Authors: I. Dahan, M.P. Dariel
Abstract: The present communication is concerned with the interdiffusion kinetics and the interface
breakdown that take place in the Nb/NbC multilayer system as the result of thermal annealing in the
400-800oC temperature range. Within this temperature range carbon is the diffusing species. Carbon
diffuses from the carbide layer into the adjacent Nb layer, depleting its concentration within the carbide,
causing the nucleation and subsequent growth of an intermediate Nb2C layer and decreasing the width of
the original Nb layer. TEM examination of the cross-sections of the multilayer specimens provides data
regarding the evolution of the microstructure and, in particular, regarding the initial nucleation stage of
the newly formed Nb2C layer.
879
Authors: Wang She Quan, Chen Li, Yin Fei, Li Jia
Abstract: Magnetron sputtered TiN, (Ti, Al)N and TiN/(Ti, Al)N multilayer coatings grown on
cemented carbide substrates have been characterized by using electron probe microanalysis (EPMA),
X-ray diffraction (XRD), scanning electron spectroscopy (SEM), nanoindentation, scratcher and
cutting tests. Results show that TiN coating is bell mouth columnar structures, (Ti, Al)N coating is
straight columnar structures and the modulation structure has been formed in the TiN/(Ti, Al)N
multilayer coating. TiN/(Ti, Al)N multilayer coating exhibited higher hardness, better adhesion with
substrate and excellent cutting performance compared with TiN and (Ti, Al)N coating.
1225
Authors: Tomoya Hattori, Yoshihisa Kaneko, Satoshi Hashimoto
Abstract: Sliding wear and hardness tests in Ni/Cu multilayers electrodeposited on polycrystalline copper
substrate were carried out. The multilayers had a total thickness of 5 μm and an individual layer thickness
from 5 to 100 nm. Hardness of the multilayers measured with a nanoindentation tester was found to be
dependent on layer thickness. The multilayer with the layer thickness of 20 nm showed the highest value
among them. It was found that the wear resistances of all the multilayers tested were higher than that of an
electrodeposited nickel coating. It was also revealed that the specific wear rate of multilayers decreased with
decreasing the layer thickness although the highest hardness was attained at the 20 nm layer thickness.
Scanning ion microscope observation showed that the subsurface area kept the layered structure of nickel
and copper even after sliding wear. The multilayer had plasticity sufficient to accommodate deformation
coming from the sliding wear, because fine grains peculiar to severe plastic deformation process were
formed near the worm surface.
2451
Authors: Jiang Ling Yue, Yan Sheng Yin, Ge Yang Li
Abstract: A series of TiAlN/Si3N4 nano-multilayer films with various Si3N4 layer thicknesses were prepared by reactive magnetron sputtering. These multilayers were then annealed at temperatures ranging from 600 to 900°C in air for 1 hour. The composition, microstructure, and mechanical properties of the films were characterized by energy dispersive x-ray spectroscopy, x-ray diffraction, scanning electron microscopy, and nanoindentation. It reveals that under the template effect of TiAlN layers in multilayers, as-deposited amorphous Si3N4 is crystallized and grows coherently with TiAlN layers when Si3N4 layer thickness is below 0.6 nm. Correspondingly, the hardness and elastic modulus of the multilayers increase significantly. With further increase in the layer thickness, Si3N4 transforms into amorphous, resulting in a decrease of hardness and modulus. The TiAlN/Si3N4 nano-multilayers could retain their superlattice structure even up to 900°C. The small decrease in the hardness of multilayers annealed below 800°C was correlated to the release of compressive stress in multilayers. However, oxidation was found on the surface of multilayers when annealed at 800°C, which resulted in a marked decrease in the hardness of multilayers. The multilayers presented higher hardness as compared with the monolithic TiAlN film.
489
Authors: Xiao Ming Bai, Wei Tao Zheng, Xiu Juan Guo, Hui She
Abstract: The polycrystalline Ti/TiN multilayer films were deposited by magnetron sputtering. We investigated the effects of mixed discharge gas pressure, bias voltage and substrate temperature on the microstructural, interfacial, and mechanical properties of the polycrystalline Ti/TiN multilayer films. X-ray reflectivity and diffraction (XRR and XRD), and nanoindentation were used to characterize the structures and mechanical properties for the films.The period of multilayer, interface width and grain size decrease with increaseing of deposition pressure. The multilayer coating at floating voltage shows TiN (111), Ti2N (103), and TiN (200) preferred crystalline orientation, whlie those at other different substrate biases show only TiN (111) and Ti2N (103) preferred crystalline orientation. It was found that the hardness increased with increasing substrate temperature. This hardness enhancement was probably caused by the modulus difference in the interface between layer Ti and TiN or the preferred crystalline orientation TiN(111).
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