Smart Wire (Smart Material)
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Product Code : SCL-CLE-12856
Smart wire is a shape memory alloy (SMA) that changes
its length with a useful pulling force when a small current is passed through
it.
SMA is a smart material which, as its name
suggests, has a memory. The most common SMA is an alloy (mixture of metals) of
nickel and titanium -called nitinol. By means of special heat treatment, a
piece of SMA can be made to 'remember' a shape. For example, a length of wire
can be made to remember that it should be straight at temperatures above 70°C.
If you bend this wire at normal room temperature into the shape of a paper
clip, it stays bent and will continue acting as a paper clip. However, if you
place it in a glass of water whose temperature is above 70°C, it immediately
straightens out! When cool, it remains straight until it is bent again. This
cycle of bending and then straightening when heated can be continued millions
of times. The temperature at which SMA 'remembers' its original form is called
the transition temperature and when this point is reached, it changes shape.
SMA has a relatively high electrical resistance and
can be heated to its transition temperature by passing an electrical current through
it.
- Resistance: 150Ω per metre
- Maximum Current: 180 milliamps
- Maximum Power: 5 Watts per metre
- Bias Force: 0.3 N
- Pulling Force: 1.5 N
Reasons to Love
- Cross applications in Science and Design
Technology classes
Learning Outcomes
- Key Stage 3 Chemistry - Materials: Properties
of ceramics, polymers and composites (qualitative)
- Key Stage 4 Chemistry - Structure, Bonding and
the Properties of Matter: Smart Materials and Their
Properties. Bulk properties of materials related to bonding and
intermolecular forces
- Key Stage 4 Chemistry
- Atomic structure and the Periodic Table: Characteristic
properties of metals and non-metals.
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