− artifcially and uniormly artifcially and uniormly 
Electricity and Chemicals requiredElectricity and Chemicals required
− electrical current asses throughelectrical current asses through
aluminum immersed in an acidaluminum immersed in an acid
solutionsolution
 !hat is Anodizing" !hat is Anodizing" It is an electrochemical
o#idation o the aluminum surace to roduce a stable flm
o aluminum o#ide $Al%O&'.
3Aluminum Anodizing
 Abrasion (esistance Abrasion (esistance − only diamond is harder only diamond is harder 
Corrosion (esistanceCorrosion (esistance −  )ithstands salt sray and CA** testing )ithstands salt sray and CA** testing
+hermal (esistance+hermal (esistance − aluminum substrate )ill melt beore the coatingaluminum substrate )ill melt beore the coating
Electrical (esistanceElectrical (esistance − -- required to ass a current through / mil o-- required to ass a current through / mil o
coatingcoating
0orous0orous − allo)s or the coloring and sealing o the coatingallo)s or the coloring and sealing o the coating
 Anodic Coating Anodic Coating
5. Coloring 6. *ealing . 7nrac1ing 8. 0ac1ing /-. 9ab
(ac1ing(ac1ing
0ro:ides a secure connection or0ro:ides a secure connection or transortation o the arts throughtransortation o the arts through the :arious chemical solutionsthe :arious chemical solutions
0ro:ides a secure connection or the0ro:ides a secure connection or the ;o) o electricity through each;o) o electricity through each indi:idual artindi:idual art
 Allo)s or uniormity and consistency Allo)s or uniormity and consistency o current ;o) rom art to arto current ;o) rom art to art
3esmut3esmut Cleaning < heated, nonetching al1aline cleaner $/-Cleaning < heated, nonetching al1aline cleaner $/-
min'min' remo:al o most sho residues and abrication oilsremo:al o most sho residues and abrication oils
no remo:al o adhesi:es, greases, or bu=ing comoundsno remo:al o adhesi:es, greases, or bu=ing comounds
Etching < heated sodium hydro#ide $-<%- min'Etching < heated sodium hydro#ide $-<%- min' roughens the surace to ro:ide a matte fnishroughens the surace to ro:ide a matte fnish
limited success at obscuring scratches, die lines, andlimited success at obscuring scratches, die lines, and
bearing mar1sbearing mar1s
remo:al o aluminum -<%.4 mil $-<54 microns' er sideremo:al o aluminum -<%.4 mil $-<54 microns' er side
3esmutting < ambient acid bath $/<4 min'3esmutting < ambient acid bath $/<4 min' remo:es etch smut resulting rom alloying constituentsremo:es etch smut resulting rom alloying constituents
7Aluminum Anodizing
 Anodizing Anodizing
Immersion in chilled /-> $:?:' suluric acid bathImmersion in chilled /-> $:?:' suluric acid bath 3C current alied at densities o <%- ams?t3C current alied at densities o <%- ams?t%%
− +ime :aries based on coating thic1ness $/-<5- minutes'+ime :aries based on coating thic1ness $/-<5- minutes'
@arrier layer ormed frst to a -.---4 mil thic1ness@arrier layer ormed frst to a -.---4 mil thic1ness Coating builds to a /.- mil $%4.2Coating builds to a /.- mil $%4.2 m' ma#.m' ma#.
thic1nessthic1ness 0ores de:elo as the acid solution dissol:es the0ores de:elo as the acid solution dissol:es the
coatingcoating − %4- < 4-- billion ores er square inch%4- < 4-- billion ores er square inch
0art dimensions increase as the coating is 2->0art dimensions increase as the coating is 2-> enetration and 5-> build<u rom the re<enetration and 5-> build<u rom the re< anodized sur aceanodized sur ace
8Aluminum Anodizing
Cross *ect ona e) o aross ect ona e) o a
3yed and *ealed Anodic3yed and *ealed Anodic
ilmilm
 Aluminum substrate
9Aluminum Anodizing
Clear Clear 
ardcoatardcoat
 Absorti:e dye Absorti:e dye − 7ta1e o organic or inorganic7ta1e o organic or inorganic
moleculesmolecules
Electrolytic +)o<steElectrolytic +)o<ste − +in 3eosition+in 3eosition
− Cobalt 3eositionCobalt 3eosition
Other Other  − Integral Color Integral Color 
− O: erdyeO: erdye
inishinish
Clear Anodic inishClear Anodic inish +ranslucent flm allo)s the aluminum
substrate surace to be :isible Coating thic1ness :aries based uon
secifcation
 Alum. Assoc. A9COA  *ecifcation Coating +hic1ness*ecifcation
 A%/ -./ mil or & microns lash  A%// -./ mil or & microns %-/  A%/% -.% mil or 4 microns %-%  A&/ -.2 mil or /- microns %-2  A2/ -.6 mil or / microns %/4
anodizing Coating $aluminum
igh )ear or abrasi:e alications
3yed Anodic inish3yed Anodic inish  Absortion o either
organic or inorganic molecules into the ores o the coating $%<&- min'
9imitless range o colors
+yically less ade resistance than other colored anodic fnishes
*te %F Electrolytic Color  − AC lating o
metal in the base o the coating ores
− @ronze colors ranging rom Chamagne to
<
14Aluminum Anodizing
*ealing*ealing 7nsealed < E#cellent base or aint and adhesi:es7nsealed < E#cellent base or aint and adhesi:es ydrothermal *eal < %--<%-4 $/4<5- min'ydrothermal *eal < %--<%-4 $/4<5- min'
− +emerature dri:es coating hydration causing coating+emerature dri:es coating hydration causing coating e#ansion to squeeze shut the ores at the suracee#ansion to squeeze shut the ores at the surace
Gid<+emerature *eal )ith Getal *alts < /- Gid<+emerature *eal )ith Getal *alts < /- $/4 min'$/4 min' − 3eosition o metal salts in ores and some sealing by3eosition o metal salts in ores and some sealing by
hydrationhydration
(oom +emerature *eal < 8- $/4 min'(oom +emerature *eal < 8- $/4 min' − Creation o a “suer molecule” at the suraceCreation o a “suer molecule” at the surace
consisting o coating, metal salts, and ;uorideconsisting o coating, metal salts, and ;uoride − 0rone to causing green tints or a uzzy surace0rone to causing green tints or a uzzy surace
0ac1ing0ac1ing
7nrac1ing < irst Insection 0oint7nrac1ing < irst Insection 0oint − Aearance Aearance − Coating +hic1nessCoating +hic1ness − *eal Huality *eal Huality 
0ac1ing < *econd Insection 0oint0ac1ing < *econd Insection 0oint and 0ac1agingand 0ac1aging − +ye+ye − *ize*ize − GaterialsGaterials
9aboratory +esting9aboratory +esting Coating +hic1ness < A*+G @%22 < Eddy CurrentCoating +hic1ness < A*+G @%22 < Eddy Current
Coating !eight < A*+G @/&6 < Acid 3issolutionCoating !eight < A*+G @/&6 < Acid 3issolution
*eal Huality *eal Huality  −  A*+G @/&5 < Godifed 3ye *tain A*+G @/&5 < Godifed 3ye *tain
−  A*+G @5- < Acid 3issolution A*+G @5- < Acid 3issolution
 Abrasion (esistance < E3<*+3</2/ Gethod Abrasion (esistance < E3<*+3</2/ Gethod
5/8%./5/8%./
loss < A*+G 34%&loss < A*+G 34%&
Corrosion (esistanceCorrosion (esistance −  A*+G @//6 < *alt *ray  A*+G @//6 < *alt *ray 
−  A*+G @&5 < CA** A*+G @&5 < CA**
 Anodizing Anodizing
ighly durableighly durable Ine#ensi:e to roduce and maintainIne#ensi:e to roduce and maintain  !onJt chi, ;a1e, eel or chal1  !onJt chi, ;a1e, eel or chal1  Gaintains metallic aearance oGaintains metallic aearance o
aluminumaluminum En:ironmentally riendlyEn:ironmentally riendly
− Bo OCJsBo OCJs − Bo hea:y metalsBo hea:y metals − @yroducts aid municial )aste)ater treatment@yroducts aid municial )aste)ater treatment acilities to searate solids and neutralize acilities to searate solids and neutralize
inishinish
 Accumulated dirt and stains Accumulated dirt and stains
can be remo:ed )ith a mildcan be remo:ed )ith a mild
detergent alied )ith andetergent alied )ith an
abrasi:e cleaning techniqueabrasi:e cleaning technique
 AAGA 5-8./ oluntary uide AAGA 5-8./ oluntary uide
or Cleaning andor Cleaning and
Gaintenance o ArchitecturalGaintenance o Architectural
 Anodized Aluminum Anodized Aluminum
 Alloy and temer selections Alloy and temer selections
Gi#ed alloys < :ariousGi#ed alloys < :arious
roductsroducts − E#trusion, sheet, orming,E#trusion, sheet, orming,
castingcasting
E#trusion deectsE#trusion deects − ot sots, corrosion, die lines,ot sots, corrosion, die lines,
bearing mar1sbearing mar1s
3esignation *ystem or3esignation *ystem or
 Aluminum inishes Aluminum inishes − E#amleF AAG/%C%%A&/E#amleF AAG/%C%%A&/
 )here AA K Aluminum Association )here AA K Aluminum Association
 )here G K Gechanical fnish )here G K Gechanical fnish
 )here C K Chemical retreatment )here C K Chemical retreatment
 )here A K Anodic coating rocess )here A K Anodic coating rocess
0honeF0honeF 462.%5%.254462.%5%.254
a#Fa#F 462.%5%.&2&8462.%5%.&2&8
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%--4 Gay;o)er%--4 Gay;o)er (oad(oad
Biles, GI 28/%-Biles, GI 28/%-
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