******* PSDS GENERATED *******

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1 This process is covered by U. S. Patent No. 4,894,127 (Method for Anodizing Aluminum) and U. S. Patent No. 4,504,325 (Methods for Sealing on Aluminum Oxide Film). Patent licenses are available. For information, contact Chief Patent Counsel, Boeing Commercial Airplane Group, P. O. Box 3707, Seattle, Washington , U.S.A. 1 SCOPE NOTE: Incorporated PSDs: 6 38, 6 41, 6 42, 6 44, 6 47, 6 49, 6 52, 6 53, 6 56, 6 57 Cancelled PSDs: None a. This specification establishes the requirements for boric acid sulfuric acid anodizing of all aluminum and aluminum alloys. b. It is acceptable for qualified processors to process hardware in accordance with a Manufacturing Process Control Document (MPCD) as defined herein. Prior to issuing an MPCD, the facility is required to have a Boeing approved Operating Procedure (OP) governing the use of MPCDs. Boeing approved OPs are listed in BSS7023. Facilities not operating to a MPCD in accordance with BSS7023, are not exempt from the provisions of this specification and shall use the reliable process method given. c. With the exception of Class 5, anodizing in accordance with this specification meets the performance requirements of MIL A 8625, Type I and Type IC. ÈÈÈÈÈ ÈÈÈÈÈ WARNING WARNINGs may be included throughout this specification. Do not take these WARNINGs to be all inclusive, nor to completely describe hazards or precautionary measures applicable to specific procedures or operating environments. Non Boeing personnel must refer to their employer s safety instructions for information concerning hazards which may occur during operations described in this specification. : 10 JUL 1990 REV: Authorizing Signatures on File REFER TO NUMERICAL INDEX FOR PSD ACTIVITY INFORMATION CAGE CODE (C) 24 MAY 1999 (D) 03 AUG 2004 BORIC ACID SULFURIC ACID ANODIZING BOEING PROCESS SPECIFICATION PAGE 1 of 21

2 2 CLASSIFICATION ******* PSDS GENERATED ******* This process specification consists of the following Classes of anodic coatings: Class 1 Class 2 Class 5 A coating with specific sealing requirements. Class 1 coating meets the performance requirement of MIL A 8625, Types I and IC and is suitable for use in service where paint adhesion is especially critical. Reserved for future use. An unsealed coating. Class 5 coatings will ensure maximum organic coating adhesion. They do not require salt spray corrosion testing. When drawings call out and no class is indicated, Class 1 applies. 3 REFERENCES The current issue of the following documents shall be considered a part of this specification to the extent herein indicated. ANSI/ASQC Z1.4 Sampling Procedures and Tables for Inspection by Attributes ASTM B 117 Salt Spray (Fog) Testing ASTM B 137 Weight of Coating on Anodically Coated Aluminum, Measurement of 5300 Forming, Straightening and Fitting Metal Parts 5408 Vapor Degreasing 5514 Common Bonding Requirements for Structural Adhesives 5626 Colored Chemical Conversion Coatings for Aluminum 5716 Preparation of Colored Anodic Films 5719 Chemical Conversion Coatings for Aluminum and Aluminum Alloys 5744 Manual Cleaning (Cold Alkaline, Solvent Emulsion and Foam Cleaners) 5748 Abrasive Cleaning, Deburring and Finishing 5749 Alkaline Cleaning 5750 Solvent Cleaning 5763 Emulsion Cleaning and Aqueous Degreasing 5765 Cleaning and Deoxidizing Aluminum Alloys 5771 Stripping Inorganic Finishes 5786 Etch Cleaning of Aluminum Alloys 5946 Temper Inspection of Aluminum Alloys BMS10 11 Chemical and Solvent Resistant Finish BSS7023 Manufacturing Facilities with Approved Operating Procedures for Manufacturing Process Control Documents Page 2

3 3 REFERENCES (Continued) ******* PSDS GENERATED ******* BSS7217 Air Cleanliness, Shop Compressed Air BSS7219 Intergranular Attack, Test Method BSS7286 Statistical Process Control of Designated Engineering Characteristics BSS7325 Gravimetric Method for Determining the Percent Hydration of Sealed Anodic Coatings BSS7343 Nondestructively Determining Presence of Non Visible Coatings, Test Method Using Resistance Probe MIL A 8625 Anodic Coatings for Aluminum and Aluminum Alloys 4 CONTENTS Section Subject Page 1 SCOPE CLASSIFICATION REFERENCES CONTENTS MATERIALS CONTROL FACILITIES CONTROL DEFINITIONS MANUFACTURING CONTROL PRECLEANING MASKING AND RACKING ALKALINE CLEANING DEOXIDIZING ANODIZING SEALING CLASS 5 PROCESSING OF PARTS WHICH ARE NOT TO BE SEALED TOUCH UP REWORK Page 3

4 4 CONTENTS (Continued) ******* PSDS GENERATED ******* Section Subject Page 9 MAINTENANCE CONTROL BORIC ACID SULFURIC ACID ANODIZING SOLUTION DILUTE CHROMATE SEAL SOLUTION RINSE WATER QUALITY CONTROL REQUIREMENTS REQUIREMENTS FOR RELIABLE PROCESS USERS REQUIREMENTS FOR MANUFACTURING PROCESS CONTROL DOCUMENT USERS TEST METHODS COATING WEIGHT CORROSION RESISTANCE QUALIFICATION LIST OF FIGURES Number Title Page FIGURE 1 CUT AND SCRATCH DEFECTS LIST OF TABLES Number Title Page TABLE I KEY CHARACTERISTICS FOR BORIC ACID SULFURIC ACID ANODIZED PARTS TABLE II KEY PROCESS PARAMETERS FOR BORIC ACID SULFURIC ACID ANODIZED PARTS Page 4

5 5 MATERIALS CONTROL ******* PSDS GENERATED ******* The following is considered part of the reliable process method. The listed non deliverable (non flyaway) materials have been found to be satisfactory for the process. In accordance with the approved operating procedure listed in BSS7023, other materials which are satisfactory when tested to the requirements of Section 11 may be used and shall be called out in an MPCD. a. Benzoic acid, 99.0 percent minimum C 6 H 5 COOH, any commercial source b. Benzoic acid sodium salt (sodium benzoate), 99.0 percent minimum C 6 H 5 COONa, any commercial source c. Boric acid, 99.8 percent minimum as H 3 BO 3, 200 ppm maximum chloride as Cl, any commercial source d. Cheesecloth, Class A, woven, BMS15 5 e. Chromic acid (chromium trioxide, CrO 3 ), O C 303 f. Magnesium chromate pentahydrate (MgCr0 4. 5H2 O), any commercial source g. Phosphoric acid, H 3 PO 4, 75 or 85 percent, O O 670 h. Sodium chromate, anhydrous (Na 2 CrO 4 ), O S 588 i. Sodium hydroxide (NaOH), flake or bead, O S 598 j. Sulfuric Acid meeting one of the following: (1) Sulfuric Acid, Electrolyte (for storage batteries), 0 S 801, Class 1, 2, 3 or 4. (2) Sulfuric Acid, any source, which meets the Material, Color, Acid Content, and Impurities requirements of 0 S 801, Class 1, 2, 3, or 4. With the exception that manganese may be up to 5 times the percent by weight specified in 0 S 801. k. Potassium chromate, anhydrous (K 2 CrO 4 ), any commercial source l. Maskants (1) Adcoat AC 828, AC Products, Inc. (2) Aluminum Tape No. 424, 3M Company (3) Turco 5696, Turco Products, Inc. a Division of Purex Corp. (4) Any maskant proven to be inert to the process solutions while providing acceptable line definitions. NOTE: Foreign processors may use their corresponding Government specifications in lieu of the U.S. Government specifications for procurement of chemicals, provided the chemicals contain less than 0.1 percent NaCl and less the 0.2 percent SO 4 (Sodium chromate shall contain less than one percent SO 4 ). Page 5

6 6 FACILITIES CONTROL ******* PSDS GENERATED ******* The following is considered part of the reliable process method. In accordance with the approved operating procedure listed in BSS7023, any MPCD documented facilities controls which meet the requirements of Section 11 may be used instead or in addition. Additional facilities controls shall be called out in a MPCD. a. The cathode area may be provided by the walls of a Type 316L or Type 304L stainless steel anodizing tank, or by separate lead, commercially pure titanium or Types 316L, 304L, and 321 stainless steel cathodes if a nonconductive tank is used. The cathodes shall have a surface area of not less than one half the surface area of the work load. Standoff insulation shall be provided to ensure that neither the parts nor the rack contact the cathodes during anodizing. b. The power supply shall be capable of automatically ramping the voltage at the start of the process at a rate of 3 to 5 volts/minute and controlling the required voltage within ± 1 volt. c. Process tanks shall be equipped with cooling, heating and agitation as required to maintain the bath temperature ranges specified in Section 9. Temperature shall be monitored continuously by certified temperature gages. d. Rinse water or process solutions operated at ambient conditions do not require continuous temperature monitoring. Monitoring of bath temperatures shall be performed at regular intervals determined through experience. e. Anodizing racks shall be made from aluminum or titanium, or from aluminum with titanium tips. Racks shall secure the parts so that good, forced, nonshifting electrical contact with a minimum of contact area is attained. f. When the interior surfaces of hollow members require anodizing, use special internal cathodes if the ratio of the length to the diameter is greater than 8 to 1. g. Compressed air used for solution agitation or for drying of parts shall be free of water, oil and solid particles when tested in accordance with BSS7217. h. Instrumentation used to monitor the power supply shall be certified to ± 5 percent of reading for digital instrumentation. The range selected for an analog meter shall be such that the maximum process voltage is at least 15 percent of the meter reading. Page 6

7 7 DEFINITIONS The following definitions shall apply to terms which are uncommon or have special meaning as used in this specification. Acceptable scribe line Scratches that are the result of scribing or scraping are allowed providing the character of the scribe line has been reduced by mechanical means from a sharp notch to a smooth depression with a width to depth ratio of at least 9 to 1. The smoothed depression depth shall not exceed 5.0 percent of nominal metal thickness. See Figure 1. Maskant Aluminum Surface Possible knife cut produced during scribing of maskant Not Acceptable 9 X (Min) X Possible cut, scratch or mark produced during scribing of maskant Acceptable FIGURE 1 CUT AND SCRATCH DEFECTS Key Characteristic (KC) A measurable feature whose variation has the greatest impact on the fit, form, performance, or service life of the finished part from the perspective of the customer. This feature may be measured directly or indirectly through a secondary set of process parameters. Key Process Parameter (KPP) Process parameters which contribute to variation of a key characteristic. These are most effectively determined by the use of designed experiments. Manufacturing Process Control Document (MPCD) A document, authorized by a process specification which provides processing requirements unique to a supplier, facility or division. Operating Procedure (OP) A document owned by Operations (and listed in BSS7023) that defines the responsibilities of the participant, establishes the accountability for changes, and establishes the maintenance and implementation of a MPCD. Reliable Process Method A manufacturing process defined in the process specification, established through testing or practice which allows the processor to meet the end item requirements. This process is optional when a MPCD is used. Water Break Free A water break free surface is a surface which maintains a continuous water film for a period of at least 30 seconds after having been sprayed or immersion rinsed in clean water at a temperature below 100 F. Page 7

8 8 MANUFACTURING CONTROL ******* PSDS GENERATED ******* ÈÈÈÈÈ WARNING This specification involves the use of chemical substances which are hazardous. Boeing personnel shall refer to the work area Hazard Communication Handbook for health effect and control measure information contained in the HazCom Info Sheets and Material Safety Data Sheets. For disposition of hazardous waste materials, consult site environmental engineers for proper disposal methods. Non Boeing personnel should refer to manufacturer s Material Safety Data Sheet(s) and their employer s safety instructions. This is the reliable method for this process. In accordance with the approved operating procedure listed in BSS7023, any MPCD documented procedure which meets the requirements of Section 11 may be used instead. Document rework as required by the applicable quality assurance provisions. a. Anodize parts after fabrication is completed and prior to assembly, except that operations that shall be performed during installation, such as trimming, drilling, etc., may be accomplished after anodizing. Close tolerance holes (± inch tolerance) drilled before or after anodizing may be brush Alodined in accordance with 5719, Type II, Class A or 5626, Type II, Class A requirements. Remove nonaluminum metal parts, such as inserts, before anodizing, whenever practical. Areas of parts not to be anodized, including dissimilar metal inserts, shall be masked or plugged. b. Do not anodize parts that are held in a stressed condition (i.e., clamped in a twisted or highly flexed position). c. Before racking parts for anodize, aluminum rack contact areas shall be stripped of anodic coating in accordance with d. Process parts from one step to the next without delay and without allowing the parts to dry. e. Immerse parts completely in the solutions during this process. f. When it is necessary to handle wet parts, wear clean latex rubber gloves. After anodizing, handle dry parts only with clean fabric gloves. g. Do not subject anodized parts to any operation, such as tumbling, sanding, or scraping, that will abrade the anodic film. h. Monitoring of bath temperatures shall be performed at regular intervals determined through experience. i. Keep bus bars clean to ensure good electrical contacts. Page 8

9 8 MANUFACTURING CONTROL (Continued) Anodizing Process Flow Diagram Preclean if Necessary (Section 8.1) Mask as Necessary (Section 8.2) Rack (Section 8.2) Alkaline Clean and Rinse (Section 8.3) Deoxidize and Rinse (Section 8.4) Anodize and Rinse (Section 8.5) Seal and Dry (Section 8.6) Dry Class 5 (Section 8.5) 8.1 PRECLEANING If needed, vapor degrease in accordance with 5408, emulsion clean in accordance with 5763, solvent clean in accordance with 5750, manual clean in accordance with 5744, alkaline clean in accordance with 5749, or a combination thereof. An optional deoxidize in accordance with 5765 may be used after alkaline cleaning to ensure maskant adhesion. Parts with open faying surfaces or spot welded joints where solution entrapment is possible shall be immersed in cold water (or in hot and cold water) for 2 minutes minimum after precleaning. Parts not requiring masking may be racked for anodizing prior to precleaning. Page 9

10 8.2 MASKING AND RACKING ******* PSDS GENERATED ******* a. Mask off any dissimilar metal inserts and any other areas required to achieve drawing requirements using materials in accordance with Section 5l. (1) If maskant scribing is required, and no subsequent 5772 chemical milling will be performed, use a scribing technique which does not cause a detrimental surface defect on the metal. Preferable practice is to scribe in such a way that the maskant is not completely penetrated. If the maskant is penetrated, the resulting scribe mark or line in the metal surface shall not have less than a 9 to 1 width to depth ratio. Refer to Section 7 for definition. CAUTION Scribe marks or cuts which penetrate the metal surface may cause loss of fatigue life. (2) A known method to meet the above criteria is the use of a soldering iron with a tip radius greater than inch. The operator shall use care to avoid cutting completely through the maskant. If the maskant is penetrated the criterion for acceptability of the resulting mark or cut on the metal surface is given in Section 8.2a.(1). b. Plug the ends of oxygen tubing. c. Position parts on rack for anodizing so that gas cannot be trapped and prevent solution contact and to facilitate solution draining from machined pockets, blind holes, flange webs, et cetera, consistent with specification requirements to anodize all surfaces. 8.3 ALKALINE CLEANING Alkaline clean and rinse in accordance with 5749 except for parts with open faying surfaces or spot welded joints, in which case, rinsing shall be for at least 10 minutes using agitation with multiple immersions (a minimum of 4 times) followed by manual spray rinsing as required to prevent solution entrapment. OPTION: Detail parts may be alkaline etch cleaned using etchant solutions in accordance with DEOXIDIZING Adhesive bonded metal to metal assemblies (5514), that will not entrap processing solutions, may be alkaline etch cleaned using etchant solutions in accordance with 5786, Type II. The maximum amount of metal removal per surface shall be limited to inch. Deoxidize and rinse in accordance with 5765 except that for parts where solution entrapment is possible, rinsing shall be accomplished using the method in Section 8.3. Deoxidizing is optional where a non directional sanded finish is specified. Parts that have been alkaline etch cleaned only need to be desmutted, not deoxidized. Deoxidize castings by either of the following methods. a. Deoxidize in accordance with 5765 (Solution 18, 27A, 29, 37, 38, or 39). If smut appears, rinse and desmut in accordance with 5765 (Solution 18, 27A, 29, 37, 38, or 39) for 10 to 30 seconds and then rinse for 10 minutes minimum. b. Dry abrasive blast castings in accordance with 5748, Type II, Class 1 and rinse. Page 10

11 8.5 ANODIZING Anodize in the Section 9.1 solution as follows: a. Use moderate agitation of the anodize solution by air or mechanical stirring during the anodize cycle. b. Lower parts into bath with current on, or apply current within 2 minutes after the start of immersion. c. Obtain 15 ± 1 volts DC with an initial setting of 5 volts maximum and a rate of increase of 5 volts/minutes maximum. Achieve 15 ± 1 volts DC within 7 minutes after application of voltage. CAUTION This procedure is critical to avoid burning of parts. 8.6 SEALING d. Anodize for 18 to 22 minutes after reaching 15 ± 1 volts. e. Remove parts from anodizing tank within 2 minutes after current is stopped. Rinsing shall commence within 3 minutes maximum after current is stopped. Failure to adhere to these limits can cause coating degradation. f. Rinse parts in cold water (maximum 95 F (35 C)) for 3 to 15 minutes (Section 9.3). Rinsing for parts where solution entrapment is possible shall be accomplished in accordance with Section 8.3. g. When parts are to be sealed proceed to Section 8.6. h. When parts are not to be sealed (Class 5), dry thoroughly at 190 F (88 C) maximum and proceed to Section 8.7. a. Seal Class 1 parts in dilute chromate solution (Section 9.2) for 23 to 28 minutes. b. Dry thoroughly. Drying temperature shall be 160 F (71 C) maximum. Keep parts clean and dry. Handle in accordance with Section 8f. until the final finish has been applied. c. For parts to be primed with BMS10 11, Type I, Grade A or B: Sealing solution entrapped in part areas which do not drain shall be removed prior to drying in accordance with Section 8.6b. by any of the following methods: (1) Compressed air at 30 psig maximum pressure (assure that relevant health and safety precautions are observed) (2) Cold water spray (10 seconds maximum impingement time at 50 psig maximum pressure on a given area) (3) Cold water immersion in rinse water meeting the requirements of Section 9.3b. (shortest time possible, but one minute maximum immersion time) (4) Absorbing in cheesecloth (Section 5d.) (5) Tipping, tilting to facilitate gravity draining Page 11

12 8.6 SEALING (Continued) ******* PSDS GENERATED ******* d. For parts to be primed with any primer other than BMS10 11, Type I, Grade A or Grade B: Any of the above methods may be used in any areas to remove dilute chromate sealing solution residue which may cause unacceptable appearance. 8.7 CLASS 5 PROCESSING OF PARTS WHICH ARE NOT TO BE SEALED 8.8 TOUCH UP 8.9 REWORK a. Keep parts clean and dry, with as little handling as possible. Handle in accordance with Section 8f. with clean lint free gloves. Avoid contact with oily, contaminated surfaces. Begin application of the required primer coating within 16 hours maximum after anodizing. b. Small areas of parts that have been contaminated with foreign substances after anodizing and before application of the first primer coating may be cleaned with water meeting the requirements of Section 9.3b. or with solvent in accordance with Dry area thoroughly prior to primer coating. Liquid droplets and light, non oily surface particles may be removed by use of compressed air (Section 6g.). c. Anodized parts which have exceeded the time limit in Section 8.7a. or have contamination that cannot be removed in accordance with Section 8.7b. shall be stripped in accordance with 5771 and reanodized in accordance with this specification one time only. Parts with the following localized imperfections shall be touched up in accordance with 5719, Type II, Class A, or in accordance with 5626, Type II, Class A, provided the parts are subsequently painted. The total area of touch up shall not exceed 5 percent of the total anodized area. a. Scratches and abrasion to the base metal shall be evaluated and reworked in accordance with 5300 prior to conversion coating touch up application. b. Rack marks and contact points which exceed the allowances as specified in Section 11.1h. All rework shall be authorized and documented in accordance with the applicable Quality Assurance provisions. Parts not meeting the requirements of Section 11 shall be stripped in accordance with 5771, and reprocessed in accordance with this specification one time only. 9 MAINTENANCE CONTROL The following is considered part of the reliable process method. In accordance with the approved operating procedure listed in BSS7023, any MPCD documented maintenance controls which meet the requirements of Section 11 may be used instead of or in addition. Page 12

13 9.1 BORIC ACID SULFURIC ACID ANODIZING SOLUTION a. Make up the solution at a nominal concentration of 45 g/l sulfuric acid (Section 5j.) and 8 g/l boric acid (Section 5c.) in water. b. Maintain the solution within the following limits: Sulfuric acid 30.5 to 52.0 g/l (3 to 5 percent by weight as H 2 SO 4 ) Boric acid 5.2 to 10.7 g/l (0.5 to 1.0 percent by weight as H 3 BO 3 ) Aluminum 5.5 g/l maximum as Al Copper 237 ppm maximum as Cu Chlorides 0.1 g/l maximum as NaCl Total chromium 500 ppm maximum as Cr Temperature 80 ± 4 F (26.7 ± 2.2 C) Maintain the solution by adding sulfuric acid (Section 5j.) and boric acid (Section 5c.) or by removing solution and adding water, sulfuric acid (Section 5j.) and boric acid (Section 5c.). c. To limit fungus growth, benzoic acid (Section 5a.) or sodium benzoate (Section 5b.) can be added to a maximum concentration in the bath of 1,000 ppm (0.10 percent by weight C 6 H 5 COO ). NOTE: The solid benzoic acid flakes are sparingly soluble at bath temperature. Therefore, for adds to a bath, the benzoic acid should be dissolved in warm water at a concentration less than 2 g/l. The concentrated solution may be added to the bath as part of makeup water or it may be used as part of the initial bath charge. Processing is not allowed if undissolved flakes are viewable on the surface. Sodium benzoate may be added directly to the bath and it will quickly dissolve. 9.2 DILUTE CHROMATE SEAL SOLUTION a. Make up to a nominal concentration of 26 g/100 gal. (approximately 70 ppm) chromic acid (Section 5e.) and 18 g/100 gal. sodium chromate (Section 5h.) or 26g/100 gal. magnesium chromate (Section 5f.) or 22 g/100 gal. potassium chromate (Section 5k.) in deionized water. b. Maintain the solution within the following limits: Hexavalent chromium 45 to 100 ppm as Cr +6 ph 3.2 to 3.8 Silicates 10 ppm maximum as SiO 2 Total dissolved solids 250 ppm maximum Temperature 195 ± 5 F (90.6 ± 2.8 C) Maintain ph and Cr +6 by adding either chromic acid (Section 5e.), sodium chromate (Section 5h.), potassium chromate (Section 5k.), magnesium chromate (Section 5f.) or sodium hydroxide (Section 5i.). Discard or purify the solution when silicates or total dissolved solids reach the upper limits. Page 13

14 9.2 DILUTE CHROMATE SEAL SOLUTION (Continued) 9.3 RINSE WATER c. Use deionized water for solution makeup and replenishment. d. The sealing solution shall be maintained free of visible sediment. a. Incoming solution makeup and rinse water shall meet the following requirements (reference World Health Organization, International Water Standards for Drinking Water, 3rd Edition, WHO, Geneva, 1971): Total Solids 500 ppm maximum Chloride 25 ppm maximum Fluoride 1.7 ppm maximum ph 5.5 to 8.0 b. Final immersion rinse water after anodizing shall be 1000 ppm maximum total dissolved solids (TDS). Control ph of final rinse after anodizing at 2.5 to 8.0. When double immersion rinse is used after anodizing, first rinse shall be 5000 ppm maximum TDS. c. To limit biocontamination growth, sodium benzoate (Section 5b.) can be added to a maximum concentration of 500 ppm (C 6 H 5 COO ) by weight in the first rinse of a double counter current rinse (DCCR) system. 10 QUALITY CONTROL Assure that the requirements of this specification are met by monitoring the process and examining the end items in accordance with established quality assurance provisions. a. The following is considered part of the reliable process method. In accordance with the approved operating procedure listed in BSS7023, any MPCD documented quality control procedures which meet the requirements of Section 11 may be used instead or in addition. (1) Conduct sampling for visual inspection of coating appearance in accordance with ANSI/ASQC Z1.4 or equivalent with an Average Outgoing Quality Limit (AOQL) of 1.5 percent. (2) Solution chemistry, water purity, air cleanliness, voltages, amperages, and temperature shall be verified at a frequency based on production experience. Records of all analyses, additions, purifications or withdrawals required to comply with this specification shall be maintained. (3) Ensure that sealing is performed in accordance with Section 8.6a. Page 14

15 10 QUALITY CONTROL (Continued) ******* PSDS GENERATED ******* (4) Coating weight in accordance with Section 11.1d. and posting of seal time, examination of stripped surfaces, and corrosion resistance testing in accordance with Section 11.1e., shall be accomplished at least monthly. However, disposition of Class 5 parts is not affected by the results of corrosion resistance testing. Corrosion resistance testing shall also be accomplished whenever the anodizing procedure is changed to utilize a different approved brand of deoxidizer or type of sealing solution. Production may continue without restriction during corrosion testing provided the solutions are maintained in strict compliance with all specification requirements. (5) Anodize voltage (Sections 8.5c. and 8.5d.) and anodize time (Section 8.5d.) shall be verified to assure that the specification range is adhered to. Noncompliance could have adverse effect on fatigue life of parts. b. When a MPCD is used, the following shall apply. (1) Identify key process parameters (KPPs) and maintain documentation to ensure the process is being operated in accordance with the MPCD. (2) Perform any test necessary to ensure that process changes made to the MPCD meet the requirements of this specification. (3) Verification intervals shall be based on statistically valid data as documented in the MPCD. The MPCD shall be an integral part of the processor s continuous quality improvement system and shall establish procedures and requirements of statistical process control in accordance with BSS REQUIREMENTS 11.1 REQUIREMENTS FOR RELIABLE PROCESS USERS Section 11.1 is not applicable when operating to a MPCD in accordance with an approved operating process listed in BSS7023. a. Anodizing in accordance with this specification shall produce light gray coatings prior to sealing, the exact shade varying with alloy and surface condition. Color intensity and uniformity are not a gage of coating quality (corrosion resistance). Appearance of a golden tint after sealing in the Section 9.2 solution is acceptable. Staining from residual dilute chromate anodize sealing solution, after treatment in accordance with Section 8.6c., shall not be cause for rejection. Coating presence can be nondestructively verified by use of the Resistance Probe in accordance with BSS7343. Page 15

16 11.1 REQUIREMENTS FOR RELIABLE PROCESS USERS (Continued) b. Parts shall be free of burned areas and areas that are not anodized. Contact areas as defined in Section 11.1h. shall not be cause for rejection. c. All parts made from extrusions, plate, castings, or forgings, and machined, formed and welded parts, shall be free of surface cracks and pits when viewed without magnification. Examine immediately after completion of the anodizing process. Solution bleedout is evidence of base metal cracks. The presence of dark areas or bands may indicate local strength variations (soft spots). Evaluate parts with dark areas or bands for electrical conductivity in accordance with Parts that pass the conductivity test are acceptable. Small areas where the anodize has been penetrated as result of hardness testing shall be touched up in accordance with 5719, Type II, Class A. Appearance variations due to fabrication, such as machining, sanding, or forming are not cause for rejection unless those areas have an unpainted surface appearance requirement as specified on the drawing or purchase order. EXCEPTION: The appearance of discolored areas associated with variations in microstructure, when viewed without magnification, shall not be cause for rejection after anodizing 7000 series aluminum alloys in the T 7XXX temper provided the following requirements are satisfied: (1) Parts exhibiting variation in color are acceptable provided that conductivity measurements, conducted across the light to dark areas, do not result in conductivity variations exceeding that allowed by 5946 for an individual piece/part, and the part meets the conductivity requirements for the specific alloy and temper. (2) All requirements of Section 11.1 shall be satisfied. d. The anodic coating weight prior to sealing shall be at least 200 mg/ft 2 when determined in accordance with Section e. Sealed anodic coatings shall be capable of passing the salt spray test when tested in accordance with Section The specimen shall show no more than five isolated spots or pits, none larger than inch in diameter in any test panel nor more than nine isolated pits or spots, none larger than inch in diameter, in a total of 90 square inches after corrosion testing, except those areas within 1/16 inch of edges, identification marks or contact points. A dark discoloration or white powder after corrosion testing is not cause for rejection. f. Color variations of the anodic coating shall not be cause for rejection. g. For Class 5, salt spray corrosion testing is not required. h. For systems requiring part clamping, the number and size of contact points shall be kept to a minimum as necessary for adequate mechanical support. Bare spots caused by contact points of part clamps require no touchup if they do not exceed a inch dimension in any direction except one bare spot may be up to inch. Bare spots located in trim/tab areas are exempt from these requirements. Page 16

17 11.1 REQUIREMENTS FOR RELIABLE PROCESS USERS (Continued) i. Coating adhesion testing described in this section shall be considered a test of the Class 5 (unsealed) anodize process. This testing shall be performed in addition to other coating adhesion testing of production parts required in the applicable coating application specification. This Class 5 (unsealed) coating adhesion testing shall be conducted in accordance with the Class 5 (unsealed) testing requirements in the applicable coating application specification. This testing shall be performed for each anodizing tank. To meet the requirements of this test, facilities which apply a variety of coatings directly over Class 5 (unsealed) anodized substrate are provided the following allowances: (1) BMS10 20 coating may represent all applied coatings for purposes of this adhesion testing. (2) If BMS10 20 coating is not applied, BMS10 11, Type I or BMS10 79 coating may represent all other applied coatings. (3) If BMS10 20, BMS10 11, Type I and BMS10 79 coatings are not applied, each applied coating shall be tested individually REQUIREMENTS FOR MANUFACTURING PROCESS CONTROL DOCUMENT USERS Section 11.2 is only applicable when operating to a MPCD in accordance with an approved operating procedure listed in BSS7023. Section 10b., Items (1), (2) and (3) are required for MPCD users. Refer to Table I for the required Key Characteristics for this process. The MPCD user may select additional Key Characteristics. Refer to Table II for the required Key Process Parameters for this process. The MPCD user may select additional Key Process Parameters. TABLE I KEY CHARACTERISTICS FOR BORIC ACID SULFURIC ACID ANODIZED PARTS KEY CHARACTERISTICS RECOMMENDED TARGET VALUE TEST METHOD Coating weight, Class 1 and Class 5 To be determined by the processor with a minimum of 200 mg/ft 2 for 2000 series alloys and with a maximum of 700 mg/ft 2 for 7000 series alloys. Section 11.2f.(3) and Section 11.2f.(4) with Section TABLE II KEY PROCESS PARAMETERS FOR BORIC ACID SULFURIC ACID ANODIZED PARTS KEY PROCESS PARAMETER RECOMMENDED TARGET VALUE Dilute Chromate Seal Tank ph 3.5 Page 17

18 11.2 REQUIREMENTS FOR MANUFACTURING PROCESS CONTROL DOCUMENT USERS (Continued) a. The complete process (including surface preparation steps such as cleaning, etching, deoxidizing and rework) shall not produce intergranular attack (IGA) in excess of inch or end grain pitting (EGP) in excess of inch when examined in accordance with BSS7219. Examine the anodized test specimens for the cumulative IGA and EGP. b. Part surfaces shall be cleaned, deoxidized or etched to remove oxide. A water break free surface is one indicator of a clean surface. c. There shall be no visible contamination, smut, stains, residual oxides, pitting or other selective attack when examined with an unaided eye before and after anodizing. Since the deposits may be faint and not noticed, the process shall be controlled to prevent them from occurring. Exception: Visual inspection after processing parts through a non chromated deoxidizer is not required if followed by Boric Acid Sulfuric acid anodize in accordance with this specification and the copper limit (in Section 9.1b.) has been established and is not exceeded. CAUTION Copper, iron, or other metals and metal oxides are sometimes deposited from deoxidizer or desmut solutions. These deposits may contribute to corrosion or reduce paint adhesion. This damage may not occur until weeks or months have passed from the time that the parts are processed. d. The total metal thickness reduction, attributed to the cumulative chemical etching processes prior to anodizing, shall not exceed the following: (1) inch on non shot peened surfaces (surfaces which are remachined or completely sanded after the metal removal may have another inch removed). (2) inch on shot peened surfaces (surfaces which are re shot peened after the metal removal may have another inch removed). e. Maintain the anodizing and seal solutions in accordance with Section 9. f. Anodizing (1) Obtain 15 ± 1 volts DC. (2) The anodic coating shall be free from powdery areas and free from discontinuities such as breaks, scratches, or other damage which are extended through the oxide coating. Parts shall be free of arc burns on any surface. (3) A minimum coating weight of 200 milligrams per square foot prior to sealing shall be met when measured on specimens in accordance with ASTM B 137 with any 2000 series alloy or with the same alloy and heat treatment being processed. Page 18

19 11.2 REQUIREMENTS FOR MANUFACTURING PROCESS CONTROL DOCUMENT USERS (Continued) (4) The coating weight shall not exceed 700 milligrams per square foot when measured on specimens in accordance with ASTM B 137 with any 7000 series alloy or with the same alloy and heat treatment being processed. (5) Coating presence can be nondestructively verified by use of the Resistance Probe in accordance with BSS7343. g. Corrosion resistance (except for Class 5 parts) (1) Salt Spray Testing Sealed anodic coatings shall be capable of passing the salt spray test when tested in accordance with Section The specimen shall show no more than five isolated spots or pits, none larger than 0.31 inch in diameter in any test panel or more than nine isolated pits or spots, none larger than 0.31 inch in diameter, in a total of 90 square inches after corrosion testing, except those areas within inch of edges, identification marks or contact points. A dark discoloration or white powder after corrosion testing is not cause for rejection. (2) Color variations of the anodic coating shall not be cause for rejection. (3) For Class 5, salt spray corrosion testing is not required. (4) For systems requiring part clamping, the number and size of contact points shall be kept to a minimum as necessary for adequate mechanical support. Bare spots caused by contact points of part clamps require no touch up if they do not exceed inch dimensions in any direction except one bare spot may be up to inch. Bare spots located in trim/tab areas are exempt from these requirements. h. Dark areas or bands may indicate local strength variations (soft spots in base metal). Inspect these areas for electrical conductivity, when necessary, in accordance with i. Sealing (1) When sealing is required (other than Class 5), the dilute chromate seal process shall produce between 8 and 14 percent hydration when tested in accordance with BSS7325. (2) Sealed parts shall be dried at no higher than 160 F. Page 19

20 11.2 REQUIREMENTS FOR MANUFACTURING PROCESS CONTROL DOCUMENT USERS (Continued) j. Subsequent coating adhesion (1) Subsequent coatings shall be adherent when tested in accordance with the applicable coating specification and remain adherent during subsequent manufacturing operations and in service. (2) Coating adhesion testing described in this section shall be considered a test of the Class 5 (unsealed) anodize process. This testing shall be performed in addition to other coating adhesion testing of production parts required in the applicable coating application specification. This Class 5 (unsealed) coating adhesion testing shall be conducted in accordance with the Class 5 (unsealed) testing requirements in the applicable coating application specification. This testing shall be performed for each anodizing tank. To meet the requirements of this test, facilities which apply a variety of coatings directly over Class 5 (unsealed) anodized substrate are provided the following allowances: (a) BMS10 20 coating may represent all applied coatings for purposes of this adhesion testing. (b) If BMS10 20 coating is not applied, BMS10 11, Type I or BMS10 79 coating may represent all other applied coatings. (c) If BMS10 20, BMS10 11, Type I and BMS10 79 coatings are not applied, each applied coating shall be tested individually. 12 TEST METHODS 12.1 COATING WEIGHT Determine anodic coating weight using undyed and unsealed specimen panels tested in accordance with ASTM B 137. Test specimens shall have a minimum length and width of 3 inches and a minimum nominal thickness of inch. Test specimens shall be made of the alloy as specified in Section 12.2a. The following solution shall be used in lieu of the phosphoric chromic acid solution in accordance with ASTM B 137. Phosphoric acid, 85 percent (Section 5g.) Chromic acid (CrO 3 ) (Section 5e.) Water to make 27 to 35 ml 20 ± 0.5 gm 1.0 liter Page 20

21 12.2 CORROSION RESISTANCE ******* PSDS GENERATED ******* Specimen for Class 1 shall be exposed for 336 hours minimum to 5 percent (nominal) salt spray test in accordance with ASTM B 117, except that the significant surface shall be inclined approximately 6 degrees from the vertical. The specimen shall be as follows: a. Panels for process control tests shall be made of one of the following alloys and shall be processed in the same way as the parts that they represent. (1) 2024 T3 bare alloy, conforming to AMS QQ A 250/4. (2) 2024 T4 alloy, bare conforming to AMS QQ A 250. or b. Production parts are not generally used for testing purposes. When testing is required for a particular lot of parts, test panels shall be furnished with the parts. c. Three panels (approximately 3 by 10 inches by to inch thick) shall be used for corrosion testing. Panels which show dark spots or unremoved corrosion after deoxidation or anodizing shall not be used. 13 QUALIFICATION Not applicable to this specification. Page 21