A torch tip is provided for a liquid-cooled plasma arc cutting torch. The torch tip includes an electrode with an elongated electrode body having a distal end and a proximal end extending along a longitudinal axis. The electrode body includes at least one interior threaded connection at the proximal end for engaging a liquid-cooled electrode holder. The electrode holder comprises a liquid coolant channel that does not extend into the electrode body. The electrode body has (i) a length extending along the longitudinal axis and (ii) a diameter associated with a widest portion of the electrode body along the longitudinal axis between the proximal and distal ends, where a ratio of the length to the diameter of the electrode body is greater than about 5.

A torch tip is provided for a liquid-cooled plasma arc cutting torch. The torch tip includes an electrode with an elongated electrode body having a distal end and a proximal end extending along a longitudinal axis. The electrode body includes at least one interior threaded connection at the proximal end for engaging a liquid-cooled electrode holder. The electrode holder comprises a liquid coolant channel that does not extend into the electrode body. The electrode body has (i) a length extending along the longitudinal axis and (ii) a diameter associated with a widest portion of the electrode body along the longitudinal axis between the proximal and distal ends, where a ratio of the length to the diameter of the electrode body is greater than about 5.

Plasma applications are disclosed that operate with argon or helium at atmospheric pressure, and at low temperatures, and with high concentrations of reactive species in the effluent stream. Laminar gas flow is developed prior to forming the plasma and at least one of the electrodes can be heated which enables operation at conditions where the argon or helium plasma would otherwise be unstable and either extinguish, or transition into an arc. The techniques can be employed to clean and activate a metal substrate, including removal of oxidation, thereby enhancing the bonding of at least one other material to the metal.

A method of making and assembling together components of a plasma torch electrode inside an oxygen-free environment. According to one implementation the method includes machining an outer surface of an emitter to produce an oxide free outer surface and machining an opening in a distal end of a main body of the electrode, the opening being bound by an oxide-free inner surface of the main body after the machining. In the oxygen-free environment, the emitter is then secured inside the opening of the main body such that the oxide-free outer surface of the emitter is secured to the oxide-free inner surface of the main body.

A method of making and assembling together components of a plasma torch electrode inside an oxygen-free environment. According to one implementation the method includes machining an outer surface of an emitter to produce an oxide free outer surface and machining an opening in a distal end of a main body of the electrode, the opening being bound by an oxide-free inner surface of the main body after the machining. In the oxygen-free environment, the emitter is then secured inside the opening of the main body such that the oxide-free outer surface of the emitter is secured to the oxide-free inner surface of the main body.

A consumables holder assembly for a plasma arc torch having a torch head, the consumables holder assembly comprising a main body, a shielding cup which engages to the main body, a connection means which engages the main body to the torch head and consumable components including an electrode, a nozzle, a plasma gas distributor, a shielding gas distributor which are all positioned inside the shielding cup, wherein that the consumable holder assembly can be detached from the torch head together with the consumable components and the shielding cup as one unit, wherein the connection means comprises a mechanical attachment mechanism which is engageable with the torch head.

A consumables holder assembly for a plasma arc torch having a torch head, the consumables holder assembly comprising a main body, a shielding cup which engages to the main body, a connection means which engages the main body to the torch head, wherein the consumable components including an electrode, a nozzle, a plasma gas distributor, a shielding gas distributor which are all positioned inside the shielding cup, wherein the consumable holder assembly can be detached from the torch head together with the consumable components and the shielding cup as one unit, wherein the nozzle comprises two focus gas passageways which lead a focus gas out of the nozzle through at least two focus holes, wherein external visual features are provided on both connection means and the torch head which are aligned to each other showing the location of the focus holes.

A consumables holder assembly for a plasma arc torch having a torch head, the consumables holder assembly comprising a main body, a shielding cup which engages to the main body, a connection means which engages the main body to the torch head, wherein the consumable components including an electrode, a nozzle, a plasma gas distributor, a shielding gas distributor which are all positioned inside the shielding cup, wherein the consumable holder assembly can be detached from the torch head together with the consumable components and the shielding cup as one unit, wherein the nozzle comprises two focus gas passageways which lead a focus gas out of the nozzle through at least two focus holes, wherein external visual features are provided on both connection means and the torch head which are aligned to each other showing the location of the focus holes.

A device and a method for fabricating a ceramic reinforced composite coating based on plasma remelting and injection. The device includes a plasma cladding assembly, a powder feeding assembly, a metal-based substrate, and a thermal infrared imager. The plasma cladding assembly comprises a plasma gun and a plasma generator. A plasma arc generated is used to heat the substrate and form a molten pool on the substrate. The powder feeding assembly comprises a powder feeder configured to feed ceramic particles to the molten pool through a powder feeding copper tube. The thermal infrared imager is configured to acquire an infrared image of the molten pool and acquire an optimal injection position of the ceramic particles according to the infrared image. The optimal injection position is a midpoint between a trailing edge of the plasma arc emitted on the substrate and a trailing edge of the molten pool.

A device and a method for fabricating a ceramic reinforced composite coating based on plasma remelting and injection. The device includes a plasma cladding assembly, a powder feeding assembly, a metal-based substrate, and a thermal infrared imager. The plasma cladding assembly comprises a plasma gun and a plasma generator. A plasma arc generated is used to heat the substrate and form a molten pool on the substrate. The powder feeding assembly comprises a powder feeder configured to feed ceramic particles to the molten pool through a powder feeding copper tube. The thermal infrared imager is configured to acquire an infrared image of the molten pool and acquire an optimal injection position of the ceramic particles according to the infrared image. The optimal injection position is a midpoint between a trailing edge of the plasma arc emitted on the substrate and a trailing edge of the molten pool.