Microwave Clad Research Articles

Characterization and erosion wear behavior of Ni-13%WC8Co microwave clad on AISI-316 steel

Characterization and erosion wear behavior of Ni-13%WC8Co microwave clad on AISI-316 steel

A comparative study on characteristics of composite (Cr3C2-NiCr) clad developed through diode laser and microwave energy

A typical ferrite/martensitic heat-resistant steel (T91) is widely used in reheaters, superheaters and power stations. Cr3C2-NiCr-based composite coatings are known for wear-resistant coatings at elevated temperature applications. The current work compares the microstructural studies of 75 wt% Cr3C2- 25 wt% NiCr-based composite clads developed through laser and microwave energy on a T91 steel substrate. The developed clads of both processes were characterized through a field emission scanning electron microscope (FE-SEM) attached with energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD) and assessment of Vickers microhardness. The Cr3C2-NiCr based clads of both processes revealed better metallurgical bonding with the chosen substrate. The microstructure of the developed laser clad shows a distinctive dense solidified structure, with a rich Ni phase occupying interdendritic spaces. In the case of microwave clad, the hard chromium carbide particles consistently dispersed within the soft nickel matrix. EDS study evidenced that the cell boundaries are lined with chromium where Fe and Ni were found inside the cells. The X-ray phase analysis of both the processes evidenced the common presence of phases like chromium carbides (Cr7C3, Cr3C2, Cr23C6), Iron Nickel (FeNi3) and chromium-nickel (Cr3Ni2, CrNi), despite these phases iron carbides (Fe7C3) are observed in the developed microwave clads. The homogeneous distributions of such carbides in the developed clad structure of both processes indicated higher hardness. The typical microhardness of the laser-clad (1142 ± 65HV) was about 22% higher than the microwave clad (940 ± 42 HV). Using a ball-on-plate test, the study analyzed microwave and laser-clad samples' wear behavior. Laser-cladding samples showed superior wear resistance due to hard carbide elements. At the same time, microwave-clad samples experienced more surface damage and material loss due to micro-cutting, loosening, and fatigue-induced fracture.

ANOVA studies and control factors effect analysis of cobalt based microwave clad

In today’s world slurry handling equipments are facing lot of engineering problems which is namely erosion. Slurry erosion plays a very important role in the design and operation of slurry transportation systems. In the work an attempt is made to reduce slurry erosion by cobalt based clad developed through microwave energy. The microwave clads are developed on AISI 420 substrate with a microwave exposure of 07 min. The developed clad shown great improvement in the erosion resistance than substrate. Slurry erosive wear studies were carried out with focus of three important parameters such as speed, impact angle and time of slurry exposure. ANOVA and control factors analysis studies were carried out with 95% of confidence level. Impact angle shown most dominating parameter on wear rate. Mixed mode of erosion was noticed on the target surface.

Influence of post clad heat treatment on microstructure and slurry erosion characteristics of Ni-based microwave clad

In this study, effect of high temperature heat treatment on microstructure and erosive wear performance of Ni-based clad was investigated. The clad was developed on a hydroturbine steel (CA6NM) substrate using microwave hybrid technique. The as-clad microstructure comprised of rod-like Cr enriched M7C3 carbides in γ-(Ni, Fe) solid solution. Post clad heat treatment at 750 °C led to M7C3→M23C6 transformation accompanied by increase in carbide volume fraction. On the other hand, heat treatment at 1000 °C clad resulted in partial dissolution of the eutectic carbides. Among the tested samples, 750 °C heat treated sample exhibited higher erosion resistance. The erosive wear behaviour of Ni-based clad, before and after heat treatment, showed good correlation with hardness (at 30°) and elastoplasticity (at 90°).

Cavitation erosion behavior of microwave-processed Ni–40Cr3C2 composite clads: A parametric investigation using ultrasonic apparatus

Cavitation erosion is the primary cause of material failure of the hydroelectric power plant components. The rapid development in the advanced surface engineering techniques has provided an effective treatment solution for cavitation erosion. One such novel method is microwave cladding. Hence, the Ni–40Cr3C2 composite clad was deposited on austenitic stainless steel (SS-316) using a microwave cladding process in the present study. The processing was carried out in a domestic microwave oven of 2.45 GHz frequency and 900 W power. The developed clad was thoroughly characterized for the metallurgical and mechanical properties related to its behavior as a successful cavitation erosion resistance material, like microstructure, crystal structure, porosity, microhardness, flexural strength, and fracture toughness. The results showed that the stripe-type and agglomerated carbides were present in the Ni–40Cr3C2 clad. The developed composite clad consists of various carbides (SiC, Ni3C, Cr3Ni2SiC, Cr7C3, and NiC) and intermetallic phases (Ni3Fe, Ni2Si, and Cr3Si). Microhardness, flexural strength, and fracture toughness of the microwave-processed clad were observed to be 605 ± 80 HV0.3, 813.23 ± 16.2 MPa, and 7.44 ± 0.2 MPa√m, respectively. The microwave-processed composite clad performance in terms of cavitation erosion resistance was determined using the ultrasonic apparatus (ASTM-G32-17). The cavitation experiments were carried out according to Taguchi L9 orthogonal array, taking into account three parameters: standoff distance, amplitude, and immersion depth. The developed composite clad exhibited significant resistance (mass loss 7.6 times lesser as compared to SS-316) to cavitation erosion. ANOVA results showed the standoff distance as the most important factor followed by amplitude and immersion depth. Least cavitation resistance was observed at a smaller standoff distance, higher amplitude, and lower immersion depth. Linear regression equations were obtained to establish the correlation between parameters and cumulative mass loss. The microwave clad specimens tested at optimized test parameters were damaged in the form of fractured intermetallic, extruded lips, pits, and craters.

Effect of rare earth on microstructure and wear behaviour of Ni based microwave clad

In the present investigation microwave energy has been utilized to develop wear resistant Ni-based clad without Nd2O3(unmodified coating) and with addition of Nd2O3 (modified coatings) in varying wt. % of 1-3. The clads have beendeveloped using domestic microwave oven at frequency of 2.45 GHz and power 900 W for duration of 360 s. Theunmodified and modified clads have been characterized in terms of microstructure, XRD, microhardness and two bodyabrasive wear. The average thickness of developed clads has been measured as 1.0 mm approximately. A two body abrasivewear behaviour of unmodified and modified coatings at sliding speed of 36 m/min & 72 m/min with abrasive grit size of 220& 600 has been investigated. The results revealed a better abrasive wear resistance at lower sliding speed and fine grit size.Further, the best results of microstructure, formation of hard phases, improved microhardness and wear resistance have beenshown by the samples having coating composition as 3 wt. % of Nd2O3.

Characterization of Cobalt Based Microwave Clad Developed on SS-355

In the present work a detailed microstructural investigation of Cobalt based microwave cladding on S-355 stainless steel was carried out. The experimentations were carried out in a home based domestic microwave oven. This article clears the circumstances of clad formation during microwave hybrid heating. The solidification texture and grain structure of the developed clad scanning electron microscope (SEM) equipped with energy dispersive X-ray spectroscopy, and measurement of Vicker’s microhardness. Cobalt based clads developed with an approximate thickness of 1 mm without interfacial cracking. The microstructure of clad clearly illustrated excellent metallurgical bond with S-355 substrate and found dominantly fine cellular grains. Iron and cobalt were recognized inside the cells while chromium was ascertained segregated around the cell boundaries. The average microhardness of the cobalt based clad was observed in the range of 402±60 HV.

Wear studies of composite microwave clad on martensitic stainless steel

In the present work, clads were developed through microwave energy which is as an emerging trend. Martensitic stainless steel (SS-420) is considered as a substrate material to improve its surface properties. In the present work, clad powder such as tungsten carbide and cobalt-based powders were used in the weight ratio of 1:0.12, respectively. The clads were developed using domestic microwave oven at 2.45 GHz frequency and 900 W power through microwave hybrid heating technique. After performing a number of trials, the clads were developed with good metallurgical bond with an exposure time of 30 min. The main objective of clad development is to obtain a good mechanical and tribological properties. Wear studies through pin-on-disc method of the developed clad was performed on the basis of Taguchi method (L9) orthogonal array. The main influencing factors considered are sliding distance, sliding speed and load. It is observed that the sliding distance is most dominating factor than load and sliding speed.

Sliding wear studies of microwave clad versus unclad surface of stainless steel 304

Small and large scale (gas power plant, hydro power plant), automobile industries are suffering by failure of component. Sometimes, it is also observed that the component which was failed due to these reasons are very much costly and replacement of those also very difficult due to the complex geometry. By using Microwave hybrid heating, WC-12Co based clads were developed on austenitic stainless steel (SS304). Microwave clads were developed by introducing the preplaced, preheated powder for a duration of 15 min to microwave radiation at 2.45GHz frequency and 900 W power in domestic microwave applicator. By using optical microscope and scanning electron microscope (SEM), the developed clads were characterized. By using pin-on-disk, wear performance of the WC-12Co based clads and unclad samples were tested. It is observed that developed clad samples performed superior wear resistance than unclad samples.

Sliding wear studies of microwave clad versus unclad surface of stainless steel 304

Sliding wear studies of microwave clad versus unclad surface of stainless steel 304

Microstructure and wear performance of heat treated WC-12Co microwave clad

In this study, WC-12Co powder was deposited onto stainless steel substrate using microwave hybrid heating technique. The deposits were then heat treated within a temperature range of 400 °C–900 °C in controlled (argon) atmosphere. In microwave cladding C and W get liberated due to decarburisation of WC and combine with Co to form amorphous phases. Changes in the constituting phases and microstructure due to post heat treatment were investigated using X-ray diffraction and scanning electron microscopy, respectively. Microstructural observations and phase analysis indicated the formation of eta-phases during heat treatment up to 400 °C, which lead to increase in the hardness and wear resistance of the clads. Microhardness examination revealed significant improvement in hardness post heat treatment at 400 °C. The abrasive wear behaviour of the WC-12Co has been correlated with microstructural and phase changes due to post clad heat treatment at various temperatures.

Structure-property correlations in nanostructured WC–12Co microwave clad

Nanostructured materials are known for enhanced properties as compared to their conventional counterparts. In the present work, microwave cladding technique was explored for depositing nanostructured WC–12Co clads on stainless steel substrates. Phase analysis of the WC–12Co microwave clads revealed the presence of Co6W6C, Co7W6, Co3W9C4, W2C and WC phases. The microstructure of the WC–12Co clads confirmed uniform distribution of nano-carbides in the form of clusters enclosed in the carbide network. Mechanical characterisation of the nanostructured clads was carried in terms of microhardness assessment and flexural strength measurement. The microwave induced clads exhibited excellent metallurgical bonding with the substrate and were free from interfacial cracks. The average microhardness of the developed clads was found in the order of 1760±128HV. The flexural strength of the developed clads was observed to be 671±28MPa. The nanostructured clads exhibited good adhesion with the substrate without getting peeled-off under a load of 3.75kN and a displacement of 3.72mm.

Prediction of Tribological Behaviour of WC-12Co Nanostructured Microwave Clad through ANN

Prediction of Tribological Behaviour of WC-12Co Nanostructured Microwave Clad through ANN

Microstructure and Abrasive Wear Performance of Ni-Wc Composite Microwave Clad

In the present work, Ni-WC powder was deposited on mild steel substrate to develop clads through microwave hybrid heating technique. The cladding trials were carried out in an industrial microwave applicator at 1.1 kW for 540 s. The Ni-WC composite clads were characterized for microstructure and abrasive wear performance through combination of x-ray diffraction, electron and optical microscopy, microhardness, and wear tests. Phase analysis of the Ni-WC clad indicated the presence of stable carbides such as WC, W2C, Ni2W4C, and Fe6W6C. The microstructure study of the clad layer revealed the presence of a uniformly distributed interlocked WC-based reinforcement embedded in the Ni-based matrix. The average Vicker’s microhardness in the clad layer was observed to be 1028 ± 90 HV, which was approximately three times the microhardness of the substrate. Abrasive wear resistance of the microwave clads was superior to the MS substrate. Abrasion was the main wear mechanism in the Ni-WC clads and the substrate samples. However, the presence of WC-based reinforcement in the composite clads reduced microcutting, resulting in enhanced wear resistance.

On Friction and Wear Behavior of WC-12Co Microwave Clad

In the present work, the friction and wear behavior of microwave-clad WC-12Co cermet was examined using a pin-on-disk tribometer as per ASTM G99. Microwave clads were tested against an EN-31 countersurface in unlubricated conditions. The WC-12Co clads were developed using an industrial microwave applicator at 2.45 GHz and 1.4 kW. The influence of varying normal load on the tribological characteristics of the microwave-induced clads have been investigated. Responses of the WC-12Co microwave clads and AISI 304 stainless steel substrate were monitored and the resulting wear was subsequently analyzed in terms of wear rate, pressure–velocity–time (p-v-t) characteristics, and friction coefficient. The worn surfaces of the WC-12Co microwave clad and AISI 304 substrate were studied using scanning electron microscope. Wear debris was analyzed using scanning electron microscopy and energy-dispersive X-ray spectroscopy. The developed clads exhibit significant resistance to wear attributable to the microwave-induced dense microstructure and material properties. The wear rate and friction coefficient were reduced by 67 and 56%, respectively for WC-12Co microwave clad compared to that of the AISI 304 substrate.

Dry erosion wear performance of Inconel 718 microwave clad

This paper reports on the dry erosive wear performance of Inconel 718 clads deposited on SS-304 substrates through microwave hybrid heating technique. Clads were deposited using a domestic microwave applicator at 2·45 GHz and 900 W. The microstructural observations of the Inconel 718 clad indicate good metallurgical bonding with the substrate and revealed no visible interfacial cracking. The microhardness of the clads was assessed using a Vicker’s microhardness tester and the average microhardness in the clads was 564±22 HV. Erosive wear performance of the clads was evaluated using an air jet erosion test setup as per ASTM G76 standard. The effect of varying impact angle was studied; the results have been discussed with the help of SEM images of the worn surfaces. It was observed that the improved erosive performance of the Inconel 718 clads was due to presence of strengthening intermetallic phases (Ni3Ti, Ni3Al) in the tough Ni–Fe–Cr matrix.

Development and characterisations of WC–12Co microwave clad

In the present work, WC–12Co based cermet clad was developed on AISI 304 stainless steel using microwave hybrid heating technique. The experimental trials were carried out in a 1.4kW industrial multimode microwave applicator. The paper explains the major events occurring during microwave irradiation and formation of clad. The developed clads were subsequently characterised through field emission scanning electron microscopy equipped with energy dispersive X-ray spectroscopy, X-ray diffraction, assessment of porosity and microhardness. The WC–12Co clads developed with an approximate thickness of 1mm, illustrated excellent metallurgical bonding with substrate. The microstructure of the WC–12Co clad mainly consists of skeleton structured carbides embedded in tough metallic phase. The phase analysis of the developed clads indicate the presence of various stable and complex carbides like Co6W6C, Co3W3C and Fe6W6C. The uniform distribution of such carbides with skeleton-like morphology in the microstructure is indicative of high hardness of the clad. The developed clads were free from visible interfacial cracking and the clad porosity was found in the order of approximately 0.98%. The average microhardness of the WC–12Co microwave clads was observed to be 1135±88HV.