I want to coat porcelain with nanoparticles on metallic substrate. I tried by electrophoretic deposition, but I got many cracks on coated layer.
I think usig screen printing could be an alternative. However, to avoid cracks, the slurry /ink has to be prepared well considering the base matrix as well the properties of ceramic printed slurry.
Spray coating could be tried.
http://www.thomasnet.com/articles/chemicals/ceramic-coating-metals
Thanks for your answers, I want to apply coating by electrophortic deposition.
I think, for the application of the ceramic layer on the metal substrate is no alternative to plasma spraying. For titanium and aluminum - more suitable micro-arc oxidation technology.
the question is, what is causing the cracks? is it because the coating is too thick (cohesive failure) or is the bonding between metal and ceramic to week (adhesive failure)? To prevent the adhesiv failure you may need a "transition bonding layer" adressing the different expansion of thetwo mterials (like written in the link of Al-Mosawi).
If there is mismatch of thermal expansion coefficient between substrate and coating, it will reduce the adhesion of coating. As you are trying to deposit a hard ceramic on soft surface due to its brittle nature of coating it definitely cracks and peeled off.
It depends on your target (thin or thick films), the required properties, the application, ----.
Generally, Plasma spraying, suspension plasma spraying, solution precursor plasma spray can be applied for ceramic coatings
I strongly recommend to use plasma spray coating, but you must take into consideration the desired properties.of the coated ceramics and their usages
Suspension Plasma Spraying (SPS) and Solution Precursor Plasma Spray (SPPS) are showing a great effect on controlling the microstructure (cracks, porosity, ---) and properties of the ceramic coatings.
The properties of Ti, Nickel-based, and Al2O3 powder coatings obtained through a new method of powder acceleration which allows to achieve the powder velocity of 1400m/s. The Ti-based coatings thus formed have nano-crystal and amorphous structure with nano-dispersed ceramic compounds inclusions, and show the hardness of up to 16GPa, high plasticity and adhesion strength. The Nickel-based alloy coatings display both nano-crystal and amorphous structure. In ceramic Al2O3 coatings high spraying velocity allows filling in the space between the deformed oxide particles (about 0.05–3 microns in size) by nano-crystal and amorphous phases; thus, the coatings acquire a high degree of plasticity retaining high hardness of 1320 HV0.3 with the porosity below 0.5%. The Al2O3 coatings were tested and found effective for covering the surface of porous metal matrixes in burners.
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