Improving Corrosion Behavior of Chemically Bonded Phosphate Ceramic Coating Reinforce with GO-TiO2 Hybrid Material

To further enhance the corrosion resistance of chemically bonded phosphate ceramic coating, TiO2 was grafted on the surface of GO to enhance the interfacial adhesion between GO and the coating. SEM results show that the presence of TiO2 on GO creates a good interfacial adhesion between GO and the coating. In addition, EIS experiments were carried out to investigate the performance of the coatings on the corrosion resistance. The result indicates that the corrosion resistance is enhanced with the introduction of GO-TiO2 hybrid material. Besides the influence of GO on the corrosion resistance, the good interfacial adhesion between GO and the coating with the presence of TiO2 hybrid material can consume more fracture energy to stop crack propagation, which leads to the high corrosion resistance.

Fabrication of Lightweight and Low Cost Shields for Gamma Ray Attenuation

Films of biopolymer (PVA) doped with titanium nanoparticles (Ti NPs) have been prepared with several ratios of PVA and Ti NPs to apply for gamma ray shielding with low unit cost, flexible, lightweight, and high corrosion resistance. The prepared nanocomposites tested for gamma ray shielding. The experimental results showed the PVA/ Ti nanocomposites films have high coefficients of attenuation for gamma ray.

Microstructure and Properties of Atmospheric Plasma Sprayed (Al,Cr)2O3–TiO2 Coatings from Blends

Coatings prepared from chromia-rich (Al,Cr)2O3 solid solution (ss) feedstock powders are intended to improve the properties of Cr2O3 coatings, but are rarely studied so far. In this work, the processability of a commercial (Al,Cr)2O3 solid solution (ss) powder containing 78 wt.% Cr2O3 by atmospheric plasma spraying (APS), the corresponding coating microstructures and properties were investigated. Possible further improvements were expected by blending with 2, 23 and 54 wt.% TiOx powder. For comparison, plain Cr2O3 and TiOx coatings were studied as well. The microstructures were analyzed using SEM, EDS and XRD measurements. Hardness (HV0.3) was measured, as well as the dry unidirectional sliding wear resistance and the abrasion wear resistance (ASTM G65). Moreover, the corrosion and electrical insulating properties were measured. The (Al,Cr)2O3 ss showed only a small change of the composition, and the formation of γ-Al2O3, as found for alumina-rich (Al,Cr)2O3 ss powders, was avoided. Compared to the plain chromia coating, some improvements of the processability and coating properties for the ss (Al,Cr)2O3 coating were found. The most balanced coating performance was achieved by blending the ss (Al,Cr)2O3 with 2 wt.% TiOx, as this coating showed both a high sliding and abrasion wear resistance, in combination with a high corrosion resistance.

Influence of Pitting Corrosion on TIG Welded Joints of AA2024 Aluminum Alloy Joints

In this investigation, AA2024 alloy was welded by tungsten inert gas welding. Access the influence of pitting corrosion on TIG weld; the joints were heat-treated after welding with different techniques. Moreover, the corrosion test was carried out with 3.5% NaCl solution under different pH values such as pH:5, pH:7, and pH: 12. From the experimental results, the joint treated with solution treatment with pH: 7 showed high corrosion resistance than its counterparts.

A Review on Laser-Assisted Joining of Aluminium Alloys to Other Metals

Modern industry requires different advanced metallic alloys with specific properties since conventional steels cannot cover all requirements. Aluminium alloys are becoming more popular, due to their low weight, high corrosion resistance, and relatively high strength. They possess respectable electrical conductivity, and their application extends to the energy sector. There is a high demand in joining aluminium alloys with other metals, such as steels, copper, and titanium. The joining of two or more metals is challenging, due to formation of the intermetallic compound (IMC) layer with excessive brittleness. High differences in the thermophysical properties cause distortions, cracking, improper dilution, and numerous weld imperfections, having an adverse effect on strength. Laser beam as a high concentration energy source is an alternative welding method for highly conductive metals, with significant improvement in productivity, compared to conventional joining processes. It may provide lower heat input and reduce the thickness of the IMC layer. The laser beam can be combined with arc-forming hybrid processes for wider control over thermal cycle. Apart from the IMC layer thickness, there are many other factors that have a strong effect on the weld integrity; their optimisation and innovation is a key to successfully delivering high-quality joints.

Bioactive Titanium-Hydroxyapatite Composites by Powder Metallurgy Route

Titanium (Ti) and its alloys have become the most promising biomaterials due to their low elastic modulus, high corrosion resistance, and relatively long-lasting ability in a physiological environment. Bioactive implants enhance the tissue interactions at the surface of the implants and promote a higher healing rate. However, titanium exhibits bio-inert nature. Hence in the present study, hydroxyapatite (HA), a well-known bioceramic, has been selected to disperse into Ti with an aim to develop bioactive Ti-based implants. Ti-HA composites with 5% and 10% HA were successfully produced by high-energy ball milling for 20 h followed by sintering (at 850 °C). Fine-grained composites were successfully produced and were found to be free from any impurities. The composites were immersed in simulated body fluid (SBF) for 4 weeks to investigate the in vitro bioactivity. From the XRD studies and scanning electron microscope observations, the presence of HA in the composite enhanced the bioactivity as reflected with higher Ca/P mineral phases on the surface of the composites compared with pure Ti substrate. From the results, it can be concluded that the bioactive nature of Ti can be enhanced by reinforcing HA to manufacture medical implants with a higher healing rate.

Manufacturing of Tool Steels by PBF-EB

Additive manufacturing (AM) of metals is stimulating the tool making industry. Moreover, besides the production of lost forms, AM processes are now being used to directly generate tools, molds or parts, leading to massive time savings. In the case of material development for AM, the challenge is to operate with carbon-containing iron-based materials distinguished by high strength and hardness, as well as high corrosion resistance and thermal conductivity. Often, those materials are susceptible to crack formation during processing. Using Electron Beam Powder Bed Fusion (PBF-EB), the challenge of crack formation can be overcome by using high process temperatures in the range 800–900 °C. In this paper, results on the processing of a cold-working tool steel (X65MoCrWV3-2) and a hot-working steel (X37CrMoV5-1) will be presented. These include the processing window, processing strategies to minimize the density of cracks and properties with respect to microstructure and hardness.