Ultrasonic spraying is a unique spraying technology, is based on ultrasonic atomization nozzle technology of a spraying method. The sprayed material is firstly in liquid state, and the liquid can be solution, sol, suspension, etc. The liquid coating is first atomized into fine particles by ultrasonic atomization device, and then evenly coated on the substrate pair surface by a certain amount of flow-carrying gas, thus forming a coating or film. Compared with the traditional pneumatic two-fluid spraying, ultrasonic atomization spraying can achieve better uniformity, thinner coating thickness and higher precision. At the same time, because the ultrasonic nozzle does not need air pressure assistance to atomize, so the use of ultrasonic spraying can significantly reduce the paint splash during the spraying process, to achieve the purpose of saving paint, ultrasonic spraying paint utilization rate is more than four times than the traditional two-fluid spraying.
Ultrasonic spraying is achieved by ultrasonic atomization technology, where the energy of ultrasonic waves disperses water or liquid to form particles of several microns to 100 microns in size, which allows ultrasonic waves to be applied for spraying. Ultrasonic atomization technology offers different types of atomizing nozzles to help determine droplet size, liquid flow rate and spray pattern, and the entire machine is used to achieve a full range of spraying to meet a variety of needs.
Application to fuel cell catalyst coating
Ultrasonic fuel cell catalyst coating systems are especially suited for these challenging applications by creating highly uniform, repeatable and durable coatings. Our ultrasonic applicator’s non-clogging technology allows for better control of coating properties, significantly reduced material usage, and less maintenance and downtime.
Ultrasonic coating systems produce highly durable, uniform carbon-based catalyst ink coatings during electrolysis in fuel cell and proton exchange membrane (PEM) electrolyzers such as Nafion, without distorting the film. Homogeneous catalyst coatings are deposited on PEM fuel cells, GDLs, electrodes, various electrolyte membranes and solid oxide fuel cells with suspensions containing carbon black inks, PTFE binders, ceramic pastes, platinum and other precious metals. Other metal alloys, including platinum, nickel, iridium and ruthenium-based fuel cell catalysts, metal oxide suspension coatings can be applied using ultrasonic spray for the manufacture of proton exchange membrane fuel cells, polymer electrolyte membrane (PEM) electrolyzers, DMFC (direct methanol fuel cells) and SOFC (solid oxide fuel cells) to produce maximum load and high cell efficiencies.
The catalyst solution does not clog the ultrasonic nozzle, uniform fuel cell catalyst coating, controlled droplet size, and flow rates from ultra-low flow rates to production scale. Our ultrasonic nozzles are ideally suited for spraying polymer solutions such as PTFE binders onto GDLs to enhance the hydrophilic or hydrophobic nature of the electrolysis process.
Advantages of ultrasonic spray nozzles for spraying fuel cell catalyst coatings
Â- Very high platinum utilization; up to 90%.
Â- Highly durable high-porosity coating that prevents catalyst layer cracking or flaking.
Â- Up to 50% material consumption reduction with reduced overspray, saving expensive catalyst inks.
Â- Clean, precise spray pattern that is easily formed for a variety of applications.
Â- Highly controllable spray that produces reliable, consistent results.
Â- Non-clogging atomized spray with no deflection.
Â- Ultra-low flow capacity, intermittent or continuous.
Â- Ultrasonic vibration continuously breaks up agglomerated particles for uniform dispersion; maximizes platinum utilization.
Â- Ability to coat proton exchange membranes with very small liquid sample sizes (only 10 ml of catalyst solution is required to coat multiple proton exchange membranes). Ideal for the R&D stage.
The ultrasonic spray nozzle, with continuous ultrasonic vibration along the length of the nozzle, separates the aggregates as it moves down the nozzle body, resulting in the most efficient use of functional particles. The use of ultrasonic spraying to break up the aggregates into uniformly dispersed catalyst layers improves the electrochemical performance and repeatability of the functional coating.
