Lapisan Plasma Spray Ni-Al dan Al-Si Pada Tabung Baja Tahan Karat Austenitik Dengan Jarak Semprot Terbatas (Atmospheric Plasma Spray Coating of Ni-Al and Al-Si on Austenitic Stainless-Steel Tube with Limited Short Spray Distance)

Atmospheric Plasma Spray (APS) coating is a widely used thermal spray coating process in industrial applications. High density and high bond strength coating are the main features of this process that is required in almost coating properties for specific applications. The geometrical condition of the workpiece substrate dictates the parameter needed to achieve a certain quality of the coating. Changes in the geometry require modification on the parameter of the process to maintain the quality of the coating. Aluminum Silicon and Nickel Aluminum coating were applied on Stainless Steel substrate casing. Due to the limitation of spray distance between nozzle gun and substrate surface of the casing, modified several parameters of the process were taken. Several parameters were investigated to find out the optimum result of coating and verified with tensile bond strength test, hardness test, and microscopic analysis examination. These activities that involved modification of parameters, mechanical testing, and visual inspection informed that power as a function of voltage and ampere, powder feed rate, the surface speed of substrate (the particular amount of workpiece rotation per minute), and traverse speed of gun, contribute to the result of the optimum coating.

Estimations on Properties of Redox Reactions to Electrical Energy and Storage Device of Thermoelectric Pipe (TEP) Using Polymeric Nanofluids

A thermoelectric pipe (TEP) is constructed by tubular graphite electrodes, Teflon material, and stainless-steel tube containing polymeric nanofluids as electrolytes in this study. Heat dissipation and power generation (generating capacity) are both fulfilled with temperature difference via the thermal-electrochemistry and redox reaction effects of polymeric nanofluids. The notion of TEP is to recover the dissipative heat from the heat capacity generated by the relevant machine systems. The thermal conductivity and power density empirical formulas of the novel TEP were derived through the intelligent dimensional analysis with thermoelectric experiments and evaluated at temperatures between 25 and 100 °C and vacuum pressures between 400 and 760 torr. The results revealed that the polymeric nanofluids composed of titanium dioxide (TiO2) nanoparticles with 0.2 wt.% sodium hydroxide (NaOH) of the novel TEP have the best thermoelectric performance among these electrolytes, including TiO2 nanofluid, TiO2 nanofluid with 0.2 wt.% NaOH, deionized water, and seawater. Furthermore, the thermal conductivity and power density of the novel TEP are 203.1 W/(m·K) and 21.16 W/m3, respectively.