Process of hollow cathode ion coating

The process of hollow cathode ion coating is as follows:

1、Put Chin ingots in the collapse.

2、Mounting the workpiece.

3、After evacuating to 5×10-3Pa, argon gas is introduced into the coating chamber from the silver tube, and the vacuum level is around 100Pa.

4、Turn on the bias power.

5、After turning on the arc power to ignite the hollow cathode discharge.The glow discharge is generated in the button tube,Discharge voltage is 800~1000V,The arc-raising current is 30~50A.Due to the hollow cathode effect of glow discharge,High glow discharge current density,The high density of rat ions in the silver tube bombards the wall of the vantage tube,Make the tube wall rapidly warm up to the emission of electron flow, the discharge mode from the glow discharge sudden change to arc discharge,Voltage is 40~70V,Current is 80~300A.Silver tube temperature reaches above 2300K,Incandescent,Emits a high density stream of arc electrons from the tube,and shot to the anode.

6、Adjustment of vacuum level.The vacuum level for glow discharge from hollow cathode gun is about 100 Pa,And the vacuum degree of coating is 8×10-1~2Pa.Therefore,After ignition of the arc discharge,Reduce the incoming argon gas as soon as possible,Adjust the vacuum level to a range suitable for coating.

7、Titanium plated base layer.Electron flow onto the anodically collapsed Chin metal ingot,Conversion of kinetic energy to thermal energy,Evaporation of Chin metal by heating,Vapor atoms reach the workpiece to form a titanium film.

8、Deposition of TiN.Nitrogen gas is supplied to the coating chamber,Nitrogen gas and evaporated atoms are ionized into nitrogen and titanium ions.Above the crucible,Higher probability of inelastic collisions of titanium vapor atoms with dense streams of low-energy electrons,The metal dissociation rate is as high as 20%~40%.,Titanium ions are more likely to react chemically with the reaction gas nitrogen,Deposition to obtain a nitride mantle film layer.The hollow cathode gun is both a vaporization source，Another source of ionization.During coating,The current of the electromagnetic coil around the crucible should also be adjusted,Focus the electron beam to the center of the collapse,Thus, the power density of electron flow is increased.

9、Power Off.After the film thickness reaches the predetermined film thickness,Turn off arc power supply、Bias power supply and air supply.