Microwave Sintering of Electroless Ni Plated WC Powders (original) (raw)
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The Effect of Microwave Sintering on the Properties of Electroless Ni Plated WC-Fe-Ni Composites
Science and engineering of composite materials, 2010
Ni-Fe metal matrix composites reinforced with WC have been fabricated by microwave sintering at various temperatures. A uniform nickel layer on WC and Fe powders was deposited prior to sintering using electroless plating technique, allowing closer surface contact than conventional methods such as mechanical alloying. The reactivity between WC and Fe powders to form carbides of Fe is controlled through Ni layer existing on the starting powders. A composite consisting of quaternary additions, WC, Ni and Fe was prepared at the temperature range 500°C-900°C under Ar shroud. X-Ray Diffraction, SEM (Scanning Electron Microscope), compression testing and hardness measurements were employed to characterize the properties of the specimens. Experimental results carried out for 900°C suggest that the best properties for omax and hardness (HV) were obtained at 900°C and the microwave sintering of electroless Ni plated WC and Fe powders is a promising technique to produce ceramic reinforced composites.
Development of Ni-WC composite clad using microwave energy
Materials Today: Proceedings, 2017
Cladding of suitably designed materials on functional surface which are subjected to sever tribological loading can lead to increase in components life. Development of clad includes several techniques such as thermal spraying, High velocity oxy fuel and laser cladding. However cladding done through the above listed process pertain certain defects like cracks, distortion, poor adhesion strength etc.In the present work a new process method has been developed to clad Ni (matrix)-80 wt.%WC (reinforcement)-20 wt.% powder on poor wear resisting material through microwave irradiation of frequency 2.45GHz. The characterization of developed clad is done using X-ray diffraction (XRD), Field emission electron microscope (FE-SEM), Back scattered electron image and Vickers micro hardness. XRD pattern of developed composite clad showed presence of compounds like NiSi, NiW, and W 2 C phase. The wear resistant complex carbide phase have been seen in the structure of the clad transverse section showed good metallurgical bonding between the substrate and the developed clad.
Production and characterization of Ni-Co (WC) composites materials
Agronomy research, 2016
Ceramic-Metal Composite such as NiWC, CoWC are among advanced technology materials that have outstanding mechanical and physical properties for high temperature applications. Especially low density and high hardness properties stand out in such ceramic-metal composite. The microstructure, mechanical properties of %60Ni, %20Co and %20WC powders have been sintered by using tube furnace at 1,000–1,100–1,200–1,300–1,400 °C temperature. Mecahnical proporties and metalograhphic analysis were investigated after sintering. NiCo phases observed after metallographic analaysis. XRD, SEM (Scanning Electron Microscope)results showed us best microhardness of composites 174.16 HV, 8,563 g cm density were obtained at 1,400 °C sintering tempareture.
Mechanical characterization of composites prepared from WC powders coated with Ni rich binders
International Journal of Refractory Metals and Hard Materials, 2008
In this study composite powders of WC and Ni/Fe/Cr were prepared in an innovative way, which consists of the sputter-deposition of the metallic binder onto the tungsten carbide particles. Compacts of coated powders were sintered by conventional vacuum sintering followed by hot isostatic pressing (HIP) to reach almost full densities. In order to evaluate the mechanical properties of reduced specimens size (microcomponents), depth-sensing indentation equipment was used. This method enabled the evaluation of the hardness, H, Young's modulus, E, and the yield stress, r y , in a non-destructive way, using only one sample. For the composites of sputter-coated WC-Ni/Fe/Cr the results showed an effective reduction of H and E due to the properties of Ni and the binder characteristics of the coated powders, such as uniform distribution and nanometer structure.
Journal of Alloys and Compounds, 2010
The effect of mechanical alloying and the sintering regime on the microstructural and the physical properties of W-SiC composites were investigated. Powder mixtures of W-20 vol.% SiC were mechanically alloyed (MA'd) using a Spex mill for 3 h, 6 h and 24 h. MA'd powders were characterized by Laser Diffraction Particle Size Analyzer, SEM and XRD investigations. MA'd W-20 vol.% SiC powder composites were sintered under inert Ar and reducing H 2 gas conditions at 1680 • C and 1770 • C for 1 h. The microstructural and mechanical characterizations of the sintered samples were carried out by scanning electron microscope (SEM) and X-ray diffraction (XRD) and Vickers Hardness analyses. The addition of SiC remarkably increases the hardness of the composites. Hardness is also increased with decreasing grain size and increasing amount of MA.
Materials Science Forum, 2017
This study aims to highlight the grains growth of tungsten carbide in the nickel binder phase, in function of sintering temperature of a hot isostatic pressed - HIP (at 60 bar) material, targeting the morphological behavior of the grain size and densification of the composite WC-8Ni. Cylindrical samples 25 mm x 15 mm were sintered in compression at temperatures ranging from 1380 °C to 1460 °C. The results showed that increasing the sintering temperature, there is an increase in WC grain size, the hardness decreases and the porosity is reduced increasing the specific gravity.
Wear Characteristics of Ni-WC Powder Deposited by Using a Microwave Route on Mild Steel
International Journal of Surface Engineering and Interdisciplinary Materials Science, 2020
In the present research work, Ni-WC powder was deposited on mild steel using a microwave applicator. Deposited clad has a thickness of 0.5 mm and deposition time taken for coating was 15 minutes for each sample size. The developed layer on the substrate was analysed through several testing techniques include mechanical characterization by the Vickers hardness test and a wear test on the Pin-on disc apparatus according to ASTM-G99 standard. Furthermore, micro structural characterization was done by using scanning electron microscopy technique and it has shown proper bonding between powder and substrate. Coating showed excellent results in terms of hardness and wear resistance as compared to base material mils steel. The pullout, scoring and abrasion were the responsible wear mechanisms in the substrate and clad.
Synthesis of WC hard materials using coated powders
Advanced Powder Technology, 2011
Nickel and cobalt were used as binder materials for tungsten carbide powders (WC) hard materials. Ni and Co binder were added individually to the WC powder by two different methods namely, mechanical mixing and chemical electroless coating. In this study WC powders of grain sizes 0.3-1.0 lm were electroless coated with either nickel or cobalt. The loading of either Ni or Co coating was 13 wt.%. The electroless-coating method conditions of both Ni and Co on WC powders are described. The coated powders were cold compacted and sintered in vacuum at different sintering temperatures. For comparison, identical materials compositions were prepared by mixing the powders constituents mechanically, compacted and sintered under the same conditions. The prepared powders and sintered materials were investigated using X-ray diffraction (XRD) and scanning electron microscope (SEM). The results revealed that coated WC materials have smaller values of porosity and more homogeneous microstructure while other properties, such as transverse rupture strength, and hardness exhibit greater values than those produced using mixing elemental powders. It is possible to outline the benefits of coated powder approach in the following: high homogeneity and better distribution of binder materials within WC hard materials, higher density and good interfacial bonding, capability of using fine powders, and possibility of using small alloying and/or reinforcement additions in a more uniform manner.
WC/Ti Composite Material Enriched with CBN Particles Produced by Pulse Plasma Sintering (PPS)
Key Engineering Materials, 2011
Tungsten carbide (WC) and WCCo powders added with 30 vol.% cubic boron nitride (cBN) and 5 and 12 wt% of Ti were sintered by the pulse plasma sintering (PPS) technique. The sintering process was conducted under a load of 75 MPa at a pressure of 5.10 -5 mbar and a temperature of 1100-1500°C for 5min. The phase composition, density, hardness and microstructure of the sintered material thus obtained were examined. In the cBN-WCTi5wt% composite with an addition of 6wt% Co, the cBN particles are well bound with the matrix. The transcrystalline fractures of the cBN particles also indicate that the binding forces between these particles and the WCCoTi matrix exceed the matrix cohesion. The interfaces between the cBN grains and the surrounding matrix are almost straight lines, and no reactions between the cBN grains and the matrix were revealed in SEM observations.
Comparative studies of WC-Co and WC-Co-Ni composites obtained by conventional powder metallurgy
Materials Research, 2011
The present work reports a comparative study of cemented carbides of compositions WC-6Co, WC-10Co, WC-20Co, WC-6Co-6Ni and WC-12Ni-6Co. The purpose was to study the powder metallurgical production process of these compositions starting from a commercial WC-6Co powder, obtaining the desired compositions by mass balance with pure Co and pure Ni powders. During the process steps mixing, milling, compacting and sintering the powders were described by its apparent density, green density, shrinkage and sintered density. Lower densities were observed in composites with higher binder content. The process was monitored by scanning electron microscopy and EDS analysis to evaluate the homogeneity of the powders, to detect contaminations by the process and to characterize the microstructure of the sintered materials. A finer microstructure was found when the binder contained Ni. Potentiodynamic polarization tests in sulfuric acid revealed pseudo-passive behavior for all the tested hard metals.