The Nitride Coatings On Aluminium Alloy Substrate By Arc Ion Plating

The possibility of wear, chemical corrosion and high temperature oxidation of the parts will be reduced by the application of physical vapour deposition(PVD). Depositing protective coatings on the aluminium alloy parts will improve the wear-resistance, corrosion-resistance, reliability and the use life of the parts. The purpose of this work is to investigate the influences of the nitrogen partial pressure, substrate bias voltage, thickness and substrate material on the structure, element content, mechanical properties, corrosion properties of (Ti,Al)N coatings prepared by arc ion plating(AIP), and deposite and explore the graded (Ti,Al)N coatings.Nitrogen partial pressure has great influence on the structure, composition and corrosion property of (Ti,Al)N coatings, which were deposited on aluminium alloy. When the nitrogen partial pressure is low, the coatings contain (Ti,Al)N phase and metal-rich (Ti,Al)2N phase; With the increase of nitrogen partial pressure, metal-rich (Ti,Al)2N phase disappears, only (Ti,Al)N phase exists; the content of aluminium and titanium decreases, the nitrogen content increases; the number of big particle reduces; the deposition rate cuts down; the corrosion-resistance of the coatings increase.Under the same processing parameters, the corrosion-resistance property of (Ti,Al)N coatings, which were deposited on the 7075 aluminium alloy substrate is slightly better than that of the coatings which were deposited on the 2024 aluminium alloy substrate.(Ti,Al)N coatings with a gradient nitrogen element distribution were deposited on the aluminium alloy substrate by gradually increasing the nitrogen flow rate during deposition. The bias voltage has big influence on the properties of graded (Ti,Al)N coatings. Compared with the low bias voltage, the properties of graded (Ti,Al)N coatings that deposited in the high bias voltage are much better, as the number of big particle reduces; the compactedness increases; the mechanical properties and corrosion-resistance increase.By the comparison of the corrosion property of graded (Ti,Al)N coatings and (Ti,Al)N coatings, the result shows that, the corrosion-resistance of graded (Ti,Al)N coatings is greatly better than that of (Ti,Al)N coatings, as the graded (Ti,Al)N coatings are quite thicker than the (Ti,Al)N coatings. The corrosion-resistance of graded (Ti,Al)N coatings is much better than anodic oxidation coatings, and the hardness of the graded (Ti,Al)N coatings is extraordinary higher than that of the anodic oxidation coatings, so under the conditions of corrosion and wear, the whole property of graded (Ti,Al)N coatings is much better than that of the anodic oxidation coatings.