The wear resistance of iron nitrides compound layers and a high nitrogen martensite phase formed in the material surface for industrial pure iron, treated by nitriding and quenching followed by aging process were studied experimentally. Both the compound layer without pores by lowering the nitriding temperature and the high nitrogen martensite phase, showed the same tendency to high wear resistance. On the other hand, the pores in the compound layer made by the longer nitriding time decreased the wear resistance due to the acceleration of crack propagation. Metal ows were observed at the ε-phase in the compound layer very close to the surface after a sliding test. However, no strain hardening was observed. It was also found that the metal ows on a large part of the martensite layer and the hardness increased considerably.These results revealed that the high hardness ε-phase shows high wear resistance due to the plastic deformation, whereas the nitrogen martensite shows high wear resistance by the plastic deformation accompanied with the strain hardening.

The wear properties of industrial pure iron treated by nitriding-quenching and carburizing-quenching were investigated. Both the nitrogen martensite and carbon martensite produced by each treatment exhibited the same high degree of wear resistance. The results of sliding tests showed that the nano-indentation hardness near the surfaces of both samples had increased. The surface hardening of the nitrogen martensite was more noticeable than that of the carbon martensite. EBSD analysis revealed that plastic strain had been induced on a relatively large scale (around 20 μm) after sliding in the case of the nitrogen martensite. It was found that the high wear resistance of the nitrogen martensite led to strain hardening through the effect of the load applied in the sliding test.

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In the present study, we have examined the wear properties of the sintered pure iron subjected to two distinct heat treatments such as nitriding-quenching (NQ) and carburizing-quenching (CQ). Based on our current observations, the martensite layer was formed on the surface layer following each treatment, whereas the hardness of the NQ martensite was much higher than that of the CQ one. The wear of the CQ specimen was slightly smaller than that of the NQ martensite, despite the lower value of the initial hardness. Meanwhile, the hardness of the CQ surface after the sliding tests significantly elevated relative to the NQ surface resulting in the better wear resistance. EBSD analysis demonstrated that the plastic deformation on the CQ surface along the sliding direction. Furthermore, the micro area X-ray diffraction along the surface layer of the CQ surface showed that a small amount of the retained austeite which reduced locally during the test. Therefore, the CQ-treated surface showed the excellent wear resistivity due to the surface hardening by the stress-induced transformation of the retained austenite dispersed in the martensite, in addition to the strain hardening of the martensite itself. In contrast, the worn surface of the NQ specimen showed slight plastic deformations of the ferrite grains beneath the martensite layer, but not in the surface martensite layer. This deformation under the martensite layer was due to the hardness gap between inward and the heat-treated surface, and might contribute to form the concave profile on the sliding surface. Consequently, this study could demonstrate such the difference in the wear mechanisms between the CQ and the NQ specimens.

Solar radiation at any time can be different due to various things such as blocking of sunlight due to clouds, the intensity of the sun from sunrise to sunset, cloudiness in the rainy season, and the presence of fog in certain areas which causes different levels of solar energy. radiation that causes the output power of solar cells to vary. and not optimal. For that we need a control device that can stabilize the energy output from solar cells called Solar Charge Controller (SCC). This research was conducted to determine the value of the output power, voltage, and current of SCC type Type Pulse Width (PWM) and Maximum Power Point Tracking (MPPT), then determine the value of efficiency, and compare which type of SCC is better to use. Sampling of solar voltage and current data in the field at 10.00 – 15.00, this is because at that time the sunlight reaches its maximum intensity. The results showed that the MPPT type SCC efficiency was higher than the PWM type SCC efficiency value, namely 84.623% the MPPT type SCC efficiency compared to 80.935% PWM type SCC efficiency. Keywords: Solar Charge Controller, Pulse Width Modulation, Maximum Power Point Tracking