Final report

2.7.4   Appendix 2-D:  Steam Cor r osion Test Photogr aphs of Incoming and Ready-to-Str ike 
Mater ials 
The corrosion test measurement of total color vector change described in this appendix is a good 
quantitative measurement of average color and reflectivity changes, but it is difficult to assess the 
aesthetic effect of steam corrosion from the number that results from the test.  The photographs 
attempt to show the optical difference between the incoming metal specimens in three states.  The 
leftmost discs represent the as-received material that has not been subjected to testing.  The 
middle column shows discs that were steam corrosion tested after being lightly sanded with 1200­
grit silicon carbide sandpaper to remove any surface contamination and expose bare material.  
The rightmost column shows discs that were steam corrosion tested in the ready-to-strike 
condition with an applied corrosion inhibitor/lubricant.  Unfortunately it is very difficult to show 
often-subtle surface color differences using photographs, but the photos provided here should give 
the reader a good sense of the appearance of the materials after steam corrosion testing.  Results 
are presented here without comments for alternative material candidates for each of the following 
denominations:  one-cent, 5-cent, quarter dollar and dollar coins.   Results are shown in Figures 2­
D-1 through 2-D-22. 
2.7.4.1  One-Cent Coin Alternative Material Candidates 
Untested, as-received on left, lightly sanded and tested in middle, and tested in ready-to-strike 
condition on right. 
Figure 2-D-1.  Steam corrosion tested copper-plated zinc planchets (incumbent US one-cent coin 
material). 
99  

Untested, as-received on left, lightly sanded and tested in middle, and tested in ready-to-strike  
condition on right.  
Figure 2-D-2.  Steam corrosion tested copper-plated steel one-cent planchets from Jarden Zinc 
Products.  
Untested, as-received on left, lightly sanded and tested in middle, and tested in ready-to-strike  
condition on right.  
Figure 2-D-3.  Steam corrosion tested copper-plated steel one-cent planchets from the Royal 
Mint.  
100  

Untested, as-received on left (one-cent coin size blank), lightly sanded and tested in middle (5­
cent coin size blank), and tested one-cent coin size blanks on right. 
Untested, as-received on left (one-cent coin size blank), lightly sanded and tested in middle (5­
cent coin size blank), and tested one-cent coin size blanks on right. 
Figure 2-D-5.  Steam corrosion tested aluminized steel blanks from Atlas. 
Figure 2-D-4.  Steam corrosion tested 5052-H32 blanks. 
101  

2.7.4.2  5-Cent Coin Alternative Material Candidates 
Untested, as-received on left, lightly sanded and tested in middle, and tested in ready-to-strike 
condition on right. 
Figure 2-D-6.  Steam corrosion tested cupronickel 5-cent planchets (incumbent US 5-cent coin 
material). 
Untested, as-received on left and tested in ready-to-strike condition on right.  
Figure 2-D-7.  Steam corrosion tested Dura-White-plated zinc 5-cent planchets.  
102  

As-received on left and ready-to-strike and tested on right, quarter dollar planchet on top and 5­
cent planchet on bottom. 
Figure 2-D-8.  Steam corrosion tested Multi-Ply-plated steel 5-cent and quarter dollar planchets. 
Untested, as-received on left, lightly sanded and tested in middle, and tested in ready-to-strike 
condition on right. 
Figure 2-D-9.  Steam corrosion tested nickel-plated steel 5-cent planchets. 
103  

Untested, as-received on left, lightly sanded and tested in middle, and tested blanks on right.  
Figure 2-D-10.Steam corrosion tested G6 mod 5-cent blanks.  
Untested, as-received on left, lightly sanded and tested in middle, and tested blanks on right.  
Figure 2-D-11.Steam corrosion tested 669z 5-cent blanks.  
104  

Untested, as-received on left, lightly sanded and tested in middle, and tested blanks on right.  
Figure 2-D-12.Steam corrosion tested 430 stainless steel 5-cent blanks.  
Untested, as-received on left and corrosion tested on right.  
Figure 2-D-13.Steam corrosion tested 302HQ stainless steel 5-cent blanks.  
105  

Nickel-plated surface after corrosion test on left, unplated, lightly sanded surface after test in 
middle, and unplated ready-to-strike after corrosion test on right. 
Figure 2-D-14.Steam corrosion tested 31157 5-cent planchets. 
2.7.4.3  Quarter Dollar Coin Alternative Material Candidates 
Untested, as-received on left, lightly sanded and tested in middle, and tested in ready-to-strike 
condition on right. 
Figure 2-D-15.Steam corrosion tested cupronickel-clad C110 quarter dollar planchets (incumbent 
quarter dollar coin material). 
106  

Untested, as-received on left, lightly sanded and tested in middle, and tested in ready-to-strike 
condition on right. 
Figure 2-D-16.Steam corrosion tested nickel-plated steel quarter dollar planchets. 
Untested, as-received on left, lightly sanded and tested in middle (as cut from incoming sheet 
material), and tested blank on right. 
Figure 2-D-17.Steam corrosion tested 669z-clad C110 material. 
107  

2.7.4.4  Dollar Coin Alternative Material Candidates 
Untested, as-received on left, lightly sanded and corrosion tested in middle, and tested in ready­
to-strike condition on right. 
Figure 2-D-18.Steam corrosion tested incumbent dollar coin planchets. 
Untested, as-received on left, lightly sanded and tested in middle, and tested blanks on right.  
Figure 2-D-19.Steam corrosion tested Y42 copper alloy dollar blanks.  
108  

Untested, as-received on left, lightly sanded and tested in middle, and tested blanks on right.  
Figure 2-D-20.Steam corrosion tested K474 copper alloy dollar blanks.  
Untested, as-received on left, lightly sanded and tested in middle, and tested blanks on right.  
Figure 2-D-21.Steam corrosion tested C69250 copper alloy dollar blanks.  
109  

Untested, as-received on left, lightly sanded and tested in middle, and tested blanks on right.  
Figure 2-D-22.Steam corrosion tested yellow bronze- (88Cu-12Sn-) plated zinc dollar blanks.  
110  

2.7.5  Appendix 2-E:  Post-Str iking Steam Cor r osion Test Photogr aphs 
Photographs of the nonsense pieces before and after steam corrosion testing are presented in this 
appendix.  For each of the below figures (Figure 2-E-1 through 2-E-23), the two pieces on the left 
are as-struck and the two on the right are after a 2-hour steam corrosion test.  Results are 
presented here, without comments for alternative material candidates for each of the following 
denominations:  one-cent, 5-cent and quarter dollar nonsense pieces. 
2.7.5.1  One-Cent Coin Alternative Material Candidates 
Two pieces on left are as-struck and two on right are after a 2-hour steam corrosion test.  
Figure 2-E-1.  Steam corrosion tested one-cent nonsense pieces (incumbent material).  
111  

Two pieces on left are as-struck and two on right are after a 2-hour steam corrosion test. 
Figure 2-E-2.  Steam corrosion tested copper-plated steel (Jarden Zinc Products) one-cent 
nonsense pieces. 
Two pieces on left are as-struck and two on right are after a 2-hour steam corrosion test.  
Figure 2-E-3.  Steam corrosion tested copper-plated steel (Royal Mint) one-cent nonsense pieces.  
112  

Two pieces on left are as-struck and two on right are after a 2-hour steam corrosion test.  
Figure 2-E-4.  Steam corrosion tested 5052-H32 one-cent nonsense pieces.  
Two pieces on left are as-struck and two on right are after a 2-hour steam corrosion test.  
Figure 2-E-5.  Steam corrosion tested aluminized steel (Atlas) one-cent nonsense pieces.  
113  

Two pieces on left are as-struck and two on right are after a 2-hour steam corrosion test.  
Figure 2-E-6.  Steam corrosion tested aluminized steel (Ryerson) one-cent nonsense pieces.  
Two pieces on left are as-struck and two on right are after a 2-hour steam corrosion test.  
Figure 2-E-7.  Steam corrosion tested 302HQ stainless steel one-cent nonsense pieces.  
114  

2.7.5.2  5-Cent Coin Alternative Material Candidates 
Two pieces on left are as-struck and two on right are after a 2-hour steam corrosion test.  
Figure 2-E-8.  Steam corrosion tested 5-cent nonsense pieces (incumbent material).  
Two pieces on left are as-struck and two on right are after a 2-hour steam corrosion test.  
Figure 2-E-9.  Steam corrosion tested Dura-White-plated zinc 5-cent nonsense pieces.  
115  

Two pieces on left are as-struck and two on right are after a 2-hour steam corrosion test.  
Figure 2-E-10. Steam corrosion tested Multi-Ply-plated steel 5-cent nonsense pieces.  
Two pieces on left are as-struck and two on right are after a 2-hour steam corrosion test.  
Figure 2-E-11. Steam corrosion tested nickel-plated steel 5-cent nonsense pieces.  
116  

Two pieces on left are as-struck and two on right are after a 2-hour steam corrosion test.  
Figure 2-E-12. Steam corrosion tested G6 mod 5-cent nonsense pieces.  
Two pieces on left are as-struck and two on right are after a 2-hour steam corrosion test.  
Figure 2-E-13. Steam corrosion tested 669z 5-cent nonsense pieces.  
117  

Two pieces on left are as-struck and two on right are after a 2-hour steam corrosion test.  
Figure 2-E-14. Steam corrosion tested 430 stainless steel 5-cent nonsense pieces.  
Two pieces on left are as-struck and two on right are after a 2-hour steam corrosion test.  
Figure 2-E-15. Steam corrosion tested 302HQ stainless steel 5-cent nonsense pieces.  
118  

Two pieces on left are as-struck and two on right are after a 2-hour steam corrosion test.  
Figure 2-E-16. Steam corrosion tested nickel-plated 31157 5-cent nonsense pieces.  
Two pieces on left are as-struck and two on right are after a 2-hour steam corrosion test.  
Figure 2-E-17. Steam corrosion tested unplated 31157 5-cent nonsense pieces.  
119  

2.7.5.3  Quarter Dollar Coin Alternative Material Candidates 
Two pieces on left are as-struck and two on right are after a 2-hour steam corrosion test.  
Figure 2-E-18. Steam corrosion tested quarter dollar nonsense pieces (incumbent material).  
Two pieces on left are as-struck and two on right are after a 2-hour steam corrosion test.  
Figure 2-E-19. Steam corrosion tested Multi-Ply-plated steel quarter dollar nonsense pieces.  
120  

Two pieces on left are as-struck and two on right are after a 2-hour steam corrosion test.  
Figure 2-E-20. Steam corrosion tested nickel-plated steel quarter dollar nonsense pieces.  
Two pieces on left are as-struck and two on right are after a 2-hour steam corrosion test.  
Figure 2-E-21. Steam corrosion tested 669z-clad C110 quarter dollar nonsense pieces.  
121  

Two pieces on left are as-struck and two on right are after a 2-hour steam corrosion test.  
Figure 2-E-22. Steam corrosion tested 302HQ stainless steel quarter dollar nonsense pieces.  
Two pieces on left are as-struck and two on right are after a 2-hour steam corrosion test.  
Figure 2-E-23. Steam corrosion tested Dura-White-plated zinc quarter dollar nonsense pieces.  
122  

2.7.6  Appendix 2-F:  Wear  Test Photogr aphs 
Pictures of the nonsense wear test pieces are included in this appendix.  Unless otherwise stated 
the nonsense pieces spent two weeks in the wear test tumblers with leather, cloth and cork 
materials, and with artificial sweat solution.  All the copper-plated nonsense pieces, including the 
incumbent one-cent copper-plated zinc coins, showed significant color changes, but only minor 
wear.  Copper alloy nonsense pieces showed darkened surfaces and visible wear, much like 
incumbent 5-cent and quarter dollar nonsense pieces. 
Nickel- and Multi-Ply-plated steel nonsense pieces showed some discoloration, but only minor 
wear.  Aluminum and Dura-White-plated zinc nonsense pieces showed minimal wear when tested 
separately, but both showed significant wear when tested with other alternative material 
candidates; this is indicative of galvanic corrosion.  It is difficult to predict how these alloys 
would wear in typical co-circulating conditions with incumbent coinage.  Aluminized steel 
nonsense pieces showed significant wear.  Stainless steel nonsense pieces were nearly unaffected 
by the wear test.  Results are presented here, with a few comments under each photo for 
alternative material candidates for each of the following denominations:  one-cent, 5-cent and 
quarter dollar coins.  Results are shown in Figures 2-F-1 through 2-F-23. 
2.7.6.1  One-Cent Coin Alternative Material Candidates 
Considerable color change, but details still present.  
Figure 2-F-1.  Wear tested one-cent nonsense pieces (incumbent material).  
123  

Color change but only slight edge wear.  
Figure 2-F-2.  Wear tested copper-plated steel (Jarden Zinc Products) one-cent nonsense pieces.  
Color change but only minor edge wear.  
Figure 2-F-3.  Wear tested copper-plated steel (Royal Mint) one-cent nonsense pieces.  
124  

Very little visible sign of wear.  
Figure 2-F-4.  Wear tested 5052-H32 one-cent nonsense pieces.  
Considerable wear (galvanic corrosion).  
Figure 2-F-5.  Wear tested aluminized steel (Atlas) one-cent nonsense pieces.  
125  

Considerable wear after one week.  
Figure 2-F-6.  Wear tested aluminized steel (Ryerson) one-cent nonsense pieces.  
Good wear characteristics.  
Figure 2-F-7.  Wear tested 302HQ stainless steel one-cent nonsense pieces.  
126  

2.7.6.2  5-Cent Coin Alternative Material Candidates 
Color change and moderate wear visible at high points of design.  
Figure 2-F-8.  Wear tested 5-cent nonsense pieces (incumbent material).  
Relatively little wear.  
Figure 2-F-9.  Wear tested Dura-White-plated zinc 5-cent nonsense pieces.  
127  

Some color change and wear on high points of design.  
Figure 2-F-10. Wear tested Multi-Ply-plated steel 5-cent nonsense pieces.  
Some color change and wear at high points of design.  
Figure 2-F-11. Wear tested nickel-plated steel 5-cent nonsense pieces.  
128  

Color change and minor wear.  
Figure 2-F-12. Wear tested G6 mod 5-cent nonsense pieces.  
Color change and minor wear.  
Figure 2-F-13. Wear tested 669z 5-cent nonsense pieces.  
129  

Minor wear (note that design was not filled during striking trial in spite of excessive coining 
load). 
Figure 2-F-14. Wear tested 430 stainless steel 5-cent nonsense pieces. 
Slight discoloration and minimal wear.  
Figure 2-F-15. Wear tested 302HQ stainless steel 5-cent nonsense pieces.  
130  

Some edge wear, underlying copper alloy barely visible.  
Figure 2-F-16. Wear tested nickel-plated 31157 5-cent nonsense pieces.  
Some color change and moderate visible wear.  
Figure 2-F-17. Wear tested unplated 31157 5-cent nonsense pieces.  
131  

2.7.6.3  Quarter Dollar Coin Alternative Material Candidates 
Significant surface wear (may be due to mixing with dissimilar metals during wear test, i.e., 
stainless steel). 
Figure 2-F-18. Wear tested quarter dollar nonsense pieces (incumbent material). 
Color change with wear.  
Figure 2-F-19. Wear tested Multi-Ply-plated steel quarter dollar nonsense pieces.  
132  

Color change and wear.  Copper visible on rim may have rubbed off from other nonsense pieces 
of different composition during the wear test. 
Figure 2-F-20. Wear tested nickel-plated steel quarter dollar nonsense pieces. 
Considerable color change and some wear.  
Figure 2-F-21. Wear tested 669z-clad C110 quarter dollar nonsense pieces.  
133  

Minor discoloration and minimal wear.  
Figure 2-F-22. Wear tested 302HQ stainless steel quarter dollar nonsense pieces.  
Very little wear.  
Figure 2-F-23. Wear tested Dura-White-plated zinc quarter dollar nonsense pieces.  
134  

2.7.7  Appendix 2-G:  Sur face Engineer ing Tr ials 
Several additional tests were performed to evaluate the impact of some non-conventional surface 
treatments being applied to alternative material candidates.  The ability to inexpensively modify 
the color and corrosion behavior of some alternative material candidates would be highly 
desirable.  Although it was recognized that none of these techniques could be fully developed 
during the course of this study, CTC completed some feasibility studies that may be valuable to 
suggest areas for possible future research. 
2.7.7.1  Ross Technology Surface Coatings 
Ross Technology Corporation is developing several proprietary surface-adsorbed compounds
62 
including two variants known as A26 and B21 to improve corrosion resistance.  Preliminary tests 
were conducted using coated planchets to determine if these coatings would allow for successful 
striking while maintaining their adherence to the surface of nonsense pieces and inhibiting 
corrosion.  The long-term goal (beyond the scope of the current study) is to evaluate if such 
coatings can obviate the need for copper or nickel electroplating to reduce the costs of producing 
coins.  As can be seen in the photographs that appear below, the application of these coatings to 
blanks was not optimized; therefore, the coating was not fully applied to the blanks causing 
striations across the surface.  Coatings were applied by hand dipping planchets into the coating 
bath hence leaving uncoated areas and a clear demarcation of coated and uncoated regions. 
A26 was applied to bare zinc alloy A190 one-cent planchets provided by Jarden Zinc Products 
(JZP).  B21 was applied to bare zinc A190 5-cent planchets.  Several examples of each type were 
struck during the second striking trials at the United States Mint in Philadelphia to evaluate 
whether the coatings would survive coining.  Nonsense pieces were subsequently steam corrosion 
tested to evaluate how well the coatings inhibit corrosion.  Both coatings are nominally colorless.  
For the 5-cent coin, such a coating could make bare zinc a viable option to obviate the costs of 
electroplating.  Both sets of test samples struck well at the normal press load used for their 
respective denomination, and showed no evidence of flaking or delamination.  Figures 2-G-1 and 
2-G-2 show the nonsense pieces after striking. 
62 
A26 is an ultraviolet-cured compound and B21 is a thermally cured compound. 
135  

Figure 2-G-1.  A26-coated A190 one-cent nonsense piece struck at 40 tonnes. 
Figure 2-G-2.  B21-coated A190 5-cent nonsense piece struck at 54 tonnes. 
Steam corrosion tests were subsequently performed on the nonsense pieces.  The test protocol 
included measuring color before steam corrosion testing and then after a two hour-exposure to 
steam at 100 °C (212 °F), as described in Appendix 2-B.  Lower total color vector change 
indicates better corrosion resistance.  Table 2-G-1 shows both the initial color readings and the 
total color vector change after steam corrosion testing for the nonsense pieces and an uncoated 
(i.e., bare) zinc planchet for comparison.  Steam corrosion results were disappointing.  Figures 2­
G-3 shows the as-coated planchets (left) and planchets after the steam corrosion test (right).  
Figure 2-G-4 shows comparisons of the as-struck one-cent nonsense pieces (on the left) with 
steam corrosion tested pieces (on the right); Figure 2-G-5 shows the corresponding 5-cent 
nonsense pieces.  Darkening or graying of the surfaces after steam exposure is clearly evident. 
A second batch of A26-coated planchets was prepared using a modified curing procedure (Type 
II); this second batch was also steam corrosion tested.  In this case zinc, copper-plated zinc and 
136  

raw steel surfaces were prepared using the coatings.  Steam corrosion performance was improved, 
although the coatings themselves were no longer colorless.  Steam corrosion total color vector 
change readings were low for the A190 surfaces before and after steam corrosion testing as shown 
in Figure 2-G-6, and copper-plated surfaces as shown in Figure 2-G-7.  The A26-coated steel 
surfaces experienced some spotting and higher total color vector change, but the steel showed 
much less color change than would be expected on raw steel (Figure 2-G-8).  Test results are 
shown in Table 2-G-1.  The Type II curing procedure showed a marked improvement compared 
with the first coating trials.  However, it must be noted that the relatively darkly colored coatings 
are difficult to compare with shiny metal surfaces and comparing numerical values may be 
misleading. 
Table 2-G-1.  Color Measurements and Total Color Vector Change Readings for Corrosion 
Inhibitor Treated Surfaces