Tribological Aspects of AlN-TiN Thin Composite Films
- PDF / 832,677 Bytes
- 6 Pages / 612 x 792 pts (letter) Page_size
- 69 Downloads / 202 Views
T3.40.1
Tribological Aspects of AlN-TiN Thin Composite Films C. Waters, G. Young, S. Yarmolenko, X. Wang, J. Sankar, North Carolina Agricultural and Technical State University, Greensboro, NC 27411, USA Abstract: Physical properties, and the friction and wear are important issues in smallscale applications, it is therefore essential that the materials used have good micromechanical and tribological properties. The adhesion, fracture toughness and wear properties of AlN-TiN thin composite films is being investigated in this study. The multilayered structures are generated using Pulsed Laser Deposition (PLD). The durability and functionality of thin films is subject to the adhesion between the coating and the underlying substrate in addition to it’s resistance to cracking. The magnitude of the critical load during a scratch test is related to the adhesion of the substrate to the coating. In this test a Berkovich indenter is used for measurements and is drawn across the surface of a coating under an increasing load. The magnitude of the critical load will be studied for various films from a monolayer TiN film to different AlN-TiN films and those relative results compared to their facture toughness and their wear properties. Despite the adhesion, the critical load depends on several other parameters including the friction coefficient. The critical characteristic load is shown to depend on the number of layers and the relative AlNTiN thickness. The fracture toughness showed a weak dependence on the layer characteristics. Introduction: The scratch hardness test has been used to supply a simple and quick means of assessing the adherence of thin, hard and wear resistant coatings to substrates. In the test’s simplest form, the diamond indenter is drawn across the coated sample at increasing values of normal load P until the coating is observed to become detached or fractured at some critical load see Figure 1. [1]. Higher scratch critical load means the material can bear larger scratch loads and normal stresses, which is desirable for tribomaterials and protective materials for thin film structures and devices such as nano- and micro-electromechanical systems and high density magnetic storage media. Experimental Analysis: The (pulsed laser deposition) PLD system at the North Carolina A&T State University consists of a KrF laser, and two PLD chambers. The KrF laser (λ=248 nm, τ=25 ns) was used for ablation of polycrystalline, stoichiometric AlN and TiN (99.99 purity) onto the Si(100) substrates. The laser induced evaporated species were deposited onto substrates kept at a distance of ~6–7 cm from the target surface in an ambient background gas pressure at 5 mtorr. The deposition rate and the film or layer thickness were controlled by total deposition time [2]. Figure 1. TEM image of 10 layer AlN-TiN film on Si(100)
T3.40.2
All of the films were between 200 and 325 nm in total thickness. The individual layer thickness varied depending on the deposition conditions. Figure 1 displays a TEM image of a 10 layer TiN-AlN film. A
Data Loading...
