Study on Corrosion Mechanism of Stellite Hard Alloy Layer of a Main Pump Component

2017 ◽  
Author(s):  
Zhang Wenguang ◽  
Yang Chenggang ◽  
Yi Zilong ◽  
Li Chan ◽  
Pu Chenghao ◽  
...  
Keyword(s):  
Hard Alloy ◽  
Alloy Layer ◽  
Corrosion Mechanism ◽  
Cobalt Chromium ◽  
Product Testing ◽  
Hard Layer ◽  
Eds Analysis ◽  
Stellite 12 ◽  
Pump Component ◽  
And Tungsten

Stellite 12 alloy was cladded on the surface of Thrust runner of a main pump using HIP technology. After product testing, lots of corrosions were found on the hard layer. SEM and EDS analysis technologies were used in order to find out the causes and mechanism inducing these corrosions. SEM results indicated that two kinds of corrosions locating on the hard layer. One type is central corrosion pit, another type is Selective Phase Corrosion (SPC).EDS showed that the central and adjacent corrosive areas were rich in carbon, low in cobalt, chromium and tungsten elements for the first type of corrosion. As for the second type of corrosion, EDS indicated that the corrosive zones were typically high in tungsten, chromium and carbon, and low in cobalt. Meanwhile, the presence of sulfur and chlorine elements may aggravate the initiation and continuation of corrosion.

Increasing the working life of a dental excavator by depositing a hard-alloy layer on the working surface

1988 ◽  
Vol 22 (1) ◽  
pp. 6-9
Author(s):  
V. K. Maksimov ◽  
I. Abdullin ◽  
V. M. Matukhnov ◽  
I. L. Balikhin ◽  
D. V. Svetlov
Keyword(s):  
Hard Alloy ◽  
Working Life ◽  
Alloy Layer ◽  
Working Surface

Experimental Study on Laser Melting of Cemented Carbide Coatings by High Velocity Oxy-Fuel Spraying

2015 ◽  
Vol 1120-1121 ◽  
pp. 785-789
Author(s):  
Xiang Fang Fan ◽  
Wei Wu ◽  
Jiang Ye ◽  
Ren Zheng Gong
Keyword(s):  
Hard Alloy ◽  
Continuous Wave ◽  
Testing Machine ◽  
Alloy Layer ◽  
Cemented Carbide ◽  
Flame Spraying ◽  
Micro Hardness ◽  
Micro Structure ◽  
Laser Melting ◽  
Carbide Layer

Ni60AA and DZ-WC-12Co cemented carbide layer was prepared on 45 steel by high-speed flame spraying, then remelted by 5KW continuous wave CO2 laser. The micro-structure was analyzed by Olympus GX51 .micro hardness and the micro hardness was measured by HXY-1000TAY micro hardness meter. The wear resistant of coating was tested by MM-W1B vertical universal testing machine. The results showed that laser melting significantly eliminate the carbide layer unmelted carbide particles, holes and cracks and other defects, the micro-structure is finer and more uniform. After laser re-melted, the average micro hardness of hard alloy layer is up to 647HV, which is five times of the matrix. Under the experimental conditions, the friction coefficient of hard alloy layer drops from 0.1373 to 0.0948 by 31%.The wear-resistance of cemented carbide layer is improved by laser melting.

scholarly journals Formation of a Calcium Phosphate Layer with Immobilized Cobalt Chromite Nanoparticles on Cobalt−Chromium Alloy by a Laser-Assisted Biomimetic Process

2020 ◽  
Vol 10 (16) ◽  
pp. 5584
Author(s):  
Ayako Oyane ◽  
Ikuko Sakamaki ◽  
Kenji Koga ◽  
Maki Nakamura
Keyword(s):  
Calcium Phosphate ◽  
Alloy Layer ◽  
Chromium Alloy ◽  
Cobalt Chromium ◽  
Metallic Biomaterials ◽  
Intermediate Layers ◽  
Transmission Electron ◽  
Cap Layer ◽  
Chromium Oxide Layer ◽  
Dental Applications

The biocompatibility and osteoconductivity of metallic biomaterials can be achieved by calcium phosphate (CaP) coating. We recently developed a laser-assisted biomimetic (LAB) process for rapid and area-specific CaP coating on several materials. In the present study, the LAB process was applied to cobalt–chromium (Co−Cr) alloy, a metallic biomaterial widely used in orthopedic and dental applications. The LAB process was conducted by irradiation of unfocused pulsed laser light onto the substrate immersed in supersaturated CaP solution. The LAB-processed substrate formed CaP on the irradiated surface within only 5 min and was coated with a micron-thick CaP layer within 30 min by the effects of laser-induced surface modification and heating. Ultrastructural analysis with transmission electron microscopy revealed that the resultant CaP layer was integrated with the underlying substrate through two intermediate layers, an upper chromium oxide layer and a lower Co-rich (Cr-deficient) alloy layer. The CaP layer was loaded with a large number of cobalt chromite (CoCr2O4) nanoparticles. The results obtained offer new insights into the mechanism of CaP coating in the LAB process and future applications of LAB-processed Co−Cr alloys.

Microstructure, heat transfer, and melting of the layers of hard alloy containing titanium and tungsten carbides in conditions of high-power pulsed treatment

2015 ◽  
Vol 56 (3) ◽  
pp. 345-352 ◽  
Author(s):  
A. K. Kuleshov ◽  
A. S. Yakushevich ◽  
V. V. Uglov ◽  
V. M. Astashinskii ◽  
N. N. Koval’ ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Hard Alloy ◽  
High Power ◽  
Tungsten Carbides ◽  
Pulsed Treatment ◽  
And Tungsten

Polyetheretherketone, hexagonal boron nitride, and tungsten carbide cobalt chromium composite coatings: Mechanical and tribological properties

2021 ◽  
Vol 138 (21) ◽  
pp. 50504
Author(s):  
Janice L. Lebga‐Nebane ◽  
Malavarayan Sankarasubramanian ◽  
Gregory Chojecki ◽  
Bo Ning ◽  
Philip A. Yuya ◽  
...  
Keyword(s):  
Boron Nitride ◽  
Tungsten Carbide ◽  
Tribological Properties ◽  
Hexagonal Boron Nitride ◽  
Composite Coatings ◽  
Cobalt Chromium ◽  
Mechanical And Tribological Properties ◽  
And Tungsten

Comparison On The Immersion Corrosion and Electrochemical Performance of WC-Al2O3 Composites and WC-Co Hard Metal in NaCl Solution

2021 ◽  
Author(s):  
Bin Han ◽  
Weiwei Dong ◽  
Bowen Fan ◽  
Shigen Zhu
Keyword(s):  
Hard Alloy ◽  
Galvanic Corrosion ◽  
Hard Metal ◽  
Electrochemical Technique ◽  
Corrosion Mechanism ◽  
Nacl Solution ◽  
Passivation Film ◽  
Immersion Corrosion ◽  
Corrosion Behaviors ◽  
Hot Pressing Sintering

Abstract WC-15wt.%Al2O3 composites was prepared via hot pressing sintering technology. The corrosion behaviors of WC-Al2O3 composites and traditional WC-Co hard alloy in NaCl solution were studied by immersion corrosion and electrochemical technique. The impedance value of WC-Al2O3 composite increased more rapidly than WC-Co hard metal during the 24 hours, which indicated that WC-Al2O3 composites has more compact passivation film than WC-Co hard metal. The results confirmed that the corrosion performance of WC-Al2O3 composites was higher than WC-Co cemented carbide in NaCl solution. The corrosion mechanism of WC-Al2O3 composites and WC-Co hard alloy in NaCl solution were also revealed by SEM, EDS, XPS and Raman. The corrosion products of WC-Al2O3 composites mainly contain WO3, while for WC-Co hard alloy are Co (OH)2, Co3O4 and WO3. The different corrosion mechanism of the two materials is attributed to the Al2O3 phase instead of the Co binder, which avoids the galvanic corrosion between WC phase and Co binder.

A correlation of CL emissions from Penrith sandstone with elemental distributions obtained by simultaneous SEM-CL and EDS analysis

1995 ◽  
Vol 53 ◽  
pp. 392-393
Author(s):  
Paul J. Wright
Keyword(s):  
Optical Microscope ◽  
Electron Gun ◽  
High Electron ◽  
Collection System ◽  
Electron Hole ◽  
Depositional Processes ◽  
Eds Analysis ◽  
Distribution Mapping ◽  
Backscattered Electron ◽  
Electron Imaging

Most industrial and academic geologists are familiar with the beautiful red and orange cathodoluminescence colours produced by carbonate minerals in an optical microscope with a cold cathode electron gun attached. The cement stratigraphies interpreted from colour photographs have been widely used to determine the post depositional processes which have modified sedimentary rock textures.However to study quartzose materials high electron densities and kV's are necessary to stimulate sufficient emission. A scanning electron microscope with an optical collection system and monochromator provides an adequate tool and gives the advantage of providing secondary and backscattered electron imaging as well as elemental analysis and distribution mapping via standard EDS/WDS facilities.It has been known that the incorporation of many elements modify the characteristics of the CL emissions from geological materials. They do this by taking up positions between the valence and conduction band thus providing sites to assist in the recombination of electron hole pairs.

Sampling and analysis of the air-water interface with SEM and EDS of microlayers

1989 ◽  
Vol 47 ◽  
pp. 1004-1005
Author(s):  
Randall W. Smith ◽  
John Dash
Keyword(s):  
Heavy Metals ◽  
Surface Microlayer ◽  
Surface Films ◽  
Water Interface ◽  
Physical Processes ◽  
Infrared Spectroscopic Analysis ◽  
Eds Analysis ◽  
Air Water Interface ◽  
Significant Area ◽  
Bulk Chemical

The structure of the air-water interface forms a boundary layer that involves biological ,chemical geological and physical processes in its formation. Freshwater and sea surface microlayers form at the air-water interface and include a diverse assemblage of organic matter, detritus, microorganisms, plankton and heavy metals. The sampling of microlayers and the examination of components is presently a significant area of study because of the input of anthropogenic materials and their accumulation at the air-water interface. The neustonic organisms present in this environment may be sensitive to the toxic components of these inputs. Hardy reports that over 20 different methods have been developed for sampling of microlayers, primarily for bulk chemical analysis. We report here the examination of microlayer films for the documentation of structure and composition.Baier and Gucinski reported the use of Langmuir-Blogett films obtained on germanium prisms for infrared spectroscopic analysis (IR-ATR) of components. The sampling of microlayers has been done by collecting fi1ms on glass plates and teflon drums, We found that microlayers could be collected on 11 mm glass cover slips by pulling a Langmuir-Blogett film from a surface microlayer. Comparative collections were made on methylcel1ulose filter pads. The films could be air-dried or preserved in Lugol's Iodine Several slicks or surface films were sampled in September, 1987 in Chesapeake Bay, Maryland and in August, 1988 in Sequim Bay, Washington, For glass coverslips the films were air-dried, mounted on SEM pegs, ringed with colloidal silver, and sputter coated with Au-Pd, The Langmuir-Blogett film technique maintained the structure of the microlayer intact for examination, SEM observation and EDS analysis were then used to determine organisms and relative concentrations of heavy metals, using a Link AN 10000 EDS system with an ISI SS40 SEM unit. Typical heavy microlayer films are shown in Figure 3.

Electron-Probe Quantitative Energy-Dispersive Analysis of Trace Magnesium Concentrations in Ag-Mg Alloys

1996 ◽  
Vol 54 ◽  
pp. 510-511
Author(s):  
R. B. Marinenko
Keyword(s):  
Electron Probe ◽  
Energy Dispersive Spectrometry ◽  
Mg Alloys ◽  
Energy Dispersive ◽  
Energy Dispersive Analysis ◽  
High Tc ◽  
Alloy Wire ◽  
High Tc Superconductor ◽  
Eds Analysis ◽  
Superior Mechanical Properties

Internally oxidized Ag-Mg alloys are used as sheaths for high Tc superconductor wires because of their superior mechanical properties. The preparation and characteristics of these materials have been reported. Performance of the sheaths depends on the concentration of the magnesium which generally is less than 0.5 wt. percent. The purpose of this work was to determine whether electron probe microanalysis using energy dispersive spectrometry (EDS) could be used to quantitate three different Ag-Mg alloys. Quantitative EDS analysis can be difficult because the AgL escape peak occurs at the same energy (1.25 keV) as the Mg Kα peak. An EDS spectrum of a Ag-Mg alloy wire is compared to a pure Ag spectrum in Fig. 1.

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