| The high specific capacitances of the etched aluminum foils play a key role in the micro-volume of aluminum electrolytic capacitor. This thesis summarizes the current studies and prospects of the enlargement of foils for aluminum electrolytic capacitor and describes D.C etching of high pure aluminum foil for area-enlarging in inorganic mixture acid.By means of weight loss, surface morphology microscopy and cyclic voltammety the effect of etching-solution on the etching behavior of foil and increasing of capacitance is studied and reasonable component and concentration are obtained. At the same time other parameters such as temperature, current density, etching time and so on are studied and more rational process condition are available.The effects of inhibitors additives on the etching of high purity aluminum under the available conditions are studied. It is found that when some aliphatic amines compounds are added to the etching solution the specific capacitances of foil increase at some degree and weight loss decreases. The inhibition efficiencies increase with the length of carbon chains. Then the tunnels of the foils profile more averagely and the capacitances increase.The effects of combined inhibitors on weight loss of foils are studied. For the corporation of the molecular the weight-loss of the foils decreases largely and better inhibition effects can be obtained comparing using single component.When some poly acrylic acid and acrylic acid inhibitors are added to the etching solution it's effect on the etching of high purity aluminum are studied. It is founded that small molecular compounds only slow down the rates of corrosion, while etching occurs at the inner tunnel and the effective area of the foils increases when polymer additives are used. So at the same weight-loss condition higher capacitance is obtained comparing using small molecular compounds. |
