TRI-SERVICE GREEN GUN BARREL An Environmentally Friendly Deposition Process to Replace Aqueous

Electrodeposition of Chrome

HARD CHROME ALTERNATIVES TEAMPROGRAM REVIEW MEETING

KENNEDY SPACE CENTER13-14 DECEMBER 2000

U.S. Army Research, Development and Engineering Center Benet Laboratory

Watervliet, NY 12189-4050John D. Vasilakis, DSN 974-5692

INTERACTIONS

ACADEMIA

• New Jersey Institute of Technology

• Rensselaer Polytechnic Institute

• SUNY - Albany

• SUNY - Stonybrook

• Stevens Institute of Technology

• INDUSTRY OTHERS

• GDAS/SACO ARDEC CCL

• UDLP ARL

• Boeing GGB Partners

Problem / Objective

• ProblemEnvironmentally unfriendly materials and processCarcinogenic chemicals (Cr VI)8% of barrel cost due to environmental compliance (target of opportunity)

Watervliet Arsenal (120-155mm)Rock Island Arsenal (25mm)General Dynamics (25mm,30mm)

ObjectiveReplace the current material and process with an environmentally friendly process for gun barrel bore protection

What is CMS ?CYLINDRICAL MAGNETRON SPUTTERING

(sputtering circa 1780) (magnetron sputtering circa 1935)

+

-+

-

I

I

GND

I

Ie- e-

I

300V

10V

Target(Cathode)

Subst

rate

(Gun T

ube)

Plasma(Ionized Inert Gas)

MagneticField Lines, B

II

PlasmaPowerSupply

TargetPowerSupply

COLLISION

e

Ar

Ar+

Ta

e-

Accomplishments/Deliverables

Coating Thickness Lands - 1.56 mils Groves - 1.5 mils

Initial Evaluation Beta Tantalum Well Adhered

Effect of Post-Heating of Coatingon Rifled Barrel Section

Groove test following the heating of the coated section. Some alpha-Ta is beginningto precipitate. Adhesion is excellent.

Groove test of specimen CMS-00317 afterapprox 1.5 mil of plating. Mainly beta-Tatexture. Knoop hardness 800-900. Much ‘decohesion’ and interfacial failure

Only for non-autofrettaged guns

GROOVE TEST ON MUZZLE END OF M242 SECTION

Photomicrograph of the

muzzle section of a fired

Bushmaster tube section.

Groove tests for adhesion

were conducted after the

firing.

SPUTTERED COATING ON GROOVE

Coating changes from alpha to betaTantalum alongthe side of thegroove.

UNAFFECTED COATING ON LAND

Alpha Tantalum

SPUTTERING TOWER

Sputtering tower isholding a 44” long45mm diameter tubesection in preparationfor plating a 45mm Casius gun tube forthe InternationalFTMA program

The same tower is willbe used to plate the 25mm Bushmaster and the GAU-12.

COATING ADHESION TESTING

Chrome Platingon Gun Steel

viaAqueous

Electrodeposition

Tantalumon Gun Steel

viaCylindricalMagnetronSputtering

Tantalumon Gun Steel

viaCylindricalMagnetronSputtering

EXCELLENT ADHESION POOR ADHESION IMPROVED ADHESION

SCHEMATIC OF CYLINDRICAL MAGNETRON SPUTTER

PROCESS

LEVERAGED PROGRAMS

• Characterization ProtocolSEM

Atomic Force Microscopy

Metallurgy

Coating Thickness

• Pulse Laser Heating

• Laser Interferometry and Bond Quality

ATOMIC FORCE MICROSCOPY

Investigating evolving morphology

Plating alpha tantalum

After 45 minutes After 120 minutes

PULSE LASER HEATING

HC chromium/steel interface after 20 laserpulses at 0.9 J/mm2 HC

Laser Pulse Heating Simulation of FiringDamage on Coated Gun Bore Surfaces

Laser SystemLaser Systemshowing generation and detection of surface waveshowing generation and detection of surface wave

Detection Laser

Generation Laser

Specular Reflection

Surface WaveSample

Decay ofAmplitude

Coating

Substrate

Low FrequencySurface Wave

High FrequencySurface Wave

Investigate dispersion curvesfor coatings that are welded (good bond) or smooth contact (poor bond).

SUMMARY

• Successful first firing test.

• Preparing new test using a conforming chamber.

• Preparing a test with a newly designed center conductor that uses permanent magnets.

• Conducting commissioning tests on 45mm Casius gun to be used in FTMA program.

• First firing tests for 45mm planned for May, 2001