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Managing Change

A Supplier’s Perspective on Qualifying LHE Zinc-Nickel as a

Cadmium Replacement For Aerospace Applications

MINASF, March 28th 2015

Dipsol of America

The Pace of Change in Surface Finishing

• Typically, it doesn’t happen quickly,

• More often, it can be measured in years….

Accelerating Change

Each industrial sector is pressured by many of the

same factors, but the rate at which they adopt the

change varies.

Some familiar factors that can initiate change...

REGULATIONS

REGULATIONS

SPECIFICATIONS

REGULATIONS

SPECIFICATIONS

NEW

TECHNOLOGY

COST REDUCTION

Technology Tradeoff /

Increase in Health &

Safety Costs

Imp

lemen

tation

REGULATION – Often initiates the change ahead of

market driven innovation

Material/Fo

rmu

la

Co

ntro

l

Hazard

/Disp

osal

Regulations Take Flight

DoD Directives for Complying with Environmental Restrictions on Cadmium & Hex Chrome

• Cadmium solutions contain cyanide and cadmium salts.

• EPA – Targeted for reduction under Industrial Toxics & Chemicals of Concern (COC)

• OSHA – Worker (PEL) limits.

• RCRA – Disposal of Hazard Materials from plating and wash down.

• REACH

Phasing out the Exemptions and Waivers

What Took So Long? Aerospace is a very risk averse industry

Cadmium & Hexavalent Chromate:

• relatively inexpensive & simple to operate, very good

corrosion resistance, adhesion to high strength steel, low

hydrogen embrittlement...etc..

• No single alternative was necessarily going to check all of the

right boxes.

In use for decades – all the infrastructure and knowledge was

embedded for supporting and maintaining this process

application, very much a tried and true process.

If It’s Not Broke....

Several Finishes Were Investigated For Landing Gear Applications

However, none were just right.

• Zinc – voluminous corrosion products.

• Sn-Zn – lower temperature resistance.

• Ti-Cd – still toxic.

• Early low nickel Zn-Ni formulas –

hydrogen embrittlement issues.

Some Examples:

Some Were Qualified

IVD – Line of sight only for O.D.

areas. Expensive to maintain.

Aluminum Sputtering –

Complex & Expensive to

operate.

Aluminum Plating – very limited

supplier base.

But still had limitations...

A Timeline of Investigation & Testing

1996-2000

Boeing developed

Acid ZnNi

Alkaline ZnNi –

Low Ni (5-8%)

2003-2005

LHE Alkaline ZnNi

– High Ni (12-15%)

2006-2007

Prototype

Installation,

Qualification

Testing

2007-2009 2009-2013

Additional

Prototype

Installations, &

Continued

Qualification

Testing

Process Qualified,

Large Scale Plating

Installations

2013 Continued Conversion

away from Cadmium.

Assessing Cobalt Free

Passivates

Phase I, II, III... Testing Verifications

The Journey – Some of the Qualification Requirements For LHE ZnNi Over High Strength

Steel 1. Adhesion (ASTM B571)

2. Corrosion (ASTM B117)

3. Fatigue (ASTM E466)

4. Hydrogen Embrittlement (ASTM F519 & USAF DWG)

5. Liquid and Solid Metal Embrittlement (ASTM F519)

6. Brush Plating for Repair of Damage (ASTM B117, B571 and F519)

Adhesion Testing

Impact at 70 in-lbs

Impact Testing

The following two slides

demonstrate that SEM

analysis shows no loss

of adhesion with the Zn-

Ni plated high strength

steel coupons.

Performance matched

that of cadmium.

Adhesion : Impact Testing of Zn-Ni

Adhesion: Impact Testing of Cadmium

Adhesion Testing

• Adhesion of the LHE Zn-Ni coating to the substrate was tested per ASTM B571

• All adhesion test coupons were manufactured from 1”x 4”x 0.040” 4130 steel sheet

• Results: All Test coupons passed

Overall Conclusions: Zn-Ni has adhesion as good as Cadmium when tested by bend-to-break and impact test methods and passes ASTM B571

Bend to Break Tests On LHE Zn-Ni Test Coupons

Corrosion Performance • Corrosion tests were conducted on LHE Zn-Ni coupons

with Cadmium as the baseline

• Testing was also performed on both cadmium and LHE Zn-Ni coated coupons with a prime/paint topcoat after being scribed (See Table below). All test coupons were 4”x 6”x 0.040” 4130 steel sheet

• All testing was performed per ASTM B117

• Test specimens were both scribed and un-scribed

Test per ASTM B 117

Corrosion Performance – LHE ZnNi

1000 hours

3000 hours

5000 hours

IZ-C

17+

Zn

-Ni w

ith T

rivale

nt C

hro

me C

onve

rsio

n C

oating

Unscribed

–A

ST

M B

117

Fig

ure

4

1000 hours

3000 hours

5000 hours

IZ-C

17+

Zn

-Ni w

ith T

rivale

nt C

hro

me C

onve

rsio

n C

oating

Scribed –

AS

TM

B 1

17

Fig

ure

6

Un-scribed Scribed

Tested per ASTM B 117

Corrosion Performance - Cadmium C

ad

miu

m w

ith

He

xa

va

len

tC

hro

me

Con

ve

rsio

n C

oatin

g

Unscrib

ed

–A

ST

M B

117

Fig

ure

3

Test Panel

Removed From

Salt Spray Cabinet –

Excess Amount

of Red Rust

Detected

Test Panel

Removed From

Salt Spray Cabinet –

Excess Amount

of Red Rust

Detected

Test Panel

Removed From

Salt Spray Cabinet –

Excess Amount

of Red Rust

Detected

Test Panel

Removed From

Salt Spray Cabinet –

Excess Amount

of Red Rust

Detected

Test Panel

Removed From

Salt Spray Cabinet –

Excess Amount

of Red Rust

Detected

1000 hours

3000 hours

5000 hours

Test Panel

Removed From

Salt Spray Cabinet –

Excess Amount

of Red Rust

Detected

Test Panel

Removed From

Salt Spray Cabinet –

Excess Amount

of Red Rust

Detected

Test Panel

Removed From

Salt Spray Cabinet –

Excess Amount

of Red Rust

Detected

Test Panel

Removed From

Salt Spray Cabinet –

Excess Amount

of Red Rust

Detected

Test Panel

Removed From

Salt Spray Cabinet –

Excess Amount

of Red Rust

Detected

Test Panel

Removed From

Salt Spray Cabinet –

Excess Amount

of Red Rust

Detected

Test Panel

Removed From

Salt Spray Cabinet –

Excess Amount

of Red Rust

Detected

Test Panel

Removed From

Salt Spray Cabinet –

Excess Amount

of Red Rust

Detected

1000 hours

3000 hours

5000 hours

Cad

miu

m w

ith

He

xa

va

len

tC

hro

me

Con

ve

rsio

n C

oatin

g

Scribe

d –

AS

TM

B 1

17

Fig

ure

5

Test Panel

Removed From

Salt Spray Cabinet –

Excess Amount

of Red Rust

Detected

Test Panel

Removed From

Salt Spray Cabinet –

Excess Amount

of Red Rust

Detected

Test Panel

Removed From

Salt Spray Cabinet –

Excess Amount

of Red Rust

Detected

Un-scribed Scribed

Corrosion Result: (Paint & Scribe)

LHE Cd w/Hex CC

Tested per ASTM B117

LHE Zn-Ni w/Tri CC

Corrosion Results

Corrosion Results

Corrosion – Testing Summary

• Plated and Scribed / Un-scribed (ASTM B-117)

• Cadmium with hex chromate: Failure at 1000 hours

• LHE ZnNi with Tri CC: Passed at 1000 hours

• Acceptable results at 5000 hours

• Plated + Paint and then Scribed (ASTM B-117) • Cadmium/Hex CC + primer + paint then Scribed: Pass at 1000 hours

• LHE ZnNi/Tri CC + primer + paint then Scribed: Pass at 1000 hours

Fatigue Testing

Load-controlled axial fatigue testing was performed to evaluate any service life impacts associated with LHE Zinc-Nickel.

Plated Test Bars Test Cell

Fatigue Validation

Test Conclusions:

LHE Zinc-Nickel was comparable to Cadmium.

200 KSI

180 KSI

160 KSI

30,000

100,000

1,000,000

# o

f Cycle

s

Hydrogen Embrittlement Testing

• V-notch test samples manufactured per ASTM F519 specifications (4340)

• Additional test samples plated and tested at additional dates

• All v-notch samples tested per ASTM F519 passed the 200 hour sustained load tests @ 75% of the tensile notch fracture strength

ASTM F519 Type 1A.1 Test Samples

Testing Equipment

New fixture and Conformal Anode Design

Additional Hydrogen Embrittlement Testing

Original Chain Design

Re-Embrittlement Testing Results

Additional, 3.5% salt water, re-embrittlement testing was conducted on LHE Zn-Ni plated coupons and they all passed the ASTM 519-06 150 hour requirement

Liquid/Solid Embrittlement Testing

• Liquid and Solid Metal Embrittlement (LME and SME) occur when one metal, either as a liquid or solid, intrudes into the structure of another, potentially causing embrittlement in the base metal

• Melting points for the coating metals are as follows:

• Cadmium ~610°F

• Zinc ~787°F

• Nickel ~2650°F

Liquid Metal Embrittlement Test #3

300M Type 1a.1 Plated with Zn-Ni (Lt.) and Cd (Rt.)

After Being Step Loaded to Failure

Cadmium = 91.5% NFS : Zinc-Nickel = 100% NFS

Fracture Surface of Zn-Ni and Cd After Step Load to

Failure – Cadmium Had Pre-Existing Crack from High

Temp Exposure Under Stress

LHE Zn-Ni and Cad Type 1a.1 Specimens After ISL Test to Determine the NFS After Exposure to 400oF for 200 Hours

Brush Plating Repair • In order for a brush LHE Zn-Ni plating to qualify it

must pass the following tests:

• Hydrogen Embrittlement (HE) testing per ASTM F519

• Bend to break adhesion test per ASTM B571

• Corrosion testing per ASTM B117

• SIFCO recommended procedures to use for plating several sets of HE type 1a.1 coupons, adhesion coupons, and corrosion coupons, using SIFCO 4018 No Bake LHE Zn-Ni brush plating solution

• Brush Plating Repair performed as well as original plated finish.

Test Results Summary

• Passed hydrogen embrittlement testing

• Passed adhesion testing on steel and LHE Zn-Ni plated steel

• Corrosion test performance is excellent

Next Steps: Prototype Implementation

• Customer implemented a tank of approximately 325 gallons for the purpose of demonstrating the LHE Zn-Ni plating process on full sized gear components

• The demonstration tank was used to develop uniform plating thicknesses and process parameters on test coupons and full scale landing gear components

• During the plating operations Quality Assurance testing has been conducted to ensure the alkaline LHE Zn-Ni solution is within proper process limits

LHE Zn-Ni Plating Tank

LHE Zn-Ni Performance Tracking Program (PTP)

• Criteria for part selection • Fixture Completed

• 2 to 3 Parts from each Weapon System

(NLG & MLG)

• Ease of access to component on aircraft

C-130 Main Landing Gear Components

Landing Gear Components

F-15 Platform F-16 Platform

MLG Axle plating in LHE Zn-Ni Solution

Before Plating After Plating

MLG Outer Cylinder

LHE Zn-Ni Conformal Anode and

Fixture Models

Complex Geometries

Field Corrosion

Component Corrosion Evaluation LHE Zn-Ni Plating (Cape Kennedy)

F-15 MLG Lower Drag Brace CAD F-15 MLG Lower Drag Brace Zn-Ni

Parts Placed 10/13/2010, Pictures taken 7/24/2012

Component Corrosion Evaluation LHE Zn-Ni Plating (Cape Kennedy)

C-5 MLG Rotation Collar Zn-Ni C-5 MLG Rotation Collar CAD

Parts Placed 10/13/2010, Pictures taken 7/24/2012

Reaching the Goal 1. Adhesion (ASTM B571) – Passed

2. Corrosion (ASTM B117) - Passed

3. Fatigue (ASTM E466) - Passed

4. Hydrogen Embrittlement (ASTM F519 & USAF DWG) - Passed

5. Liquid and Solid Metal Embrittlement (ASTM F519) - Passed

6. Brush Plating for Repair of Damage (ASTM B117, B571 and F519) - Passed

• Qualified:

• Boeing BAC 5680 & Boeing BAC 5637

• USAF Drawing# 201027456

• UTC Aerospace Systems LGPS 1106 Landing System

• Heroux-Devtex HPS-138

• SAE AMS 2417

• Bell Helicopter #5445

A Change for the Better

• LHE Zn-Ni and trivalent passivate most closely matched and in many cases surpassed the performance requirements of cadmium and hexavalent chromate.

• Provided a process that was more of a “drop-in” replacement compared to other technologies.

• Legacy knowledge and infrastructure was more readily transitioned over to LHE Zn-Ni + trivalent passivate.

• Zinc-Nickel plating continues to be a viable option for existing and new applications that require replacement finishes to meet regulatory or increased performance requirements.

Or Is It?

Successful Change, So...

Nickel? Chrome

Free Cobalt Free

From Hexavalent to

Trivalent Passivates

Staying Relevant

AUTOMOTIVE

Our Industry Continues to Innovate

From Cyanide to

Alkaline Non-Cyanide

Plating

• Regulations will continue to push changes in our industry.

• Timeframes narrow as replacement substances then become future candidates for restriction.

• Competent & willing partners may be needed to share in the costs of developing these alternative technologies.

AEROSPACE

ELV

“When you’re finished changing, you’re finished.”

- Benjamin Franklin

Thank you

Questions or Comments

Dipsol of America