Degradation characteristics of porous Fe-Mn-C alloys obtained by sintering-dissolution process (SDP) for metallic bone scaffold

Porous degradable metal is a promising material for hard-tissue scaffold application. It offers better mechanical properties than polymer and easier cell proliferation. However, the corrosion process in the porous metallic implant usually causes toxicity on patient. Therefore, corrosion process is the key for the development of the alloy. The previous study has successfully formed a porous Iron-35%Manganese-1%Carbon (Fe-35Mn-1C) alloy using Potassium carbonate (K2CO3) as foaming agent with powder metallurgy process. This study focused on the degradation behavior and phase analysis of Fe-Mn-C product by polarization test in ringer solution, Atomic Absorption Spectrometry (AAS), X-Ray Diffraction, and Energy Dispersive Spectroscopy. This process resulted in nonmagnetic Austenitic phase that is beneficial for MRI application. The result showed that Fe-Mn-C alloy with foaming structure is suitable for degradable biomaterials. The density of the product is 3.2 gr/cm3, which is only half of the bulk material. The degradation rate of the metals also increases to 6 mm/year, but the maximum ion released is still under the limit in terms of toxicity against human

THE EFFECT OF PYROLYSIS DURATION ON THERMAL CONDUCTIVITY, STABILITY, AND VISCOSITY OF DISPERSED PCB-BASED PARTICLES IN THERMAL FLUID

Solid particles have a higher thermal conductivity compared to a fluid. Therefore, it is a common practice to disperse solid particles inside a base fluid to increase its thermal conductivity. The particle-dispersed fluid is called a thermal fluid. Thermal fluid, such as a coolant, is widely used as a heat transfer fluid. Several types of particles can be used to increase the thermal conductivity of the fluid, i.e., metallic particles, metal-oxide particles, or even carbon-based particles. In this research, a carbon-based particle was used as the dispersed particle. The particle was obtained by processing electronic waste, specifically Printed Circuit Board (PCB). The PCB was pyrolyzed for variable duration at 15, 30, and 45 minutes to increase the carbon content. After pyrolyzing, the particle was milled to reduce its size. Subsequently, the PCB particle was added to distilled water. Sodium Dodecylbenzene Sulfonate (SDBS) was added as a surfactant to increase fluid stability and prevent particle agglomeration. Thermal conductivity was improved by up to a 13% increase at the 15-minute pyrolysis. Adding SDBS surfactant also improves the thermal fluid's stability to -29,1 mV. The fluid's viscosity was slightly increased up to a maximum of 0.984 mPa.S

Effect of Firing Temperature and Holding Time on Characterization of Al/SiC Metal Matrix Composites Produced by Pressureless Infiltration.

&nbsp;The production of Al-SiC metal matrix composite can be carried out by pressureless metal infiltration processs (PRIMEX). The experiment was conducted using aluminium AC2B ingot as a matrix and 50%Vf SiC powder as a reinforcement which is mixed with&nbsp; 10% Mg powder for wetting agent. The variables of this experiment are holding time and firing temperature to investigate the effect of these conditions on mechanical properties of Al-SiC metal matrix composites. Holding time was conducted for 2,5,8,10,12 hours and firing temperatures was 750, 800, 900, 1000, 1100°C respectively.. The composites produced are analysed both mechanical properties and metalography such as densities, porosities, hardness, as well as wear rate. The results showed that the longer holding time and increasing firing temperature will increase mechanical properties of Al-SiC metal matrix composites, and it is found that the optimum mechanical properties at 1000°C for 10 hour.<br

Comparison of wet and dry milling on carbon biomass as dispersed particle in quench medium for steel heat treatment application

Particle dispersion in the quench medium can alter its properties, particularly its thermal conductivity. Modulating the quench medium’s thermal conductivity can impact the steel’s hardness after heat treatment. In this study, micron-sized particles of carbon biomass derived from coconuts were obtained by milling the biomass via wet and dry methods. The milling duration for both methods was 10, 15, and 20 h, while the speeds were 250, 500, and 750 rpm for each duration. Particle size analysis revealed that dry milling could decrease the particle size by up to 60% from its initial size, whereas wet milling could only decrease it by up to 43%. A thermal conductivity test was conducted on the water-based quench medium supplemented with milled particles, demonstrating an increase in thermal conductivity up to 0.68 W mK ^−1 and 0.83 W mK ^−1 for dry and wet milling, respectively. All steel quenched with particle-added quench medium showed a hardness up to 21% higher than steel quenched with distilled water. The increase in hardness suggests that the cooling rate during quenching was faster because of the additional dispersed particle, determined by the quench medium’s thermal conductivity