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Journal ArticleDOI

Electroless nickel-phosphorus coating on Ti and Al elemental powders

31 Jul 2001-Scripta Materialia (Elsevier BV)-Vol. 45, Iss: 2, pp 183-189
About: This article is published in Scripta Materialia.The article was published on 2001-07-31. It has received 32 citations till now. The article focuses on the topics: Electroless nickel & Metal powder.
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Journal ArticleDOI
TL;DR: In this paper, a nanocomposite powder was deposited with Ni-P by electroless plating under the agitation of ultrasonic wave at room temperature, and the morphology, crystal structure, complex permittivity and complex permeability of the composite powder were investigated with field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), energy dispersive analysis of X-rays (EDS) and vector network analyzer.

16 citations

Journal ArticleDOI
TL;DR: In this article, the preparation of Invar powders was attempted by electroless nickel (EN) coating on iron powders followed by heat treatment, and the experimental results showed that a pretreatment in slight alkaline solution before EN coating was required to obtain a uniform deposit of Ni on Fe powder.
Abstract: The preparation of Invar powders was attempted by electroless nickel (EN) coating on iron powders followed by heat treatment. The experimental results showed that a pretreatment in slight alkaline solution before EN coating was required to obtain a uniform deposit of Ni on Fe powder. The amount of Ni, which meets the Invar composition could be coated by adjusting the EN solution volume-to-Fe weight ratio. X-ray diffraction, energy dispersive spectroscopy and X-ray mapping were employed to examine the homogeneity of the various heat-treated EN-coated powders. A homogeneous Fe–Ni powders with Invar composition could be successfully synthesized with proper control of the EN bath and subsequent heat treatment. In this study, no deflocculant was added in the plating bath. The van der Waals forces between the as-coated particles caused them to attract each other. As revealed in Figs. 4 and 8(c), a clear Ni layer appeared in the interface of the agglomerated particles. These results indicated that agglomeration occurred right after EN coating, regardless of post heat treatment.

16 citations

Journal ArticleDOI
TL;DR: In this article, pure titanium powder with an average size of 20 μm was treated by electroless nickel plating to obtain titanium-nickel composite/duplex powder, and two plating procedures were applied; continuous short period (CSP) and discontinuous long period (DLP) processes.
Abstract: In this study, pure titanium powder with an average size of 20 μm was treated by electroless nickel plating to obtain titanium–nickel composite/duplex powder. Two plating procedures were applied; continuous short period (CSP) and discontinuous long period (DLP) processes. The plated titanium powder particles as well as unplated ones were characterised by energy dispersive spectrometry (EDS), scanning electron microscopy (SEM), particle size analysis and X-ray mapping analysis methods. The nickel plated titanium powder was sprayed on the steel substrate by atmospheric plasma spray technique. Furthermore, the mixed titanium–nickel powder was also sprayed. The morphology of sprayed powders was compared with each other. It was found that nickel forms fine dispersed nodules on the surface of titanium powder particles in the CSP process, whereas it appeared as homogeneous layers on the surface of all the particles in the DLP process. Also, it was found that the mass deposited on the powder increased wit...

15 citations


Cites background or methods from "Electroless nickel-phosphorus coati..."

  • ...At the base, the surface of powder particles may be covered with a monolayer of nickel atoms during pretreatment.(23) It acts as seed for the deposition of Ni–P....

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  • ...For this purpose, the particles were subjected to pretreatment in solution with composition shown in Table 1.(23) The electroless plating was performed using a bath of pH 8–9 at 85–90uC....

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Journal ArticleDOI
01 Mar 2017
TL;DR: In this paper, a two-step electroless plating process has been developed to synthesize nickel-aluminum core-shell structures, which function as microreactors, which provide the energy for the thermal joining process.
Abstract: Reactive systems, which are widely used in combustion synthesis, represent a promising solution for challenging joining tasks. They are able to undergo a self-sustaining, highly exothermic reaction when exposed to an external energy source. Reactive foils are the only systems that are currently commercially available. However, their industrial use is limited due to the brittle nature of the material and the restriction to planar geometries. Reactive particles represent a more flexible format, but are currently not commercially available. Therefore, a two-step electroless plating process has been developed to synthesize nickel-aluminum core-shell structures. These structures function as microreactors, which provide the energy for the thermal joining process. Ignition tests with electromagnetic waves were performed in order to investigate the overall reactivity. Energy input and particle size significantly influence the activation and the reaction behavior of the core-shell structures. Furthermore, a general approach to use reactive particles as a heat source in joining applications is proposed.

10 citations

Journal ArticleDOI
TL;DR: In this paper, the microstructure and phase analysis of sintered composites were investigated using field emission scanning electron microscope, transmission electron microscope and X-ray diffraction.

10 citations

References
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01 Jan 1985
TL;DR: In this article, the authors describe the behavior of grain boundaries in a two-dimensional model ordered alloy and the effects of elastic anisotropy on the anomalious yield behavior of cubic ordered alloys.
Abstract: This book contains over 50 selections. Some of the titles are: Order-disorder behavior of grain boundaries in a two-dimensional model ordered alloy; Dislocation reactions at grain boundaries in Ll/sub 2/ ordered alloys; Creep cavitation in a nickel aluminide; Effects of elastic anisotropy on the anomalious yield behavior of cubic ordered alloys; and Processing technology for nickel aluminides.

2,123 citations

Book
Ian M. Watt1
30 Jun 1985
TL;DR: The electron microscopy with light and electrons (EM) family as discussed by the authors is a family of microscopy techniques that use electron microscopes for high-vacuity measurements. But the electron microscope family is not suitable for the analysis of high-voltage measurements.
Abstract: 1. Microscopy with light and electrons 2. The electron microscope family 3. Rudiments of specimen preparation and interpretation of micrographs 4. Specialised techniques in electron microscopy 5. Examples of the use of electron microscopy Appendix 1: Production and measurement of high vacua Appendix 2: Vacuum deposition of thin metallic and carbon films for electron microscopy Appendix 3: X-ray generation and analysis Appendix 4: Electron sources for electron microscopes.

170 citations

Journal ArticleDOI
TL;DR: In this paper, the effects of Cr additions to y-base alloys have been investigated, using bulk materials consolidated from rapid solidification-processed ribbons, and it was concluded that the ductilization effect of Cr in duplex alloys is partially due to the tendency of Cr to occupy Al lattice sites.
Abstract: The effects of Cr additions to y-base alloys have been investigated, using bulk materials consolidated from rapid solidification-processed ribbons. The composition ranges studied were 0 to 4 at. pet Cr and 44 to 54 at. pet Al. It was found that Cr additions do not affect the deformation behavior of single-phase γ alloys. However, they significantly enhance the plasticity of Al-lean duplex alloys which contain grains of single-phase γ and grains of lamellar γ/α2. Other Cr effects on microstructure, phase stability, site occupancy, and deformation sub-structures were characterized and correlated to the observed mechanical behavior. It was concluded that the ductilization effect of Cr in duplex alloys is partially due to the tendency of Cr to occupy Al lattice sites. Ductilization is also partially due to the ability of Cr to modify the Al partitioning and, therefore, the thermal stability of transformed α2 laths.

158 citations

Journal ArticleDOI
TL;DR: In this article, the ternary alloys of arc-melted, nearequiatomic TiAl alloys containing boron additions are analyzed and compared with those of binary Ti-Al and Ti-B alloys processed in a similar fashion.
Abstract: Solidification microstructures of arc-melted, near-equiatomic TiAl alloys containing boron additions are analyzed and compared with those of binary Ti-Al and Ti-B alloys processed in a similar fashion. With the exception of the boride phase, the matrix of the ternary alloy consists of the same α2 (DO19) and γ (Ll0) intermetallic phases found in the binary Ti-50 at. pct Al alloy. On the other hand, the boride phase, which is TiB (B27) in the binary Ti-B alloys, changes to TiB2 (C32) with the addition of Al. The solidification path of the ternary alloys starts with the formation of primary α (A3) for an alloy lean in boron (∼1 at. pct) and with primary TiB2 for a higher boron concentration (∼5 at. pct). In both cases, the system follows the liquidus surface down to a monovariant line, where both α and TiB2 are solidified concurrently. In the final stage, the α phase gives way to γ, presumably by a peritectic-type reaction similar to the one in the binary Ti-Al system. Upon cooling, the α dendrites order to α2 and later decompose to a lath structure consisting of alternating layers of γ and α2.

109 citations