The particles of aluminum powder used in the pigments are scaly. The scaly particles are what give the aluminum powder a metallic colour and shielding effect. Metal aluminum powder is produced industrially since a very long time. Ramming was the early production method. The aluminum crumbs was placed in the groove of punching machine. The machine drove a ramming hammer to continuously punch aluminum crumbs into the groove. The ductile metal gradually breaks into flakes under the impact. The aluminum is then screened to remove the powder that is suitable for the product. Ramming produces a low-quality product, is difficult to control, and creates a lot dust, which can easily catch fire or explode.
German Hamtag began producing aluminum powder using a mill in 1894. Steel balls and aluminum scraps along with lubricants, were placed in the ballmill. Flying steel balls crushed the aluminum scraps to produce scaly aluminium powder. The method of “dry production” is still being used for gas. J. Hall, a scientist in the United States who invented this method, added petroleum solvents to the ballmill to replace the inert air. The powdered aluminum was then mixed into a solvent slurry in order to create slurry aluminum pigment. This method has been widely adopted because it is safe and easy to use. The “wet method” is the method used by most modern aluminum powders. Aluminum powder is also used to make fireworks and explosives. Certain types of electronic devices are also made from it. A lot of paints and sealing agents contain aluminum powder.
Is Aluminum Powder Dangerous?
Exposure to fine particles can cause lung scarring (pulmonary fibrosis), which is accompanied with coughing and shortness in breath. Aluminum powder can be a flammable, solid substance that may pose a fire risk.
The powder coating carries a lower risk of fire than regular paint. Comparing powder/air to solvent/air, the ignition energy is 50-100x higher. All flammable powders or dusts will, however, form a dangerous explosive mixture with the air. Transport, storage, and processing are all safe if the appropriate measures are taken beforehand. To ensure safety, the powder concentrations for the powders listed above must not exceed 10g/m3. In the spray zone, this concentration often exceeds 10g/m3. There is always enough oxygen in the air, so it is essential to avoid sparks with more energy.
Comparing resin powders without pigments, when aluminum powder of 5-6% is added, both the “powder constant” (also known as Dust Constant or explosive power), and the maximum explosion pressure, increase by 10%. As the amount of aluminum powder increases, so will the explosive power. Aluminum powder with a content greater than 25 percent will have the same explosive power as pure metal powder. The dependence on pigments made from aluminum powder does not affect the initiation energy. Pure resin powder will not reach the required initiation energy, no matter what dispersion technique is used. Aluminum powder with a pigment content >10%, fine particles and uncoated aluminium powder can reduce the ignition energy.
Aluminum-containing powder coated coatings are identical to pigmented powder coated coatings. Fire or explosion is not a problem as long they don’t exceed the specified limit.
Aluminum powder must not be separated, accumulated or concentrated in the factory to ensure the safety of spraying. These requirements are also applicable to solvent-based paints that contain gold and copper powder. The explosion risk directly caused by the copper-zinc powder alloy is lower than that of aluminum.
Aluminum powder suitable for the pigment is the type of aluminum powder with scales. It is also coated on the surface. Aluminum powder paste consists of a pigment, aluminum powder and solvent. Aluminum powder is used and has similar characteristics. The output and dosage is larger because it’s easy to use. Comparing to other pigments, the aluminum powder for paints has more features in these aspects:
1. Scaly coverings have certain characteristics.
The particles of aluminum powder are scaly and have a diameter-to-thickness ratio of about (40 to 1) – 100:1. Aluminum powder dispersed on the carrier has the characteristic of being perpendicular to the substrate. A number of aluminum powders is connected. The powders are stacked together to create a metal film that covers the surface and reflects light from outside. The uniqueness of aluminum powder lies in its ability to hide. The surface area of the aluminum powder is a function of the diameter-to-thickness ratio. Aluminum is stretched during the grinding process, the diameter-to-thickness ratio continues to increase, and the hiding power also increases.
2. Aluminum powder has shielding properties
Aluminum powder in the carrier floats and, as a result, it always forms a parallel layer of aluminum powder on the substrate. Multiple layers are arranged parallel in the film carrier. The spacing between the layers of aluminum powder prevents the capillary pores in the carrier film from allowing moisture or gas to pass through. This is due to the physical shielding properties of aluminum powder.
3. Aluminium powder with optical properties
Aluminum powder with high metallic luster and light color. Its smooth surface can reflect between 60% and 90% of visible, ultraviolet and infrared lights. The surface of the object is silvery, bright and coated with paint that contains aluminum powder. This is aluminum powder’s characteristic.
4. Aluminum powder can produce a two-color effect
Aluminum powder exhibits a metallic luster, and is parallel to the coated item. The gloss and color depth change depending on the angle and viewing angle the incident light. The “two color effect” is the name of this characteristic. The aluminum powder in the coating is arranged differently in different layers. When light strikes each layer of aluminum flake, the film thickness is affected by the light differently. Also, the brightness of the reflected light varies. As light enters a film that contains transparent pigments, it passes through the particles of pigment to become colored and is then reflected by various levels of aluminum. This results in changes of color tone and metal light. This property of aluminum powder has led to its widespread use in coatings such as metallic paint and hammer paint.
5. Aluminium powder has a floating characteristic
The large floating type of aluminum pigment and paste is characterized as scaly floating over the surface of coating film.
The aluminum powder used to 3D print this fully functional electric bike allows it to be easily assembled.
Airbus has entered the 3D motorcycle market. Light Rider is a 3D printed electric bicycle that is also the future for electric cars.
This 3D bike was launched by APWorks, a subsidiary of Airbus, and was described by them as “corrosion-resistant, combined with lightweight aluminum and almost specific strength titanium.” Scalmalloy – a special alloy for APWorks – is responsible for these qualities. Aluminum powder developed by researchers.
How do you print something so strong as a bicycle using powder? Airbus has explained that Light Rider is made of thousands thin layers with a thickness of 60 microns. Hollow frame adds to the appeal of this 3D printed electric bike. Comparing to other bicycles the frame weight has been reduced by 30%. Joachim Zettler – CEO Airbus APWorks GmbH – explained that this bicycle cannot be made using traditional milling or welding techniques. The team decided on a hollow, branched structure. So, now each Light Rider 3D printed weighs less than 35kg.
Light Rider may seem like a toy but it is incredibly practical. The top speed of the Light Rider is 49m/h, despite not being Harley. The company is aiming to use 3D-printed electrical bicycles mostly for urban driving. Airbus claims the battery of its electric vehicle can travel 37 miles after each charge.