Разработка ионно-плазменной технологической установки для нанесения функционального покрытия на крышки масляных фильтров, страница 31

Design of AAL is presented on sheet ХАИ.461.06.ДП.12.ВО.01.

3.7 The critical parameters of the source of ions for surface preparation calculation

For the calculation of critical parameters of AAL intended for clearing of products surfaces from adsorbed molecules of air by ion beam, we shall take advantage of a following technique [19].

Let's define the discharge voltage necessary for reception of established ion energy in the plasma beam from the following ratio [19]:

U_р = E/q_i,                                                    (3.29)

U_р = 1000 В.                                              

At the following stage of calculation we shall define ion speed in the plasma beam under the following formula [19]:

V_i = ,                                                           (3.30)

where m_i  - argon ion  weight,  kg.

V_i ==6.946×10⁵ m/s.                                      

For definition of the mass charge of the working medium we shall take advantage of the formula [19]:

= m_i×j_i/q_i,                                                        (3.31)

==6,632×10^-6 kg/s.                               

3.8 Calculation of magnetic system of a source of ions for preparation of a surface

To maintenance of necessary value of intensity of a magnetic field we apply solenoids through which the constant electric current flows. High efficiency of AAL can be received in that case when the maximum radial components of magnetic field are realized near to the section of the accelerator. Characteristic values of a magnetic field induction in a maximum make (1…5) ×10^-2 tesla. Therefore we shall set value of magnetic field intensity H = 600 h [18].

Structurally we arrange solenoids around of the accelerating channel. As a material of magnetic conductor it is chosen carbonaceous steel with factor of magnetic permeability m = 26 h/m. This steel is a good conductor and has high factor of magnetic permeability.

Value of magnetic field induction we shall define on the following ratio [19]:

B = H×m×m₀                                                                           (3.32)

B ==0.0195 tesla.                                

As already it has been specified above, in AAL exists thin anode layer of ionization. To define thickness of this layer we shall take advantage of the following formula [19]:

L_c = .                                              (3.33)

Knowing value of an induction of magnetic field B, it is possible to define cyclotron electron frequency from the following ratio [19]:

w_е = B×q_i/m_e.                                                      (3.34)

w_е = 3,44×10⁹ hetz                                  

Let's assume, that probability of ionization is 100 %, that is ideal, dissipativeless case. Then frequency of electron-neutral collisions will be equal to frequency of ionization, that is: J₀ = J_I, and consequently their ratio will be equal to unit [19].

Using the formula (3.33) in view of the formula (3.34) we shall calculate value of the anode layer width:

L_c = 3,854×10^{-3 m}.                         

Means, the anode layer  width makes ~4 mm. The width of this layer can be varied, changing magnetic field. The minimal width of the layer is of the larmor electron radius order.

At the following stage of magnetic system calculation it is necessary to carry out a choice of a winding of the solenoid. For this purpose we shall structurally set by following parameters of the solenoid:

- Diameter of the core  d_с = 26 mm;

- Length of the core  wound part L = 30 mm;

- Admissible electric current  density of solenoid  passing through a winding

J = 3 А/мм².

Let's choose as a winding of the solenoid the copper trunk in the size 1.5 mm´6 mm, and we shall make verifying calculation of the coil.

Let's define quantity ampere turns, necessary for maintenance of the established force of the magnetic field, under the following formula [19]: