Development of nanocrystalline ironchromium alloy by means of sintering and ion implantation for interconnect application in high-temperature solid oxide fuel cells

This research is aimed to develop the nanocrystalline iron-chromium (FeCr) alloys by two different sintering methods, spark plasma sintering (SPS) and hot pressing (HP). The sintering temperatures in SPS are designed at 800 and 900 o C; meanwhile o in HP at 1000 C. The lower sintering temperature in SPS than HP was carried out in order to obtain the relatively similar in theoretical density of alloy with a minimum grain growth. The alloy has a potential application as interconnector in solid oxide fuel cell (SOFC). The beneficial effect of the reactive element by means of lanthanum (La) into the alloys surface which is introduced using ion implantation is also evaluated. The study focused on the properties, including thermal expansion, oxidation behaviour and electrical resistance of the surface oxide scales. Oxidation testing was conducted at 900-1100 o C for 100 h in laboratory air. Characterizations by using X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) were carried out before and after each route or process to investigate the microstructure, phase change, and formation of the oxide layer. The specific aspects studied were the effects of nanocrystalline structures, which influenced by the sintering method; and surface treatment through La ion implantation of chromia-forming alloys may improve their high thermal stability. The commercially available ferritic steel is chosen as the comparison with other high-Cr ferritic model alloys. The results revealed that the FeCr alloy prepared by SPS, to be more effective to retain nanocrystalline and better properties than those prepared by HP and commercially available ferritic steel. For all types of materials, the presence of La had no detectable effect on thermal expansion but a major effect on oxide scale adherence. The results consistently showed that better reduction in electrical resistance corresponds with excellent oxidation resistance of the alloy. The performance of FeCr alloy sintered by SPS and implanted by La exhibited the lowest oxidation and electrical resistance of the oxide scale

SIMULATION AND EXPERIMENTAL INVESTIGATION OF WRINKLE DEFECT IN DEEP DRAWING PROCESS OF CARBON STEEL SPCC SHAPED CYLINDER FLANGE CUP

A Sheet Metal Forming (SMF) process, especially deep drawing, is one of the manufacturing processes that commonly used in the automotive industry. Compared with casting and forging, the SMF process has several advantages, including lesser weight materials and broader variations in shape that can be made. One of the problems in the SMF process is the wrinkling phenomenon, which can cause the size and appearance defects of sheet products. The wrinkle occurs because of the mechanical properties of the material, product geometry, and blank holder force (BHF). Several variations of BHF were applied in these simulations and experiments to eliminate the wrinkle defects of cylinder flange cup test products. The characteristic of the cylinder flange cup is from the cold-rolled coiled steel plate (SPCC) type of material with a thickness of 0.8 and 1.0 mm, the height of 10 mm, the inner diameter of 58 mm, and flange diameter of 76 mm. Simple simulations of the SMF process were carried out by using Solidworks with version 2017, and the experiment was carried out at a 600 kN press with a punch velocity of 40 strokes per minute and blank holder force variations from 0 to 21 kN. The experimental data performed with a single die on a flanged cup cylindrical test material shows that the higher the blank holder force (BHF) number, the smaller the wrinkle defect, and it can be eliminated starting from the BHF number of 15 kN

DESIGN OF ANTI-SLIP SHOES FOR 12 TON PALM OIL TRUCK WHEELS

The rainy season will have a severe problem to the transportation sector (including heavy-duty trucks) in the off-road area in Indonesia, especially in areas that do not have permanent access roads (asphalt or concrete roads). For heavy vehicles, especially oil palm transport trucks will experience such obstacles, including slippage when crossing muddy dirt roads, and it will have an impact on the logistics delivery process. Therefore, it is necessary to design a support system, especially on the wheels, to reduce the risk of skidding or rolling on truck-type vehicles. In this work, the design of the anti-slip shoe wheels of the colt diesel double type truck (CDD) is used on the rear-wheel-drive as a tool for handling the slippage. In this design, the maximum traction factor of the wheels based on the calculation on the rolling resistance should be higher than 594 kg. The next step is to determine the value of soil cohesion and soil internal friction angle obtained from the previous studies. In this study, a calculation simulation was carried out to accomplish the design of the main components of the anti-slip of a truck wheel in the form of a traction rod fin. The design is namely U channel profile steel based on SNI 07-0052-2006 type U50, U65, and U80 with dimensions of the fin depth (z) are 3.8 cm, 4.2 cm, and 4.5 cm and length of 30 cm. The results show that the three types of U channel iron used for the anti-slip shoes are useful for freeing trucks from slippage with a total load of 12 tons. Thus, the truck will be safe when crossing the muddy roads with clay, muddy clay, and sandy loam under the following conditions: minimum cohesion number of 0.008 kg/cm2, minimum internal friction angle in the soil of 4.631°, and the maximum water content of 59.6%

Battery charging and discharging control of a hybrid energy system using microcontroller

This study aims to control charging and discharging the battery for hybrid energy systems. The control system works by selecting the right energy source to supply voltage to the load. And also this control system can regulate charging and discharging the battery automatically. The voltage source consists of two energy, namely from the battery and DC source. The control system that has been designed has the ability to choose the right DC source when the battery capacity is less than 80%. This system also has a good ability to choose a battery source when the battery reaches 100% capacity and the DC source has a voltage drop of more than 20%. This control system is equipped with excessive electric current protection so that the security level is high

Desain Sepatu Antiselip untuk Roda Truk Colt Diesel di Jalan Berlumpur

The rains will make a serious problem for the transportation sector in Indonesia, especially in areas that do not have permanent access roads (asphalt or concrete roads). Heavy vehicles such as oil palm trucks will go into the skid when crossing muddy dirt roads, and it makes an impact on the logistics delivery process. It is necessary for designing a support system, especially on the part of the wheel, to reduce the risk of skidding or rolling. Anti-slip shoe wheels of the colt diesel double (CDD) type truck is used on the rear-wheel-drive as a tool for handling slippage. Calculations and corrections are performed for maximum traction of the ground rolling resistance at ≥ 396 kg. Furthermore, the value of soil cohesion and soil shear angle was determined from the previous studies. In this study, a calculation simulation was carried out to obtain the design of the main components of an antislip wheel of a truck, which is in the form of a traction rod fin using steel UNP SNI 07-0052-2006 with a fin depth of 4.5 cm and a length of 20 cm. These dimensions are effective enough to increase the truck wheel traction of 8 tons when used to cross muddy roads with a maximum water content of 59.6% and a minimum cohesion value of land (C) of 0.108 kg/cm

Perovskite Manganit Analysis Based on La0.7Ca0.3Mn1-xTixO3 (x=0, 0.1, 0.2, and 0.3) as Potential Microwave Absorber Material with Sol-Gel Method

Electromagnetic wave is an energy flow in the form of electric and magnetic field as the technology development causes electromagnetic wave exposure level changes significantly and resulting an electromagnetic wave radiation that leads bad impacts on human health. In this case, manganite perovskite became an interesting topic of study that aims to produce material engineering to obtain a material with the best property as absorber. This study is based on lanthanum manganite La0.7Ca0.3Mn1-xTixO3 (  and ) using sol-gel method with the with a heating temperature in the oven of 200oC for 2 hours, calcination temperature of 600oC for 6 hours, and sintering temperature of 1000oC for 12 hours. The sample is characterized using X-Ray Diffraction (XRD) that shows the sample had succeeded to form single phase and had crystal cubic structure with space group p m -3 m, the substitution of Ti3+ions did not cause the structural changes, but it was marked with the changes of lattice parameter, unit cell volume and average crystallite size. Meanwhile Vector Network Analyzer (VNA) on the frequency range 8-12 GHz shows that the sample has ability to absorb microwave until 90.16% on 10.4 GHz frequency. Therefore, the material based on lanthanum manganite La0.7Ca0.3Mn1-xTixO3has the potential as the microwave absorber material

PENGARUH PENAMBAHAN IRON MILL-SCALE DAN TEMBAGA SEBAGAI MATERIAL PELAT BIPOLAR

Bipolar plate is an important component of proton exchange membrane fuel cell (PEMFC), which provides fuel and oxidant to reactive sites, collect produced current, and mechanical support for the cell in the stacks. This study concerns to find the optimum composition and sintering temperature of iron mills-cale in matrix aluminium as bipolar plate material. This work firstly carried out by downsizing aluminium flake from scrap into powder using high energy milling for 120 min and treated the iron mill-scale at 300 and 1000 oC for 60 min. The waste aluminium powder, after sieving of 150 mesh, was mixing with iron mill-scale containing 30 to 50 vol.% using shaker mill for 10 min. The mixed powders were then pressed 300 MPa and sintered with temperature of 500-600 oC for 60 min and flowed with N2 gas. The structural changes, physical, and mechanical properties of the sintered sample were studied by optical micrograph, density, porosity, hardness Vickers, and electrical conductivity test. The result showed that the optimum composition Fe is 40 vol. % and sinter temperature is 550 oC. Conductivity value of 45.406 S/cm and hardness 183.96 HV hasn’t meet expectation. Cu added containing 4-10 vol. % Fe aims to improve physical properties composites as bipolar plate material PEMFC. The result showed Cu 4 vol. % Fe can increase conductivity value 64.481 S/cm and hardness 340.13 HV

Analysis of crystal structure and reflection loss of material based on La0.7Sr0.3Mn1-x(Ni, Ti)x/2O3 (x=0.1, 0.3, and 0.5) applications for microwave absorbers

In this research, structural engineering of lanthanum manganite material based on La0.7Sr0.3Mn1-x(Ni,Ti)x/2O3 (x = 0.1; 0.3 and 0.5) was synthesized using the sol-gel method. The prepared samples were then characterized using X-ray Diffraction (XRD) and Vector Network Analyzer (VNA). X-Ray Diffraction (XRD) characterization results obtained a single. Substitution of Ni and Ti ions with a concentration of x = 0.1; 0.3; and 0.5 indicate that the formed sample has a rhombohedral structure with a space group R -3c, the presence of Ni and Ti ion substitution does not cause a change in the structure but there is a change in the lattice parameters and crystal size. Vector Network Analyzer (VNA) characterization in the range of 8 – 12 GHz produces the most optimal reflection loss intensity value of -11.8 dB at an optimal frequency of 10.58 GHz at a concentration of x = 0.5 with the ability to absorb microwaves of 93.39%. Thus the material La0.7Sr0.3Mn1-x(Ni,Ti)x/2O3 (x = 0.1; 0.3 and 0.5) can be used as a microwave absorbent material

Analysis Perovskite Material Absorber Based on Nd0.6Sr0.4MnxFe1/2(1-x)Ti1/2(1-x)O3 (x = 0, 0.1, 0.2) by Sol-Gel Method

The purposes of this research is to synthesis Nd0.6Sr0.4MnxFe1/2(1-x)Ti1/2(1-x)O3 (x = 0. 0.1, 0.2) materials as electromagnetic wave absorber using the sol-gel method. Materials characterized using X-Ray Diffraction (XRD) to determine the phase formed and Vector Network Analyzer (VNA) to determine the ability or strength of absorption of electromagnetic waves. The result of  XRD material has a structure orthorhombic with space group P b n m (62-3), the substitution of Mn+3 ions on Fe+3 ions and Ti+4 ions causes a phase change of the material from when x  =0 in the absence of Mn+3 ions 2 phases are formed, while when Mn+3 is substituted 1 phase is formed. The result of VNA with a frequency range of 8 – 12 GHz shows that the material has the ability to absorb electromagnetic waves up to 98,22% at a frequency of 9,5 GHz when x = 0.2. Thus, the material synthesis Nd0.6Sr0.4MnxFe1/2(1-x)Ti1/2(1-x)O3 has been successfully synthesized and has the ability to absorb electromagnetic waves