Brass is primarily an alloy composed of copper and zinc and brass is a general name for a series of copper and zinc alloys. Brasses have different proportions of zinc and copper, which can be altered to produce a series of alloys having different characteristics. Brass with a higher proportion of zinc gives strength and flexibility to the material. However, brass can vary from red color to yellow, which significantly depends on the zinc content in the alloy.
Brass is utilized for decorative ideas principally due to its similarity in appearance to gold. As brasses have good workability and stability, it is additionally used to design musical devices.
So, while talking about brasses, which are composed of copper and zinc, and we all know that copper is the second-best conductor after silver, which is widely used in wires, one crucial question arises: whether brass conducts electricity?
Yes, brass is a good conductor of electricity as its metallic crystal arrangement enables the electrons to move freely. However, the gradual addition of zinc into copper, which leads to the formation of brass alloys, decreases the electrical conductivity by restricting the free flow of the electrons in the crystal arrangement. Brass with 70% copper content has electrical conductivity, but with the increase in zinc content, the electrical conductivity decreases whereas greater content of copper makes it a good conductor of electricity.
However, the addition of zinc improves the durability and elasticity of copper. Thus, the greater concentration of zinc makes the resultant brass alloy stronger and more flexible
Let’s first understand electrical conductors and the factors that affect the electrical conductivity
What are Electrical Conductors?
Electrical conductors have the exceptional feature of carrying electric charges, which are conductive and conduct electricity. Electric conductors have mobile electrically charged particles called “electrons.”
When an electric charge is passed through metal, the electrons in the atom will move freely and allow the electricity flow. Metals with high electron movement are good conductors, while metals with low electron flow are not good conductors but are referred to as “insulators”.
The extent of electrical conductivity greatly depends on the number of valence electrons in the outermost shell of an atom, where most conductors have one, two, or sometimes three valence electrons.
Let us have a look at the periodic table elements to understand which metals are the best electrical conductor.
There are some metals that are highly conductive than others. For example, silver is the most conductive metal, followed by copper, then gold. The conductivities of other metals drop after these three metals.
Although aluminum is somewhat at a fourth position, it is inexpensive and light, so it is extensively used across the globe in power transmission wires. Following aluminum, most other metals show electrical conductivity but to a lesser extent.
However, various metal elements are mixed to develop alloys with higher durability and stability and do not rust easily. Zinc is the most employed metal to form alloys, and the alloys of zinc have various practical applications.
Let us talk about the most common zinc alloy, i.e., brass, formed by mixing zinc with copper.
But first, let us understand the conductivity of copper and zinc?
Copper is the most conductive metal only after silver. As copper is cheaper and easily affordable, it finds many applications as compared to silver. Copper is widely used in electrical wires, thereby supporting electrical conduction.
Interestingly, it is more commonly used in circuit boards and electromagnets, substituting aluminum because of its higher conductivity.
Moving on to understand zinc conductivity, zinc is significantly less conductive in contrast to gold, copper, and silver, and it can be a more economical option to these above-mentioned expensive metals. Moreover, zinc yields good conductivity and excellent durability.
Factors that affect the electrical conductivity
Several factors can impact electrical conductivity. Let us go through these factors.
1. Temperature: Altering the temperature of any conductor changes its conductivity. Usually, raising the temperature leads to excites the atoms and reduces conductivity, thereby enhancing resistance to the flow of electrons in the lattice structure.
2. Impurities: The addition of impurity to a conducting material lowers its conductivity as the presence of impurities in the material resists the flow of electrons.
3. Crystal arrangement and states: The material in different states will exhibit different conductivity due to different lattice structures. As a result, the electrons will flow at different rates in different states.
4. Electromagnetic fields: When an electric current is passed through a conducting material, it produces its electromagnetic fields with a perpendicular magnetic field.
The electromagnetic fields from the outside can create magnetoresistance, which can therefore reduce the current flow.
Let’s dive more into the details of brass.
How was brass first formed?
Brass has been used for centuries, and still today, it has broad applications. The discovery of brass was seen in Breinigerberg village of Germany by melting copper with calamine, which is a zinc ore.
The melting of the copper and calamine leads to the extraction of the zinc from the calamine, which eventually mixes with the copper, forming a brass alloy.
What is brass?
Since brass is an alloy formed by combining metals like copper and zinc, and the ratio of zinc metal and copper metal can be altered.
Different copper and zinc alloys have copper ratios from 15%, also referred to as red brass, while brass alloy with a 40% zinc level is known as yellow brass. However, zinc level with less than 15%, despite brass is indicated as bronze.
Why does the conductivity of pure copper drop on forming brass?
Pretty clearly, the conductivity of metal will be greatly influenced by combining an alloying component. Every metal holds a specific inherent electrical conductivity in the pure form as per its outer electron configuration.
However, for any metal, the addition of two or more metals to form alloy changes the electron flow in the metal crystal framework. Consider the brass formation from copper and zinc. Copper possesses the second-best conductivity; however, zinc has relatively poor conduction of electricity.
Even if pure copper is combined with a small quantity of zinc, a meagre reduction in conductivity is observed in contrast to pure copper, just because of the intervention in the free pathway of electrons moving through the crystal arrangement.
Various other metals like lead, iron, tin, silicon, aluminum, and manganese are sometimes added to form novel combinations of properties. The lead metal of approx 2% is usually added to the brass to increase the machinability of alloy.
But, notable leaching of lead is frequently observed, also in brass containing a relatively low overall lead concentration. As a result, the application of brass alloy usually includes musical devices, radiators, building trim, pistol cartridge casing, pipes, screws, and decorative articles.
Brass is nevertheless an essential alternative for electrical conductors as it possesses comparatively high-grade durability and conductivity to other metals or alloys, for example, steel. Brass is placed at fifth position with respect to electrical conductivity in the conductivity scale after silver, copper, gold, and aluminum.
Properties of Brass
- Being a copper-zinc alloy, brass illustrates most of the properties typical of copper. Nonetheless, the alloy shows several distinguished properties in contrast to pure copper and alloys. For instance:
- Brass is a good conductor of heat.
- Brass has a melting point of nearly 900°C. The precise melting point varies depending on the other metal concentration in the alloy.
- Since brass is not ferromagnetic, it is significantly simpler to treat for recycling.
- Brass possesses higher malleability as compared to other materials like bronze or zinc, and it is simple to work.
- Brass usually owns a sparkling gold color. However, it can additionally comprise a reddish-gold or silvery color. The higher content of copper produces a rosy tint, while the presence of more extra zinc gives silvery-white color.
- Brass has acceptable acoustic characteristics suitable for application in musical devices.
- The metal shows moderate friction and can withstand corrosion.
In this article, we understood that brass is a good conductor of electricity. However, the addition of zinc into copper, to form brass alloys, reduces the electrical conductivity by restricting the free flow of the electrons in the crystal arrangement. The higher concentration of zinc makes the brass alloy stronger and flexible, whereas the higher content of copper makes it a good conductor of electricity.
Brass establishes the standard to estimate the machinability of different metals. Furthermore, it does not break at low temperatures like mild steel. Brass also possesses superior thermal conductivity and remains the leading option for use as heat exchangers.
Fun fact: Interesting feature of brass is that it kills common pathogens on its surface in hours, thereby acting as disinfection and allowing it to be used indoors and different tools usually touched by a human.