High-rate pulsed reactive magnetron sputtering of oxide nanocomposite coatings

Abstract

The article reports on the oxide nanocomposite coatings reactively sputtered by a pulsed dual magnetron and is divided into two parts. The first part briefly describes main problems in the reactive sputtering of oxides, i.e. low deposition rate aD and arcing at the target surface and then focuses on the discharge of the dual magnetron. The ways how aD can be increased and arcing eliminated are shown. The second part is devoted to transparent oxide coatings. Two types of oxide coatings are described in detail: (1) Si–Zr–O coatings containing ≤5at.% of Zr and (2) Zr–Al–O coatings with Zr/Al>1. It is shown that (a) Si–Zr–O coatings exhibit high thermal stability up to 1500°C, almost 100% optical transparency and can be deposited with very high aD≈800nm/min from a molten magnetron target and (b) Zr–Al–O coatings with relatively high hardness H≈18–19GPa, low effective Young’s modulus E∗ satisfying the ratio H/E∗>0.1 are highly elastic (the elastic recovery We>70%) and exhibit an enhanced resistance to cracking. The last finding is of key importance for development of new hard coatings with enhanced toughness.