BRASS

Brass is, in technical terms, an alloy composed primarily of copper and zinc, in which the latter does not exceed 50% by mass. This proportion defines the conventional limit for classifying an alloy as Brass, although in practice, the criterion is more flexible. Provided that zinc acts as the main alloying element within a copper matrix, the alloy can be considered Brass, even if other metals are incorporated in significant proportions. It is common to find variants that include tin, aluminum, manganese, or silicon, which modify its mechanical, thermal, or aesthetic properties without altering its general classification. 

This adaptability has made Brass one of the most widely used materials in industrial, ornamental, and domestic applications. Its corrosion resistance, ease of machinability, and attractive golden color make it especially valuable in contexts where both functionality and appearance are required. Although its definition may seem strict from a chemical standpoint, modern metallurgy recognizes Brass as a family of alloys whose rich composition allows for an enormous variety of uses and behaviors. 

Brass, an alloy of copper and zinc, has accompanied humanity for at least nine centuries, although its history is more diffused and less documented than that of bronze. The great civilizations of antiquity—Egypt, Babylon, Persia, Greece, and Rome—did not fully understand Brass, nor did they clearly distinguish it from bronze, whose manufacture was more accessible and whose chemical composition was better understood. To obtain bronze, copper—or one of its minerals, like malachite—was melted with metallic tin—or its mineral, cassiterite—in a furnace, through a reduction process with coke or charcoal. The nobility of both metals allowed them to be introduced directly into the furnace in their mineral form, where, after roasting, they released their components and combined to form the desired alloy. 

The discovery of Brass appears to have been equally accidental. It is presumed that, as with bronze, someone mixed zinc minerals with molten copper, thus obtaining a new alloy that would begin to gain relevance in regions such as Arabia, Persia, and India. Curiously, Brass was discovered before pure zinc, which explains why, for centuries, the identity of the "other metal" that gave Brass its distinctive properties was unknown. Unlike bronze, whose bicomponent nature was known, Brass was produced without knowing exactly what made it different. In fact, objects that could be considered Brass have been found in territories as diverse as Mexico and Peru, belonging to pre-Columbian cultures, suggesting that its discovery may have occurred simultaneously and spontaneously in different parts of the world. 

Although there are Brass pieces dating from the Roman period, they are considered accidental products. The joint presence of zinc and tin minerals in certain mines may have led artisans to melt them without distinguishing between them, thus obtaining an unintentional alloy. In an era when even the most basic steel was unknown, such confusions were understandable. It was not until the Middle Ages that references began to appear to the mineral known as spelter—not to be confused with pewter—or calamine, a term still used in certain contexts. However, Brass remained an incipient alloy, without a consolidated technical understanding. 

It was around the 10th century when Indian metallurgists succeeded in isolating elemental zinc and deliberately combining it with copper, thus obtaining quality Brass. Unlike previous discoveries, this process was conscious and controlled, although they are not credited with the invention of the alloy, given that Brass objects produced unconsciously already existed. What distinguishes this historical moment is the intention: for the first time, it was known what was being done. 

The main advantage of Brass over bronze lies in its appearance. Its golden luster, similar to gold, makes it an aesthetically more attractive option for most people. Additionally, Brass retains its shine more easily than bronze, which tends to develop a more robust green patina over time due to copper sulfation. Although Brass also forms its own greenish patina, this is easier to maintain, which has favored its ornamental use over its mechanical properties. However, this does not imply that it is weak or useless from a structural point of view; on the contrary, Brass possesses respectable mechanical qualities, although its beauty has historically been its most powerful calling card. 

After bronze, Brass ranks as the most widely used copper alloy in the world. Its popularity varies depending on the availability of its constituent elements, especially zinc, which is generally more abundant and economical than tin. In regions where the latter is scarce or costly—as in the United States, Canada, and certain South American countries—Brass has displaced bronze as the primary copper alloy, relegating bronze to more specific uses, such as the manufacture of statues, medals, or coins. In contrast, in Europe and much of Asia, bronze is still frequently used, maintaining its classic formula: copper with between 5% and 22% tin by mass. 

The confusion between both alloys intensifies when mixed compositions are present, in which copper constitutes approximately 90%, and zinc and tin are in similar proportions—for example, 5% each. In these cases, the denomination can fluctuate between Brass and Bronze, depending on the context, the intended use, and technical interpretation. However, it is essential to establish a clear distinction between the two. From an aesthetic point of view, Brass is usually preferred for its golden color, which resembles gold and makes it especially attractive in ornamental applications, such as in the manufacture of wind musical instruments—trumpets, flutes, tubas—where its shine and malleability are ideal. 

On the other hand, Bronze surpasses Brass in mechanical, electrical, and corrosion resistance properties. This technical superiority also translates into a higher cost, due to two main factors: tin is more expensive than zinc, and bronze typically contains a higher proportion of copper. Thus, Brass becomes a more economical alternative, without implying a total loss of quality, especially in contexts where aesthetics and price outweigh durability or conductivity. 

Historically, Bronze has a much more significant trajectory. It was the first alloy discovered and worked by humans, marking the beginning of a technological era that transformed civilization. Its legacy endures to this day, although Brass, for reasons of cost and appearance, has gained ground in multiple sectors. This duality between tradition and functionality, between nobility and accessibility, defines the relationship between both alloys, which continue to coexist in the vast universe of modern metallurgy. 

The proportion of zinc directly influences the mechanical properties of Brass. As its content increases—up to approximately 40–45% by mass—a significant improvement in hardness and corrosion resistance of pure copper is observed. However, when this threshold is exceeded, the alloy begins to lose toughness and gain brittleness, which limits its use in applications requiring structural strength. This variability responds to the specific needs of each use: a Brass intended to imitate gold in a picture frame is not the same as one designed to withstand the mechanical demands of a naval propeller. Although both may share a golden appearance, their internal properties are radically different.

The inclusion of elements such as nickel, manganese, or even aluminum can further modify the behavior of Brass, adapting it to particular requirements. Some Brasses are formulated to maximize corrosion resistance, others to facilitate cold forming, and others to withstand high mechanical loads. This diversity makes Brass a family of alloys rather than a single entity, and its study demands a detailed understanding of its chemical composition.

Finally, it is important to note that not all Brasses respond equally to heat treatment. Some can be hot hardened, as occurs with certain types of steel; others, however, cold harden, like austenitic stainless steel; while there are Brasses that do not permit thermal hardening at all, regardless of the temperature applied. This difference, once again, is explained by the specific chemical composition of each variant, reaffirming the need to approach Brass not as a unique alloy, but as a set of metallurgical solutions adaptable to multiple contexts.

In its simplest form, low Brass—with less than 30% zinc—presents a face-centered cubic (FCC) crystal structure, identical to that of pure copper. This phase, known as the alpha phase, is associated with austenite in the context of steel, although in the case of Brass, it should not be confused with any ferrous alloy. The alpha phase retains the characteristic malleability and ductility of copper, albeit with slightly higher hardness, making it ideal for applications requiring ease of forming without sacrificing basic strength.

When the zinc content reaches or exceeds 30%, a second crystalline phase begins to form: the body-centered cubic (BCC), known as the beta phase. This structure, analogous to ferrite in steel, provides greater hardness and wear resistance, but significantly reduces the material's ductility and flexibility. In this range—between 30% and 40% zinc—Brass is considered duplex, as its microstructure combines regions of alpha phase with regions of beta phase. This coexistence of phases gives the material a balance between workability and strength, although the relative proportion of each phase will determine its final behavior.

It is important to avoid using the term "ferrite" to describe the beta phase of Brass, as this term is reserved for iron-based alloys. Brass, being a copper alloy, has no structural or chemical relationship with iron, so it is more accurate to refer simply to the beta phase or the body-centered cubic structure.

The alpha phase is characterized by its face-centered cubic (FCC) crystal structure, identical to that of pure copper. This phase remains stable as long as the zinc content does not exceed 30% by mass, allowing for a homogeneous, malleable, and ductile alloy. Its corrosion resistance is high, and it does not present a risk of dezincification, a phenomenon that negatively affects certain high-zinc Brass alloys. The alpha phase is especially valued in aesthetic applications, such as jewelry or decoration, where workability and surface finish are priorities. A particularly popular combination in this context is 75% copper and 25% zinc, which offers a balance between color, shine, and ease of forming.

The duplex phase represents a transition between alpha and beta. It forms when the zinc content is between 30% and 40%, resulting in a microstructure where both phases coexist. This hybrid configuration gives Brass a hardness superior to that of the alpha phase, although with a partial loss of malleability and ductility. Duplex Brasses are used in intermediate applications where both an attractive appearance and moderate mechanical strength are required. Their versatility makes them a frequent choice in sectors that demand a balance between aesthetics and functionality.

The beta phase, for its part, appears when the zinc content exceeds 40% and can reach up to 45% by mass. Its crystal structure is body-centered cubic (BCC), similar to that presented by several refractory metals and some elements of the first transition series, such as vanadium, chromium, manganese, and iron. Curiously, pure zinc does not adopt this structure, but it does in combination with copper when the mentioned threshold is reached. The beta phase is the hardest and most rigid of the three, making it suitable for applications requiring high wear resistance, such as in bearings or components subjected to constant friction. However, this phase presents limited workability and a particular vulnerability: dezincification. This phenomenon, little known in the Latin sphere—including Spain and Italy—consists of the selective loss of zinc in corrosive environments, which weakens the material's structure and compromises its long-term integrity.

This film gives Brass considerable resistance to seawater, as well as freshwater, making it a viable option for nautical and domestic applications. It also shows good tolerance to contact with alcohols, bleaches, organic substances—such as food and beverages—and other everyday compounds. Regarding its behavior against cold acids and alkalis, the resistance is moderate, allowing its use in slightly aggressive, though not extreme, environments.

Brass's main asset in this area is its ability to retain its golden and shiny coloration for long periods, surpassing bronze in this aspect. However, this aesthetic advantage should not be confused with total immunity to corrosion. Zinc, an essential component of Brass, occupies a low position in the galvanic series, which indicates lower electrochemical "nobility." This characteristic makes it susceptible to accelerated corrosion processes when exposed to strong acids such as hydrochloric (HCl), nitric (HNO₃), or sulfuric (H₂SO₄). Under such conditions, Brass can deteriorate rapidly, losing both its appearance and its mechanical properties.

Therefore, although Brass offers notable resistance in multiple contexts, it is essential to understand its limits and avoid its prolonged exposure to highly aggressive media. In the next section, we will address one of the most relevant problems of Brass in relation to corrosion: dezincification, a phenomenon that affects its behavior in specific environments and deserves special attention.

Dezincification is a galvanic corrosion process that affects certain Brasses with a high zinc content, in which this metal, at a granular level, progressively detaches from the copper matrix and dissolves into the surrounding medium. This phenomenon creates porosities on the surface and inside the material, weakening its structure and compromising its mechanical integrity. The main cause lies in the low galvanic potential of zinc, comparable to that of magnesium —an alkali metal— which makes it a "sacrificial" element in the presence of an electrolytic medium, such as salt water.

Copper, for its part, can only dissolve a limited amount of zinc without losing its most stable crystalline structure, the face-centered cubic (alpha phase). When the zinc content exceeds that threshold, it begins to form microscopic intermetallic compounds instead of homogeneous solid solutions. In prolonged contact with aggressive environments, such as seawater, these compounds disaggregate, and the zinc migrates in the form of nodules, leading to the appearance of pores. The result is a transformation of the material: from a solid, massive piece, it becomes a structure comparable to a sponge or cheese, with a significant loss of strength.

This problem was identified in the early years of naval industrialization, when Brass began to replace bronze for economic reasons, especially in countries like the United States, England, and Germany. The propellers of steamships, made with zinc-rich Brasses, began to show signs of fragility due to the formation of pitting on their blades. Unlike localized oxidation, dezincification is an internal, silent, and progressive process that compromises the metal mass from its core.

The presence of other alloying elements can influence the appearance or mitigation of the phenomenon. Lead, for example, tends to favor dezincification, while tin acts as a stabilizer. Even discrete amounts —on the order of 1% by mass— are sufficient to reinforce the copper-zinc solution and prevent zinc migration. However, the cost and scarcity of tin in certain countries limit its use in large-scale industrial applications. While adding tin to a two-ton church bell might seem reasonable, the scenario changes when manufacturing thousands of fifty-kilogram naval propellers. In that context, 500 grams of tin per unit becomes a considerable economic barrier.

Commercial alloys, therefore, are designed to meet functional needs with the minimum necessary ingredients, prioritizing the most accessible metals without entirely compromising quality. Brass has replaced bronze in numerous types of vessels, but in no case does it surpass it in terms of fatigue resistance, protection against galvanic corrosion, or defense against colonization by metal-eating microorganisms. Dezincification, although little known in the Latin world, represents a real threat to the durability of parts made with zinc-rich Brasses, and its study is essential to understanding the limits of this versatile yet vulnerable alloy.

Brass is utilized for two fundamental reasons that, although distinct in nature, converge in its versatility and practical value. The first, and perhaps the most evident to the casual observer, is its aesthetic appearance. Its golden color resembles low-karat gold, making it a symbolic and visually attractive substitute in multiple contexts. It is used to manufacture ornamental objects such as vases, plates, picture frames, handrails, doorknobs, and trim in sectors as diverse as automotive, architecture, and the naval industry. Its presence in the international monetary system, though not literal, is manifested in the choice of golden finishes for elements that evoke prestige or value. In reality, almost any quality object with a golden hue is usually made of Brass or, at least, coated with a superficial layer of this alloy. Everyday examples abound: the frames of sunglasses, the rivets of an executive suitcase, tie pins, commemorative embossed plaques, among others.

The second reason, more relevant from the perspective of the technician, artisan, or jeweler, lies in its mechanical properties and ease of work. Brass is a non-toxic, completely recyclable, and relatively easy-to-obtain alloy, making it an ideal material for personal creative projects, such as lost-wax casting of a statue or the manufacture of a women's bracelet. Its excellent fabricability, malleability, and ductility allow it to be molded with precision and detail, while its durability makes it suitable for demanding applications. In mechanics, it is especially valued for its low coefficient of friction, which translates into remarkable self-lubricity. This property is indispensable in sectors such as the food industry or textiles, where direct contact between metal parts must minimize wear.

The steel-steel combination, for example, is detrimental in gear systems, as constant friction systematically degrades the contacting surfaces. The use of Brass in these cases acts as a shock absorber: by "sliding" better against steel, it prolongs the lifespan of both the ferrous part and itself. This principle explains why, even today, high-end watch manufacturers continue to use Brass for the internal parts of the case. In fact, many gold watches manufactured in the first half of the 20th century —today highly collectible and valuable— were constructed with Brass instead of solid gold, contrary to what is often assumed. This choice was not only due to economic reasons but also to technical criteria: Brass offered a combination of beauty, precision, and strength that gold, on its own, could not guarantee.

Brass is utilized for two fundamental reasons that, although distinct in nature, converge in its versatility and practical value. The first, and perhaps the most evident to the casual observer, is its aesthetic appearance. Its golden color resembles low-karat gold, making it a symbolic and visually attractive substitute in multiple contexts. It is used to manufacture ornamental objects such as vases, plates, picture frames, handrails, doorknobs, and trim in sectors as diverse as automotive, architecture, and the naval industry. Its presence in the international monetary system, though not literal, is manifested in the choice of golden finishes for elements that evoke prestige or value. In reality, almost any quality object with a golden hue is usually made of Brass or, at least, coated with a superficial layer of this alloy. Everyday examples abound: the frames of sunglasses, the rivets of an executive suitcase, tie pins, commemorative embossed plaques, among others.

The second reason, more relevant from the perspective of the technician, artisan, or jeweler, lies in its mechanical properties and ease of work. Brass is a non-toxic, completely recyclable, and relatively easy-to-obtain alloy, making it an ideal material for personal creative projects, such as lost-wax casting of a statue or the manufacture of a women's bracelet. Its excellent fabricability, malleability, and ductility allow it to be molded with precision and detail, while its durability makes it suitable for demanding applications. In mechanics, it is especially valued for its low coefficient of friction, which translates into remarkable self-lubricity. This property is indispensable in sectors such as the food industry or textiles, where direct contact between metal parts must minimize wear.

The steel-steel combination, for example, is detrimental in gear systems, as constant friction systematically degrades the contacting surfaces. The use of Brass in these cases acts as a shock absorber: by "sliding" better against steel, it prolongs the lifespan of both the ferrous part and itself. This principle explains why, even today, high-end watch manufacturers continue to use Brass for the internal parts of the case. In fact, many gold watches manufactured in the first half of the 20th century —today highly collectible and valuable— were constructed with Brass instead of solid gold, contrary to what is often assumed. This choice was not only due to economic reasons but also to technical criteria: Brass offered a combination of beauty, precision, and strength that gold, on its own, could not guarantee.

Brass has established itself as one of the most suitable alloys for coin manufacturing, thanks to its ease of production, relatively low cost, and its golden appearance which, although symbolically, evokes gold. The latter, displaced from the monetary system by its high price and the volatility associated with its value, has given way to more accessible materials, among which Brass stands out on its own merits. Its use in coinage dates back at least five centuries, especially in the Western periphery, including the New World, where the need for functional and aesthetically pleasing metals drove its adoption.

Brass brings together all the advantages of bronze in this context, but with a significant addition: its greater ease of stamping. This property allows for the precise engraving of details, which is essential in the mass production of coins. Furthermore, its golden color gives it a visual appeal that has been utilized by numerous monetary systems throughout history. In the era of the old Spanish peseta, for example, some coins were nicknamed "rubias" (blondes) precisely because of their hue, which recalled gold. This chromatic tradition continues today with the 10, 25, and 50 euro cent coins, which use Brass in their composition or coating, thus maintaining an aesthetic continuity that the public recognizes and associates with value.

Alongside cupronickel and cuproaluminum, Brass forms part of the trio of most popular alloys in contemporary numismatics. Its wear resistance, chemical stability, and ability to retain its luster make it a preferred option for daily circulation coins. It not only meets the technical requirements demanded by central banks but also provides a symbolic dimension: the golden color of Brass, though not gold, still represents wealth, permanence, and tradition. In this sense, Brass is not simply a functional metal, but also a vehicle of collective memory, an alloy that unites economy, aesthetics, and history in every piece that passes from hand to hand.

Brass, due to its golden appearance, has found a prominent place in low-profile jewelry, especially in large-scale commercial production. Its warm, metallic hue makes it a visually attractive alternative to gold, without incurring the prohibitive costs of the latter. This aesthetic quality has made Brass an omnipresent material in mass-market costume jewelry, found in markets on all continents and in practically every country in the world.

Contrary to popular belief, Brass is not as cheap as it is often assumed. Its price varies according to the specific composition of the alloy (mainly copper and zinc, with possible traces of other metals), the manufacturing process, and the surface finish. It is used to make a wide range of pieces: hoops, rings, bracelets, anklets, earrings of various styles, pendants, and, more occasionally, chains. This last category, however, reveals the limitations of Brass in applications requiring high chemical and mechanical resistance.

Brass chains are uncommon for two fundamental reasons. Firstly, although Brass is ductile, the artisanal process of manufacturing individual links is laborious and unprofitable, especially compared to other more malleable or resistant metals. Secondly, and more significantly, chains are often in direct contact with areas of the body that exude more sweat—the neck, for example—which exposes the alloy to a chemically aggressive environment. Human sweat is not a single substance but a complex mixture of water, salts, fatty acids, urea, and other compounds that, when interacting with Brass, can accelerate its surface degradation. This translates into a loss of shine, the appearance of stains, and even localized corrosion, depending on the specific chemical formula of the alloy.

It should be noted that freshly cast Brass can exhibit a surprisingly similar appearance to gold, which makes it especially attractive at the time of its manufacture. However, this golden illusion is ephemeral: the color fades relatively quickly, especially if the alloy has not been treated with protective coatings or if it contains high proportions of zinc. Therefore, in low-profile jewelry, Brass is valued more for its initial aesthetics and moderate cost than for its long-term durability.

The incorporation of tertiary alloying elements into brass, copper-zinc based alloys, allows for substantial modification of their mechanical, chemical, and structural properties. It is important to note that certain elements common in steel metallurgy, such as carbon (C), chromium (Cr), or molybdenum (Mo), are not considered here due to their scarce or null capacity to form useful or stable compounds within the family of copper alloys, such as brass. Their exclusion, therefore, responds to criteria of chemical compatibility and metallurgical functionality.

Aluminum (Al) is introduced into brass to improve corrosion resistance and toughness. In reduced concentrations, between 0.1% and 0.6% by mass, it acts as a deoxidizer, partially emulating the role of manganese (Mn). When added in higher proportions, between 3% and 10%, its effect on corrosion resistance intensifies, although a concentration above 5% transforms the nature of the alloy, which ceases to be considered brass and is classified as cuproaluminum.

Despite its low cost and good miscibility, aluminum is used cautiously, as its small atomic radius disturbs the crystalline structure of brass, generating reluctance in its industrial use.

Silicon (Si), although less common, is also used as a deoxidizer. In more specific applications, it can contribute to improving toughness and corrosion resistance. Its presence is more common in other copper alloys, such as cuproaluminum or silicon bronze, where its effect is more pronounced and desired.

Magnesium (Mg) is a rare alloying element in brass, generally present as an impurity. In exceptional cases, it is used as a deoxidizer, although its use is limited by its high cost and by not offering significant advantages over aluminum in terms of metallurgical performance.

Manganese (Mn), on the contrary, is a common component in brass. Its action as a deoxidizer is powerful, and it also contributes to grain refinement, increasing the toughness and hardness of the material. Its role as a dopant makes it a key element in copper alloy engineering.

Phosphorus (P) is found virtually in all brass, at least in a proportion of 0.1% by mass. Its main function is to act as a deoxidizer, and its low cost makes it especially attractive for large-scale industrial applications.

Iron (Fe), although more frequent in cuproaluminum, can be part of certain grades of brass where an increase in toughness, rigidity, and hardness is sought. Its addition is never done in isolation but in combination with nickel (Ni), with the aim of stabilizing certain crystalline phases according to the overall composition of the alloy.

Nickel (Ni) is one of the most valuable alloying elements in copper metallurgy. In moderate concentrations, between 2% and 4%, it favors the formation of the alpha phase (austenite) in brass, especially when combined with iron. Furthermore, it improves toughness, hardness, and structural rigidity, prolonging the service life of the parts. When its content exceeds 10%, the alloy ceases to be considered brass and becomes part of the German silver or nickel silver family (Cu–Zn–Ni), also known as hotel silver or imitation silver. It is essential to distinguish between these families: white brass is a nickel silver, while cupronickel (Cu–Ni without Zn) constitutes a third category of copper alloys.

Tin (Sn) is added in minimal proportions of 1% by mass to prevent dezincification, a phenomenon that compromises the integrity of brass in corrosive environments. Its presence improves galvanic corrosion resistance, especially in contact with steel, and also increases the toughness of the material.

Lead (Pb) and Bismuth (Bi) are incorporated for similar purposes, although the lead content is usually significantly higher. Both elements, insoluble in copper but partially soluble in zinc, form intergranular inclusions that act as solid lubricants. This property is especially useful in components subjected to direct friction, such as bearings or shafts, where the goal is to reduce the metal-on-metal friction coefficient. Lead can reach up to 20% by mass in certain brass alloys, optimizing machinability and allowing for more efficient machining processes. Although the corrosion resistance of leaded brass is comparable to that of conventional brass, the addition of bismuth, even in proportions as low as 0.5%, can significantly improve this resistance.

Brass, like other copper-based alloys, exhibits remarkable resistance to the destructive action of metal-eating marine organisms, that is, those that literally feed on metallic structures such as steel. This phenomenon, known in English as biofouling, represents a considerable risk in nautical applications, especially in the case of vessels whose hulls are usually made of steel and coated with protective materials to prolong their useful life.

In marine environments, steel and iron are particularly vulnerable to parasitic colonization by microorganisms that adhere to their surface, forming biofilms that accelerate their wear and corrosion. These organisms not only attach to the metal but actively deteriorate it, compromising the structural integrity of exposed parts.

Conversely, copper alloys, such as brass, not only resist this type of biological attack but also exert a biocidal action on organisms attempting to colonize their surface. This property makes brass an ideal material for marine applications, as it does not require additional treatments to prevent biofouling and, furthermore, actively contributes to the protection of metallic structures against biological degradation.

Brass, although not used directly in the human body—for example, as a material for implants—has proven to be very useful in medical settings thanks to its ability to inhibit the growth of microorganisms on its surface. This property derives from copper (Cu), the base element of the alloy, known for its lethal action against bacteria, viruses, and parasites at the microscopic level.

Copper's antimicrobial activity is manifested in its ability to destroy the cell membranes of various pathogens, alter their metabolic processes, and destabilize their genetic material, preventing their proliferation. This action does not require external intervention: it occurs spontaneously upon contact with the metal surface.

For this reason, brass has been incorporated into multiple everyday items in hospitals and clinics, such as doorknobs, handrails, medical scale bases, and other components exposed to frequent contact. Its presence is not only due to aesthetic criteria—such as its characteristic golden hue—but, above all, to its effectiveness as a passive barrier against the transmission of pathogens. In an environment where hygiene is critical, brass offers a functional and durable solution that complements conventional disinfection measures.

In many film productions set in Ancient Rome or Classical Greece, it is common to see golden armor worn by gladiators, soldiers, and officers. This representation, although visually appealing, does not correspond to historical reality. The golden color associated with these armors comes from the use of brass in the manufacture of film replicas, an alloy of copper (Cu) and zinc (Zn) that was neither known nor used by classical civilizations.

The film industry chose brass for practical reasons: it is cheaper than bronze, easier to mold, and offers a similar, albeit shinier, appearance. In ancient times, armor was primarily made of bronze, typically composed of 90% copper and 10% tin (Sn). This material had a reddish or dull red hue, which could acquire greenish stains as a result of the natural oxidation of the copper. Therefore, the golden image of Roman or Spartan soldiers disseminated by cinema is a modern interpretation with no historical basis.

In ceremonial contexts, such as military parades or triumphal entries, certain high-ranking officials—including centurions and emperors—could wear armor made from alloys of gold (Au) and copper. These pieces, with a more intense golden appearance, were not used in combat due to gold's physical properties, which make it unsuitable for structural applications: its high density and low hardness make it an ornamental rather than a functional metal.

In short, the golden representation of armor in cinema responds to aesthetic and logistical decisions, but does not accurately reflect the materials and colors used in the manufacture of military equipment in ancient times. Bronze, not brass, was the predominant metal in the war metallurgy of classical civilizations.