scholarly journals Investigation on Microstructure, Hardness, and Corrosion Resistance of Mo–Ni–B Coatings Prepared by Laser Cladding Technique

Coatings ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 856 ◽  
Author(s):  
Xiaojie Ni ◽  
Shengze Wang ◽  
Yuantao Zhao ◽  
Wenge Li ◽  
Xiong Jiao
Keyword(s):  
Corrosion Resistance ◽  
Laser Cladding ◽  
Laser Scanning ◽  
Bottom Layer ◽  
Scanning Speed ◽  
Corrosion Current ◽  
Corrosion Resistant ◽  
Cermet Coatings ◽  
Laser Scanning Speed ◽  
Corrosion Resistant Coatings

The hard and corrosion resistant coatings of Mo2NiB2 cermet were prepared by the laser cladding technique. The influences of the Mo:B ratio and the laser scanning speed on the microstructure and property of the Mo2NiB2 cermet coatings were investigated. The results showed that the laser scanning speed of 1.5 mm/s and the Mo:B ratio of 1 were more beneficial to the formation of Mo2NiB2 cermet than 2.0 mm/s and 0.8, 1.2, respectively. The amount of the Mo2NiB2 ceramic phases were decreased from the top layer to the bottom layer of the coating. The changes of microstructure and composition led to the changes of hardness and corrosion resistance of the Mo2NiB2 cermet coatings. The coating prepared at the Mo:B ratio of 1 and the scanning speed of 1.5 mm/s possessed the highest hardness, and the hardness gradually decreased from the top layer to the bottom layer of the coating. The formation of Mo2NiB2 and {FeM} phases led to the enhanced corrosion resistance of the Mo2NiB2 cermet coatings, and the coating prepared at the Mo:B ratio of 0.8 possessed the best corrosion resistance and the minimum corrosion current.

Influence of Scanning Speed on Microstructure and Hardness during Laser Cladding High-Cr Cast Iron

2013 ◽  
Vol 395-396 ◽  
pp. 1127-1131 ◽  
Author(s):  
Wei Zhang
Keyword(s):  
Cast Iron ◽  
Laser Cladding ◽  
Laser Scanning ◽  
Scanning Speed ◽  
Fish Bone ◽  
Cladding Layer ◽  
Metallurgical Bonding ◽  
Laser Scanning Speed ◽  
Gas Cavity ◽  
Cladding Layers

The experiments of laser cladding on the surface of 20 steel were made. High-chromium (Cr) cast iron powder was used as cladding material. The microstructure and hardness of laser cladding layers under different scanning speed were studied. The experiments showed that high-Cr cast iron cladding layer had better properties such as minute crystals, high density, no crack, no gas cavity and good metallurgical bonding with base metal. When the scanning speed was low, such as 10mm/min, the microstructure of cladding layer was cellular dendrite. There were much carbide with the shape of fish-bone distributing among cellular grains. Under higher scanning speed (from 100mm/min to 300mm/min), needle-shaped primary cementite would come into being. When laser scanning speed was 500mm/min, the carbide of cladding zone was very thin. With the increasing of laser scanning speed, the average hardness of cladding zone increased from 388HV0.2 to 580 HV0.2.

scholarly journals Microstructure and Properties of M3B2-Type Boride-Based Cermet Coatings Prepared by Laser Cladding Synthesis

Coatings ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 476 ◽  
Author(s):  
Zhaowei Hu ◽  
Wenge Li ◽  
Yuantao Zhao
Keyword(s):  
Corrosion Resistance ◽  
Laser Cladding ◽  
Metal Layer ◽  
Surface Hardness ◽  
Electrochemical Corrosion ◽  
Bottom Layer ◽  
Cermet Coatings ◽  
Good Surface ◽  
Order Of Magnitude ◽  
Metal Phases

Although Q235 steel materials are widely used in offshore engineering, the service life is severely shortened by its inferior resistance to wear and corrosion in harsh marine working environments. Boride-based cermet composites could be a good surface-protective coating to enhance surface hardness, wear resistance, and corrosion resistance. M3B2 (M: Mo, Ni, Fe, Cr) boride-based cermet coatings composed of hard ceramics of M3B2-type complex borides and an {Fe, Ni} metal matrix was fabricated on Q235 steels with mixed Mo, Cr, B, and Ni60 powders using a laser cladding synthesis technique. The influences of laser cladding parameters on the microstructure, phase composition, microhardness, and corrosion resistance of the coatings were comprehensively investigated. Results showed that the microstructures of the coatings mainly consisted of three layers, which were, from the top to bottom layer, a metal layer with fewer ceramic phases, a ceramic layer with fewer metal phases, and another metal layer with fewer ceramic phases. The ceramic phases were mainly M3B2-type borides, and the metal phases were mainly {Fe, Ni} alloys. The appearance of Fe-enriching metal phases was due to the supply of Fe elements from Q235 substrates. With squash pretreatment and without a remelting aftertreatment, ceramics uniformly dispersed in the cermet coatings, and their sizes decreased. The results of microhardness showed that the microhardness of the coating first increased and then decreased from the top layer to the bottom layer, and maximum microhardness was obtained in the layer of ceramics with less metal phases. An electrochemical corrosion test showed that the cermet coatings (jcorr = 6.35 μA/cm2) could improve the corrosion resistance of Q235 steels (j = 43.76 μA/cm2) by one order of magnitude.

scholarly journals Effects of Laser Scanning Speed on Microstructure, Microhardness, and Corrosion Behavior of Laser Cladding Ni45 Coatings

2020 ◽  
Vol 2020 ◽  
pp. 1-11 ◽  
Author(s):  
Yanxin Qiao ◽  
Jie Huang ◽  
Ding Huang ◽  
Jian Chen ◽  
Wen Liu ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Behavior ◽  
Laser Scanning ◽  
Scanning Speed ◽  
Primary Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Microhardness Distribution ◽  
Laser Scanning Speed ◽  
The One

The effects of laser scanning speed on the microstructure, microhardness, and corrosion behavior of Ni45 coatings were investigated by using optical microscopy (OM), scanning electron microscopy (SEM), X-ray diffraction (XRD), microhardness, and electrochemical measurements. The results showed that increasing laser scanning speed promotes the transformation from planar crystals to dendrites and refines the grains concurrently. The γ-(Ni, Fe), FeNi3, and M23(C,B)6 are identified as the primary phase composition in the Ni45 coatings regardless of the laser scanning speed. Thereinto, the formation and growth of M23(C,B)6 precipitates can be inhibited with increasing laser scanning speed due to the higher cooling rate, which affects the microhardness distribution and corrosion resistance of the coating. On the one hand, the microhardness of the whole coating presents a downtrend with increasing laser scanning speed due to the reduction of M23(C,B)6 phase. On the other hand, the corrosion resistance in 0.5 M NaCl solution is improved to some extent at higher laser scanning speed because the less precipitation of M23(C,B)6 reduces the depletion of Cr around the precipitates. In contrast, all the coatings exhibit undifferentiated but poor corrosion resistance in the highly corrosive 0.5 M NaCl + 0.5 M H2SO4 solution.

Influence of laser scanning speed on corrosion resistance and hardness properties of Fe-Mn-Si-Cr-Ni-Co alloy coating

2019 ◽  
Vol 198 (1) ◽  
pp. 109-115 ◽  
Author(s):  
Fuxing Fu ◽  
Hao Cheng ◽  
Jianshe Feng ◽  
Genrong Chang ◽  
Mingxia Liu ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Laser Scanning ◽  
Scanning Speed ◽  
Alloy Coating ◽  
Laser Scanning Speed

Effect of laser speeds on the mechanical property and corrosion resistance of CoCrW alloy fabricated by SLM

2017 ◽  
Vol 23 (1) ◽  
pp. 28-33 ◽  
Author(s):  
Yanjin Lu ◽  
Yiliang Gan ◽  
Junjie Lin ◽  
Sai Guo ◽  
Songquan Wu ◽  
...  
Keyword(s):  
Mechanical Property ◽  
Corrosion Resistance ◽  
Yield Strength ◽  
Laser Scanning ◽  
Scanning Speed ◽  
Track Width ◽  
Content Type ◽  
Electrochemical Tests ◽  
Dental Application ◽  
Laser Scanning Speed

Purpose The aim of the study is to obtain dense Ni-free CoCrW parts fabricated by selective laser melting (SLM) technique for dental application. Design/methodology/approach The optimum of processing CoCrW powders was investigated by the varying laser scanning speeds between 200 and 1,500 mm/s with the other parameters fixed as constants. The investigations of density, phase, mechanical property and corrosion resistance were conducted. Findings It was found that a maximum relative density of 99.4 per cent was obtained with the preferable laser scanning speed of 700 mm/s; the outcome from the tensile test suggested that the 0.2 per cent yield strength of the specimen fabricated at 700 mm/s satisfied the type 5 criteria in ISO22764 for dental application, whereas the electrochemical test indicated that the specimens fabricated at 700 mm/s existed excellent corrosion resistance. The high precision dental denture could be fabricated by SLM. Originality/value In the study, the Ni-free CoCrW parts fabricated by SLM was investigated by the tensile and electrochemical tests. The yield strength, corrosion resistance and margin fit accuracy met requirements for dental application. It was considered that the speed of 700 mm/s with the laser powers of 95 W, the track width of 0.11 mm and the layer thickness of 25 μm are promising candidates for fabricating the CoCrW parts.

Effect of laser scanning speed on microstructure and wear properties of T15M cladding coating fabricated by laser cladding technology

2018 ◽  
Vol 110 ◽  
pp. 163-171 ◽  
Author(s):  
Xiangyi Jiao ◽  
Jun Wang ◽  
Canming Wang ◽  
Zhengqi Gong ◽  
Xinxing Pang ◽  
...  
Keyword(s):  
Laser Cladding ◽  
Laser Scanning ◽  
Scanning Speed ◽  
Wear Properties ◽  
Laser Scanning Speed

scholarly journals The Effect of Laser Scanning Speed on Microstructure and Performance of Cr3C2-NiCr Cermet Fabricated by in-situ Laser Cladding

2021 ◽  
pp. X
Author(s):  
Deyuan LOU ◽  
Shaokun YANG ◽  
Sheng MEI ◽  
Qing LIU ◽  
Jian CHENG ◽  
...  
Keyword(s):  
Laser Cladding ◽  
Laser Scanning ◽  
Scanning Speed ◽  
Powder Mixtures ◽  
Laser Scanning Speed ◽  
Nickel Based Alloy ◽  
And Performance ◽  
Microstructure And Performance ◽  
Carbide Content

To explore the effect of laser scanning speed on the microstructure and performance of Cr3C2-NiCr cermet layers fabricated by in-situ laser cladding, Cr3C2-NiCr cermet layers were laser cladded from Ni/Cr/Graphite (25:65:10 wt.%) elemental powder mixtures. The microstructures of the laser cladded cermet layers and the formation mechanism were investigated. In addition, the effect of laser scanning speed on the microstructure, friction and corrosion performance of the Cr3C2-NiCr cermet layers was studied. The results indicated that the in-situ laser cladded Cr3C2-NiCr cermet layers were composed of NiCr binder and Cr3C2. The laser scanning speed had a significant influence on the carbide content, composition and size. Furthermore, it affected the in-situ laser cladded cermet layer’s hardness and wear resistance. The corrosion resistance of the in-situ laser cladded cermet layer was superior to that of laser cladded nickel-based alloy and was improved with decreasing laser scanning speed.

Dissolution Behavior of WC Reinforced Particles on Carbon Steel Surface during Laser Cladding Process

2012 ◽  
Vol 430-432 ◽  
pp. 137-141 ◽  
Author(s):  
Zhong Zhang ◽  
Hong Xi Liu ◽  
Xiao Wei Zhang ◽  
Sheng Wei Ji ◽  
Ye Hua Jiang
Keyword(s):  
Carbon Steel ◽  
Composite Coating ◽  
Laser Cladding ◽  
Laser Scanning ◽  
Energy Dispersive Spectrometer ◽  
Scanning Speed ◽  
Decomposition Reaction ◽  
Medium Carbon Steel ◽  
Dissolution Behavior ◽  
Laser Scanning Speed

Ni60WC35 self-fluxing composite coating was fabricated by transverse-flow CO2 laser apparatus on 45 medium-carbon steel surfaces. The microstructure and phase transform behavior of WC reinforced particles under the laser cladding conditions was investigated by X-ray diffraction (XRD), scanning electron microscope (SEM) and energy-dispersive spectrometer (EDS). The results show that laser scanning speed has a great important influence on the microstructure of Ni-based WC composite coating, WC particles has a transition to the Ni-based coating. The main feature of WC particle is its edge hard phase has transformed into needle phase, and the needle phase areas increase with the decrease of the laser scanning speed. Some WC particles turn into needle clusters structure, and then white block phase. In addition, WC particle has some microscopic defects, and the surface priority defect can be dissolved. When the pool temperature rises to 1250°C, WC decomposition reaction become W2C and C. The elements diffusion can promote the dissolution of WC particles when the pool temperature rises continuously.

Laser Cladding In Situ Tungsten Carbide Reinforced Ferrous Matrix Surface Composites

2011 ◽  
Vol 189-193 ◽  
pp. 771-776 ◽  
Author(s):  
Ying Ying Chen ◽  
Wen Ge Li
Keyword(s):  
Tungsten Carbide ◽  
Laser Cladding ◽  
Laser Power ◽  
Laser Scanning ◽  
Synthesis Method ◽  
Scanning Speed ◽  
Hardness Measurement ◽  
Element Distribution ◽  
Matrix Surface ◽  
Laser Scanning Speed

Tungsten carbide cermets coating on carbon steel were fabricated by laser clad cooperation combustion synthesis method. The microstructure, phase, element distribution and microhardness have been analyzed with the aid of SEM, XRD, EDS, EPMA and microhardness-tester. It is shown that the coating consisted of WC, CW3, W2C, WCx, and FeNi3. The results of hardness measurement showed that the hardness was superior to substrate. Analyze the effect of different laser power and different laser scanning speed on the quality of the laser cladding surface, the surface quality gets better with the increasing of the laser power, and gets better with the reducing of the scanning speed.

A STUDY ON SCAN SPEED RELATIONSHIP WITH MICROSTRUCTURAL EVOLUTION, PHASE COMPOSITION AND MICROHARDNESS OF Ni-CONTAINING INTERMETALLIC COATINGS ON Ti–6Al–4V USING LASER CLADDING TECHNIQUE

2018 ◽  
Vol 25 (08) ◽  
pp. 1950035 ◽  
Author(s):  
O. S. ADESINA ◽  
A. P. I. POPOOLA ◽  
S. L. PITYANA ◽  
D. T. OLORUNTOBA
Keyword(s):  
Laser Cladding ◽  
Laser Scanning ◽  
Gas Flow ◽  
Microstructural Analysis ◽  
Scanning Speed ◽  
Metallurgical Bonding ◽  
Clad Layer ◽  
Fine Microstructure ◽  
Scan Speed ◽  
Laser Scanning Speed

Titanium alloys have been used for variety of engineering applications but their relatively low hardness and low thermal conductivity are shortcomings that have reduced their potential use. In this work, attempts have been made to study the effects of laser scanning speed and admixed fraction of reinforced Ni–Co powders on clad layer formation and its corresponding properties on Ti–6Al–4V. Laser power of 750[Formula: see text]W, beam size of 3[Formula: see text]mm with argon shield gas flow rate of 1.2[Formula: see text]L/min was made constant, while the powders were premixed and deposited on Ti–6Al–4V with varying compositions at different scanning speeds of 0.6 and 1.2[Formula: see text]m/min. The microstructural analysis, phase constituents and hardness properties of Ni–Co intermetallics reinforced clads were also examined. The morphology of the resultant coatings was analyzed using X-ray diffractometry (XRD) and scanning electron microscopy (SEM) equipped with energy dispersive spectrometry (EDS). The research results showed that laser cladding coatings displayed enhanced properties such as fine microstructure and good metallurgical bonding with the substrate containing minimal pores with respect to the substrate. Furthermore, the microstructure revealed the formation of various fractions of interdendritic compounds/intermetallics dispersed within the coating matrix which could be responsible for the increased hardness obtained. The average hardness of the coating was about 856[Formula: see text]HV [Formula: see text], which was about 2.5 times that of the substrate.

Sign in / Sign up

Export Citation Format

Share Document