Разработка ионно-плазменной технологической установки для нанесения функционального покрытия на крышки масляных фильтров, страница 30

Now there is no reliable not destroying method of the adhesion estimation of coverings. The method of kinetics research of non-stationary reevaporation of metals atoms at films formation in vacuum is developed for qualitative assessment of adhesion. It is not destroying method of the qualitative control of formed coverings adhesion. The metal atoms stream gets from the evaporator on a substrate and the quartz sensor, and the corresponding record of evaporation speed (on the weight gain of a films metal on the sensor in unit of time) is made on the tape of the device. At hit of the atoms stream from the evaporator on a substrate the part of atoms is reflected from its surface. Especially strong reflection is characteristic for an initial stage of evaporation and condensation before formation of continuous film. The reflected stream of atoms gets on the sensor of reevapourated stream. Reflection speed is fixed on the weight gain of the reflected atoms stream. The ratio between weights of the reflected and evaporated atoms characterizes condensation factor of metal at different stages of film formation and growth during its receiving.


3.6 Description of the source of ions for surface preparation design

For clearing of products surface at a final stage of surface preparation before deposition of covering the accelerator with an anode layer is used. For effective clearing of surface quantity and an arrangement of accelerators it is chosen similar to MAS, i.e. nine accelerators, two for clearing of lateral surfaces of everyone row of products, and one for clearing of each bottom.

The plasma electromagnetic accelerator with electric acceleration of ions in an anode layer (AAL) represents a source of the accelerated stream of plasma. It is formed and accelerated in the discharge on the working medium "burning" in crossed electric and magnetic fields. The accelerator consists of the anode-gas distributor, the cathode, the discharge chamber limiting the accelerating channel, the magnetic system containing of the magnetization coil and magnetic conductor.

The magnetic system is designed in such a manner that in the ring accelerating channel mainly radial magnetic field is realized. The discharge voltage is enclosed between the anode and the cathode, and the electric field in the channel is directed approximately in parallel to the accelerator axis. The working gas moves in the accelerating channel, through the anode-gas distributor though use of the separate gas distributor [18] is possible.

The accelerator works as follows. The working medium acting in the channel near to the anode is ionized by electrons, moving under action of an electric field from the cathode to the anode in a cross-section magnetic field.

The value of the magnetic field induction selects in such a manner that larmor electron and ion radiuses, calculated on energy, satisfied to condition [18]:

RЛe << L <<RЛi,                                           (3.28)

where L-characteristic size of the acceleration zone.

Ions, by virtue of condition (3.28), practically not magnetized, move mainly along an electric field and are accelerated in this field. The stream expiring from the accelerator "grasps" with itself necessary quantity of electrons and creates a stream of ions with demanded energy.

Drifting in an azimuthal direction electrons compensate a volumetric charge of ions in the channel of the accelerator [18].

As the cathode in AAL is used the gas-discharge source of electrons similar to the  hollow cathode containing thermo-emitter of electrons, streamlined by a working substance stream and warmed up by a heater. Ignition of a charge in it is carried out by means of a trigger electrode. On operating conditions electrons, leaving from the cathode, are accelerated in cathode change of potential at the emitter surface and ionize atoms of working substance which are being near to this surface. One part of electrons gets in the accelerating channel, and another leaves with expiring from the accelerator ions stream [19].