Formation of boron carbide coating by electromagnetically accelerated plasma spraying

Boron carbide (B 4C) coating formation is investigated using an electromagnetically accelerated plasma spraying, which can generate a dense and a high velocity plasma jet of 1 MPa and 2.0–2.5 km/s by applying a pulsed high-current arc-discharge to accelerate and heat powders. Highly crystalline B 4C coatings with roughened coating-substrate interfaces were formed on mirror-polished stainless (SUS304) substrates without a binder material. The density and uniformity of the coating are improved by changing the source powder size from 30 to 10 μm, where the estimated porosity is decreased from 9 to 4%.