Hardness Regulation of Fe-Based Amorphous Composite Coatings by Laser Remelting

2014 ◽  
Vol 789 ◽  
pp. 64-69 ◽  
Author(s):  
Yong Tian Wang ◽  
Ming Ming Yuan ◽  
Jing Kang Duan ◽  
Run Sen Jiang ◽  
Lin Hu ◽  
...  
Keyword(s):  
Composite Coating ◽  
Laser Power ◽  
Volume Fraction ◽  
Steel Substrate ◽  
Composite Coatings ◽  
Power Input ◽  
Arc Spraying ◽  
Laser Remelting ◽  
Application Fields

A Fe-based amorphous composite coating was deposited on a carbon steel substrate by arc spraying, and remelted with different laser energies by the Nd: YAG laser cladding system, in order to improve the mechanical properties of the coatings. The microstructure and microhardness of the composite coatings were investigated. The variation of harndness was measured as a function of the modified layer depth, which indicates that the laser remelting improves the bonding strength and hardness. Increasing the laser power, the quality of coating gets better, but the amorphous volume fraction decreases. It is obtained that the optimal laser electric current for the coating of 280 μm thickness is about 300 A, in which the remelted coating with medium energy densities has the highest average Vickers hardness of 741. Through the volume fraction change of the nanocrytals, the hardness of the composite coating is regulated by the laser power input, which amplified the application fields of the amorphous coatings.

scholarly journals The Effect of Laser Power on the Interface Microstructure of a Laser Remelting Nano-SiC Modified Fe-Based Ni/WC Composite Coating

Coatings ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 297 ◽  
Author(s):  
Yuncai Zhao ◽  
Wen He ◽  
Huihui Du ◽  
Peng Luo
Keyword(s):  
Composite Coating ◽  
Laser Power ◽  
Intermediate Phase ◽  
Composite Coatings ◽  
Peak Height ◽  
Interface Microstructure ◽  
Laser Remelting ◽  
General Terms ◽  
Sic Particles ◽  
Average Grain Size

The plasma sprayed Fe-based Ni/WC composite coating on the surface of 45 steel was post-treated by laser remelting with the addition of nano-SiC. The effect of laser power on the interface microstructure of a laser remelting nano-SiC modified Fe-based Ni/WC composite coatings were researched. The metallographic structure, microscopic morphology, phase composition, and microhardness of the remelted layer were visually analyzed by metallographic microscope, scanning electron microscope (SEM), X-ray diffractometer (XRD), and microhardness tester, respectively. The results showed that the nano-SiC modified remelted coating was smooth and compact, and with no fine cracks. The remelted layer was mainly composed of [Fe,Ni], Cr, Fe0.04Ni0.36 phase. The metal elements Fe, Ni, Cr, and Si, and non-metallic element C, appeared to diffuse, and there was metallurgical bonding between the coating and the matrix. With the increase of laser power, the smaller the average grain size, the wider the half-peak height (FWHM), and the more obvious the grain refinement. When the laser power was 500 W, the interface metallurgical showed the best effect. Furthermore, the nano-sized SiC particles served as the core of the heterogeneous nucleation to refine the grains on the one hand, and promoted the formation of a hard intermediate phase in the coating on the other hand. Therefore, the laser remelting and the addition of nano-SiC particles greatly improved the microhardness of the coating. The larger the laser power, the smaller the microstructure characteristics and the fewer the number of holes. With increasing laser power, the hardness increased in general terms and the maximum hardness increased by 51%.

MICROSTRUCTURE AND PROPERTIES OF IN SITU SYNTHESIZED ZrC-ZrB2/Fe COMPOSITE COATING PRODUCED BY GTAW

2009 ◽  
Vol 23 (06n07) ◽  
pp. 1438-1443 ◽  
Author(s):  
ZHENTING WANG ◽  
LILI CHEN ◽  
XIANYOU ZHANG
Keyword(s):  
Wear Resistance ◽  
Composite Coating ◽  
Volume Fraction ◽  
Steel Substrate ◽  
Composite Coatings ◽  
Energy Dispersive Spectrum ◽  
X Ray Diffraction ◽  
Gas Tungsten Arc ◽  
C 30

A metal matrix composite coating reinforced by ZrC - ZrB 2 particulates has been successfully fabricated utilizing the in situ reaction of Zr , B 4 C and Fe pre-placed mixed powders by gas tungsten arc welding (GTAW) cladding process. Various volume fraction of ZrC - ZrB 2 particulates composite coatings were produced through cladding different weight ratios of Zr + B 4 C (30%, 50%, 70%) to improve the wear resistance of AISI1020 steel substrate. The Microstructure of the coating was analyzed by scanning electron microscopy (SEM), X-ray diffraction (XRD), energy-dispersive spectrum (EDS), meantime microhardness and wear resistance at room temperature of the composite coating were examined by means of Microhardness Tester and Wear Tester, respectively. The results show that the main phases of the composite coating obtained by GTAW are ZrC , ZrB 2 and α- Fe , ZrC exhibits hexahedron and petal shapes, ZrC - ZrB 2 compound presents acicular and clubbed forms. With the increase of content of Zr + B 4 C , the maximum volume fraction of ZrC - ZrB 2 particulates can reach 16.5%, microhardness is up to 1300HV, and wear resistance is about twenty times higher than that of AISI1020 steel substrate.

scholarly journals Fe-Based Amorphous Composite Coating Prepared by Plasma Remelting

2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Zhisheng Li ◽  
Zongde Liu ◽  
Yongtian Wang ◽  
Shunv Liu ◽  
Runsen Jiang ◽  
...  
Keyword(s):  
Composite Coating ◽  
Steel Substrate ◽  
Composite Coatings ◽  
Arc Spraying ◽  
X Ray Diffraction ◽  
X Ray ◽  
Microhardness And Microstructure ◽  
Internal Relationship ◽  
Scanning Electron ◽  
Microhardness Tester

Fe-based amorphous composite coating was deposited on the carbon steel substrate by arc spraying and then remelted by a plasma remelting system, in order to improve the mechanical properties of the coatings. The composition, microstructure, and properties of the composite coating were analyzed by means of the metallographic microscope, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), and microhardness tester. The results showed that the amorphous composite coatings had more homogeneous and finer microstructure after the plasma remelting. The coating is metallurgically bonded with the substrate, and the hardness of the Fe-based amorphous composite coating is up to 1220 HV. The internal relationship between microhardness and microstructure has been discussed.

Microstructure and Tribological Properties of Self-Lubricating Graphite/Ni60 Composite Coatings Prepared by Laser Cladding

2012 ◽  
Vol 583 ◽  
pp. 27-31 ◽  
Author(s):  
Jiao Xi Yang ◽  
Zhi Cheng Wang ◽  
Xuan He Miao ◽  
Xi Bing Wang
Keyword(s):  
Composite Coating ◽  
Laser Cladding ◽  
Steel Substrate ◽  
Composite Coatings ◽  
Solid Lubricants ◽  
Composition Analysis ◽  
Metallurgical Bonding ◽  
Lubricating Property ◽  
Increasing Temperature

Ni60 superhard alloy with the additions of graphite solid lubricants was successfully prepared on 45 carbon steel substrate by means of laser cladding. The quality of coating was relatively high and had metallurgical bonding with the substrate. The morphology of laser cladding layer was observed by SEM, composition analysis was applied by EDS. Elevated temperature frictional behaviors of graphite/Ni60 composites coatings were investigated on MMG-10 wear machine. The results showed that the friction coefficient of graphite/Ni60 composite coating was obviously decreased from 0.55 to 0.20 with increasing temperature. The wear mechanism transformed from adhesion to oxidation with the increase of temperature. The graphite/Ni60 composite coating material showed the optimum self-lubricating property at 500°C.

scholarly journals Microstructural and Corrosion Behavior of High Velocity Arc Sprayed FeCrAl/Al Composite Coating on Q235 Steel Substrate

Coatings ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 542 ◽  
Author(s):  
Ndumia Joseph Ndiithi ◽  
Min Kang ◽  
Jiping Zhu ◽  
Jinran Lin ◽  
Samuel Mbugua Nyambura ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Composite Coating ◽  
High Velocity ◽  
Steel Substrate ◽  
Arc Spraying ◽  
Spray Parameters ◽  
Q235 Steel ◽  
Electrochemical Tests ◽  
Al Composite ◽  
Al Coating

High velocity arc spraying was used to prepare FeCrAl/Al composite coating on Q235 steel substrate by simultaneously spraying FeCrAl wire as the anode and Al wire as the cathode. The composite coating was sprayed with varying voltage and current to obtain optimum coating characteristics. FeCrAl coating was also prepared for comparison purposes. The surface microstructure of the coatings was characterized by scanning electron microscope (SEM) and X-ray diffraction (XRD). The average microhardness of the coatings and the substrate was analyzed and compared. Corrosion resistance was investigated by means of electrochemical tests. The image results showed that a lamellar structure consisted of interwoven layers of FeCrAl and Al. Al and FeCr constituted the main phases with traces of oxides and AlFe intermetallic compounds. The average porosity was reduced and microhardness of the coatings was improved with increasing voltage and current. The FeCrAl/Al coating formed alternating layers of hard and ductile phases; the corrosion resistance of the coatings in the sodium chloride (NaCl) solution depended on the increase in Al content and spray parameters. The corrosion resistance tests indicated that FeCrAl/Al coating had a better corrosion resistance than the FeCrAl coating. FeCrAl/Al can be used to coat steel substrates and increase their corrosion resistance.

Cladding of Inconel 625+WC Composite Coatings Using a Direct Diode Laser

2014 ◽  
Vol 1036 ◽  
pp. 212-217
Author(s):  
Damian Janicki
Keyword(s):  
Diode Laser ◽  
Laser Power ◽  
Erosion Resistance ◽  
Volume Fraction ◽  
Composite Coatings ◽  
Optical Metallography ◽  
Inconel 625 ◽  
Homogeneous Distribution ◽  
Wear Properties ◽  
Low Degree

In the present study, a high power direct diode laser (HPDDL) was used to deposit composite coatings consisted of Ni-based superalloy Inconel 625 matrix and of WC reinforcement particles with a volume fraction of 60%. The influence of parameters, such as laser power beam (heat input) and WC particles size in the cladding powder on the coatings microstructure and erosion wear properties was investigated. The coatings were examined by optical metallography and scanning electron microscopy. The results showed that direct diode laser cladding provides non-porous coatings with homogeneous distribution of WC particles and very low degree of WC dissolution during cladding process. Erosion resistance of the composite coatings decreases with the size of WC particles decreasing.

Electrodeposition of the Ni-Mo+MoO2 Composite Electrocoatings

2015 ◽  
Vol 228 ◽  
pp. 132-137 ◽  
Author(s):  
B. Łosiewicz ◽  
Grzegorz Dercz ◽  
Magdalena Popczyk
Keyword(s):  
Composite Coating ◽  
Steel Substrate ◽  
Composite Coatings ◽  
Chemical Properties ◽  
Alloy Coating ◽  
Composite Component ◽  
Powder Particles ◽  
Physical And Chemical ◽  
And Chemical Properties

The Ni-Mo+MoO2composite coatings were obtained onto the steel substrate using anin situco-deposition of a Ni-Mo alloy and MoO2powder particles maintained in suspension in the potassium pyrophosphate bath. To characterize the physical and chemical properties of the obtained coatings, SEM, EDS, and XRD methods, were applied. It was found that the co-deposited MoO2particles strongly influenced the properties of the Ni-Mo alloy coating. In comparison with the comparable Ni-Mo deposit containing 45 at.% of Mo, the presence of MoO2embedded into the composite coating diminished the content of Mo alloyed with Ni to 23 at.%. The electrodeposited Ni-Mo+MoO2composite coating obtained under proposed electrochemical conditions contained 25 at.% of MoO2. The effect of the embedded MoO2as composite component on changes of the surface morphology and structure of the Ni-Mo binary alloy, was also discussed.

MICROSTRUCTURE AND WEAR PROPERTIES OF LASER CLAD TiB2 + TiC/Fe COMPOSITE COATING

2012 ◽  
Vol 19 (05) ◽  
pp. 1250052 ◽  
Author(s):  
X. H. WANG ◽  
M. ZHANG ◽  
B. S. DU ◽  
S. LI
Keyword(s):  
Wear Resistance ◽  
Composite Coating ◽  
Laser Cladding ◽  
Volume Fraction ◽  
Composite Coatings ◽  
Wear Properties ◽  
Friction Coefficients ◽  
Iron Based

Iron-based composite coatings reinforced with TiB2–TiC multiple ceramic have been fabricated from a precursor of B4C , TiO2 and Al powders by laser cladding. The effect of TiO2 and Al on the microstructure and wear properties of the coatings was investigated. The results showed that the volume fraction, type and size of the reinforcements were influenced by the content of TiO2 and Al . TiB2 and TiC were evenly distributed in the coating; however, most of Al2O3 were ejected from the coatings, only few of them retained in the coating acting as nucleation core of reinforcement or inclusion. The microhardness and wear resistance of the coatings were improved, whereas the friction coefficients of the coatings were considerably lower than that of substrate.

Temperature Profiles and Thermal Stress Analysis of Plasma Sprayed Glass-Composite Coatings

2000 ◽  
Author(s):  
T. Zhang ◽  
Z. Qiu ◽  
Y. Bao ◽  
D.T. Gawne ◽  
K. Zhang
Keyword(s):  
Thermal Stress ◽  
Volume Fraction ◽  
Spray Deposition ◽  
Steel Substrate ◽  
Composite Coatings ◽  
Operating Conditions ◽  
Second Phase ◽  
Temperature Profiles ◽  
Glass Composite ◽  
Phase Volume Fraction

Abstract Experimental measurements have been carried out with the aim of investigating the residual stresses generated during plasma spray deposition of glass composite coatings. The research shows that the behaviour of these materials is fundamentally different from metals and ceramics. The quench stress in the glass composites can be eliminated by plasma-scanning. This is attributed to their low glass transition temperatures, which enable the stresses to be completely relaxed. The work also shows that the addition of alumina as a second phase allows the expansion mismatch between the coating and the steel substrate to be controlled. Control of the second-phase volume-fraction enables the residual stress in the composite coatings to be reduced to zero. Real-time measurements on deflection and temperature show that the dimensions of the substrate, plasma operating conditions and scanning rate have substantial effects on the temperature profiles within the deposits. Keywords: glass composite coatings, thermal stress, plasma spraying.

Effects of Current Density on the Microstructure and Properties of Electrodeposited Black Cr-C Nano-Composite Coatings on Steel Substrate

2011 ◽  
Vol 687 ◽  
pp. 641-646 ◽  
Author(s):  
Xue Song Li ◽  
Yue Yang ◽  
You Yang ◽  
Hua Wu
Keyword(s):  
Composite Coating ◽  
Current Density ◽  
Steel Substrate ◽  
Composite Coatings ◽  
Scanning Electronic Microscopy ◽  
Electronic Microscopy ◽  
Particle Content ◽  
Nano Composite ◽  
X Ray ◽  
Nano Composite Coating

Eelectrodeposited black Cr-C nano-composite coating was prepared on the steel substrate and the effects of current density on the properties of the composite coating were studied in the present paper. The surface morphology and phase composition of the composite coatings were analyzed by means of scanning electronic microscopy (SEM) and X-ray diffractometer (XRD). Microhardness was determined by micrometer and the wear resistance of the coatings was evaluated by CETR using a universal materials tester (UMT). The results showed that formed under the condition of current density of 100A/dm2, temperature of 15°C, and the optimum particle content in electrolyte was 10g/l. The maximum microhardness of black Cr-C nano-composite coating was 10.8 Gpa, simutaneously, the wearing resistance of the coating improved significantly compared to the steel substrate.

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