Effect Of Energy Parameters On The Growth Of Ceramic Prepared On Aluminum Alloys By Micro-Arc Oxidation

The relationships of arcing time with current density and duty cycle, and of arcing voltage with current density and duty cycle, effect of temperature, duty cycle, voltage on the adhesion strength between ceramic and aluminum alloy, growth kinetics of ceramic, and influence of current density and specimen size upon the polish of ceramic made by micro-arc oxidation have been researched by MAO240/750 micro-arc oxidation power supply, TT260 thickness gauge and WGG60-E4 polish gauge. In addition, JSM6460 SEM and Oxford INCA EDS have been used to analyze surface morphology and element composition of the specimen surfaces, and to compare surface morphology and element content of the samples different-time-oxidized.The results indicate that surface critical condition and energy critical condition for arcing of micro-arc oxidation on aluminum alloy are the whole specimen surface being covered by a layer of AlxOy film and current density 0.2A/dm~2, respectively Before arcing, non-crystalline oxide AlxOy grows on the surface in point- plane mode and after arcing, non-crystalline AlxOy begins to transform to crystalline oxide, and ceramic layer grows in point-line-net-plane mode. Arcing time and arcing voltage fall with the decrease of duty cycle and specimen size, respectively. Solution temperature, duty cycleand voltage all have an effect on the adhesion strength between ceramic and substrate, and with the rising of temperature, duty cycle and voltage, the adhesion strength rises, low limits of temperature, duty cycle and voltage which can satisfy the adhesion strength are 45 ℃, 21 % and 600 V, respectively. And temperature effects adhesion by the means of ionization degree of electrolyte. Duty cycle has no bearing on ceramic's growth, but current density and temperature have great influence on it. Growth speed increases with the rising of current density and temperature. Surface polish is related to not specimen size but current density, at the initial stage, surface polish falls with the increasing of current density, while at the middle and latter stage, it is not effected by current density, and with the prolonging of oxidizing time, the polish becomes worse.