Unlike traditional nozzles that rely on high-speed pressure to shear fluid into small droplets, ultrasonic atomization nozzles use vibration energy to generate low-speed mist. Ultrasonic nozzle is a spray nozzle that uses high-frequency vibration generated by a piezoelectric transducer to act on the nozzle head to generate capillary waves in the liquid film. Once the amplitude of the capillary waves reaches a critical height (due to the power level provided by the generator), they become too high to support themselves, and tiny droplets will fall from the tip of each wave, causing atomization.
Ultrasonic atomizing nozzles have many applications in the production field, including drug-eluting stents and drug-coated balloons, fuel cells, transparent conductive membranes, carbon nanotubes, etc. The next article will discuss the application of ultrasonic atomizing nozzles Give a specific introduction.
Drugs such as sirolimus (also known as rapamycin) and paclitaxel are used on the surface of drug-eluting stents (DES) and drug-coated balloons (DCB) with or without excipient coating. These devices greatly benefit from ultrasonic nozzles because they can apply coatings with little or no loss. Medical devices such as DES and DCB require very narrow spray patterns, low-speed atomized sprays and low-pressure air due to their small size.
The fuel cell
Studies have shown that ultrasonic nozzles can be effectively used to make proton exchange membrane fuel cells. The commonly used ink is a platinum-carbon suspension, where platinum acts as a catalyst inside the battery. Traditional methods of applying the catalyst to the proton exchange membrane usually include screen printing or doctor blades. However, because the catalyst tends to form agglomerates, the gas flow in the battery is uneven, and the catalyst is prevented from being completely exposed, and there is a risk that the solvent or carrier liquid may be absorbed, so this method may have poor battery performance. Into the membrane, all hinder the efficiency of proton exchange.
When using an ultrasonic nozzle, the droplet size can be small and uniform, the distance that the droplet travels can be changed, and a lower heat is applied to the substrate, so that the droplet can reach the desired degree of dryness during the drying process. Before reaching the substrate, let in air. Compared with other technologies, process engineers can better control these types of variables. In addition, because the ultrasonic nozzle provides energy to the suspension just before and during the atomization, the possible agglomerates in the suspension are destroyed, resulting in a uniform distribution of the catalyst, which leads to a higher efficiency of the catalyst, which in turn leads to fuel The efficiency of the battery is higher.
Transparent conductive film
Ultrasonic nozzle technology has been used to create an indium tin oxide (ITO) film during the formation of a transparent conductive film (TCF). ITO has excellent transparency and low sheet resistance, but it is a scarce material and is prone to cracking, so it is not suitable for use as a new flexible TCF. On the other hand, graphene can be made into a flexible film, which is extremely conductive and highly transparent. When silver nanowires (AgNWs) are used in combination with graphene, they are reported to be promising and are superior to TCF alternatives to ITO.
Previous research has focused on spin coating and bar coating methods that are not suitable for large-area TCF. Multi-step process, using graphene oxide ultrasonic spraying and traditional AgNWs spraying, then using hydrazine vapor to reduce, and then coating polymethyl methacrylate (PMMA) topcoat to form a peelable TCF, which can be removed Scale to a larger size.
A printed circuit board
The non-clogging characteristics of the ultrasonic nozzle, the small and uniform droplet size produced by it, and the fact that the spray plume can be formed by a strictly controlled air forming device make this application quite successful in the wave soldering process. The viscosity of almost all fluxes on the market is very suitable for the capabilities of this technology. In soldering, "no-clean" flux is highly preferred. However, if an excessive amount is used, the process will result in corrosion residues on the bottom of the circuit assembly.
Both photovoltaic and dye-sensitized solar technologies require the use of liquids and coatings in the manufacturing process. Since most of these substances are very expensive, the use of ultrasonic nozzles can minimize any loss due to overspray or quality control. In order to reduce the manufacturing cost of solar cells, it is traditionally done using batch-type phosphoryl chloride or POCl3 methods. It has been shown that the use of ultrasonic nozzles to spread water-based films on silicon wafers can be effectively used as solar cells. The diffusion process produces an N-type layer with uniform surface resistance.
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