Physical and mechanical properties of Ti/Al multilayer heat releasing coatings

The paper reports on physical and mechanical properties of sputtered Ti/Al multilayer coatings with a bilayer thickness Λ ranging from 2 to 172 nm releasing heat during annealing. The temperature Thr at which the heat is released during reaction between Al and Ti atoms is investigated. It was found that: 1) Thr: a) decreases from ∼420 to 390°C for the coatings with Λ decreasing from 172 to 17 nm; b) ranges from ∼480 to ∼600°C for the coatings with Λ ≤ 12 nm; 2) the heat ΔHTi/Al evolved in the reaction increases from 5 to 35 kJ/mol with increasing Λ. Besides, it is shown that: 1) the heat can be released also during one pulse of the rapid thermal annealing up to 600°C with heating rate 100°C/s; 2) the released heat results in a strong interaction of the Ti/Al multilayer coating with Si substrate. The mechanical properties of the as-deposited Ti/Al multilayer coatings are also given. Copyright © 2015 Inderscience Enterprises Ltd.