In Reply to: Re: need help on aluminizing mirrors posted by charlie on 07/23/01 at 4:50 PM:
Using of glow discharge with spiral cathode on Ar/O2 mixture can take a good help with adhesion.
Parameters of discharge:
Gas mixture: 10% vol. of Ar + 90% vol of O2.
U = 1000V
J = over 3A (when gas pressure is near 1 Pa )
Better material for cathode is Ti wire with diameter 4 mm.
Diameter of spiral cathode is 40 mm. Better length of cathode is 400 mm. With wave number as 50.
Gas mixture must be flowing through vacuum chamber. Vacuum tap must be little open. (not full, because it is no good for oil of vacuum pump flow of oxygen )
After pumping chamber you must take a voltage to the cathode and after this up the pressure and controlling the current.
How only discharge started , it need up and up pressure while current will 1A. In this condition it need 2 minutes for process of activation of surface. After this it need up pressure else while current will 3-5 A. In this case cathode will heating and substrate will heating also. In this condition it need ordinary 2-4 minutes for little heating of substrate.