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The movement of molecules on the surface of corrosion-resistant vacuum pump is called migration. The gas molecules in thermal motion move from one part of the space to another part of the space, and move the physical quantities from the place with high concentration to the place with small concentration until the physical quantities reach uniform distribution. The diffusion, viscosity and heat conduction of corrosion resistant vacuum pump gas are migration phenomena.

1. Diffusion

The movement of a gas in another medium due to its concentration gradient is called diffusion. The medium can be another gas (in this case the diffusion is called interdiffusion) or it can be a condensable substance.

In a corrosion-resistant vacuum pump, helium permeation through the glass can reach 10-13 L / s. Hydrogen can penetrate iron at 300 ~ 400 ℃, nickel at 450 ℃, glass at 600 ℃, and copper at 640 ℃. Diffusion coefficient. The ratio of the absolute value of the mass flow rate per unit area to the normal concentration gradient per unit area. Diffusion has been widely used in practical technology such as diffusion pump and surface physics.

2. Gas viscosity and heat conduction

The phenomenon of momentum transfer and momentum exchange between layers in any medium is called the viscosity of this medium. The ratio of tangential force to velocity gradient per unit area is the viscosity coefficient.

Based on the contents explained in this paper, we can get a general understanding of the gas migration of corrosion-resistant vacuum pump. As we all know, heat conduction is caused by the energy exchange due to the different temperature of each part of the gas and the thermal movement of gas molecules, which makes the colder part get heat. The heat conduction of gas is related to the level of pressure. I hope the content explained in this paper can help you Use.