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Plasma nitriding and plasma nitrocarburizing are thermochemical processes used to increase the surface hardness of materials without significantly reducing toughness. This work investigated the increase in surface hardness of commercially pure titanium due to plasma nitriding and plasma nitrocarburizing processes and compared them. Plasma nitriding and nitrocarburizing processes were carried out at temperatures of 350 °C and 450 °C for 2, 3, 4, and 5 hours. The hardness of untreated commercially pure titanium was 105.75 VHN. The maximum hardness achieved in this research for the nitriding process was 227.46 VHN while for the plasma nitrocarburizing process it was 312.68 VHN. It could be concluded from this research that plasma nitriding and plasma nitrocarburizing could increase the hardness of commercially pure titanium. The hardness value achieved by the plasma nitrocarburizing process was higher than that of plasma nitriding. [ABSTRACT FROM AUTHOR]

Plasma nitrocarburizing is a surface hardening method by depositing nitrogen ions and carbon ions on the material's surface to form a hard nitride and carbide phase. This research was aimed to determine the plasma nitrocarburizing's effect on the surface hardness and surface roughness of commercially pure titanium. Phases present in untreated commercially pure titanium were observed with an optical microscope. Then the plasma nitrocarburizing process was performed on commercially pure titanium at an elevated temperature of 450 oC and process duration 4 hours. Surface hardness on untreated and plasma nitrocarburized commercially pure titanium was tested with a micro-Vickers tester. Meanwhile, the surface roughness test was carried out before and after the plasma nitrocarburizing process. The thickness of the thin film was observed with a Scanning Electron Microscope. X-Ray Diffraction Testing was applied to determine the compounds formed on a thin layer. Metallographic testing with an optical microscope showed that the material had only phases α. A thin layer thickness of 1.88 µm was observed with a Scanning Electron Microscope. This thin layer was known to be formed from titanium nitride (TiN) and titanium carbide (TiC) compounds based on the results of X-Ray Diffraction testing. The surface hardness of untreated and plasma nitrocarburized were 105.75 VHN and 312.68 VHN, respectively. The surface roughness of untreated and plasma nitrocarburized were 0.11 Ra and 0.13 Ra, respectively. According to the findings of this study, the plasma nitrocarburizing process increased the surface hardness and surface roughness of commercially pure titanium. [ABSTRACT FROM AUTHOR]

Commercially pure titanium has excellent hardness and wear resistance. However, if commercially pure titanium is utilized as a friction component, hardness and wear resistance must be increased. The goal of this research is to improve the surface hardness and wear resistance of commercially pure titanium. Plasma Nitriding was carried out on commercially pure titanium with temperature variations of 350 oC and 450 oC. While the process durations were 2, 3, 4, and 5 hours, respectively. On untreated and plasma nitrided commercially pure titanium, hardness testing with a Vickers hardness tester, wear testing with an Ogoshi High-Speed Universal Wear Testing Machine, metallographic observations with a Scanning Electron Microscope, and composition testing with the X-Ray Diffraction method was performed. Hardness test on plasma nitrided commercially pure titanium at 350 oC with process durations of 2, 3, 4, and 5 hours resulted in surface hardness of 135.84 VHN, 156.54 VHN, 171.34 VHN, and 179.86 VHN, respectively. In the same way, the hardness test on plasma nitrided commercially pure titanium at a temperature of 450 °C with a process duration of 2, 3, 4, and 5 hours resulted in surface hardness of 149.52 VHN, 183.16 VHN, 227.46 VHN, and 193.64 VHN, respectively. The results of the wear test on the untreated and plasma nitrided commercially pure titanium at a temperature of 450 oC showed a wear value of 4.0148 × 10−8 mm²/kg and 7.89 × 10−9 mm²/kg. The metallographic test showed the formation of a thin layer with a thickness of 1.09 µm. X-Ray Diffraction test showed that this thin layer was formed from Titanium Nitride compound. Based on the findings of this investigation, it was established that plasma nitriding might improve the surface hardness and wear resistance of commercially pure titanium. [ABSTRACT FROM AUTHOR]

When used as a friction-prone component, commercially pure titanium must be hardened. Plasma nitrocarburizing can increase the hardness of commercially pure titanium. N2 and CH4 gases are used as nitrogen and carbon ion sources in plasma nitrocarburizing. The objective of this work is to investigate how the ratio of N2 to CH4 gas flow rates affects the thickness and hardness of the thin layer created. At a pressure of 1.6 mbar and a temperature of 450 oC, plasma nitrocarburizing was carried out for 4 hours with different gas flow rate ratios of 1:1, 1:2, 1:3, and 1:4. To analyze the microstructure and surface composition of the material, a metallographic test was performed using a ZEISS EVO Scanning Electron Microscope-Energy Dispersive Spectrometry. To determine the compounds formed, a composition test was conducted using X-ray Diffraction (XRD) with the brand Pw3040 60 X Pert Pro Mpd Diffractometer. The Matsuzawa MMT-X7 Micro Vickers Hardness tester was used to measure surface hardness. Hardness testing on commercially pure titanium nitrocarburized plasma with variations in gas flow rate ratios of 1:1, 1:2, 1:3, and 1:4 resulted in hardness of 312.68 VHN, 134.96 VHN, 111.56 VHN, 109.3 VHN, respectively. The metallographic test by using Scanning Electron Microscope results showed the formation of a thin layer. The thicknesses were 1.88 µm, 1.69 µm, 1.65 µm, and 1.44 µm. This thin layer was confirmed by a composition test formed from TiN and TiC compounds. The plasma nitrocarburizing technique increased the hardness of commercially pure titanium, according to the test results, however, when the flow rate of CH4 was increased by a ratio of 1:2, 1:3, and 1:4, there was a decrease in hardness compared to a ratio of 1:1. Plasma nitrocarburized commercially pure titanium has the potential to be used in the medical field as a material for hip joint arthroplasty. [ABSTRACT FROM AUTHOR]

As an implant material, SS 316 L has limited due to its low hardness and wear, for this application they require the benefits of surface treatment. In this research, a plasma nitriding technique has been applied to improve the hardness of SS 316 L. For these purposes, plasma nitriding was carried out for different composition of nitrogen and argon gases such as 100% nitrogen, 95% N2 + 5% Ar, 90% N2 + 10% Ar, 85% N2 + 15% Ar, and 80% N2 + 20% Ar. Meanwhile, the other parameters such as 1.6 mbar of pressure, 400°C of temperature, and 4 hours of time were kept constant. After this process, the samples were then continued with a post-treatment process using argon gas for 20 minutes at a pressure of 1 mbar and a temperature of 350°C. Plasma nitrided and un-plasma nitrided samples were tested their hardness using the Vickers hardness test. The formation of phases was analyzed using an X-ray diffractometer (XRD). Based on the hardness test, the optimum hardness was obtained under conditions of 85% N2+15% Ar. At this condition, the hardness is 398.33 VHN while for the un-plasma nitrided sample the hardness is 159.75 VHN, or increases by factor 1.97. From the XRD, it was found that the formed phases are Fe4N, Fe3N, Fe2N, FeNFe2O3, Fe3O4, Cr2N, and CrN. The formation of these phases has hard properties so they can increase the surface its surface hardness. [ABSTRACT FROM AUTHOR]

Austenitic stainless steels are well known for their excellent corrosion resistance based on their high contents of chromium and nickel, which stimulate the formation of stable and passive oxide layers (Cr2O3) on the surface. Due to the limited hardness, wear, and corrosion properties of the austenitic stainless steel, for some applications, their surface needs to be treated. In this study, we choose the plasma carbonitriding technique to improve the surface properties of austenitic SS 316L steel. For this purpose, the experiment was carried out for various processing time such as 1 hour, 2 hours, 3 hours, 4 hours, and 5 hours at 1.6 mbar, 903 V, 408 mA, and 508 °C. As a carbon and nitrogen source, we use a mixture of 3.05 % of CH4, 19.31 % of H2, and N2 balance. Surface properties of untreated and treated samples were characterized by their hardness, surface morphology, chemical composition, and corrosion resistance using microhardness tester, scanning electron microscope (SEM), energy dispersive spectroscopy (EDS), and potentiodynamic, respectively. It has been found that the hardness increased by a factor of 1.94. From the measurement of profile depth hardness, it is found that the diffusion depth is around 129 µm, the surface of the polished (untreated) sample is very smooth, after being carbonitrided the surface becomes rough and grain boundary cavities were observed. The carbon content is 44.40 mass % and the nitrogen content is 22.45 mass %. From the corrosion test, it is found that all treated samples show the deteriorating corrosion resistance or drop in the corrosion properties. [ABSTRACT FROM AUTHOR]

Aluminum 5083 is widely used for shipbuilding because of its lightweight and strong resistance to corrosion. However, because of its low hardness and wear resistance, it causes limitations in its application. Because of this, there is a need to improve the mechanical properties of the material surface. To improve the surface mechanical properties of Al-5083, the thin film of titanium nitride (TiN) was deposited with the DC sputtering technique on the surface of Al-5083. The method of deposition has been carried out for varying periods of time such as 60, 90, 120, 150, and 180 minutes with 70Ar:30 N2 of gas ratio. From this time variation, it is expected that the optimal conditions of time can be obtained that produce an optimum hardness. Based on optimum conditions, the deposition process was continued for various of Ar:N2 gas ratio such as 60Ar:40N2, 70Ar:30N2, 80Ar:20N2, and 90Ar:10N2. The effect of thin layer deposition on the material on its hardness was characterized using a Vickers microhardness tester, wear using the Ogoshi method, surface morphology and chemical composition using Scanning Electron Microscopy (SEM) - Electron-Dispersive Spectroscopy (EDS). Based on research done, it was found that the optimum condition of time is reached at 120 minutes and 70Ar: 30N2 of the gas mixture with the highest hardness in order of 94.7 VHN from the initial hardness of 52.14 VHN. At optimum conditions, the wear resistance decreased to 8.25 × 10-8 mm2/kg from the initial 54.8 x 10-8 mm2/kg or increase wear resistance by factor 6.6. At this condition, the maximum thickness layer is about 26.79 µm, and the detected of Ti and N with Ti = 83.2 % wt and N = 0.6 % wt. [ABSTRACT FROM AUTHOR]

In Indonesia, several procedures have been proposed for the development of artificial bone implant technologies; e.g., the improvement of mechanical properties of artificial bones, the discovery of synthetic artificial bone materials from the local biomaterial industry and the enhancement of biocompatibility of existing artificial bones. However, not much work has been performed on the functionalization of existing artificial bone surfaces. For example, artificial bone surfaces may be functionalized by the formation of amino groups through plasma polymerization. It is known that the surface modification of biomaterial implant surfaces with amino groups has advantages for the immobilization of biomolecules and the stimulation of more rapid healing processes. In this study, amino groups were deposited by low-pressure plasma polymerization with a DC-plasma source that was developed and built at BATAN. Plasma polymerization was performed between the parallel stainless-steel electrodes of the system with a DC power supply. The pressure was maintained below 5 × 10−2 mbar via a rotary pump. The power, pressure, flow rate, electrode size and shape, and deposition time were varied to examine the film deposition rates and plasma stability. A mixture of hydrocarbon and nitrogen gases was needed in the plasma polymerization processes to form amino groups on biomaterial surfaces. In the mixed gas used in this study for amino-group functionalization, acetylene (C2H2), nitrogen (N2), and argon (Ar) were used as a monomer gas, a reactive gas, and an inert gas, respectively. Furthermore, the formation of functional groups on the surface after a DC-plasma treatment was identified and analyzed by Attenuated Total Reflectance-Fourier transform infrared spectroscopy (ATR-FTIR). [ABSTRACT FROM AUTHOR]

Vehicle braking is essential for safety as well as slowing down or stopping the vehicle. Friction-based braking between the brake pads and the surface of the rotor such as disc brakes is one of the critical safety components of an automobile. The consequence of friction between the brake pads and the surface of the rotor then produce a wear which is related to the lifetime. Techniques for an increasing lifetime can be done by increasing the surface quality using surface treatment methods such as plasma nitro-carburizing. Plasma nitro-carburizing is a technique of surface treatment using glow-discharge plasma technology to introduce elemental nitrogen and carbon to the surface of a metal part subsequent diffusion into material. Because of the formation of high compressive residual stresses in the case region and formation of nitride and carbide layer, the surface hardness is increase and cause a remarkable improvement in the mechanical properties of steels. For the purpose, the material was plasma nitro-carburized using a gas mixture of 50% N2, 50% CH4 gas and for various of argon gas such as of 5%, 10%, 15% and 20%, followed by post-treatment for various of time such as 10, 20, 30 and 40 minutes. From hardness measurement it is found that for plasma nitro-carburized samples treated for 50% of N2 and 50% of CH4 the hardness and wear resistance increases by factor 1.4 and 3.25 times respectively. After being added by 10% of argon followed by post treatment for 20 minutes, the hardness and wear increases by factor 2.46 and 14.88 times respectively. Based on analysis using X-rays Diffractometer (XRD), Fe2N, the Fe3N, Fe3C, FeO2, Fe2O3 and Fe3O4 phases are observed. From chemical compositions analysis using Energy Dispersive Spectroscopy (EDS) it is detected that the carbon and nitrogen content is 10.0 wt%, and 5.6 wt% respectively. It can be concluded that the formation of these phases give main contribution in increasing of the hardness and wear significantly. [ABSTRACT FROM AUTHOR]

Diamond like carbon (DLC) is very important materials for mechanical industryespeciallycutting tools, automotive and production machines components. Formation of DLC on metal surface usually use a mixture of hydrocarbon/Ar plasma, such asCH4/Ar, C2H6/Ar, and C2H4/Arplasma. These materials are expensive. Therefore, the aim of this study is to replace the hydrocarbon/Arwith the carbon source of LPG/Ar mixture because it is cheaper and easy to get in the market. The formation of DLC wasconducted by using home madeDC plasma glow discharge device, and carbon sourceof LPG/Ar gasmixture with ratio 9: 1. The formation was carried out with pressure variation of 1.4 mbar, 1.6 mbar, 1.8 mbar, 2 mbarand time variation of 2 hours, 3 hours, 4 hours, and 5 hours at constant temperature 400 °C.The DLC formation was analyzed byusingVickers hardness test, wear test, corrosion test and microstructure test (SEM-EDS and XRD). The optimum hardness and wear resistance are225.3 VHN and 1.7 x 10-8 mm²/kg, and this was achievedrespectively, at 1.6 mbar and a 4 hours. Meanwhile, the un-coated materials are 115.5 VHN and 1.4 x 10-7 mm²/kg. The results show that hardness and wear resistance increase ifcompared to the un-coated materials. The microstructure observed using SEM-EDS show that thickness of hard layer is about one 5 μm. From XRD analyzed show that the formed phase is Fe2C phase. Based on these results it is expected that the formingDLC can be applied for the machine components and can increase the life time and mechanical efficiency so that the operation is more efficient because the friction losses become smaller. [ABSTRACT FROM AUTHOR]

The objective of the present work was to investigate the mechanical properties of NiCr-Al coating deposited by plasma sputtering technique. NiCr was firstly deposited on a carbon steel surface using sputtering times of 60, 90, 120, 180 and 240 minutes, whereas Al was subsequently deposited using a time of 30 minutes for all specimens. The results showed that the structure of the surface observed by SEM indicates a good density. The structure formation of NiCr-Al was clarified by XRD. The hardness test of the product surface conducted by a Vickers indentation tester indicates that the average hardness of uncoated steel substrate was 172.512 HV. The hardness of NiCr surface was 191.256 HV. Further layer addition using Al on NiCr indicates that the hardness of NiCr-Al surface sputtered by NiCr for 60, 120, 180 and 240 minutes, followed by Al for 30 minutes, were 279.912, 253.056, 231.264 and 213.888 HV, respectively. The reduced hardness of NiCr-Al with the increased sputtering time was attributed to the higher diffusion of Al into NiCr. [ABSTRACT FROM AUTHOR]

HQ 805 is known as a super strength alloys steel and widely applied in military equipment and, aircraft components, drilling device and so on. It is due to its excellent behavior in wear, fatigue, high temperature and high speed operating conditions. The weakness of this material is the vulnerablality to corrosion when employed in sour environments where hydrogen sulfide and chlorides are present. To overcome the problems, an effort should be made to improve or enhance the surface properties for a longer service life. There are varieties of coatings developed and used to improve surface material properties. There are several kinds of coating methods; chemical vapour deposition (CVD), physical vapour deposition (PVD), thermochemical treatment, oxidation, or plasma spraying. This paper presents the research result of the influence of Diamond-Like Carbon (DLC) coating deposited using DC plasma enhanced chemical vapor deposition (DC-PECVD) on corrosion rate (by potentiodynamic polarization method) of HQ 805 machinery steel. As a carbon sources, a mixture of argon (Ar) and methane (CH4) with ratio 76% : 24% was used in this experiment. The conditions of experiment were 400 °C of temperature, 1.2 mbar, 1.4 mbar, 1.6 mbar and 1.8 mbar of pressure of process. Investigated surface properties were hardness (microhardness tester), roughness (roughness test), chemical composition (Spectrometer), microstructure (SEM) and corrosion rate (potentiodynamic polarization). It has been found that the optimum condition with the lowest corrosion rate is at a pressure of 1.4 mbar with a deposition duration of 4 hours at a constant temperature of 400 °C. In this condition, the corrosion rate decreases from 12.326 mpy to 4.487 mpy. [ABSTRACT FROM AUTHOR]

Surface treatment by implantation with nitrogen-ion was performed on the commercial feritic high strength steel AISI 410 which is termed for high temperature applications. The aim of this research was focused on the surface modification to improve its high temperature oxidation property in the early stages. Ion implantation was carried out at acceleration energy of 100 KeV and ion current 10 mA for 30, 60 and 90 minutes. The samples were subjected to the high temperature oxidation test by means of thermogravimetry in a magnetic suspension balance (MSB) at 500 °C for 5 hours. The scanning electron microscopy (SEM), X-ray diffraction spectrometry (XRD) and Vickers Hardness measurement were used for sample characterization. The formation of ferro-nitride phase after implantation did not occur, however a thin layer considered to contain nitrogen interstitials was detected. The oxidation of both samples before and after implantation followed parabolic kinetics indicating inward growth of oxide scale characteristically due to diffusion of oxygen anions towards matrix surface. After oxidation test relativelly stable oxide scales were observed. Oxidation rates decreased proportionally with the increasing of implantation time due to the formation of oxide layer which is considered to be effectiv inhibitor for the oxygen diffusion. [ABSTRACT FROM AUTHOR]