method as in  claim 82  wherein the insulating material comprises a cylindrical sleeve, the cathode comprises a metallic disk disposed in the cylindrical sleeve, the insulating material comprises a cylindrical sleeve and the anodic hood comprises a frustoconical shell extending from the cylindrical sleeve to the discharge opening.  
     
     
         85 . A method as in  claim 82  wherein the electric power supplied is DC power.  
     
     
         86 . A method as in  claim 82  wherein the coating vapor is supplied by melting and vaporizing a solid material.  
     
     
         87 . A method as in  claim 82  wherein the coating vapor is supplied by melting and vaporizing a plurality of different solid materials.  
     
     
         88 . A method as in  claim 82  wherein the coating vapor has a composition and the cathode vaporizes to form a composition different from the coating vapor composition.  
     
     
         89 . A method as in  claim 82  further comprising controlling the power supply for the electric arc discharge apparatus independently from power supplied to the coating vapor source.  
     
     
         90 . A continuously fed electrode comprising: 
 a plurality of electrode members which vaporize when discharged in an electric arc discharge;    a housing defining a loading chamber for receiving the electrode members in series; and    an electrode member feeder for continuously feeding the plurality of electrode members, in series, through the housing to an electric arc discharge position so that one of the plurality of electrode members is in the electric arc discharge position at a time.    
     
     
         91 . An electrode as in  claim 90  further comprising a hood for at least partially covering the one electrode member in the electric arc discharge position, the hood including a discharge opening.  
     
     
         92 . An electrode as in  claim 90  wherein the electrode functions as a cathode in an electric arc discharge apparatus.  
     
     
         93 . An electrode as in  claim 90  further comprising a magazine for feeding the plurality of electrode members, in series, into the housing.  
     
     
         94 . An electrode as in  claim 93  wherein the magazine automatically feeds the electrode members into the housing so that the electrode member feeder can continuously feed the plurality of electrode members, in series, through the housing to the electric arc discharge position.  
     
     
         95 . An electrode as in  claim 90  wherein the electrode members each have a cavity in one end and a protrusion in an opposite end so that the protrusions and cavities of the plurality of electrode members mate when the electrode members are fed through and out of the housing.  
     
     
         96 . An electrode as in  claim 90  further comprising a cooler for cooling the one electrode member in the electric arc discharge position.  
     
     
         97 . An electric arc discharge apparatus comprising the continuously fed electrode of  claim 68 , an anode, and an electric power supply for supplying electric power to the one electrode member and the anode so that the one electrode member and the anode become oppositely charged with the one electrode having a cathodic charge and the anode having an anodic charge, and create an electric arc discharge between the one electrode member and the anode, so that the plurality of electrode members are vaporized, in series, at the electric arc discharge position.  
     
     
         98 . An electric arc discharge apparatus comprising the continuously fed electrode of  claim 91  and an electric power supply, wherein: 
 the continuously fed electrode further comprises an electrical insulating material insulating the one electrode member from the hood in the electric arc discharge position;  
 the hood is arranged to form an ionization chamber into which the electrode members are fed from the housing; and  
 when the electric power supply supplies electric power to the electric arc discharge apparatus, the one electrode member in the electric arc discharge position in the ionization chamber becomes negatively charged and the hood becomes positively charged so that an electric arc discharge is created between the one electrode member and the hood in the ionization chamber, the one electrode member emits electrons, vaporizes and forms an ionized cathode vapor within the ionization chamber, and the ionized cathode vapor is emitted from the discharge opening of the hood.  
 
     
     
         99 . A vapor deposition coating system comprising: 
 a vacuum cell capable of maintaining a vacuum within the vacuum cell;    a source of coating vapor disposed in the vacuum cell;    the continuously fed electrode of  claim 90  disposed in the vacuum cell;    a second electrode disposed in the vacuum cell;    an electric power supply for supplying electric power to the one electrode member and the second electrode so that the one electrode member and the second electrode become oppositely charged, create an electric arc discharge, and ionize the coating vapor.    
     
     
         100 . A vapor deposition coating system as in  claim 99  further comprising an evacuation cell for feeding electrode members into the vacuum cell while the vacuum cell maintains a vacuum, the evacuation cell being capable of receiving electrode members from outside the vacuum cell, evacuating air from the evacuation cell under vacuum, and feeding the electrode members into the vacuum cell without disrupting the vacuum within the vacuum cell.  
     
     
         101 . A method for producing an electric arc discharge comprising the steps of: 
 continuously feeding a plurality of electrode members, in series, through an electrode housing to an electric arc discharge position so that one of the plurality of electrode members is in the electric arc discharge position at a time; and    supplying electric power to the one electrode member as the one electrode member is fed to the electric arc discharge position and to a second electrode proximate the one electrode member, so that the one electrode member and the anode become oppositely charged with the one electrode having a cathodic charge and the anode having an anodic charge, and create an electric arc discharge between the one electrode member and the anode, so that the plurality of electrode members are vaporized, in series, at the electric arc discharge position.    
     
     
         102 . A method as in  claim 101  further comprising cooling the electrode members in the electric arc discharge position.  
     
     
         103 . A method for vacuum vapor deposition coating comprising the steps of: 
 forming a vacuum within a vacuum cell;    supplying a coating vapor in the vacuum cell;    producing an electric arc discharge in the vacuum cell in accordance with the method as in claim  101 ; and    passing the coating vapor adjacent the electric arc discharge.    
     
     
         104 . A vapor deposition coating system comprising: 
 an ionized vapor enclosure;    an evaporator for producing coating vapor in the ionized vapor enclosure at a rate of evaporation;    an ionizing source for ionizing the coating vapor to a degree of ionization; and    an apparatus for measuring the rate of evaporation from the evaporator and the degree of ionization of the coating vapor comprising:    an electrically conductive element;    an ammeter connected to the electrically conductive element for measuring electric current through the electrically conductive element;    an electric power supply for supplying electric current to the electrically conductive element through the ammeter; and    a switch for selectively connecting the electric power supply to the electrically conductive element, closing the electric circuit, and causing the power supply to heat the electrically conductive element, and, alternatively, disconnecting the electric power supply from the electrically conductive element, opening the electric circuit, and allowing the electrically conductive element to cool,    wherein, when the switch is open and electric power is supplied to the electrically conductive element, a first circuit is formed and electric current flows from the electric power source, through the electrically conductive element, ammeter, and the ionizing vapor to a ground, and when the switch is closed and electric power is supplied to the electrically conductive element, a second circuit is formed and electric current flows from the power supply, through the electrically conductive element, the ammeter, and the switch.    
     
     
         105 . A measuring apparatus as in  claim 104  further comprising a timer for controlling the opening and closing of the switch.  
     
     
         106 . A measuring apparatus as in  claim 104  wherein the electrically conductive element is positioned in the ionized vapor enclosure such that, when the switch is open and electric power is supplied to the electrically conductive element, the electric current flows from the electrically conductive element to the ionized vapor enclosure and to ground.  
     
     
         107 . A measuring apparatus as in  claim 104  wherein the electrically conductive element is a wire.  
     
     
         108 . A measuring apparatus as in  claim 104  wherein the electrically conductive element is a first electrically conductive element and the measuring apparatus further comprises a second electrically conductive element positioned in the ionized vapor enclosure such that, when the switch is open and electric power is supplied to the first electrically conductive element, the electric current flows from the first electrically conductive element to the second electrically conductive element and to ground.  
     
     
         109 . A method for measuring the degree of ionization in a vapor deposition coating system which comprises an ionized vapor enclosure, an evaporator for producing coating vapor in the ionized vapor enclosure, and an ionizing source for ionizing the coating vapor to a degree of ionization, the method comprising the steps of: 
 exposing an electrically conductive element to the ionized coating vapor in the ionized vapor enclosure;    supplying electric current to the electrically conductive element so that the electric current flows through the electrically conductive element and the ionized vapor to ground; and    measuring electric current through the electrically conductive element with an ammeter.    
     
     
         110 . A method as in  claim 108  wherein the electric power is supplied to the electrically conductive element flows from the electrically conductive element to the ionized vapor enclosure and to ground.  
     
     
         111 . A method as in  claim 108  wherein the electrically conductive element is a wire.  
     
     
         112 . A method for measuring the rate of evaporation from an evaporator in a vapor deposition coating system which comprises an ionized vapor enclosure, the evaporator for producing coating vapor in the ionized vapor enclosure at a rate of evaporation, and an ionizing source for ionizing the coating vapor, the method comprising the steps of: 
 exposing an electrically conductive element to the ionized coating vapor;    supplying electric current to the electrically conductive element and closing a first circuit including the electrically conductive element to heat the electrically conductive element;    opening the first circuit; and thereafter    while still supplying electric current to the electrically conductive element, measuring the rate of change of the electric current through the electrically conductive element and the ionized coating vapor to ground with an ammeter.    
     
     
         113 . A method as in  claim 112  wherein the electric power supply is a DC power supply.  
     
     
         114 . A method as in  claim 112  wherein the electric power is supplied to the electrically conductive element flows from the electrically conductive element to the ionized vapor enclosure and to ground.  
     
     
         115 . A method as in  claim 112  wherein the electrically conductive element is a wire.  
     
     
         116 . A vapor deposition coating system comprising: 
 a vacuum cell having an interior and capable of maintaining a vacuum within the vacuum cell;    a source of ionized coating vapor disposed in the vacuum cell;    an electrode disposed in the vacuum cell; and    an ionizing power supply connected to the electrode for supplying sufficient power to the electrode to ionize gas in the vacuum cell so that the ionized gas removes deposited volatile material from the interior of the vacuum cell.    
     
     
         117 . A vapor deposition coating system as in  claim 116  wherein the ionizing power supply is selected from high frequency, radio frequency, or DC power.  
     
     
         118 . A vapor deposition coating system as in  claim 116  further comprising a plurality of electrodes disposed in the vacuum cell and wherein the power supply is connected to the plurality electrodes for supplying sufficient power to the electrode to ionize gas in the vacuum cell so that the ionized gas removes deposited coating vapor from the interior of the vacuum cell  
     
     
         119 . A vapor deposition coating system as in  claim 116  wherein the ionized gas removes volatile or oxidizable particles deposited from the coating vapor on the interior of the vacuum cell.  
     
     
         120 . A method for removing material deposited in a vacuum cell from a coating vapor in a vapor deposition coating system comprising the step of supplying sufficient ionizing power to an electrode disposed in the vacuum cell to ionize gas in the vacuum cell so that the ionized gas removes the deposited coating vapor from the interior of the vacuum cell.  
     
     
         121 . A method as in  claim 120  further comprising supplying sufficient power to a plurality of electrodes to ionize gas in the vacuum cell so that the ionized gas removes the deposited coating vapor from the interior of the vacuum cell.  
     
     
         122 . A method as in  claim 120  wherein the ionizing power is selected from high frequency, radio frequency, or DC power.  
     
     
         123 . A method as in  claim 120  wherein the ionized gas removes volatile or oxidizable particles deposited from the coating vapor on the interior of the vacuum cell.