Study On The Preparation And Properties Of Conductive Antistray Coatings On Al-Si Alloy Surface

Aluminum-silicon alloy has low density,low thermal expansion coefficient,and good thermal conductivity.It is an ideal optical-mechanical structural material for spacecraft.Ensuring the imaging quality of space-borne detectors requires high-light absorption of the opto-mechanical structure,at the same time,the spacecraft's stable flight in orbit requires the surface structure material to be conductive.Therefore,the preparation of conductive high solar light absorption coating on the surface of aluminum-silicon alloy has wide application value.In this thesis,a combination of micro-arc oxidation technology(MAO)and magnetron sputtering technology(MS)is used to prepare a conductive high solar absorption coating on the surface of an aluminum-silicon alloy,the coating roughness and thickness,micro-morphology,and phase composition were characterized.The solar light absorption and conductivity of the coating were tested,and the changes in coating performance and structure were systematically analyzed.The coating of high solar absorption rate was prepared on the surface of aluminum-silicon alloy by using micro-arc oxidation technology.The influence of electrolyte composition,current density,power frequency and duty cycle on the absorption rate of the coating was studied.XRD analyzed the crystal structure and composition of the coating.The results show that when the electrolyte is composed of sodium hexametaphosphate,sodium silicate,potassium hydroxide and sodium metavanadate,their concentrations are 30g/L,20 g/L,6 g/L and 10 g/L in turn.When the density is 10 A/dm2,the power frequency is 500 Hz,and the duty cycle is 20%-30%-20%,the prepared coating has the highest solar absorption rate of 0.965.XRD analysis results show that the addition of sodium metavanadate additive successfully introduces VO with high solar absorption rate into the coating,which in turn improves the solar absorption rate of the coating.In the experiment,the magnetron sputtering technology was used to prepare AZO transparent conductive film on the micro-arc oxidation coating substrate.The effects of sputtering pressure,sputtering power,substrate temperature and sputtering time on the micro-morphology and performance of the composite coating were studied.The experiment obtained the best magnetron sputtering process parameters: sputtering pressure 0.1 Pa,sputtering power 300 W,substrate temperature 200 ?,sputtering time 120 min,the square resistance of the conductive dissipative light coating prepared under the optimal process parameters 10.3 ?/sq,the solar absorption rate is 0.957,the coating's electrical conductivity has been greatly improved.