Effect of plating on consolidation of commercially pure titanium powders
TL;DR: In this paper, Ni-P is used as the coating material, to coat hydrogenated/dehydrogenated titanium powders, and a diametrical compression test was carried out to evaluate green strength of the particles when consolidated before and after coating.
Abstract: Blending of elemental powders is a common powder metallurgical processing route to produce titanium alloys designed to meet the required properties. An alternative to blending is coating the base titanium powders with specific metal ions by an electroless route to maximise advantages associated with homogeneous coating. In this work, Ni–P is being used as the coating material, to coat hydrogenated/dehydrogenated titanium powders. The particle size distribution of uncoated and coated powders was used to explain the change in tap density. A diametrical compression test was carried out to evaluate green strength of the particles when consolidated before and after coating.
...read more
Citations
More filters
TL;DR: In this article, two types of irregularly shaped powders, which differ in particle size distribution, are coated with nickel-phosphorus (NiP) and nickel-boron (NiB) and a novel method, combining aspects of the Kawakita and Alderborn approaches, has been employed in order to understand compaction behavior.
Abstract: Electroless plating is used as an alternative approach to alloying the commercially pure titanium powders. Two types of irregularly shaped powders, which differ in particle size distribution, are coated with nickel–phosphorus (Ni–P) and nickel–boron (Ni–B). A novel method, combining aspects of the Kawakita and Alderborn approaches, has been employed in order to understand compaction behaviour. The overall consolidation is described by a Kawakita–Ludde relationship, and the transition pressures which demarcate the limits of rearrangement only and plastic deformation only are identified using a modification of the Alderborn relationship. A significant increase in green strength is achieved with the Ni–B coated powders, and this is attributed to a modification of friction conditions and the number of possible contacts, which lead to an increased contribution from plastic deformation. The Mohr–Coulomb model and Ohyane equations are used to describe the contribution of the number of contacts on green strength.
12 citations
TL;DR: In this paper, a review of Ni-based composite powder (NCP) is presented, focusing on the application of NCP in electrocatalysis, functional coating, and energy field.
Abstract: Ni-based composite powder (NCP) has attracted increasing attention due to its unique advantages. Various NCPs have been synthesized successfully by different raw powders, and synthesis strategies and applications of NCP have been designed. However, the mechanism of Ni coating is still in the early stage, and timely updates of recent research progress on new remarkable breakthroughs in NCP are highly desired. In light of the above, the novel synthesis designs and mechanism of NCP were discussed in this review. In addition, this review focused on the application of NCP in electrocatalysis, functional coating, and energy field. The future directions of various NCPs were summarized. Some innovative suggestions were discussed at the end of the article.
1 citations
TL;DR: In this article, Ni-P plated Ti powders with core-shell structure were analyzed by field emission scanning electron microscopy (FESEM) with an energy dispersive spectrometer (EDS).
Abstract: Ni-P plated Ti powders with core-shell structure were prepared by Ni electroless plating. The micromorphology and growth mechanism of core-shell Ti@Ni-P powders were analyzed by field emission scanning electron microscopy (FESEM) with an energy dispersive spectrometer (EDS). The results show the overall uniformity of Ni-P coated Ti powders is improved by two pretreatments, namely NaOH preprocessing and alkaline electroless preplating, compared with a single alkaline electroless pretreatment. The surface morphology of the Ni-P plated powders is a typical spaced spherical nodular structure. Meanwhile, the growth mechanism of the Ni-P coated Ti powder is illuminated in detail.
1 citations
References
More filters
Book•
01 Jan 1990
TL;DR: The Electroless Plating: Fundamentals and Applications (ESPA) as discussed by the authors is a comprehensive text that covers both fundamental and applied aspects of electroless deposition, and was first introduced at SUR/FIN '91.
Abstract: Many texts have been written on surface finishing over the years that deal with electroless deposition as a sidelight. Through the talents and efforts of Glenn Mallory and Juan Hajdu, a comprehensive text, entitled Electroless Plating: Fundamentals and Applications, is available through AESF Headquarters. The editors have combined the efforts of 27 contributing authors to produce a wide-ranging text that covers both fundamental and applied aspects of the subject. Published by the AESF, the book was first introduced at SUR/FIN ‘91—Toronto.
962 citations
TL;DR: In this paper, the Particle Deformation and Sliding During Compaction of Spherical Powders: A Study by Quantitative Metallography is presented. But this study is limited to the case of spherical powders.
Abstract: (1978). Particle Deformation and Sliding During Compaction of Spherical Powders: A Study by Quantitative Metallography. Powder Metallurgy: Vol. 21, No. 4, pp. 179-187.
101 citations
TL;DR: In this article, a plasticity theory for a powdered metal compact is developed for describing asymmetric behavior of powdered metal compacts in tension and in compression, and three parameters α, δ, and p are involved in the yield function: α and δ are determined from the behavior of sintered powdered compacts as functions of relative density R.
Abstract: A plasticity theory is developed for a powdered metal compact. The yield criterion used for sintered powdered metals is modified for describing asymmetric behavior of powdered metal compacts in tension and in compression. Three parameters α, δ, and p are involved in the yield function. The two parameters, α and δ, are determined from the behavior of sintered powdered compacts as functions of relative density R. Green strength vs relative density R relationship for powdered metal compacts is used for defining completely the yield function with the effect of relative density. Predictions are made for compaction pressures as functions of relative density for unidirectional, bidirectional and isostatical compaction, and compared with experimental data for copper and iron powders. Also yield surfaces for various density levels are compared with the experimental data with copper powders.
45 citations
TL;DR: In this article, the particle-packing factor was proposed to describe the packing state due to both deformation and rearrangement of individual particles within a powder compact, and it was shown that the particle packing state can be tightened up to a fractional compact density of 0.92.
Abstract: Densification in powder compaction occurs due to the motion of particle centers toward each other, including particle rearrangement and particle deformation. The process of particle sliding and rearrangement has a critical influence on densification in practice, especially during the first stage of compaction. Analytic models and experimental measurements show that the movements of individual particles within a powder compact cause continuous tightening of the bulk packing state up to a fractional compact density of 0.92. For a mass of powder with an initial packing density of 0.64, up to a 40 pct green density increase during the first stage of densification occurs by particle rearrangement. The present study proposes a parameter, termed the particle-packing factor, that describes the packing state due to both deformation and rearrangement.
24 citations