Filling of surface cracks in MAX phase ceramics using cathodic electrophoretic deposition

It is well known that surface defects, such as cracks, are electrochemical more active than a smooth surface and usually work like seeds for the deposition processes. The present work used this enhanced activity to locally deposit surface-charged Al2O3 and TiC micro and nano-particles into surface cracks in Ti2AlC substrates. The formed deposit was compact and adhered well to the crack walls. A crack of about 30 μm could be filled with alumina particles in 10 min when applying 15 V and using a 5 wt% alumina suspension in ethanol. The deposition of TiC was more challenging due to coarseness of the particles. Grinding these particles to 1–2 μm yielded a very stable suspension and an improvement in the crack filling behaviour.