1. TRI-SERVICE GREEN GUN BARREL PROGRAM REVIEW MEETING
An Environmentally Friendly Deposition Process to Replace Aqueous Electrodeposition of Chrome
HARD CHROME ALTERNATIVES TEAM
PROGRAM REVIEW MEETING
KENNEDY SPACE CENTER
13-14 DECEMBER 2000
U.S. Army Research, Development and Engineering Center
Benet Laboratory
Watervliet, NY
John D. Vasilakis, DSN

2. 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

3. Problem / Objective Problem
Environmentally unfriendly materials and process
Carcinogenic chemicals (Cr VI)
8% of barrel cost due to environmental compliance (target of
opportunity)
Watervliet Arsenal ( mm)
Rock Island Arsenal (25mm)
General Dynamics (25mm,30mm)
Objective
Replace the current material and
process with an environmentally
friendly process for gun barrel
bore protection

4. What is CMS ? CYLINDRICAL MAGNETRON SPUTTERING + 300V - 10V I
(sputtering circa 1780) (magnetron sputtering circa 1935) + - I
GND e-
300V
10V
Target
(Cathode)
Substrate
(Gun Tube)
Plasma
(Ionized Inert Gas)
Magnetic
Field Lines, B
Power
Supply
COLLISION e Ar
Ar+ Ta

5. Accomplishments/Deliverables
Initial Evaluation
Beta Tantalum
Well Adhered
Coating Thickness
Lands mils
Groves mils

6. Effect of Post-Heating of Coating on Rifled Barrel Section
Groove test of specimen CMS after
approx 1.5 mil of plating. Mainly beta-Ta
texture. Knoop hardness Much
‘decohesion’ and interfacial failure
Groove test following the heating of the
coated section. Some alpha-Ta is beginning
to precipitate. Adhesion is excellent.
Only for non-autofrettaged guns

7. 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.

8. SPUTTERED COATING ON GROOVE
changes from
alpha to beta
Tantalum along
the side of the
groove.

9. UNAFFECTED COATING ON LAND
Alpha Tantalum

10. SPUTTERING TOWER Sputtering tower is holding a 44” long
45mm diameter tube
section in preparation
for plating a 45mm
Casius gun tube for
the International
FTMA program
The same tower is will
be used to plate the
25mm Bushmaster and the GAU-12.

11. COATING ADHESION TESTING
Chrome Plating
on Gun Steel
via
Aqueous
Electrodeposition
Tantalum
on Gun Steel
via
Cylindrical
Magnetron
Sputtering
Tantalum
on Gun Steel
via
Cylindrical
Magnetron
Sputtering
EXCELLENT ADHESION
POOR ADHESION
IMPROVED ADHESION

12. SCHEMATIC OF CYLINDRICAL MAGNETRON SPUTTER PROCESS

13. LEVERAGED PROGRAMS Characterization Protocol SEM Pulse Laser Heating
Atomic Force Microscopy
Metallurgy
Coating Thickness
Pulse Laser Heating
Laser Interferometry and Bond Quality

14. ATOMIC FORCE MICROSCOPY
Investigating evolving morphology
Plating alpha tantalum
After 45 minutes
After 120 minutes

15. PULSE LASER HEATING

16. Laser System showing generation and detection of surface wave
Investigate dispersion curves
for coatings that are welded (good
bond) or smooth contact (poor bond).
Detection Laser
Generation Laser
Specular Reflection
Surface Wave
Sample

17. 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