As opposite to light absorbing coatings in many parts there are areas with highly reflective surface, like mirrors or semi mirrors. One of the popular reflective coatings is aluminum.
Outside surface: aluminum coating, internal surface: Acktar Fractal BlackTM coating
Aluminized coating is a surface treatment that can be applied to different base metals but is typically used together with steel. Applying this coating combines the benefits of both of these popular and ideal manufacturing materials. The result is a compound material with the advantages of aluminum’s corrosion resistance while maintaining the strength of the steel. Although aluminized steel is relatively new to the industry, it has become extremely popular because of its many advantages and is ideal for situations when high temperatures are involved.
One of the most common ways that aluminizing is applied is in a process called hot dipping which is effective, and creates a strong bond between the materials. Hot dipping requires the base metal to be cleaned and then it is submerged in a very hot bath to create the coating. When heated, the vapors form a thin aluminum oxide layer at the surface, which creates a barrier protecting against future oxidation.
There are two types of aluminized steel. Type 1 is hot-dip coated with a combination of aluminum and a silicon alloy. The steel is submerged in a high temperature composition containing 5-11% silicon alloy. This type of coating is used mostly in situations when high temperatures are involved with the need for corrosion resistance. Type 2 is hot-dip coated with pure aluminum and used in situations that require atmospheric corrosion resistance.
Advantages of using aluminum coating
Corrosion resistance: aluminizing has a self-protecting characteristic to oxidation. This means it has a high resistance to corrosion and typically won’t rust unless it’s damaged. It can withstand many atmospheric conditions that other metals cannot. Aluminizing steel gives the final product these characteristics. In addition to oxidation resistance, aluminizing also has sulfidation resistance and carburization resistance. It provides chemical protection against hydrogen sulfide (H2S) and sulfur oxides (SO2, SO3). Aluminized steel is more corrosion resistant than carbon steel and even aluminum on it’s own. This is a benefit of the hot dipping process used to form the coating, which protects the base metal.
High temperature resistance: aluminum coating is highly reflective and bounces away about 80 percent of visible light in addition to about 90 percent of radiant heat that comes into contact with its surface. It can protect the base material for temperatures up to 800 degrees Celsius (1,470 Fahrenheit), which is much more compared to galvanized steel that has a recommended maximum temperature of about 200 degrees Celsius (392 degrees Fahrenheit). It also is less likely to deform under heat stress than some other materials such as stainless steel.
Lower cost: aluminum is a particularly abundant metal and widely used. The hot dipping process is also more efficient and cost effective than other methods to produce. This makes it available at an economic price, which means its cost is lower than other similar options.
Good formability: because aluminum can be fabricated into any form, aluminized steel can be bent, folded, corrugated, and rolled without it breaking. It’s high yield strength means that it’s unlikely to deform when shaped and has many versatile applications.
Common uses for aluminum coating
Heating appliances: because aluminized steel has a resistance to high temperatures, it’s ideal to be used in ovens, heaters, kitchen ranges, boilers, incinerators, and barbeque burners.
Cooking ware: aluminum coating being resistant to corrosion means it doesn’t rust. This naturally makes it a sanitary option to be used for pots and baking pans – which indeed need to withstand high temperatures. Aluminizing steel also transfers heat faster so it’s a good choice for anything that requires heating materials. It’s important to note that aluminum coating doesn’t affect the flavor of food.
Automotive: aluminized steel is a preferred manufacturing material in car and motorcycle exhaust systems. It can also be used for aerospace components.
Industrial applications and construction: resistance to corrosion makes aluminum coating especially beneficial to be used in HVAC components and pipes that transport corrosive substances. Its heat resistant properties also mean that aluminizing is a good choice for use in chimneys. Aluminized coating is a beneficial choice for use in refineries and gas plants. Pure aluminum coating can be found in corrugated roofing and siding, which need to be resistant to atmospheric corrosionץ