Cutting fluids are crucial to machining, providing essential lubrication and thermal management during the process. Commercial Cutting Fluids (CCF) are generally based on mineral oils, with emulsifiers and additives that are produced chemically. Green Cutting Fluid (GCF), which is generally based on biodegradable plant-based oils, is an emerging alternative to CCF and is eco-friendly, non-toxic, and sustainable. In the present work, the viability of a coconut oil-based GCF has been evaluated to determine its suitability and effectiveness across a wide range of machining operations, by mimicking the surface roughness of various machining operations. For this, Ti–6Al–4V samples were prepared with unidirectional surface roughness in the 111- to 1350-nm range; the roughness range of various machining operations. The behavior of the GCF and CCF, including their Wettability, Interfacial Tension, Surface Energy, and tribological lubrication effectiveness, were studied and compared over these surfaces. The results show that the concentration of cutting fluid and surface roughness greatly influence the wettability and surface energy, respectively. GCF has shown competitive performance in comparison with CCF, showing its potential as a viable alternative to CCF . The article also includes a discussion on the sustainability and Strengths, Weaknesses, Opportunities and Threats (SWOT) analysis of the GCF, and the work is in line with the United Nations Sustainable Development Goals (UN SDGs) 3, 11, 12, 13, and 15.

This study aims to evaluate the tribological properties of two protic ionic liquids (PILs) under different tribological conditions as a sustainable alternative for mineral oil-based neat lubricants. The synthesis of PILs in this study uses a relatively simple and less expensive method. The Fourier transform infrared (FTIR) spectroscopy results help validate the synthesised PILs’ formation. Further, their physicochemical and tribological properties were investigated. The PILs as neat lubricants were tested on a ball-on-plate reciprocating tribometer using bearing steel–bearing steel and bearing steel–aluminium alloy friction pairs at 30 °C and 80 °C. The results show that the investigated PILs significantly reduced the coefficient of friction and wear. The dodecylamine-based PILs performed better in friction and wear reduction than the other investigated lubricants. The formation of the adsorption layer on the friction pairs was assumed to be the dominant friction and wear reduction mechanism.

In recent years, a noticeable growth has been observed in the research and development of manufacturing methods for biomedical implants. Extensive research has been conducted for orthopedic and dental implants due to their huge market size worth 4.5 billion dollars. Titanium (Ti) and its alloys are the most widely acknowledged biomaterials used in the production of orthopedic and dental implants due to their intriguing physical and biological properties including higher mechanical strength, excellent corrosion resistance, and biocompatibility. Apart from pure titanium (CP-Ti) and Ti-6Al-4V alloy, β-titanium has recently emerged as one of the important biomaterials for specific orthopedic applications due to its harmless chemical composition and low modulus. Over the years, Ti-based bioimplants were manufactured by conventional machining techniques which were less economical. With the growing demand across the world for the fabrication of customized biomedical implants, researchers were focusing on the development of new approaches and techniques for these implants. Recently, additive manufacturing (AM) has emerged as a potential fabrication method for biomedical implants due to its ability to produce customized products in less time with higher precision and flexibility. In addition, AM-fabricated bioimplants have shown improved osseointegration when compared to conventionally processed implants. In this chapter, various AM methods used for the fabrication of Ti-based implants were summarized with a special focus on the process parameters, microstructure, and related mechanical properties of the end product. Further, the effect of porous structures on the performance of Ti-based bioimplants was highlighted. This study will be helpful in identifying the pros and cons of AM methods in the manufacturing of bioimplants and leads to the advancement of research direction in biomedical sectors. <!----> <!----> <!----> <!---->

Laser-directed energy deposition (LDED) is a very useful additive manufacturing technique for repairing and manufacturing complex-shaped parts compared to traditional manufacturing techniques. However, the inadequate surface quality of the LDED fabricated components limits their direct utilization in different sectors. In addition, improving the surface finish of the curvilinear surfaces (useful for cooling channels and fuel nozzles) is also challenging. Hence, the current study focuses on surface modification of LDED fabricated SS 316L hollow cylindrical samples by combining electropolishing and electroless coating. We have performed electropolishing (two different currents, 8 A and 15 A) on the as-deposited (AD) sample with and without the application of the grinding process. The electropolishing reduced the roughness of the AD sample from 3.2 µm to 0.85 µm and 0.74 µm for 8 A and 15 A, respectively. The reduction in roughness was more at a higher current value due to the rapid anodic dissolution of the surface peaks. A further reduction in roughness was observed when grinding was performed before electropolishing. However, grinding resulted in higher material removal from the deposited surfaces and reduction in roughness was also minimal. Hence, only the electropolishing sample was selected for the next step, in which Ni-P electroless coating was performed on the surface to form a protective layer. After electroless coating, the coefficient of friction and wear-rate were reduced by 9.5% and 25.6% compared to the AD sample. Delamination and severe plastic deformation were the major wear mechanisms for the AD sample, whereas abrasion was dominant for the coated sample. The current work proposes a combined surface modification approach of electropolishing and electroless coating for the LDED processed components with curvilinear surfaces.