altin

AlTiN, or aluminum titanium nitride, is a hard protective coating applied to cutting tools and other wear components to improve wear resistance and thermal stability. It is a solid solution of aluminum nitride and titanium nitride, typically represented as (Al,Ti)N, with a composition that can vary to optimize performance. The coating generally adopts a cubic NaCl-type crystal lattice characteristic of transition-metal nitrides. Increasing aluminum content enhances oxidation resistance while maintaining hardness, up to practical limits where the phase balance changes.

The coating is commonly deposited by physical vapor deposition methods, including cathodic arc evaporation and magnetron sputtering, in nitrogen-containing atmospheres. It can be applied as a single layer or as part of multilayer stacks designed to improve toughness, thermal stability, and adhesion. Some formulations incorporate silicon or other dopants to influence microstructure and density, yielding variations such as Si-containing (Al,Ti)N coatings.

In service, AlTiN provides high hardness, typically in the tens of gigapascals, and notable thermal stability. A key feature is pronounced oxidation resistance at elevated temperatures: a thin protective alumina layer forms on the surface, slowing further wear and enabling longer tool life during high-speed machining. This makes AlTiN well suited for cutting hard metals, hardened steels, and difficult-to-machine alloys, where conventional nitrides may oxidize more rapidly.

Compared with TiN and some TiAlN coatings, AlTiN generally offers improved high-temperature oxidation resistance and thermal stability, though performance can depend on deposition parameters and exact composition. Variants exist, including multilayer and doped versions, which are tailored to balance hardness, toughness, and oxidation behavior for specific tooling applications.