Gradients In Thin Films Research Articles

Fe-N gradient thin films prepared by facing targets sputtering

The functionally gradient materials (FGMS) are important in both theory and practical applications. UP to now, almost all previous work has been concentrated on bulk materials. This paper describes the preparation of Fe-N gradient thin films by a facing targets sputtering system. Rutherford backscattering spectrometry (RBS) shows that the concentration of Fe atoms or N atoms varies gradually from the substrate to the surface throughout the whole thickness of the film. The Fe-N gradient films contain crystal phases of zeta -Fe2N, epsilon -FexN(2<x<or=3), gamma '-Fe4N, and alpha "-Fe16N2 as well.

Synthesis of gradient thin films by ion-beam-enhanced deposition: Liu, X. Zou, J., Zhou, S., Taniguchi, S., Schroer, A. and Wolf, G.K. Mater. Sci. Eng. A July 1991 A139, (1–2), 220–224

The effects of test temperature, stress intensity factor, sodium impurity content and aging condition on the short transverse sustained-load (creep) cracking of AlLiCuMgZr 8090 alloy plate have been studied. Creep cracking was orders of magnitude faster, and threshold stress intensity factors were much lower, than for conventional aluminium alloys such as 2014-T651. Significant rates of cracking were observed in alloy 8090 at temperatures as low as 60 °C at stress intensity factors as low as about 5 MPa m12. For a given stress intensity factor, cracking rates were similar for underaged, peak-aged and overaged conditions but were higher for alloys with higher sodium impurity levels. Metallographic and fractographic observations suggest that the presence of liquid sodium-rich impurity phases promote creep cracking in alloy 8090. Creep cracking in conventional aluminium alloys is probably promoted by solid impurity phases such as lead which are less mobile and therefore less damaging than sodium-rich phases.

Synthesis of gradient thin films by ion beam enhanced deposition

Gradient thin films consisting of Si 3N 4 were prepared on metals (nickel, steel, AlC fibre, Ni 3Al etc.) by ion-beam-enhanced deposition. The coating deposited on one side of the sample has a high resistance (10 8 Ω) while that on the other side has a low resistance (1 Ω) with a gradual change in the interface region. Composition profiles, hardness, adhesion, fatigue life, corrosion resistance and high temperature oxidation behaviour were measured and are discussed.

Gradient thin films synthesized by ion beam enhanced deposition

Gradient thin films synthesized by ion beam enhanced deposition