Applications of Metal Powder
Electronic & Electrical Manufacturing
Electrical resistance is proportional to temperature. Resistance in a circuit produces heat, and as the system temperature increases the resistance increases. This can produce a cascade effect to the detriment of system performance. That is why many electrical devices use fans or other cooling systems to remove heat away from electronic components within a device. These cooling systems often employ the use of copper materials, due their excellent thermal conductivity which provides excellent capability in transferring heat.
Devices utilising radio frequencies to send receive and process information are ubiquitous in everyday life. Phones, computers, satellite dishes, GPS tracking, just to name a few, all rely on an ability to sort through a plethora of signals permeating throughout the surrounding space and selectively capture and process only those that are intended for the individual device. A key piece of engineering in the design of these devices is the incorporation of shielding that prevents interaction or interference from other signals and stray electromagnetic (EM) radiation. Copper powder coatings and paints containing copper provide a straightforward means of shielding electronic components. Coating a surface in order to produce a barrier to EM radiation is generally more efficient than fabrication of an individual metal sheet or enclosure, which can be especially difficult when dealing with microelectronic devices.
Materials used to fabricate circuits, whether traditional wire or printed circuit boards (PCBs), should possess high conductivity, allowing free flow of electrons. All materials have some level of electrical resistance which converts some portion of the electrical energy passing through it into heat. This diminishes the strength of the electrical signal and, in cases of excessive heat generation, can cause irreparable damage to the system. Therefore, when designing circuitry it is desirable to use materials with the least resistance possible. With the exception of silver, copper has the lowest electrical resistance of any metal. Additionally, it is malleable and in powder form can readily be formulated into conductive paints. That is why it is by far the material of choice for both wired circuits and PCBs.
Welding and Brazing
For relatively low voltage applications, such as the electricity supply in our homes, circuit breakers are employed as an automatic safety shut-off to cut power when dangerous conditions occur. A common example would be when a device plugged into a wall outlet short-circuits and increased electrical resistance in the circuit begins to produce excessive heat. To prevent permanent damage or fire, the circuit breaker is designed to sense the increase in resistance and consequently “break” the circuit in order to remove electricity form the system. Normally this is a mechanical switch that trips when a certain electrical resistance is reached. For medium voltage applications, one to seventy-two kilovolts, vacuum interrupters are used as circuit breakers. Two metal contacts, normally made from copper alloys, comprise the breaking switch. They remain in contact within a vacuum sealed chamber, but become separated when the resistance threshold is reached. The vacuum environment helps to ensure that electricity will not transfer across the gap, what is known as arching.