Search results

1 – 10 of 58
Article
Publication date: 16 June 2021

Jashanpreet Singh and Jatinder Pal Singh

This study aims to deal with development and performance analysis of high-velocity oxy-fuel (HVOF) thermally sprayed Mo2C-based WC-CoCr (tungsten carbine cobalt chrome) (Co-10…

Abstract

Purpose

This study aims to deal with development and performance analysis of high-velocity oxy-fuel (HVOF) thermally sprayed Mo2C-based WC-CoCr (tungsten carbine cobalt chrome) (Co-10% and Cr-4%) cermet coating deposited on the pump impeller steel 316 L.

Design/methodology/approach

In this work, a study was carried out by modifying the conventional WC-CoCr powder with a small addition of molybdenum carbide (Mo2C). Reinforcement was done by 1–4 wt.% addition of Mo2C feedstocks in WC-CoCr powder by using a jar ball mill process. The design of experiment was implemented for optimization of the percentage of Mo2C feedstock. L16 (4 × 4) orthogonal array was used to design the experiments for erosion output for the input parameters namely velocity, particle size, concentration and Mo2C proportion.

Findings

Results show that the Mo2C-based WC-CoCr coating provides better microhardness as compared to conventional WC-CoCr coating. The present study also reveals that the deposition of conventional WC-CoCr coating has improved the wear resistance of SS 316 L by 9.98%. However, the slurry erosion performance of conventional WC-CoCr coating was improved as 69.6% by the addition of 3% Mo2C.

Practical implications

WC-CoCr coatings are universally used for protecting the equipment and machinery from abrasion, erosion and corrosion. So, the 3% Mo2C-based WC-CoCr can be useful in power plants and various industries like mining, chemical, automobile, cementing and food processing industries.

Originality/value

A new HVOF coating has been developed by the addition of Mo2C feedstock in WC-CoCr powder (Co 10% and Cr 4%) and the percentage of Mo2C feedstock was optimized to improve the tribological behavior of WC-CoCr coating.

Details

Industrial Lubrication and Tribology, vol. 74 no. 4
Type: Research Article
ISSN: 0036-8792

Keywords

Article
Publication date: 25 June 2019

Karanjit Singh, Khushdeep Goyal and Rakesh Goyal

This paper aims to investigate hot corrosion behaviour of different Cr3C2–NiCr coatings on boiler tube steel.

Abstract

Purpose

This paper aims to investigate hot corrosion behaviour of different Cr3C2–NiCr coatings on boiler tube steel.

Design/methodology/approach

High velocity oxy fuel technique has been used to deposit different coatings on commercially available ASTM-SA213-T22 boiler tube steel. The hot corrosion studies have been performed in molten salt environment at 900°C temperature in silicon tube furnace in laboratory.

Findings

The results showed that uncoated superalloy suffered intense spalling and the weight change was massive during each cycle on studies of hot corrosion 900°C. The 100 per cent NiCr and 10 per cent (Cr3C2) – 90 per cent (NiCr) coatings provided better protection to T22 steel against the hot corrosion because of the formation of Ni and Cr3C2 layers.

Originality/value

In this research a variety of coatings have been used. This research work has been aimed to investigate the hot corrosion behavior of Boiler Steel b with different Cr3C2–NiCr coatings, under molten salt environment in Silicon tube furnace at 900°C, under cyclic conditions.

Details

World Journal of Engineering, vol. 16 no. 4
Type: Research Article
ISSN: 1708-5284

Keywords

Article
Publication date: 21 March 2008

Manpreet Kaur, Harpreet Singh and Satya Prakash

This paper seeks to summarise the results of available research on the use of high velocity oxy‐fuel (HVOF) thermal‐spray technique to provide protection against high temperature…

1451

Abstract

Purpose

This paper seeks to summarise the results of available research on the use of high velocity oxy‐fuel (HVOF) thermal‐spray technique to provide protection against high temperature corrosion and erosion‐corrosion of materials.

Design/methodology/approach

This paper describes one of the recent thermal‐spray processes, namely HVOF thermal‐spray technology and presents a survey of the studies on the use of this technique to provide protection against corrosion and erosion‐corrosion of high temperature alloys, with a special emphasis on boiler steels.

Findings

High temperature corrosion and erosion‐corrosion are serious problems observed in steam‐powered electricity generation plants, gas turbines, internal combustion engines, fluidized bed combustors, industrial waste incinerators and recovery boilers in paper and pulp industries. These problems can be prevented by changing the material or altering the environment, or by separating the component surface from the environment. Corrosion prevention by the use of coatings for separating materials from the environment is gaining importance in surface engineering. Amongst various surface modifying techniques, thermal spraying has developed relatively rapidly due to the use of advanced coating formulations and improvements in coating application technology. One of the variants of thermal spraying, namely HVOF has gained popularity in recent times due to its flexibility for in‐situ applications and superior coating properties.

Research limitations/implications

This review covers mainly information that has been reported previously in the open literature, international journals and some well‐known textbooks.

Practical implications

The paper presents a concise summary of information for scientists and academics, planning to start their research work in the area of surface engineering.

Originality/value

This paper fulfils an identified information/resources need and offers practical help to an individual starting out on a career in the area of surface engineering for erosion‐corrosion and wear.

Details

Anti-Corrosion Methods and Materials, vol. 55 no. 2
Type: Research Article
ISSN: 0003-5599

Keywords

Article
Publication date: 28 October 2014

Abdul Quddus, Anwar Ul-Hamid and Huseyin Saricimen

– The purpose of this investigation was to evaluate the performance of high velocity oxy fuel (HVOF) coated SS-310 samples in a carburizing environment.

Abstract

Purpose

The purpose of this investigation was to evaluate the performance of high velocity oxy fuel (HVOF) coated SS-310 samples in a carburizing environment.

Design/methodology/approach

The carburization behavior of metallic coatings with three different compositions was studied under isothermal carburizing exposure conditions at 900°C for 125 hours. The coatings were deposited on SS 310 substrates using the HVOF technique. The ASTM Standard method was used to evaluate coating adhesion. Scanning electron microscopy coupled with energy dispersive X-ray spectroscopy, X-ray diffraction and weight gain were used to evaluate the surface morphology, microchemical composition, phase constitution and degree of environmental protection imparted by the coatings.

Findings

The experimental results indicate that Ni-rich coating offered better protection to SS 310 alloy compared to Co-rich coatings in carburizing environments. This was thought to be due to the formation of a continuous protective layer of Cr2O3 on the Ni-rich coating surface.

Originality/value

The study has direct practical relevance to the petrochemical industry, particularly for refinery applications. In refinery service, SS310 is used in header damper plates. The useful service life of such header plates can be extended by the use of high temperature corrosion resistant metallic coatings. The present investigation highlighted the protection offered by Ni-based HVOF coated SS-310 samples in carburizing environment.

Details

Anti-Corrosion Methods and Materials, vol. 61 no. 6
Type: Research Article
ISSN: 0003-5599

Keywords

Article
Publication date: 3 July 2007

D. Rezakhani

Four thermal spray coatings were subjected to high temperature corrosive environments of oil‐fired boiler conditions to compare their corrosion protection under simulated…

1157

Abstract

Purpose

Four thermal spray coatings were subjected to high temperature corrosive environments of oil‐fired boiler conditions to compare their corrosion protection under simulated conditions. The coatings included FeCrAl, Tafaloy 45CT, which were arc‐sprayed, 50Ni‐50Cr and Cr3C2‐NiCr, which were coated by high velocity oxy fuel spray (HVOF) method.

Design/methodology/approach

The coating substrates used were SA213TP 347H, SA213 T11 and SA213 T22 alloys that are widely used as boiler tube materials. Specimens were covered with a synthetic ash mixture of 70 per cent V2O5‐20 per cent Na2SO4‐10 per cent NaCl and exposed to 550°C and 650oC°for 192 h (6 cycles). After high temperature corrosion tests, weight change curves were obtained; specimens were examined by metallographical techniques, scanning electron microscopy and EDX analyses.

Findings

Salt deposits attacked steels and coatings during the exposure. The corrosion rates were strongly affected by the composition of the scale formed adjacent to the steels and coatings surfaces. Austenitic steel was only bare material that experienced uniform corrosion in the tests. Ferritic steels were primarily attacked by grain boundary corrosion. Thermally sprayed coatings were mainly attached through oxides and voids at splat boundaries. FeCrAl and 50Ni‐50Cr were prone to spalling. Tafaloy 45CT is also a promising method for producing homogenous coatings. Cr3C2‐NiCr 80/20 coating remained mostly intact.

Originality/value

This paper provides useful information about corrosion behaviours of four coatings used for common boiler tubes. It shows with a practical explanation how the bare material and coatings react in corrosion simulated environments.

Details

Anti-Corrosion Methods and Materials, vol. 54 no. 4
Type: Research Article
ISSN: 0003-5599

Keywords

Article
Publication date: 4 September 2017

Varinder Pal Singh Sidhu, Khushdeep Goyal and Rakesh Goyal

This paper aims to use the high-velocity oxy fuel (HVOF) spraying process for depositing 93(WC–Cr3C2)–7Ni, 75Cr3C2–25NiCr, 83WC–17CO and 86WC–10CO–4Cr coatings on ASME SA213 T91…

Abstract

Purpose

This paper aims to use the high-velocity oxy fuel (HVOF) spraying process for depositing 93(WC–Cr3C2)–7Ni, 75Cr3C2–25NiCr, 83WC–17CO and 86WC–10CO–4Cr coatings on ASME SA213 T91 to study the corrosion resistance of these coatings in an actual boiler environment.

Design/methodology/approach

The HVOF spraying process was used for depositing 93(WC–Cr3C2)–7Ni, 75Cr3C2–25NiCr, 83WC–17CO and 86WC–10CO–4Cr coatings on ASME SA213 T91. All the coatings obtained are found to be uniform, dense and having thickness between 200 and 250 μm. All the coatings were exposed in an actual boiler environment at 900°C temperature for 10 cycles. Each cycle consisted of 100 h heating followed by 1 h cooling at ambient conditions. X-ray diffraction, scanning electron microscopy and energy-dispersive spectroscopy techniques were used to analyse corrosion products.

Findings

All the coated samples were found to be having higher corrosion resistance than the uncoated samples. Among coated specimens, 93(WC–Cr3C2)–7Ni coating has shown maximum and 75Cr3C2–25NiCr coating has shown minimum resistance to corrosion.

Originality/value

This paper is original research.

Details

Anti-Corrosion Methods and Materials, vol. 64 no. 5
Type: Research Article
ISSN: 0003-5599

Keywords

Article
Publication date: 11 April 2023

Ronnarit Khuengpukheiw, Anurat Wisitsoraat and Charnnarong Saikaew

This paper aims to compare the wear behavior, surface roughness, friction coefficient and volume loss of high-velocity oxy-fuel (HVOF) sprayed WC–Co and WC–Cr3C2–Ni coatings on…

Abstract

Purpose

This paper aims to compare the wear behavior, surface roughness, friction coefficient and volume loss of high-velocity oxy-fuel (HVOF) sprayed WC–Co and WC–Cr3C2–Ni coatings on AISI 1095 steel with spraying times of 10 and 15 s.

Design/methodology/approach

In this study, the pin-on-disc testing technique was used to evaluate the wear characteristics at a speed of 0.24 m/s, load of 40 N and test time of 60 min under dry conditions at room temperature. The wear characteristics were examined and analyzed by scanning electron microscopy and energy dispersive X-ray spectroscopy. The surface roughness of a coated surface was measured, and microhardness measurements were performed on the cross-sectioned and polished surfaces of the coating.

Findings

Spraying time and powder material affected the hardness of HVOF coatings due to differences in the porosity of the coated layers. The average hardness of the WC–Cr3C2–Ni coating with a spaying time of 15 s was approximately 14% higher than that of the WC–Cr3C2–Ni coating with a spraying time of 10 s. Under an applied load of 40 N, the WC–Co coating with a spraying time of 15 s had the lowest variation in the friction coefficient compared with the other coatings. The WC–Co coating with a spraying time of 10 s had the lowest average and variation in volume loss compared to the other coatings. The WC–Cr3C2–Ni coating with a spraying time of 10 s exhibited the highest average volume loss. The wear features changed slightly with the spraying time owing to variations in the hardness and friction coefficient.

Originality/value

This study investigated tribological performance of WC–Co; WC-Cr3C2-Ni coatings with spraying times of 10 and 15 s using pin-on-disc tribometer by rotating the relatively soft pin (C45 steel) against hard coated substrate (disc).

Details

World Journal of Engineering, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 1708-5284

Keywords

Article
Publication date: 16 May 2023

Khushdeep Goyal, Davinder Singh, Harvinder Singh and Charanjit Singh

This paper aims to investigate the high temperature corrosion behaviour of ZrO2-reinforced Cr2O3 matrix-based composite coatings on ASTM-SA213-T-22 steel at 900°C in molten salt…

Abstract

Purpose

This paper aims to investigate the high temperature corrosion behaviour of ZrO2-reinforced Cr2O3 matrix-based composite coatings on ASTM-SA213-T-22 steel at 900°C in molten salt environment. The different coatings were deposited by high velocity oxy fuel (HVOF) method.

Design/methodology/approach

Hot corrosion studies were conducted in simulated boiler environment in silicon carbide tube furnace at 900°C for 50 cycles on bare and HVOF-coated boiler steel specimens. Each cycle consisted 50 h of heating in the simulated boiler environment followed by 20 min of cooling in air. The weight change measurements were performed after each cycle to establish the kinetics of corrosion using thermogravimetric technique. X-ray diffraction and scanning electron microscopy techniques were used to analyse the corroded specimens.

Findings

The addition of 20 Wt.% ZrO2 in Cr2O3 helped reduce corrosion rate by 89.25% as compared to that of uncoated specimen. The phase analysis revealed the presence of Cr2O3 and ZrO2 phases in composite coating matrix, which may have prevented the base metal from interacting with the corrosive elements present in the highly aggressive environment and thus had increased the resistance to hot corrosion.

Originality/value

It should be mentioned here that high temperature corrosion behaviour of thermally sprayed ZrO2–Cr2O3 composite coatings has never been studied, and to the best of the authors’ knowledge, it is not available in the literature. Hence, present investigation can provide valuable information for application of ZrO2-reinforced coatings in high temperature fuel combustion environments.

Details

Anti-Corrosion Methods and Materials, vol. 70 no. 4
Type: Research Article
ISSN: 0003-5599

Keywords

Article
Publication date: 3 April 2019

Jashanpreet Singh, Satish Kumar and S.K. Mohapatra

This study/paper aims to investigate the erosion wear performance of Ni-based coatings [Ni-Cr-O and NiCrBSiFe-WC(Co)] under sand-water slurry conditions.

Abstract

Purpose

This study/paper aims to investigate the erosion wear performance of Ni-based coatings [Ni-Cr-O and NiCrBSiFe-WC(Co)] under sand-water slurry conditions.

Design/methodology/approach

A high-velocity oxy-fuel (HVOF) process was used to deposit the Ni-based coatings [Ni-Cr-O and NiCrBSiFe-WC(Co)] on the surface of stainless steel (SS 316L) substrate. A Ducom TR-41 erosion tester was used to conduct the tribological experiments on bare/HVOF coated SS 316L. The erosion wear experiments were carried out for different time durations (1.30-3.00 h) at different impact angles (0-60°) by running the pot tester at different rotational speeds (600-1,500 rev/min). The solid concentration of sand slurry was taken in the range of 30-60 Wt.%. The surface roughness of Ni-based coated surfaces was also measured along the transverse length of the specimens.

Findings

Results show the arithmetic mean roughness (Ra) values of Ni-Cr-O and NiCrBSiFe-WC coated SS-316L were 7.04 and 6.67 µm, respectively. The erosion wear SS-316L was almost 3.5 ± 1.5 times greater than that of the NiCrBSiFe-WC coatings. NiBCrSi-WC(Co) sprayed SS-316L showed lower erosion wear than Ni-Cr-O sprayed SS-316L. Microscopically, the eroded Ni-Cr-O coating underwent plowing, microcutting and craters. Ni-Cr-O coating have shown the ductile nature of erosion wear mechanism. NiBCrSi-WC(Co) surface underwent craters, plowing, carbide/boride pullout, fractures and intact. Erosion wear mechanisms on the eroded surface of NiBCrSi-WC(Co) were neither purely ductile nor brittle.

Practical implications

It is a useful technique to estimate the erosion wear of hydraulic machinery coated with Ni-based coatings imposed under mining conditions.

Originality/value

The erosion wear performance of HVOF-sprayed Ni-Cr-O and NiCrBSiFe-WC(Co) powders was investigated through extensive experimentation, and the results are well supported by scanning electron micrographs and 3D topology.

Details

Industrial Lubrication and Tribology, vol. 71 no. 4
Type: Research Article
ISSN: 0036-8792

Keywords

Article
Publication date: 10 June 2021

Jashanpreet Singh

The purpose of this paper is to carry out erosion wear investigation on high-velocity oxy-fuel (HVOF)-deposited 86WC-10Co4Cr and synergistic Ni/Chromia powder (i.e. 80Ni-20Cr2O3

Abstract

Purpose

The purpose of this paper is to carry out erosion wear investigation on high-velocity oxy-fuel (HVOF)-deposited 86WC-10Co4Cr and synergistic Ni/Chromia powder (i.e. 80Ni-20Cr2O3) on AISI 316L.

Design/methodology/approach

Design of experiments-artificial neural network (DOE-ANN) methodology was adopted to calculate the erosion wear. Taguchi’s orthogonal array L16 (42) was used to perform set-of-erosion experiments followed by lower-the-better rule. The artificial neural network (ANN) model is used on erosion wear data obtained from the experiments.

Findings

Experimental results indicate that 86WC-10Co4Cr provided better erosion wear resistance as compared to Ni/Chromia. The erosion wear of 86WC-10Co4Cr and synergistic Ni/Chromia coatings increases with an increase in time duration, solid concentration and time. The magnitude of erosion generated by ashes was comparatively lower than sand. The arithmetic mean roughness (Ra) of finished AISI 316L, 86WC-10Co4Cr and Ni/Chromia coating was found as 0.46 ± 0.13, 6.50 ± 0.16 and 7.04 ± 0.23 µm, respectively. Surface microhardness of AISI 316L, 86WC-10Co4Cr and Ni/Chromia coating was found as 197 ± 18, 1,156 ± 18 and 1,021± 21 HV, respectively.

Practical implications

The present results can be useful for estimation of erosion wear in slurry pumps used in mining industry for the conveying of sand and in thermal power plants for the conveying of ashes to the dyke area.

Originality/value

The erosion wear of HVOF-sprayed 86WC-10Co4Cr and Synergistic Ni/Chromia powders was studied experimentally as well as predicted by the ANN model, and wear mechanisms are well discussed by scanning electron micrographs.

Details

Industrial Lubrication and Tribology, vol. 73 no. 5
Type: Research Article
ISSN: 0036-8792

Keywords

1 – 10 of 58