scholarly journals Characterization and Microstructural Evolution of WC-Co Cemented Carbides

2021 ◽  
Vol 45 (3) ◽  
pp. 245-249
Author(s):  
Hassiba Rabouhi ◽  
Youcef Khelfaoui ◽  
Abdelkrim Khireddine
Keyword(s):  
Hot Isostatic Pressing ◽  
Appearance Energy ◽  
Dispersion Analysis ◽  
Liquid Phase Sintering ◽  
Cemented Carbides ◽  
X Rays ◽  
Closed Porosity ◽  
Surface Appearance ◽  
Three Samples ◽  
Type Carbide

Two types of cemented carbides have been elaborated from three mixtures of WC and Co powders containing 3, 5 and 6% of cobalt mass. Three samples of these mixtures have been obtained by liquid phase sintering and three others of the same composition have been sintered then densified by hot isostatic pressing (HIP). Observations by scanning electronic microscope have allowed to note that the samples elaborated by sintering followed by an HIP densification have a more homogeneous structure than that observed in the sintered samples. Under the compression, the WC grains flattens and interlock more easily from one another which gives a uniform surface appearance. Energy dispersion analysis shows that these samples contain a very small voluminal fraction of graphite and residual porosities, these are more pronounced in sintered samples, especially in the case of alloys with a low Co content (3 and 5%). X rays diffraction analysis allowed to show clearly the existence of cobalt type carbide in the sintered samples. Measurement of the closed porosity allows to observe that the sintering process followed by densification by HIP leads to the elaboration of alloys with a low rate of closed porosity. Microhardness of these samples have improved hardnesses.

TEM Studies of Grain Boundary Films in Si3N4 Ceramics

1991 ◽  
Vol 49 ◽  
pp. 930-931
Author(s):  
H.-J. Kleebe ◽  
J.S. Vetrano ◽  
J. Bruley ◽  
M. Rühle
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Silicon Nitride ◽  
Hot Isostatic Pressing ◽  
Amorphous Film ◽  
Liquid Phase Sintering ◽  
Second Phase ◽  
High Temperature Mechanical Properties ◽  
Triple Points ◽  
Boundary Films

It is expected that silicon nitride based ceramics will be used as high-temperature structural components. Though much progress has been made in both processing techniques and microstructural control, the mechanical properties required have not yet been achieved. It is thought that the high-temperature mechanical properties of Si3N4 are limited largely by the secondary glassy phases present at triple points. These are due to various oxide additives used to promote liquid-phase sintering. Therefore, many attempts have been performed to crystallize these second phase glassy pockets in order to improve high temperature properties. In addition to the glassy or crystallized second phases at triple points a thin amorphous film exists at two-grain junctions. This thin film is found even in silicon nitride formed by hot isostatic pressing (HIPing) without additives. It has been proposed by Clarke that an amorphous film can exist at two-grain junctions with an equilibrium thickness.

scholarly journals Development and Characterization of Teflon-Copper Composite Material

2018 ◽  
Vol 778 ◽  
pp. 225-229
Author(s):  
Imran Hamid ◽  
Abdul Rauf ◽  
Faisal Nasim ◽  
Muhammad Siddique ◽  
Adnan Gul
Keyword(s):  
Composite Material ◽  
Hot Isostatic Pressing ◽  
Solid Lubricants ◽  
Powder Metallurgy Technique ◽  
Covalent Bonds ◽  
Secondary Bonds ◽  
Three Samples ◽  
Commercial Applications ◽  
Copper Composite

Composites are the combination of materials that are mixed together to achieve specific structural properties. Teflon (Polytetrafluoroethylene PTFE) consists of long-chain molecular structure. Its monomer consists of two carbon atoms each of them having flourine atoms attached. Bonds within each chain are strong covalent bonds where as the secondary bonds between two chains are weaker. By raising temperature, the distance between the chains increases providing good adjustment of the atoms of other materials due to anisotropy of its mechanical properties. Powder metallurgy technique using hot isostatic pressing, a hybrid densification process in which pressure and temperature are applied at the same time, has been used to develop a teflon-copper composite material. Three samples were prepared by changing the teflon-copper composition as 60:40%, 65:35% and 70:30% by weight. Commercially available powders of teflon and copper of grain size ~ 40 μm was used. The aim to develop this type of material was to increase its density (~ 4 g/cm3), and hardness. The commercial applications of such type of composite material are solid lubricants, sleeves, bearings etc. In this paper the effect of composition on hardness, tensile strength and surface roughness is studied.

Liquid Phase Sintering of (Ti,W)C-Ni-Co-Cr Cermets: Microstructure and Abrasive Wear Behavior

2018 ◽  
Vol 274 ◽  
pp. 1-8 ◽  
Author(s):  
I. Iparraguirre ◽  
L. Lozada ◽  
F. Ibarreta ◽  
R. Martinez ◽  
J.M. Sanchez
Keyword(s):  
Liquid Phase ◽  
Grain Growth ◽  
Abrasion Resistance ◽  
Wear Behavior ◽  
Liquid Phase Sintering ◽  
Point Of View ◽  
Cemented Carbides ◽  
Microstructural Refinement ◽  
Abrasive Wear Behavior ◽  
High Degree

TiC-WC-(Ni,Co,Cr) cermets are potential candidates for the substitution of straight cemented carbides in certain wear applications. This work analyses the effect of Ti/W and Co/Ni ratios on the microstructure and abrasion resistance of this type of cermets. From a microstructural point of view, cermets in the (Ti,W)C-(Ni,Co,Cr) pseudo-binary region show uncontrolled (Ti,W)C grain growth and a high degree of contiguity of the carbide phase. A microstructural refinement is observed as the Ti/W ratio decreases, especially when WC precipitation occurs. Abrasion resistance in these materials is dominated by hardness.

scholarly journals Plasma-Assisted Chemical Vapor Deposition of TiBN Coatings on Nanostructured Cemented WC-Co

Metals ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1680
Author(s):  
Matija Sakoman ◽  
Danko Ćorić ◽  
Mateja Šnajdar Musa
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Hot Isostatic Pressing ◽  
Base Material ◽  
Surface Preparation ◽  
Chemical Vapor ◽  
Hard Coatings ◽  
Cemented Carbides ◽  
Wear Properties ◽  
Coating Adhesion

The plasma-assisted chemical vapor deposition (PACVD) technique has shown many advantages in applications, where thin coatings with superior wear properties are demanded, especially for geometrically complex parts. In this study, multilayered gradient TiBN coatings that were deposited on nanostructured cemented carbides by the PACVD method were investigated. Nanostructured samples of cemented carbides with the addition of 5 and 15 wt.% Co were sintered by the hot isostatic pressing, sinter-HIP technique. Surface preparation was conducted on samples in order to enable maximum coating adhesion. Tests that were conducted on produced samples aimed to investigate the mechanical and physical properties of coated samples. These tests included nanoindentation, surface layer characterization, and coating adhesion evaluation while using the Rockwell and scratch test. The obtained results confirmed that the PACVD process can be utilized for applying thin hard coatings to nanostructured cemented carbides that are produced by the sinter HIP process, resulting in a base material/ coating system that exhibits excellent physical and mechanical properties. The results presented in this paper give a valuable contribution to the research of TiBN coating systems and their potential for application under heavy wear conditions.

Characterization of WC-VC-Co Cemented Carbides Using Scanning Electron Microscopy (SEM) and Energy Dispersive X-Ray Spectroscopy (EDS)

1997 ◽  
Vol 3 (S2) ◽  
pp. 717-718
Author(s):  
F. Arenas ◽  
I. B. de Arenas ◽  
J. Ochoa ◽  
S. A. - Cho
Keyword(s):  
Cutting Tool ◽  
Tool Material ◽  
Liquid Phase Sintering ◽  
Cemented Carbides ◽  
Metal Carbides ◽  
Vacuum Sintering ◽  
X Ray ◽  
Transition Metal Carbides ◽  
Cylindrical Samples

The two important constituents of metallic tool alloys are transition metal carbides and metals of the iron group, Fe, Ni, Co. Combining them, based on WC, it is obtained a hard and tough cutting tool material. Many attempts have been made to develop alternative cemented carbide systems by substituting a portion of WC by other hard phases. In this investigation, microstructure and phases composition of 90 mass% [ (1-y) WC - y VC ] - 10 mass% Co with y = 0, 0.2, 0.4, 0.6 and 1.0 sintered cemented carbides were studied by Backscattering electron (BSE) compositional images, elemental dot maps and X - ray microanalysis. These techniques have allowed to determine the different phases present, their morphology and composition.Cylindrical samples of 10 mm. in diameter and height were manufactured by vacuum sintering at 1400°C of uniaxially pressed compacts at 350 MPa. Liquid phase sintering is the predominant consolidation mechanism present in this system.

scholarly journals Some Properties of WC-Co Cemented Carbides Prepared by Hot-Isostatic Pressing

1975 ◽  
Vol 21 (8) ◽  
pp. 222-226 ◽  
Author(s):  
Hisashi Suzuki ◽  
Kozi Hayashi ◽  
Tsutomu Yamamoto ◽  
Kazuo Miyake
Keyword(s):  
Hot Isostatic Pressing ◽  
Cemented Carbides ◽  
Isostatic Pressing

Liquid phase sintering and oxidation resistance of WC–Ni–Co–Cr cemented carbides

2010 ◽  
Vol 28 (4) ◽  
pp. 516-522 ◽  
Author(s):  
M. Aristizabal ◽  
N. Rodriguez ◽  
F. Ibarreta ◽  
R. Martinez ◽  
J.M. Sanchez
Keyword(s):  
Liquid Phase ◽  
Oxidation Resistance ◽  
Liquid Phase Sintering ◽  
Cemented Carbides

Influences of Ball-Milled Time on Properties and Microstructure of Ultrafine WC-10Co Cemented Carbide

2007 ◽  
Vol 121-123 ◽  
pp. 1337-1340
Author(s):  
Xiao Liang Shi ◽  
Gang Qin Shao ◽  
Xing Long Duan
Keyword(s):  
Milling Time ◽  
Rupture Strength ◽  
Hot Isostatic Pressing ◽  
Cemented Carbide ◽  
Cemented Carbides ◽  
Vacuum Sintering ◽  
Average Grain Size ◽  
Fine Microstructure ◽  
Nanocomposite Powders ◽  
Ball Milling Time

WC-10Co nanocomposite powders prepared by spray pyrogenation-continuous reduction and carburization technology were consolidated by vacuum sintering plus hot isostatic pressing (HIP). Influences of ball-milled time on properties and microstructure of ultrafine WC-10Co cemented carbide were investigated. The results show that ultrafine WC-10Co cemented carbides can reach 99.79% relative density, and transverse rupture strength is more than 3750MPa, Rockwell A hardness is more than 92.6, the average grain size is less than 440 nm, when ball-milled time is 48 hours, ultrafine WC-10Co cemented carbide with excellent properties and fine microstructure is obtained. The optimum ball-milling time is 48 hours.

Influences of Ball-Milled Time on Properties and Microstructure of Ultrafine WC-10Co Cemented Carbide

2007 ◽  
Vol 121-123 ◽  
pp. 159-162
Author(s):  
Xiao Liang Shi ◽  
Gang Qin Shao ◽  
Xing Long Duan
Keyword(s):  
Milling Time ◽  
Rupture Strength ◽  
Hot Isostatic Pressing ◽  
Cemented Carbide ◽  
Cemented Carbides ◽  
Vacuum Sintering ◽  
Average Grain Size ◽  
Fine Microstructure ◽  
Nanocomposite Powders ◽  
Ball Milling Time

WC-10Co nanocomposite powders prepared by spray pyrogenation-continuous reduction and carburization technology were consolidated by vacuum sintering plus hot isostatic pressing (HIP). Influences of ball-milled time on properties and microstructure of ultrafine WC-10Co cemented carbide were investigated. The results show that ultrafine WC-10Co cemented carbides can reach 99.79% relative density, and transverse rupture strength is more than 3750MPa, Rockwell A hardness is more than 92.6, the average grain size is less than 440 nm, when ball-milled time is 48 hours, ultrafine WC-10Co cemented carbide with excellent properties and fine microstructure is obtained. The optimum ball-milling time is 48 hours.

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