Study On The Residual Stress Of The Metallized Coating On The Hemispherical Harmonic Oscillator

As the core component of inertial navigation system in high-end equipment such as aerospace,HRG plays a decisive role in the flight accuracy and attitude stability of tactical weapons.In the manufacturing process,the metallization coating of the hemispherical resonator is very important,but the film stress has a great influence on the Q value of the resonator,which directly determines the final performance of the hemispherical resonator gyroscope.This paper investigates the research background of the hemispherical harmonic oscillator metallization coating,the comparison and selection of the coating process,the cause and classification of the residual stress,and mainly focuses on the influence of process parameters on the residual stress of the hemispherical harmonic oscillator during the film deposition process.Then the Stoney formula and XRD method for measuring residual stress are introduced,and XRD method was selected for calculation.For the flat quartz glass sheet after coating,the influence of the coating process parameters sputtering rate,deposition time(film thickness),and substrate temperature on the residual stress were studied.The results showed that with the increase of sputtering power,the film stress would increase from the compressive stress first and then decrease,and there was a tendency to transform into tensile stress;with the increase of the film thickness,the film stress decreased slightly and then increased,and was always a compressive stress;The substrate temperature changes multiple factors at the same time,which acted on the residual stress of the film,so no obvious law was shown.The best process parameters of electron beam evaporation were as follows: the sputtering rate was 0.9nm/s and the substrate temperature is 75°C to deposit a 100 nm thick metal film with the smallest residual stress.Annealing experiments were subsequently conducted to explore the influence of annealing process on the residual stress of the film.Annealing gradients of 200°C,300°C,and 400°C were set for the inner and outer curved pieces,and the conclusions were as follows: Annealing is beneficial to promote the polycrystalline transformation of Au particles,and is also beneficial to the elimination of residual stress in the film,but the temperature should not be too high.From the initial state to annealing at 200°C and annealing at 300°C,the residual stress gradually decreases and can be reduced by about half.However,when annealing at 400°C,the residual stress will increase again,but it is still lower than before annealing.The residual stress in the above process All manifested as tensile stress.Annealing experiments were subsequently conducted to explore the influence of annealing process on the residual stress of the film.The most suitable annealing process parameters for the inner sample are as follows: the temperature is increased to 300°C at a constant rate of 3h,the temperature was kept for 2h,and the residual stress of the film is271.5MPa.In summary this article focuses on the surface residual stress of the hemispherical harmonic oscillator after metallization,and studies the influence of sputtering rate,deposition time and substrate temperature on the residual stress of the film during the processing.The subsequent study of the annealing process on the film quality and residual stress.On this basis,the appropriate process parameters in the deposition process are given to ensure that the residual stress of the sample film is minimized.This paper provides the influence rules of some process parameters for the residual stress control technology of curved thin films,and also has important guiding significance for the establishment of the relationship model between the residual stress of the thin film and the Q value of the harmonic oscillator.