Reduction of macro-particle density on surfaces of TiN coatings grown by pulsed-bias arc ion plating

Here, we addressed reduction of density of macro-particles (MPs) on the surfaces of TiN coatings synthesized by pulsed-bias arc ion plating. The influence of the deposition conditions, including the target-substrate alignment, rotation of substrate, and pulsed bias, on density and distribution of MPs were investigated. The MPs' microstructures were characterized with scanning electron microscopy. We concluded: first, when unbiased, the perpendicular target-substrate alignment resulted in smaller number and area fraction of MPs than the parallel alignment; second, while the arc current increased from 80 to 90 A, aligned perpendicularly to the target and biased at identical voltage, a rota ting-substrate had higher MP-formation probability than a static-one did; besides, a rotating substrate produced bigger irregularly-shaped MPs and larger MP area fraction; and finally, as the pulsed bias increased from -500 to-600 V, the area fraction of MPs increased, possibly because MP formation outpaced film growth due to stronger ion sputtering and lower deposition rate. The lowest MPs' area fraction was obtained at a bias of -400 V.