Metals and Alloys, Surfaces, Coatings and Films, Industrial and Manufacturing Engineering, Modeling and Simulation
15
Scopus Publications
Scopus Publications
Statistical-experimental modeling of the effect of process parameters on geometric characteristics of laser cladding of stellite 6 on SS316 using second-order regression Sayed Hamid Hashemi, Reza Vafaei, Reza Shoja Razavi Journal of Materials Research and Technology, 2024 Applications of 316 stainless steel can be developed by laser cladding of the Co-based superalloys, which has multiple enhancement properties and creates a small heat affected zone. Quantitive investigation of the effect of process parameters on geometrical features and providing reliable models to achieve the desirable metallurgical bond, minimal structural defects, and predicting the dimensions of the geometry without conducting excessive experimental tests are an important issue. This study evaluate the effects of the main process parameters of laser cladding on geometric characteristics of stellite 6 using the response surface methodology. A quadratic model was developed for each of the geometric characteristics. Laser power, scanning speed, and powder feed rate ranged between 400 and 600 W, 6–10 mm/s and 12–20 gr/min, respectively, were considered as the input variables and height, width, penetration depth and dilution were considered as responses. The experiments were designed using the box-behnken method. The accuracy and fitness of the models were evaluated using analysis of variance method. The results indicated the R2 factors obtained for height, width, penetration depth and dilution are equal to 0.89, 0.98, 0.98 and 0.96 respectively. After obtaining the desirability factor of 0.795, the optimal set of process parameters were selected equals to the laser power of 510 W, scanning speed of 10 mm/s and powder feed rate of 13 gr/min. Verification of the optimization was done by performing experimental test and it was found that the error rate of the data obtained with the results predicted by the model is less than 13 %.
Evaluating the Effect of Laser Surface Modification on the Corrosion Behavior of Ni-P-SiC Electroless Coating Deposited on Al356 Alloy Sayed Hamid Hashemi, Reza Shoja-Razavi, Ali Ashrafi, Mohammad Erfanmanesh, Sajjad Khalili Transactions of the Indian Ceramic Society, 2023 AbstractRegarding their higher wear/corrosion resistance than conventional coatings, nickelphosphorus based composite coatings can reduce components' costs and degradation. This study employed laser surface modification of Ni-P-SiC electroless coatings deposited on Al356 substrate, followed by investigating their microstructural changes and corrosion behavior. The results showed that increasing the laser power increases surface defects and causes substrate diffusion to the coating, which significantly reduces the corrosion resistance of the coating. In contrast, low-power laser operations can improve the corrosion resistance of Ni-P-SiC composite coatings by creating stable nickel phosphide phases, more uniform element distribution, and enhanced SiC particle-substrate coherence. All these factors increase the wear and corrosion resistance simultaneously.Keywords: Electroless Ni compositeLaser surface modificationCorrosion
High-temperature wear behavior of HVOF sprayed, laser glazed, and laser cladded Stellite 6 coatings on stainless steel substrate Mohammad Erfanmanesh, Reza Shoja-Razavi, Masoud Barekat, Sayed Hamid Hashemi, Mohammad-Reza Borhani, Hamed Naderi-Samani, Morteza Ilanlou, Amin Nourollahi Journal of Adhesion Science and Technology, 2023 In this study, the Stellite 6 coating was applied on 316 stainless steel substrates through the high-velocity oxygen fuel method (ST-HVOF). Then, the laser-glazed sample (ST-Glazing) was deposited on the as-sprayed Stellite 6 coating using optimal conditions. Afterward, the Stellite 6 powder was optimized on the stainless-steel substrate by laser cladding process (ST-Clad) using 300 W and 5 mm/s of laser power and beam scanning speed, respectively. The microstructural characterization and phase analysis of ST-HVOF, ST-Clad, and ST-Glazing coatings were performed by field-emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDS), and X-ray diffraction (XRD) techniques. The microscopic observation results revealed that laser glazing significantly decreased the porosity of ST-HVOF (from about 2.3% to about 0.3%) and formed a dense coating with a uniform microstructure and strong adhesion to the substrate. Also, ST-Clad coating showed a porosity of 0.2% and a compact and uniform microstructure with a high-strength bonding to the substrate. Tribological evaluation of the coatings indicated a 67% and 58% increase in wear resistance of ST-Clad and ST-Glazing coatings compared to ST-HVOF coating, respectively. The high-temperature wear results suggested the following mechanisms for the studied coatings: plastic deformation mechanisms, wear adhesion, brittle fracture, and delamination.
Characterisations of low phosphorus electroless Ni and composite electroless Ni-P-SiC coatings on A356 aluminium alloy S. H. Hashemi, A. Ashrafi Transactions of the Institute of Metal Finishing, 2018 A low phosphorus electroless nickel coating of Ni-2.5 wt-%P alloy and a composite coating of Ni-5 wt-%P-SiC were prepared on A356 aluminium alloy substrates using two types of electroless bath solutions, an alkaline bath for low phosphorus and acidic for composite plating. The coatings morphologies have been characterised using optical and scanning electron microscopy. In addition, X-ray diffraction, microhardness, reciprocating wear testing and adhesion tests have been conducted to characterise structure and mechanical properties of the resulting coatings. The results obtained revealed that a crack-free and homogeneous coating could be produced using an optimum bath formulation. The maximum thickness of the composite coatings was 50 µm, the thickness of coatings tested. The composite coating was more resistant to wear in comparison to the low phosphorus nickel one, but had lower adhesion.
Wear properties of as plated Ni-2.5%P and Ni-5%P-SiC on Al356 Annual International Technical Conference of the National Association for Surface Finishing Sur Fin 2007, 2007
