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Author: Ali Kosari Mehr
Being a thick-film deposition method, aerosol deposition is regarded as an exception among other directed coating techniques since liquid ink is not utilized in this process. However, it should be taken into account that this method brims with some features similar to those of spray coating. The thickness capability of aerosol deposition is in the range of 10μm to 200μm. In this method, a cloud of fine dust created through agitating a dry powder, in lieu of atomizing a fluid ink, is lifted and conveyed by a high-speed carrier gas – this process can resemble a powder blasting system. Furthermore, high-density films are enabled by the effect of high-speed solid particles and their subsequent plastic flow, in lieu of the deposition of ink and subsequent sintering of a film. Provided having a fairly low velocity, the particles impinging on the substrate surface may not have sufficient energy to allow the plastic flow required for the formation of films, resulting in the particles eroding away the substrate surface in the same manner as powder blasting. Thus, the key to the successful deposition of films by means of this method is to maintain the balance between particles’ impact velocity and powder characteristics.
Being a thick-film deposition method similar to spray coating, mist coating has the advantage of being gentler in order that very fragile substrates can be deposited by this means. The method’s thickness capability, ink viscosity range, and powder loading are 1-100 μm, <5 mPa-s, and <5 vol%, respectively. In this method, a suspension mist spreads across the substrate surface, in lieu of a directed flow of droplets to be deposited on the substrate surface. By this means, the inside of cylindrical structures can also be coated owing to the omnidirectional flow of the mist across the surface.
