Breaking Boundaries With Bi-metal
Jarden Zinc is now offering its ZincSecure™ coin blank in a bi-metal (two-piece) coin option. This option provides enhanced security to mints and central banks to replace high denomination bi-metal coins or more expensive banknotes.
Bi-metal ZincSecure™ coins provide several advantages such as:
- Different plating available using different ZincSecure™ alloys (or combined with other substrates) for core and ring
- Enhanced security
- High aesthetic appeal
Using different ZincSecure™ alloys for the outer ring and the inner core for the bi-metal coin strengthens its security. Each of the alloys provides its own distinct EMS. Upon assembly of the core and ring, the bi-metal exhibits a unique EMS that would be difficult to replicate (see figure 1).
Figure 1. Distinct EMS for Alloy Bi-Metal Combinations
Through internal testing, ZincSecure™ bi-metal coins have proven to excel in separation force, corrosion resistance and wear resistance. The performance meets and exceeds that of the other circulated coins in the industry.
ZincSecure™ bi-metal separation force exceeds the typical industry minimum range (see figure 2) as it has a high degree of locking between core and ring(see figure 3).
Figure 2. ZincSecure™ Bi-Metal Separation Force
Figure 3. ZincSecure™ Bi-Metal High Degree of Locking
Corrosion and Wear Resistance
Bi-metal ZincSecure™ coins are found to have excellent corrosion resistance. Testing revealed no signs of corrosion especially at the core-ring interface which is the highest risk. ZincSecure™ bi-metal coins showed no evidence of corrosion at the core/ring interface after being submerged in a 2% salt solution that was pH adjusted for 4 hours.
Figure 4. ZincSecure™ Bi-Metal Stamped Coin Blanks Post Four-hour Corrosion Test
ZincSecure™ bi-metal coins are also found to superior resistance to wear. Wear testing results showed that the ZincSecure™ ring and core combinations had less wear when compared with some commonly used coin materials (see figure 5). The coins were placed inside a set of tumble cylinders on rollers @ ~37 rpm with 5mls of artificial sweat solution added. This attempts to replicate common environments that coins would be subject to such as inside a pocket.
Figure 5. ZincSecure™ Bi-Metal Coin Blanks 1000 Hour Wear Test