Control Stability Of Large Vacuum Magnetron Sputtering Equipment And Preparation Of Electrical Thin Films

Electrical steel is indispensable magnetic materials in electricity, telecommunication and instrumentation industries. Naturally, electrical steel is closely related with national energy consumption. All along, electrical steel production involves complex processes and strict manufacturing technology. Both at home and abroad, production technologies of electrical steel are protected by patents, which is the basis of existence of the business. Generally, electrical steel manufacturing technology and quality is an important indicator of the level of special steel production and national technological development.This dissertation explores the technology that not only injects silicon into cold-rolled steel but also forms the surface insulating film of cold-rolled steel by magnetron sputtering under large vacuum equipment so as to improve the performance of electrical steel. Especially, the control stability is the key during magnetron sputtering under large vacuum equipment.The dissertation studies the working mechanism of magnetron sputtering, and analyzes plasma generation and microphysical processes. Based on the above, the control model that attempts to link charged and neutral particles collision course and collective effects on the atomic scale with the plasma acts at meter level, is built based on energy conservation.According to the feature of magnetron sputtering processes, adaptive fuzzy PI(Proportional integral) control strategy is adopted. Taking advantage of PI rapidity, magnetron sputtering discharge can quickly enter abnormal glow discharge stage; taking advantage of PI characteristic without static error, actual ion current and desired operating current is completely consistent in the steady-state phase of magnetron sputtering system. Simultaneously, using fuzzy rules, PI control parameters are adjusted adaptively, in order to overcome the dynamic instability caused by big overshooting and oscillating during PI control with fixed parameters. Based on the adaptive fuzzy PI(Proportional integral) control method, the current workspace of plasma is not out of working range, which guarantees not only magnetron sputtering discharge against accidentally entering arc discharge from the abnormal glow discharge but also magnetron sputtering power supply and vacuum equipment against being damaged. In summary, using fuzzy control rules adjusting PI parameters adaptively ensures that the vacuum magnetron sputtering equipment works in the best working condition and achieves dynamic stability and static stability during magnetron sputtering coating processes.Magnetron sputtering coating is a dynamic process. In order to meet process requirements, the dissertation proposes the method that determines the stability of the closed-loop system and optimizes system performance based on the deviation te)( and deviation change de(t)/de. On this basis, the fuzzy control rules adjusting online adaptive control parameters is established.Simulation results show that: PI parameters online fuzzy self-tuning provides the technical foundation of system stability and process standards during magnetron sputtering, and magnetron sputtering process can achieve automatic stability control under the variation of system parameters.The experimental results show that: magnetron sputtering technique can achieve deep processing of cold-rolled steel sheet. Magnetron sputtering processing that injects silicon into cold-rolled steel and generates the surface film of cold-rolled, can reduce iron loss, obtain surface insulating film of electrical steel under large vacuum equipment, and improve performance of electrical steel. Comparing artificial coating, magnetron sputtering technique has a high level of automation, produces no toxic substances, and acquires strong adhesion film. It is no doubt that magnetron sputtering process can achieve automatic stability control under the variation of system parameters.