scholarly journals Creation of Ni-B/Ni-P electroless coating on the WC particles without surface activator

2018 ◽  
Vol 23 (4) ◽  
pp. 347-352
Author(s):  
Ali Mahtab ◽  
Kamran Amini ◽  
Nader Mohammadian ◽  
Syed Amirhosein Emami ◽  
Mohammad Hosein Bina
Keyword(s):  
Electron Microscopy ◽  
Surface Preparation ◽  
Electroless Coating ◽  
Ceramic Particles ◽  
X Ray ◽  
Coating Morphology ◽  
Metal Ceramic ◽  
Coating Formation ◽  
Electroless Ni ◽  
Scanning Electron

One of the methods for improving metal-ceramic interface and suppression of agglomeration is the formation of a monolayer electroless coating on the particles. Investigations indicated that Ni-B monolayers should be first formed to develop in the next process an electroless Ni–P coating with the morphology of cauliflower. It was possible to produce a Ni-B layer on WC particles when a bath was heated at a temperature of 95 °C by using sodium borohydride and an appropriate stabilizer. Following this process, the Ni–P electroless coating was deposited on WC particles at 85 °C. In this way, two layers of electroless coating of Ni–B/Ni–P on the WC ceramic particles without using the surface activator were produced successfully. The coating morphology and surface analysis were performed by scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX). The results showed that only the degreasing with acetone as a surface preparation of ceramic particles is sufficient to make a Ni–P or Ni–B coating. Electroless Ni–B coating with appropriate adhesion to the surface produces an acceptable surface for the electroless Ni – P coating formation.

scholarly journals Chemical and Wetting Analysis of the Ni-Ti Coating on SiC Improved by a 2-Step Coating-Sintering Process

Materials ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5235
Author(s):  
Yang Liu ◽  
Ying-Xin Wang ◽  
Qiang Yang ◽  
Fu Wang
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Sintering Process ◽  
X Ray Diffraction ◽  
Control Groups ◽  
X Ray ◽  
Surface Energies ◽  
Metal Ceramic ◽  
Sintering Conditions ◽  
Scanning Electron

A two-stepped coating-sintering process to prepare the qualified Ni–Ti transition applied in metal-ceramic bonding proved to be effective to improve the wetting abilities. The method was introduced in detail and compared with 2 control groups. To analyze the benefits, the morphology and composition were captured by field emission scanning electron microscopy (FE-SEM), energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD). The comparisons of different coating depths and different sintering conditions were also recorded and analyzed. The influence of the EDS detecting depth was a concern in the discussions. Finally, the contact angle tests and surface energies were also estimated to verify the reliability of the transition layer. The results indicated that the coating-sintering process combined with protective sintering was preferred and necessary to increase the activeness.

Preparation of Electroless Ni-Mo Coated TiC Powder

2010 ◽  
Vol 434-435 ◽  
pp. 522-525
Author(s):  
Wu Peng ◽  
Yong Zheng ◽  
Quan Yuan ◽  
Hai Zhou Yu ◽  
Shao Gang Wang
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Thin Layers ◽  
Surface Microstructure ◽  
X Ray ◽  
Unknown Phase ◽  
Supersaturated State ◽  
Diffraction Peaks ◽  
Electroless Ni ◽  
Scanning Electron

Ni-Mo coated TiC powders were prepared by electroless plating technique assisted by ultrasonic wave with hydrazine as reducing agent. The surface microstructure of the Ni-Mo coated TiC powders was characterized with scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX) and X-ray diffractometry (XRD). The results showed that the as-plated powders, which were of nearly spheric shape, were the composite of TiC and Ni-Mo alloy. The Ni and Mo elements were uniformly distributed around the TiC powders with some plating leakage. In addition, the Ni-Mo plated thin layers on the surface of TiC powders were amorphous or microcrystalline in a supersaturated state. Diffraction peaks corresponding to Ni and Mo weren’t found, and the Ti (NO3)4 and an unknown phase were formed as the load decreased from 15 g/L to 5 g/L.

High Temperature Chemical Interaction Between SSiC Substrates and Ag-Cu Based Liquid Alloys in Vacuo

2006 ◽  
Vol 509 ◽  
pp. 111-116 ◽  
Author(s):  
Jorge López-Cuevas ◽  
Juan Carlos Rendón-Angeles ◽  
J.L. Rodríguez-Galicia ◽  
M. Herrera-Trejo ◽  
J. Méndez-Nonell
Keyword(s):  
Electron Microscopy ◽  
Chemical Interaction ◽  
Silica Film ◽  
Liquid Alloys ◽  
Ceramic Surface ◽  
X Ray Diffraction ◽  
Metal Interface ◽  
X Ray ◽  
Metal Ceramic ◽  
Scanning Electron

The interfaces formed at 850 °C under vacuum between polished or oxidized substrates of pressureless sintered α-SiC (SSiC) and Cusil, Cusil-ABA and Incusil-ABA brazing alloys have been characterized by X-ray diffraction, scanning electron microscopy and energy dispersive spectroscopy. No chemical interaction is observed for Cusil on both SSiC substrates. In contrast, the Ti contained in the Cusil-ABA and Incusil-ABA alloys promotes the occurrence of chemical reactions at the metal/ceramic interface with both SSiC substrates. The formation of TiC and Ti5Si3 is observed for Cusil-ABA and Incusil-ABA on untreated SSiC, following the sequence SiC → TiC → Ti5Si3 at the metal/ceramic interface. The formation of Ti5Si3 and Cu3Ti3O, following the sequence SiC → Ti5Si3 → Cu3Ti3O, is observed for both Ti-containing alloys on pre-oxidized SSiC. During the wetting experiments, Ti5Si3 and Cu3Ti3O detach from the ceramic surface, floating away from the ceramic/metal interface into the liquid alloy, where the latter phase partially dissolves. It is concluded that for both Ti-containing alloys in contact with pre-oxidized SSiC, the Ti remaining after the reaction with the silica film is insufficient to decrease the contact angle to the values observed for untreated SSiC or to produce a strong metal/ceramic joint.

EFFECT OF DIFFERENT PRETREATMENTS TO ELECTROLESS NICKEL OR COBALT PLATING ON HOLLOW MICROSPHERES

2010 ◽  
Vol 24 (15n16) ◽  
pp. 2706-2711
Author(s):  
YAN ZHAO ◽  
RUN ZHANG ◽  
TONG ZHANG ◽  
YUEXIN DUAN
Keyword(s):  
Electron Microscopy ◽  
Electroless Nickel ◽  
Single Step ◽  
Chemical Compositions ◽  
Electroless Nickel Plating ◽  
Nickel Plating ◽  
X Ray ◽  
Surface Morphologies ◽  
Electroless Ni ◽  
Scanning Electron

Different pretreatment methods for electroless nickel and cobalt plating are demonstrated and compared in the present investigation. The surface morphologies of the nickel or cobalt deposits are investigated by scanning electron microscopy (SEM), and the chemical compositions of the coatings are analyzed by energy-dispersive X-ray spectroscopy (EDX). Method of single-step pretreatment is selected as the optimized method for electroless nickel plating process, while improved two-step sensitization-activation and single-step pretreatment methods can be selected for electroless cobalt plating. It can be found that the content of free Co is much lower compared to electroless Ni plating.

ELECTROLESS DEPOSITION OF Ni-P ALLOYS ON CENOSPHERES BY USING SILVER AS THE CATALYST

2006 ◽  
Vol 20 (12) ◽  
pp. 715-723
Author(s):  
JIAN XU ◽  
WEIHAO XIONG ◽  
AIXIANG ZENG
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Energy Dispersive Spectroscopy ◽  
Electroless Deposition ◽  
Coating Process ◽  
X Ray Diffraction ◽  
Experimental Conditions ◽  
X Ray ◽  
Electroless Ni ◽  
Scanning Electron

Electroless deposition of Ni-P alloys on cenospheres is demonstrated in the present investigation. AgNO 3 is used as an activator to replace the conventional PdCl 2 activator and [Formula: see text] in the coating bath is used as the reducing agent to replace Sn 2+ in order to lower the overall cost of the coating process. The coated cenospheres are characterized by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDX) and powder X-ray diffraction (XRD). It shows that Ni-P alloys uniformly deposit on the surface of the cenospheres under experimental conditions. The possible mechanism of electroless Ni-P alloys coating of cenospheres by using silver as the catalyst is suggested.

Evaluation of Wear and Corrosion Resistances of Oxide Coatings Formed on Magnesium Alloys by Micro Arc Oxidation

2017 ◽  
Vol 263 ◽  
pp. 125-130
Author(s):  
Mustafa Tekin ◽  
Cengizhan Taslicay ◽  
Faiz Muhaffel ◽  
Huseyin Cimenoglu
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Magnesium Alloys ◽  
Oxide Coatings ◽  
X Ray ◽  
Wear And Corrosion ◽  
Coating Morphology ◽  
Micro Arc Oxidation ◽  
Wear Tests ◽  
Scanning Electron

In the present study, wear and corrosion resistances of magnesium alloys were analyzed after coated by micro arc oxidation (MAO) process for potential protection of gear component, which is the most wearing part of a conventional bicycle. Two of the most common magnesium alloys (AZ31 and AZ91) were used in the study and they were oxidized in three different electrolytes (aluminate-, silicate-and phosphate-based). Scanning electron microscopy (SEM) was utilized in order to analyze the coating morphology and wear tracks obtained during wear tests. Energy dispersive X-ray spectroscopy (EDS) analyses were implemented to determine the elemental composition of the coatings. Wear and corrosion tests were applied to compare the performances of the coatings. Experimental results showed that wear and corrosion resistances of the samples generally increased after coated by MAO process and the best protection against wear and corrosion related failures, was achieved by utilizing silicate-based electrolyte for MAO process of magnesium alloys under selected process parameters.

Structure and Composition of Rhinoceros Horn

1992 ◽  
Vol 292 ◽  
Author(s):  
Ann Chidester Van Orden ◽  
Joseph C. Daniel
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Optical Microscopy ◽  
Breeding Success ◽  
The Other ◽  
X Ray Diffraction ◽  
Structural Morphology ◽  
X Ray ◽  
Metal Ceramic ◽  
Scanning Electron

AbstractRhinoceros horn has been used medicinally and as a talisman in many cultures and animals are slaughtered to obtain the horn. With the dwindling populations of rhinos, and the limited number and breeding success of captive rhinos, there is a critical need to learn as much as is possible about their horns to find an adequate substitute. Examination of rhino horn was made using optical microscopy, scanning electron microscopy (SEM), energy dispersive x-ray spectroscopy (EDS), and x-ray diffraction (XRD). The structure of the horn is unusual and consists of two separate phases, one of hair-like filaments, built around a central core in circumferential layers and the other surrounding and filling in the spaces between the filaments as a matrix. Together, these two structures make up a biological composite, structurally similar to metal, ceramic or polymer based composites. The structural morphology, the dimensions of the structures, and the chemistry of the horn are discussed. Comparisons are made between horn, hoof, and hair of rhinos and hoof and hair from horses, their nearest living relatives.

Sem Studies of Co-Cr-Mo Surgical Implant Alloy Corrosion Behavior

1982 ◽  
Vol 40 ◽  
pp. 520-521
Author(s):  
Ann Chidester Van Orden ◽  
John L. Chidester ◽  
Anna C. Fraker ◽  
Pei Sung
Keyword(s):  
Electron Microscopy ◽  
Corrosion Behavior ◽  
Anodic Polarization ◽  
Saline Solution ◽  
Saturated Calomel Electrode ◽  
Physiological Saline ◽  
X Ray ◽  
Physiological Saline Solution ◽  
Scanning Electron

The influence of small variations in the composition on the corrosion behavior of Co-Cr-Mo alloys has been studied using scanning electron microscopy (SEM), energy dispersive x-ray analysis (EDX), and electrochemical measurements. SEM and EDX data were correlated with data from in vitro corrosion measurements involving repassivation and also potentiostatic anodic polarization measurements. Specimens studied included the four alloys shown in Table 1. Corrosion tests were conducted in Hanks' physiological saline solution which has a pH of 7.4 and was held at a temperature of 37°C. Specimens were mechanically polished to a surface finish with 0.05 µm A1203, then exposed to the solution and anodically polarized at a rate of 0.006 v/min. All voltages were measured vs. the saturated calomel electrode (s.c.e.).. Specimens had breakdown potentials near 0.47V vs. s.c.e.

Identification of calcium oxalate crystals in dried or fixed tobacco leaf

1984 ◽  
Vol 42 ◽  
pp. 288-289
Author(s):  
Vicki L. Baliga ◽  
Mary Ellen Counts
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Calcium Oxalate ◽  
Growth And Development ◽  
Polarized Light ◽  
Calcium Oxalate Crystals ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Electron

Calcium is an important element in the growth and development of plants and one form of calcium is calcium oxalate. Calcium oxalate has been found in leaf seed, stem material plant tissue culture, fungi and lichen using one or more of the following methods—polarized light microscopy (PLM), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and x-ray diffraction.Two methods are presented here for qualitatively estimating calcium oxalate in dried or fixed tobacco (Nicotiana) leaf from different stalk positions using PLM. SEM, coupled with energy dispersive x-ray spectrometry (EDS), and powder x-ray diffraction were used to verify that the crystals observed in the dried leaf with PLM were calcium oxalate.

Use of SEM, X-ray analysis and TEM to localize Fe3+ reduction in roots

1988 ◽  
Vol 46 ◽  
pp. 392-393 ◽  
Author(s):  
William P. Wergin ◽  
P. F. Bell ◽  
Rufus L. Chaney
Keyword(s):  
Electron Microscopy ◽  
Root Hairs ◽  
Rapid Reduction ◽  
X Ray ◽  
Physical Evidence ◽  
Transmission Electron ◽  
Young Root ◽  
Insoluble Precipitate ◽  
Uptake And Transport ◽  
Scanning Electron

In dicotyledons, Fe3+ must be reduced to Fe2+ before uptake and transport of this essential macronutrient can occur. Ambler et al demonstrated that reduction along the root could be observed by the formation of a stain, Prussian blue (PB), Fe4 [Fe(CN)6]3 n H2O (where n = 14-16). This stain, which is an insoluble precipitate, forms at the reduction site when the nutrient solution contains Fe3+ and ferricyanide. In 1972, Chaney et al proposed a model which suggested that the Fe3+ reduction site occurred outside the cell membrane; however, no physical evidence to support the model was presented at that time. A more recent study using the PB stain indicates that rapid reduction of Fe3+ occurs in a region of the root containing young root hairs. Furthermore the most pronounced activity occurs in plants that are deficient in Fe. To more precisely localize the site of Fe3+ reduction, scanning electron microscopy (SEM), x-ray analysis, and transmission electron microscopy (TEM) were utilized to examine the distribution of the PB precipitate that was induced to form in roots.

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