Keith LeggRowan Technology Group, Libertyville, IL847-680-9420,klegg@rowantechnology.comWebsite:www.rowantechnology.comEmail:klegg@rowantechnology.com`Drivers`TechnologiesChromate-free conversion coatings and adhesionpromotersChromate-free primersAnodizingAnodize sealingPlasma electrolytic oxidationCold sprayDesign tools for corrosion predictionWebsite:www.rowantechnology.comEmail:klegg@rowantechnology.com`REACH is a big driver in the US because of theinternational nature of the aerospace and defensemarketsPotential loss of chromates from market`EPA proposals forTighter rules on Cr6+emissionsRestrictions on Cr6+in drinking water`DoD Cr6+minimization memoDoD depots and program offices encouraged to reduce Cr6+use as far as possibleDefense Federal Acquisition Regulations (DFARS) prohibitCr6+in coatings like primers and sealants, but permit it inconversion coatings – new weapons systems onlyWebsite:www.rowantechnology.comEmail:klegg@rowantechnology.comRivet rash`Most industrial users have gone over to Cr3+and non-Crtreatments for Al , just as in EuropeAerospace and defense still mainly use chromateIn the US one of the most successful has been TCP,developed by Craig Matzdorf and coworkers as NAVAIR3⁄4Also validated for anodize sealing`Adhesion promoters are proving to be a goodalternative even without inhibitorsPantheon Prekote used by USAFBoeing uses AC 131 for aircraft OML to prevent rivet rash3⁄4AC130 also used as an adhesive bond primerWebsite:www.rowantechnology.comEmail:klegg@rowantechnology.com`Increasing use of chromate-free primers on Al andcompositeA-64 Apache helicopter uses Deft non-Cr primerF-35 uses Deft non-Cr primerStill using chromate pretreat, but working on adoptingnon-chromateNon-Cr primer beginning to be used on commercialaircraft, but less widely used than in EuropeF-35 with Deft non-Cr primerEnables Moving Production Line‘Shirt Sleeve’ MaintenanceASETSDefense 2011Website:www.rowantechnology.comEmail:klegg@rowantechnology.com`Frankel, Buchheit, Jaworowski, Swain`Study of how non-chromate primers workCa, Pr, Zn, Mg, Mo etc.`Final report will probably be publicly available 2012Website:www.rowantechnology.comEmail:klegg@rowantechnology.comWebsite:www.rowantechnology.comEmail:klegg@rowantechnology.comAll results on Al2024-T3Cr6+vs organic inhibitorwww.crosslinkusa.com3500 h (primer only)ChromateBoeAero TC3500 h (topcoat)ChromateBoeAero 7500 hBoeAero TCBoeAero: Crosslink internalformulation designed as a primerBoeAero TC: Crosslink internal formulation designed for use with a topcoatWebsite:www.rowantechnology.comEmail:klegg@rowantechnology.com`Kleinschmidt, Mazza, Jaworowski, Blohowiak, Jensen`Current non-chromate bond primers do not providerobust corrosion inhibition to Al alloys in standard tests`TasksUnderstand role of corrosion in adhesive bond joint decayDesign of tests and samples relevant to bonded structuresTesting chromate and nonchromate adhesive bond primersystemsCreate corrosion risk assessment methodology foradhesively-bonded structures`Started 2011, end 2015Website:www.rowantechnology.comEmail:klegg@rowantechnology.com`Boeing uses boric-sulfuric(BSAA), vs Airbus tartaricsulfuric (TSAA)`Sulfuric (SAA), Thin filmsulfuric (TFSAA) mostwidely used in USA`Navy (Jacksonville) hasqualified Metalast SAAusing controller, with Cr3+sealer for Al landing gear,other componentsCr3+sealer energy costsaving from lower bathtemperatureWebsite:www.rowantechnology.comEmail:klegg@rowantechnology.com`Builds up compound layers rather than simple anodizedlayers`Tagnite used in US for Mg for many years`Keronite beginning to be used in US for Al`Henkel Alodine EC2 is being used in the USTiO2-based coating for use on Al and TiAvailable from vendorsNot yet used for aerospace or defense, but under test forseveral applications, including chromate primer alternative`These types of PEO coatings could be particularly usefulfor Al wheels and the increasing number of Ticomponents being used in aircraftKeronite and Tagnite both approved for Mg by NAVAIRWebsite:www.rowantechnology.comEmail:klegg@rowantechnology.com`Tagnite from TAG in N. DakotaAuthorized by NAVAIR for Mg alloys (gearboxes), but notwhen they include Cd-plated inserts and studs`Cold spray using 6061 Al (MIL-STD-1321)Developed by Army Research Lab for Al components andMg gearbox repair to reclaim damaged gearboxes`Moog and TAG have developed Tagnite + Al alloy coldspray combination for Mg gearbox corrosion/damagerepair and protectionHad to develop ways to shield steel inserts, bolts duringTagnite processWebsite:www.rowantechnology.comEmail:klegg@rowantechnology.comWebsite:www.rowantechnology.comEmail:klegg@rowantechnology.com`Cold spray Al repair to fill indamage and bring back toprint dimensions`Finish with Tagnite`Equally applicable to repairAl componentsMight well finish withKeronite`May sometimes restoresome strength to Mg alloysProbably not to Al alloysWebsite:www.rowantechnology.comEmail:klegg@rowantechnology.comWebsite:www.rowantechnology.comEmail:klegg@rowantechnology.comBest Dressed Cold Spray OperatorOldest Cold Spray OperatorWebsite:www.rowantechnology.comEmail:klegg@rowantechnology.comWebsite:www.rowantechnology.comEmail:klegg@rowantechnology.comAl substrateHigh-P Electroless NiElectroless Ni- PTFE}~15μm}~15μm`Most US suppliers (also Radiall) moving toward EN-PTFE`Looks pretty good, apparently without galvanicproblems we had expected`Users in aerospace and defense will need good, soliddata to show3⁄4There is no galvanic corrosion issue3⁄4Electroless Ni barrier layer will not lead to disastrouscorrosion of Al if imperfect or damagedWebsite:www.rowantechnology.comEmail:klegg@rowantechnology.comWebsite:www.rowantechnology.comEmail:klegg@rowantechnology.comWebsite:www.rowantechnology.comEmail:klegg@rowantechnology.comWebsite:www.rowantechnology.comEmail:klegg@rowantechnology.com`Galvanic corrosion prediction likely to prove particularlyuseful when replacing chromate conversion, Cd, andother corrosion-resistant finishes on AlHow will new finishes and materials interact in new designs?`Software from Elsyca NV in Belgium being developed inthe US under US Navy fundingAircraft, ships, vehicles`Aim is software integrated into CAD design packages tocheck for galvanic corrosion problems during design,rather than fix them later at great expenseWebsite:www.rowantechnology.comEmail:klegg@rowantechnology.comWebsite:www.rowantechnology.comEmail:klegg@rowantechnology.comCdAl backplanecorrodes right atsocket to protect NiIf water accumulates aroundconnector, corrosion worsethan standard B117 salt fogWhat if youconnect an ENplated plug toa Cd platedsocket?NiZnNiAl backplaneCdAl connector shellZnNi on socketcorrodes to protectelectroless Ni onconnectorBut EN-PTFE is not Ni.We have no galvanicdata for it. So, what willhappen with EN-PTFE?Data generation to bedone soon – we hope!Website:www.rowantechnology.comEmail:klegg@rowantechnology.comWebsite:www.rowantechnology.comEmail:klegg@rowantechnology.comWebsite:www.rowantechnology.comEmail:klegg@rowantechnology.com`ProblemLightweight, high-strength aluminum alloys, such as 7050-T74, aresusceptible to stress corrosion cracking and general corrosion in chlorideenvironmentsAlloys are typically anodized to increase corrosion resistance, but reducesfatigue life by up to 40%`DesignEquivalent strength to 7050-T74, with 100% improvement in resistance tostress corrosion cracking`BenefitReduce SCC failures and associated maintenance costsElimination of anodizing processImproved corrosion resistance to allow for trivalent chromate conversioncoatingsExtruded bars of prototype alloyWebsite:www.rowantechnology.comEmail:klegg@rowantechnology.com`ProblemAircraft wheels are subject to high energy braking events that requirethermally stable alloys for structural integrityCurrent alloys, such as 2040, can be prohibitively expensive and causethe user to use legacy alloys such as 2014`DesignLower-cost compared to 2014 with increased strength and ductility,increased thermal stability, increased fatigue performance, andequivalent corrosion resistance`BenefitImproved performance compared to 2014 with equivalent costReduced component weight and increased component life-cyclePhoto courtesy of: http://www.goodrich.com/gr-exttemplating/images/Goodrich%20Content/Business%20Content/Aircraft%20Wheels%20and%20Brakes/Products/Literature%20Listing/F16%20Block60%20Fact%20Sheet.pdfHalf section of aircraft wheelWebsite:www.rowantechnology.comEmail:klegg@rowantechnology.com`Comprehensive evaluation and transition of non—chromated paint primer`Corrosion protection mechanisms of rare-earthcompounds based on Ce and Pr`Scientific understanding of the mechanisms of nonchromate corrosion inhibitors`Ultraviolet-curable powder coatings`Morphology and mechanism of benign inhibitorshttp://www.serdp-estcp.orgWebsite:www.rowantechnology.comEmail:klegg@rowantechnology.comWebsite:www.rowantechnology.comEmail:klegg@rowantechnology.comWebsite:www.rowantechnology.comEmail:klegg@rowantechnology.comWebsite:www.rowantechnology.comEmail:klegg@rowantechnology.comhttp://www.asetsdefense.orgWebsite:www.rowantechnology.comEmail:klegg@rowantechnology.comWebsite:www.rowantechnology.comEmail:klegg@rowantechnology.comASETSDefense 2012: Sustainable SurfaceEngineeringfor Aerospace and DefenseRancho Bernardo Inn17550 Bernardo Oaks DriveSan Diego, CA 92128http://www.asetsdefense.org/UpcomingWorkshops.aspxAugust 28-30, 2012May have half day session on 27thfor connectors