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Ni60 cladding layers added with different amounts of rare-earth CeO 2 , Y 2 O 3 , and La 2 O 3 were prepared on the surface of 6063 aluminum alloys through laser cladding. The effects of such cladding layers on the macroscopic morphology, section morphology, micro-hardness, phase composition, microstructure, and composition distribution of the laser clad Ni-based coating were investigated by performing metallographic microscopy, X-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy, and micro-hardness test. Cladding layers with the optimum rare-earth contents were 4% CeO 2 + Ni60 cladding layer, 5% Y 2 O 3 + Ni60 cladding layer, and 5% La 2 O 3 +Ni60 cladding layer. The main phase composition of the cladding layers included β-NiAl (Cr), Al 3 Ni, AlNi 3 , and Al. The Ni60 cladding layers added with rare-earth oxides produced a chemical reaction that was involved in the cladding process to form stable rare-earth compounds. Ni60 cladding layers added with 4% CeO 2 , 5% Y 2 O 3 , and 5% La 2 O 3 were preferable over those without rare-earth oxides, as the former displayed smoother micro-morphologies without obvious pores and cracks. The dendritic structures of the Ni60 cladding layers were coarse; moreover, many grain segregations that were accompanied by a large number of pores were observed in the local area. By contrast, the Ni60 cladding layers added with rare-earth oxides displayed compact dendritic structures, and the grains were obviously refined. The hardness of the cladding layers from the surface to the substrate was gradually decreased as the cladding layer depth increased. Compared with Ni60 cladding layer, the transitions of Ni, Al, Cr, and other elements in the Ni60 cladding layers added with different amounts of CeO 2 , Y 2 O 3 , and La 2 O 3 were became more observable with increasing depth, and the dilution rate of the cladding layer was reduced. [ABSTRACT FROM AUTHOR]

A series of 2.1 GHz surface acoustic wave filters with Al/Ti/Cu/Ti four-layer electrode using different Cu thickness were fabricated. Power durability test show an improvement from 24.5 dBm to 28 dBm by electrode with Al (111 nm)/Ti (5 nm)/Cu (15 nm)/Ti (5 nm) to widely used Al (155 nm)/Ti (5 nm). The different frequency response, electrode morphologies before and after power durability test indicate different failure mechanism of these samples. By checking the microstructures and distribution of elements in those conditions, the enhanced power durability can be attributed to: 1) using of Cu layer, 2) fine grain strengthening, 3) solution strengthening. Concurrently, Increased resistance of electrode induced by electrode structure design and atoms diffusion will deteriorate filter performance and accelerate atoms migration. In this work Al (111 nm)/Ti (5 nm)/Cu (15 nm)/Ti (5 nm) made a compromise in the above factors and achieved higher resistance to acoustomigration, which is promising for higher power surface acoustic wave filters. [ABSTRACT FROM AUTHOR]