8778

8139

كارشناسي ارشد

شناسايي و انتخاب مواد

اصفهان: دانشگاه صنعتي اصفهان، دانشكده مواد

1392

پانزده،86ص.: مصور،جدول،نمودار(رنگي)

ص.ع.به فارسي و انگليسي

فخرالدين اشرفي زاده

3/2/93

حسين ادريس، شهاب ميرآقايي

مهندسي مواد

ID8139

88 Isfahan University of Technology Department of Soil Science Optimization of Optical Properties of Anodizing of Aluminum Impregnated with Nanoparticles for Solar Absorber Coatings Maryam Bagheri Bagheri maryam@ymail com Submitted on December 30 2013 Department of Materials Engineering Isfahan University of Technology Isfahan 84156 83111 IranAbstractSolar absorber is one of the important parts in a solar collector with a surface that musthave high absorbance in the visible and near infrared regions and low emission in theinfrared region The purpose of this study was to optimize the optical properties ofanodizing of aluminum impregnated with nanoparticles for solar absorber coatings Theeffects of key factors such as coating thickness time and voltage of coloring process aswell as the influence of heat treatment zincating ordering of the coating pores and multi step anodizing was evaluated Absorbing surfaces were prepared by anodizing in sulfuricand phosphoric acid followed by a black coloration process using Ni and Cu based bathsand optimal conditions were selected Coatings formed in phosphoric acid had lessthickness and better selective optical properties absorbance 0 9733 and emission 0 2539 than coatings in sulfuric acid Scanning electron microscope SEM and optical microscopewere employed for evaluation of structure and thickness of coatings Optimal conditionobtained at 12 V and 5 min for coloring Effect of heat treatment on optical properties wasinvestigated To this end aluminum substrate was annealed at 400 C in a furnace for 3hour and as coated samples were annealed at 400 500 and 600 C for 1 hour X raydiffraction XRD was used for evaluating the effects of heat treatment on coatingstructure Substrate annealing increased emission with no change in the value ofabsorbance Heat treatment after coloring increased absorbance of the coating Alsoemission was increased by annealing at 400 C but decreased after 500 and 600 Cannealing Zincate treatment was used by immersion in zincate solution for 30 seconds results of energy dispersive spectroscopy EDS analysis and SEM images showed thatzincate treatment before and after coloring decreased absorbance and emission of coatings For ordering the pores the layer created in one step anodization was removed by a mixtureof H3PO4 6 wt and Cr2O3 1 8 wt and anodizing was carried out again Experimental findings showed that ordering of the pores decreased emission In multi stepanodization between the two stages of anodizing the pores have been widened by 5 vol phosphoric acid solution at 30 C The results indicated that two step anodization increasedabsorbance and emission and three step process for low thickness coatings decreasedemission Keywords Anodizing Pigmentation Selective absorber surface Absorption coefficient Emission coefficient Anodic oxide layer

فخرالدين اشرفي زاده

حسين ادريس، شهاب ميرآقايي