The demands to increase range, rate of fire, and muzzle velocity have resulted in increased wear and erosion problems in gun tubes. To increase the service life of gun tubes, a number of bore-coating systems are being considered for replacement of the current electroplated high-contractile chromium coating. Two such coating systems are cylindrical magnetron sputtered (CMS) Cr coatings and CMS TaCr bilayer coatings. Cylindrical magnetron sputtering is a high-rate vacuum deposition process that has been applied to 120mm tubes. Characterization studies of the electroplated and CMS coatings were completed to determine the applicability of these coating/substrate systems for gun bore protection. Each coating system is subjected to a series of tests, including adhesion, microhardness, compositional analysis, and vented erosion-simulation testing (VES). VES testing is completed via a laboratory combustion chamber that reproduces the transient thermal and chemical environments of tank cannon firing on small chord sections of 120mm coated gun tubes. In addition to the aforementioned characterization tests, metallography, scanning electron microscopy, and energy dispersive spectroscopy are conducted on each specimen before and after VES testing to evaluate the thermal stability of the coating and the severity of the thermal damage imposed. The mechanisms of damage are investigated, including void formation and micropit growth, oxidation and erosion, and thermomechanical cracking. In addition, methods to further increase resistance to thermal damage are discussed to increase the service life of future gun tube systems.

1.
Cote
,
P. J.
,
Todaro
,
M. E.
,
Kendall
,
G.
, and
Witherell
,
M.
, 2003, “
Gun Bore Erosion Mechanisms Revisited With Laser Pulse Heating
,”
Surf. Coat. Technol.
0257-8972,
163–164
, pp.
478
483
.
2.
Cote
,
P.
, and
Rickard
,
C.
, 2000, “
Gas-Metal Reaction Products in the Erosion of Chromium-Plated Gun Bores
,”
Wear
0043-1648,
241
(
1
), pp.
17
25
.
3.
Sopok
,
S.
,
Pflegl
,
G.
, and
Rickard
,
C.
, 2002, “
Erosion Predictions for the Final Configuration of the M829E3 Round
,”
Proc. of the 51st JANNAF Propulsion Meeting
, CPIA (Chemical Propulsion Information Agency) Columbia, MD.
4.
Underwood
,
J. H.
,
Parker
,
A. P.
,
Vigilante
,
G. N.
, and
Cote
,
P. J.
, 2003, “
Thermal Damage, Cracking and Rapid Erosion of Cannon Bore Coatings
,”
ASME J. Pressure Vessel Technol.
0094-9930,
125
(
3
), pp.
299
304
.
5.
Ahmad
,
I.
, 1988,
Gun Propulsion Technology
,
Progress in Astronautics and Aeronautics Series
,
AIAA
,
Washington, DC
, pp.
311
.
6.
Vossen
,
J. L.
, and
Kern
,
W.
, 1991,
Thin Film Processes II
,
Academic Press
,
New York
, pp.
177
204
.
7.
Yee
,
F.
,
Wotzak
,
M.
,
Cipollo
,
M.
, and
Truszkowska
,
K.
, 2004, “
Cylindrical Magnetron Sputtering in a Ferromagnetic Cylinder
,”
SVC 47th Annual Technical Conference Proceedings
, Society of Vacuum Coaters, Albuquerque, NM, pp.
421
425
.
8.
Truszkowska
,
K.
,
Wotzak
,
M.
,
Yee
,
F.
,
Vigilante
,
G. N.
, and
Cipollo
,
M.
, 2004, “
Cylindrical Magnetron Sputter Deposition of Chromium Coatings for Erosion and Wear Resistant Application
,”
SVC 47th Annual Technical Conference Proceedings
, Society of Vacuum Coaters, Albuquerque, NM, pp.
282
288
.
9.
Thornton
,
J. A.
, 1977, “
High Rate Thick Film Growth
,”
Annu. Rev. Mater. Sci.
0084-6600,
7
, pp.
239
260
.
10.
Read
,
M. H.
, and
Altman
,
C.
, 1965, “
A New Structure in Tantalum Thin Films
,”
Appl. Phys. Lett.
0003-6951,
7
(
3
), pp.
51
52
.
11.
Krikorian
,
E.
, and
Sneed
,
R. J.
, 1966, “
Deposition of Tantalum, Tantalum Oxide, and Tantalum Nitride With Controlled Electrical Characteristics
,”
J. Appl. Phys.
0021-8979,
37
(
10
), pp.
3674
3681
.
12.
Matson
,
D. W.
,
Merz
,
M. D.
, and
McClanahan
,
E. D.
, 1992, “
High Rate Sputter Deposition of Wear Resistant Tantalum Coatings
,”
0022-5355,
10
(
4
), pp.
1791
1796
.
13.
Lee
,
S. L.
,
Windover
,
D.
,
Audino
,
M.
,
Matson
,
D. W.
, and
McClanahan
,
E. D.
, 2002, “
High-Rate Sputter Deposited Tantalum Coating on Steel for Wear and Erosion Mitigation
,”
Surf. Coat. Technol.
0257-8972,
149
(
1
), pp.
62
69
.
14.
Cote
,
P. J.
,
Kendall
,
G.
, and
Todaro
,
M. E.
, 2001, “
Laser Pulse Heating of Gun Bore Coatings
,”
Surf. Coat. Technol.
0257-8972,
146–147
, pp.
65
69
.
15.
Underwood
,
J. H.
,
Witherell
,
M. D.
,
Sopok
,
S.
,
McNeil
,
J. C.
,
Mulligan
,
C. P.
,
Vigilante
,
G. N.
, and
Troiano
,
E.
, 2004, “
Thermomechanical Modeling of Transient Thermal Damage in Cannon Bore Materials
,”
Wear
0043-1648,
257
(
9–10
), pp.
992
998
.
16.
Massalski
,
T.
, 1990,
Binary Alloy Phase Diagrams
,
2nd ed.
,
ASM International
.
17.
Pfandzelter
,
R.
,
Igel
,
T.
, and
Winter
,
H.
, 1997, “
Interfacial Mixing of Ultrathin Cr Films on Fe(100) Studied by Auger Electron Spectroscopy
,”
Surf. Sci.
0039-6028,
377–379
, pp.
963
968
.
18.
Glazman
,
O.
, and
Hoffman
,
A.
, 1997, “
Adhesion Improvement of Diamond Films on Steel Subtrates Using Chromium Nitride Interlayers
,”
Diamond Relat. Mater.
0925-9635,
6
(
5–7
), pp.
796
801
.
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