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Silicon Bronze

What is Silicon Bronze

Silicon bronze is a type of copper alloy that is becoming increasingly popular due to its combination of excellent physical and chemical properties. It’s used in various applications, including marine hardware, electrical, and architectural components. In this blog post, we’ll look at the composition and properties of silicon bronze and its various applications.

Silicon bronze properties
Silicon bronze is an alloy composed primarily of copper (Cu) with small amounts of silicon (Si), iron (Fe), manganese (Mn), and zinc (Zn). Its composition can be expressed as either C65100 or C65500, depending on the amounts of each element contained within it.

The presence of silicon gives the material excellent strength and ductility while providing improved corrosion resistance compared to other alloys such as brass or steel. It also has a high electrical conductivity, making it ideal for electrical components. Additionally, silicon bronze has good thermal conductivity and excellent resistance to wear and abrasion, making it useful in various applications.

type of bronze that contains silicon.

Silicon bronze is stronger than other types of bronze.
Silicon bronze is more resistant to corrosion than other types of bronze.
Silicon bronze has a lower coefficient of thermal expansion than other types of bronze.
Silicon bronze is more electrically and thermally conductive than other types of bronze.
Silicon bronze is non-magnetic.
Silicon bronze is used in a variety of applications, including electrical wiring and marine hardware
Silicon Bronze Corrosion Resistance
Silicon Bronze is an alloy that uses a mix of copper, aluminum, and silicon to provide superior corrosion resistance and strength. This makes it an ideal choice for uses where reliability and durability are required, such as outdoor construction, coastal installations, and outdoor sculptures. Silicon Bronze has been used for centuries in these demanding conditions. Its impressive toughness and resistance means that it can withstand the harsh conditions of salt water exposure without succumbing to corrosion or damage from temperature fluctuations. With its low upkeep requirements, Silicon Bronze products often last much longer than other metal alloys that might require more maintenance over time. As such, it is an excellent option for many metalworking projects where superior corrosion resistance is needed.

Silicon Bronze uses
Due to its impressive physical and chemical properties, silicon bronze is used in many different industries, including automotive, aerospace, medical equipment and marine hardware. It’s also often used in architectural applications due to its attractive appearance when exposed to air or water. In the automotive industry, it’s commonly used for exhaust systems due to its ability to withstand high temperatures without deforming or corroding over time. In the aerospace industry, it’s often used for aircraft components such as wing parts because it offers superior strength without being overly heavy or bulky. Finally, it’s commonly used for marine hardware due to its excellent corrosion resistance when exposed to salt water or other harsh elements found in aquatic environments.

Architectural & ornamental decoration.
Hydraulic applications.
Welding rods.
Marine shafting and hardware.
Silicon Bronze Chemical Composition
The chemical composition of silicon bronze includes 97.5-98.5% copper, 0.3-1.4% iron, 0.2-1% manganese, 0.2-0.7% aluminium, and 0.2-1% zinc, along with small amounts of nickel, lead, tin and other elements that are less than 0.3%. All these elements combine to create an alloy that is strong and resistant to corrosion in both marine environments and industrial conditions where air pollution is present. The most common type of silicon bronze contains 6% silicon which helps increase the strength and wear resistance while still maintaining excellent machinability properties that make it suitable for many applications including fasteners and castings.

Silicon Bronze Conductivity
One of the main advantages of using silicon bronze is its high conductivity (it has electrical conductivity about two times higher than brass). This makes it perfect for applications where electrical current needs to be transferred efficiently such as in electrical connectors or terminals for batteries or solar cells. Additionally, the alloy has good corrosion resistance due to its high copper content which helps protect against oxidation even in humid or salty environments like those found in marine settings or near industrial sites with heavy air pollution levels present in the atmosphere. Finally, silicon bronze has excellent formability properties, so it can be easily shaped into complex shapes that may not be possible with other metals like steel or aluminium alloys; this makes it great for creating intricate castings or custom fasteners that require extra strength without sacrificing too much weight or flexibility during manufacturing processes such as a cold heading or extrusion methods.

Silicon bronze is a versatile metal alloy made up mostly of copper with some added elements like iron, manganese and zinc that contribute to its strength, corrosion resistance and electrical conductivity properties – making it perfect for many different types of applications including automotive parts, marine hardware and electrical connectors/terminals among others! Thanks to the combination of good machinability properties (allowing complex shapes to be formed), high conductivity levels (allowing efficient current transfer) and exceptional corrosion resistance (protecting against oxidation from salty sea air or pollutants), this unique material can provide manufacturers with a cost-effective solution when a stronger alternative than brass is required for their application needs! If you’re looking for an alloy that offers all these benefits plus more, then look no further than silicon bronze – one key ingredient to success when searching for your next manufacturing material! Silicon bronze is an incredibly versatile material with many uses across multiple industries. Its combination of strength, ductility and corrosion resistance make it an ideal choice for many applications including automotive parts, aircraft components, medical equipment and architectural projects. If you’re looking for an alloy with superior performance characteristics that won’t break the bank, then look no further than silicon bronze!Physical Properties of Silicon Bronze
We recommend reading our article on the types of bronzes so that you can become familiar with the general characteristics across all bronzes, as well as their shared applications.

Below, in Figure 1, is a qualitative description of the composition of most silicon bronzes:

Pie chart showing the qualitative breakdown of the components in Silicon Bronze
Figure 1: Qualitative breakdown of silicon bronze.
Silicon bronze is like most other bronzes in that it is a copper alloy – that is, the base alloying metal is pure copper, imbued with other elements. It is made using around 94-96% copper by weight, and the rest is typically 2.5-6% silicon and a mixture of other metals such as aluminum, zinc, lead, iron, manganese, and more.

Silicon bronze’s density is 8.53 g/cm3 (0.308 lb/in3) and alloys of this class benefit from both cold and hot working, as well as the heat treatment process. It is readily weldable, joinable, soldered, and cast, and is generally one of the easiest copper-based materials to form/pour. It sports a good corrosion resistance, strength, and formability, and is also considered one of the best-looking copper alloys. Its formability mixed with its aesthetics allows silicon bronze to find many applications in decorative and architectural uses, as it has an attractive reddish-gold coloration and is resistant to deformation. It has low magnetic permeability and is conductive (though, it is typically not specified for its current-carrying capabilities). It is a mainstay in most blacksmith forges, as silicon bronze works especially well under high heat and can be cold formed between anneals. Besides a decorative metal, silicon bronze finds applications in marine hardware, electrical components, and chemical processing equipment, to name just a few of its uses.

Resistances and weaknesses
Silicon bronze is more resistant to water corrosion than brass, making it highly useful for marine applications. It is resistant to freshwater, saltwater, fog/mist, alkalis, acids, and organic chemicals, and is only susceptible to attack via sulfides, nitric acid, chromates, ferric chloride, and other oxidizing salts. Silicon bronze is also anti-biofouling, meaning it is inherently antimicrobial and will passively defend against the spread of germs. The only major weaknesses of this alloy are its expensive price tag, as well as its difficulty being recycled, as the silicon is difficult to remove from the matrix formed in the alloying process. Besides these minor disadvantages, however, silicon bronzes stand above traditional alloys as an exceptionally resistant, yet handsome material for marine applications.

Mechanical Properties
Table 1, below, shows some mechanical values pertinent to silicon bronze and its attributes. These values were averaged from a range of specific silicon bronze alloys in industry and are meant to provide an estimated range. There may be specific alloys that fall out of these bounds, but this will be dependent upon the manufacturer, heat treatment, and other variables, so take this into considerations when looking at these properties:

Table 1: Summary of mechanical properties for aluminum bronze; note these values are summarized from different alloys.
Mechanical Properties



Tensile yield strength

105-415 MPa

15200-60200 ksi

Modulus of Elasticity

115 GPa

16700 ksi

Elongation at Break

16.2 µm/m-°C

9.00 µin/in-°F

Hardness (Rockwell B)





The tensile yield strength of silicon bronze comes in a wide range, but the higher silicon bronze alloys are impressively strong (~400 MPa). The tensile yield strength is a measure of how much stress (or force per unit area) that a specimen of metal can endure without plastically (permanently) deforming in tension. It is a necessary value to understand when implementing a material into any load-bearing application and is used to see if a material can withstand the stresses of a particular project. Silicon bronze comes in a range of tensile strengths, but it can easily surpass some other aluminum alloys and carbon steels if tempered correctly. If looking for an aesthetically pleasing metal that can hold its own, consider a high alloy silicon bronze.

A material’s modulus of elasticity is a measurement of how stiff/elastic material is – in other words, how does it react to stress and how likely it is to return to its original shape. A high modulus of elasticity suggests a stiff, often brittle material, while a lower value represents an elastic one. Silicon bronze has an elastic modulus that is half that of some steels, which shows that it is both ductile and more difficult to machine, as machinists would rather a metal “chip” and not pull. This does not mean that silicon bronze is non-machinable, but we will explain this more once we get to the machinability rating.

Hardness is a value that is dependent on the scale and describes a material’s resistance to surface deformation (scratching, etching, etc.). The scale used in Table 1 is the Rockwell B hardness scale, which simply means many materials are rated by the standard Rockwell B hardness indenter machine and put into a comparative matrix. For reference, the Rockwell B hardness of copper is 51, showing that silicon bronze alloys are more resistant that its pure base metal. Hardness also describes how brittle material is, as very hard materials (glass, ceramic, quartz) tend to shatter and not yield under stress. This means that silicon bronze will not typically stress crack when bent but note that an overworked piece of silicon bronze will fracture, so use your annealing steps carefully to keep this from happening.

Machinability is a percentage that shows how well material machines and is in reference to a standard machining material. For the case of bronze, this standard material is UNS C36000 free cutting brass which has a machinability rating of 100%. Percentages below 100% suggest that the chosen metal is more difficult to machine, while percentages over 100% suggest the opposite; from this explanation, silicon bronze is shown to have some difficulty with machining processes. This is not to say that it cannot be machined, but fabricators must be careful when using mills, lathes, and dies with silicon bronze, as there is a low tolerance for messy work. This machinability rating is compensated for by silicon bronze’s exceptional formability and weldability, which means machining may not be necessary, depending upon the application. So, while it doesn’t score highly in this category, it does not mean silicon bronze is difficult to shape.

Applications of Silicon Bronze

As with other copper alloys, silicon bronze is finding more and more uses by the day. It is currently most useful for decorative, architectural, and marine applications, but it will certainly find more niches as technology advances and demands more specialized alloys. For now, the main applications of this attractive metal are as follows:

Architectural & ornamental decoration
Hydraulic applications
Welding rods
Marine shafting and hardware
and more.

Consider silicon bronze if it seems applicable to your projects, and don’t hesitate to ask your supplier for more information.


XTJ is a leading OEM Manufacturer that is dedicated to providing one-stop manufacturing solutions of  Silicon Bronze Parts  from prototype to production. We are proud to be an ISO 9001 certified system quality management company and we are determined to create value in every customer relationship. We do that through collaboration, innovation, process improvements, and exceptional workmanship.




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