Nanocellulose is the most abundant material extracted from plants, animals, and bacteria. Nanocellulose is a cellulosic material with nano-scale dimensions and exists in the form of cellulose nanocrystals (CNC), bacterial nanocellulose (BNC), and nano-fibrillated cellulose (NFC). Owing to its high surface area, non-toxic nature, good mechanical properties, low thermal expansion, and high biodegradability, it is obtaining high attraction in the fields of electronics, paper making, packaging, and filtration, as well as the biomedical industry. To obtain the full potential of nanocellulose, it is chemically modified to alter the surface, resulting in improved properties. This review covers the nanocellulose background, their extraction methods, and possible chemical treatments that can enhance the properties of nanocellulose and its composites, as well as their applications in various fields.

Shape memory alloys (SMAs) are a type of smart material and have excellent engineering and medical applications. TiNi binary alloys possess remarkable shape recovery, mechanical properties, corrosion resistance, and excellent biocompatibility. By ternary elements addition just like Au, Pt, Pd, Hf, and Zr, increases transformation temperatures, leading to high-temperature shape memory alloys (more than 100°C) but other elements (Fe, Cu, Co, and Mo) form low-temperature shape memory alloys, (lower than 100°C). In the present work, it is reported that the effect of ternary element addition on microstructural properties, shape memory properties, mechanical properties, corrosion resistance, and biocompatibility of ternary shape memory alloys. Ag, Au, and Cu-based TiNi ternary alloys have excellent biocompatibility. The addition of ternary elements such as Ag and Nb increases corrosion resistance, Fe rises the hysteresis loop, Hf enhances thermal stability, and Mo raises workability.

Equiatomic TiNi alloy composites, reinforced with 0, 5, 10, and 15 vol% ZrO₂, were synthesized using conventional sintering approach. Equiatomic TiNi pre-alloyed powder and ZrO₂ powder were mixed in planetary ball mill for 6 h followed by cold compaction and pressure-less sintering, respectively. The sintered density was found to vary inversely with the addition of ZrO₂ content. The X-ray diffraction (XRD) spectra have shown the formation of multiple-phases which were resulted from the decomposition of the B19′ and B2 phases of the equiatomic TiNi alloy due to the addition of ZrO₂ and higher diffusion rate of Ni than that of Ti in the alloy composite. An increase in hardness was noted due to the addition of ZrO₂, measured by micro and nanoindentation techniques. Potentiodynamic polarization scan revealed a 10% decrease in the corrosion rate of the composite containing 10 vol% ZrO₂. Electrochemical impedance spectroscopy (EIS) results indicated an increase in passive layer resistance (R_coat) due to the increase in charge transfer resistance (R_ct) caused by the reduced leaching of ions from the surface.

Titanium-Nickel pre-alloyed powder was reinforced with Nano-Silica in 2%, 4% , 6% and 8 wt. % due to effectiveness of Nanoscale ceramic Reinforcement in improving the properties of Metals and Alloys. The compositions of the Pre-Alloyed powders and Nano Silica Approximately 50 nm in diameter and spherical in shape were weighed and mixed in Planetary Ball Mill followed by compaction at 50 MPa using a Uniaxial Compaction machine The green pellets obtained were sintered in Argon Environment for 5 hrs and allowed to furnace cool. The pellets were then sectioned through their cross-section for slices 3 mm thick followed by Cold-mounting and Soldering followed by cold mounting additionally. The Samples were analyzed via X-Ray Diffraction (XRD) for phase distribution as a function of variation in nano-Silica reinforcements and Microstructural analysis was performed via Optical Microscope. The effect of Volume percentage on the densification was determined via Archimedes principle and Micro-Vickers hardness was used for mechanical Evaluation. The Electrochemical Properties were evaluated using Potentio-Dynamic Polarization and Electrochemical Impedance Spectroscopy (EIS) in neutral salt solution (3.5% NaCl). The results indicated increasing dissolution of the TiNi phase into intermetallic Titanium-rich and Ni-rich phases in the matrix and hardening due to the Nano-Silica effect of Grain Boundary impingement and phase dissolution of Equiatomic phase and mixed behavior in Corrosion properties as determined by the electrochemical techniques whereas densification decreased due to poor plasticity of Nano-Silica and hinderance in diffusion during the sintering process.

This study assesses recent advances in the preparation and microstructure, oxidation, and hot corrosion properties of diffusion coatings on super alloys for turbine applications. Surface alloying of super alloys by diffusion coating is regarded as an effective method of protecting super alloys against oxidation and hot corrosion degradation. A co-deposition of Pt, Ge, Ta, Ni, Ti, and Ru with a diffusion coating is stated to give outstanding protection against hot corrosion and cyclic oxidation. The review articles start by diffusion coatings, diffusion coating synthesis techniques, various types of diffusion coatings, recent advancements in diffusion coatings, and diffusion coating degradation mechanisms. Diffusion coatings are classified as aluminide, chromide, silicide, boronizing, and nitriding. Pack cementation, chemical vapor deposition (CVD), molten salt bath, and slurry coating process are the several types of diffusion coating synthesis processes. Degradation mechanisms of coatings involve cyclic oxidation, hot corrosion, mixed oxidant corrosion, interdiffusion, and erosion.