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Nitrogen ion implantation at 50 keV of energy on the surface of SS 316 stainless steel, by calculation will only be able to reach a depth of 561 Å and the ions will be distributed Gaussian effectively at a depth of 561 Å ± 339 Å, so that from the surface to a depth of 222 Å is not filled by ions (empty) which of course will affect the properties of the implanted surface. The solution to the problem is to implant the target several times at

Titanium tends to form nitrides and carbides. The plasma nitrocarburizing technique can generate these nitride and carbide compounds on the material's surface. The objective of this research is to use a plasma nitrocarburizing process to increase the hardness and corrosion resistance of commercially pure titanium. The generation of a thin layer with an average thickness of 1.88 μm was discovered using a Scanning Electron Microscope. The X-Ray Diffraction technique identifies this thin layer made of TiN and TiC compounds. The untreated commercially pure titanium hardness was 105.75 VHN, and the plasma nitrocarburized commercially pure titanium hardness was 312.68 VHN, according to the Vickers micro tester. After plasma nitrocarburizing, the corrosion rate of untreated commercially pure titanium decreased from 0.0061 mmpy to 0.00077 mmpy. The plasma nitrocarburizing process resulted in a 196 percent increase in hardness and an 87 percent reduction in corrosion rate.

Aluminum is a lightweight material that is commonly used in engine components. However, aluminum's low hardness and wear resistance, requires special treatment before being used as a component. Increasing the hardness and wear resistance of aluminum can be done by coating Titanium Nitride (TiN) with the sputtering method. In this study, the effect of sputtering time on Al-TiN coating on hardness and wear resistance was obtained. The deposition of titanium nitride thin films on aluminum using a gas ratio of Ar: N ((70:30%) with varied treatment times of 30, 60, 90, and 120 minutes. Hardness and wear resistance were observed using Vickers hardness tester and Ogoshi High-Speed Universal. Whereas the morphology of the wear surface was observed by SEM. The result shows that the treatment time of 60 minutes obtained the highest hardness and minimum specific wear rate.

The tribological properties of commercially pure titanium need to be improved when applied as a friction component. This research investigated the effect of plasma nitrocarburizing process on the hardness and wear resistance of commercially pure titanium. The plasma nitrocarburizing process was carried out with a ratio of the composition of N2 gas and CH4 gas of 1:1, 1:2 and 1:3. Metallographic test by scanning electron microscopy was carried out to observe phase modifications on the surface of the material. Compounds formed in a thin layer on the surface of the commercially pure titanium were observed by X-Ray Diffraction testing. Furthermore, Vickers hardness and wear testing were carried out to determine the effect of the plasma nitrocarburizing process. The results showed an increase in hardness and wear resistance. The surface hardness of the untreated commercially pure titanium was 105.75 VHN and increased to 156.76, 211.12 and 236.32 VHN after the plasma nitrocarburizing process was carried out with a ratio of N2 gas and CH4 gas composition of 1:1, 1:2 and 1:3, respectively. The reduction in specific wear rate was experienced by commercially pure titanium. The specific wear rate of the untreated commercially pure titanium was 4.468E-8 mm2/kg. The plasma nitrocarburizing process, which was carried out with a ratio of N2 gas and CH4 gas composition of 1:1, 1:2 and 1:3, reduced the specific wear rate to 2.812E-8, 1.176E-8 and 6.14E-9 mm2/kg, respectively.

This research aims to study the behavior of monotonic and cyclic plastic deformation on commercially pure titanium which has undergone surface treatment using the nitrogen ion implantation method. The doses of 2.0×1017 ions/cm2 and the energy of 100 keV were used to implant the nitrogen ions into the CpTi. Monotonic properties tests were performed in a laboratory air and at room temperature using ASTM E8 standard specimens. Fatigue and corrosion fatigue tests were conducted in a laboratory air and in artificial saline solutions, at room temperature using ASTM 1801-97 specimens. Tensile tests were carried out with constant displacement rate and fatigue tests were carried under fully-reversed with stress-controlled conditions with stress amplitudes 230, 240, 250, 260, 270 and 280 MPa. The results showed the material properties of monotonic behavior for CpTi and Nii-Ti; tensile strength (σu) of 497 and 539 MPa and for 0.2% offset yield strength (σy) of 385 and 440 MPa, respectively and of cyclic behavior; cyclic strength coefficient (k’) of 568.41 and 818.64 and cyclic strain hardening exponent (n’) of 0.176 and 0.215, respectively. This study has succeeded in producing useful new material properties that will contribute to the field of material science and engineering.

AISI 316L is widely used for implantation in orthopedic surgery due to its good corrosion resistance, mechanical properties and low cost. However, AISI 316L is not well suited for biocompatibility with the body, so implant material with AISI 316L can’t be used for a long time. One way to improve the corrosion resistance and mechanical properties of AISI 316L is to perform a surface treatment such as sputtering. This study discusses the effect of deposition sputtering TiN of 60, 90, 120 and 150 minutes on roughness and surface hardness at a ratio of argon gas and nitrogen to 80% Ar:20% N2. The results of the surface roughness value of the TiN sputtering layer deposited to AISI 316L for 60, 90, 120, and 150 minutes were 0.02 μm, 0.04 μm, 0.06 μm, and 0.04 μm respectively. This shows that the coating time of TiN in AISI 316L has no significant influence on value of surface roughness. Surface hardness results at 60, 90, 120, and 150 minutes were obtained with 268 HVN, 275 HVN, 278 HVN and 282 HVN. Increased hardness value, as the TiN thin layer has a higher hardness value compared to AISI 316L. The longer the deposition time, the more layers are formed and the layer becomes thicker. With the thickness of the layer, the density at the grain boundary increases. Because the higher density leads to grain growth, in which form micropores.

One of the surface treatments to improve the hardness of the surface is by ion implantation process. This paper presents an equation to predict the surface hardness with the variable of the process time in ion implantation surface treatment. The hardness of three surfaces data were collected experimentally from various process times, i.e. 140 minutes, 280 minutes and 560 minutes. Lagrange polynomial interpolation was then used to generate quadratic mathematical formula of the surface hardness based on experimental data. The verification results show that the proposed equation accurately predict the surface hardness of commercially pure (cp) titanium under ion implantation process with the error less than 0.5 %. This equation can be used to set the appropriate treatment process time to achieve the expected surface hardness without costly trial experimental settings.

Plasma nitriding has attracted much interest to improve the hardness of aluminium alloys. However, the contradictive properties can be produced on the metal surface due to the saturated condition of the diffused nitrogen atom in the metal surface layer. The objective of this work was to investigate the effect of nitriding time and gas pressure to improve the hardness of aluminium using plasma nitriding. The nitriding processes were conducted in a DC glow discharge with nitrogen gas flowing inside the vacuum chamber. Firstly, the sample was nitrided using a fixed gas pressure of 1.2 mbar with the varied nitriding times of 3, 4, 5 and 6 hours. The optimum time producing the highest hardness of the surface was then used in the next nitriding process with varied gas pressure of 1.2, 1.4, 1.6 and 1.8 mbar (1 bar = 105 Pa). The optimum gas pressure producing the highest hardness was then used again in the last nitriding process using varied nitriding time of 3, 4, 5 and 6 hours. The result showed that the highest hardness was achieved using the gas pressure and nitriding time of 1.6 mbar and 4 hours, respectively. The formed AlN phase on the aluminium surface was identified by XRD, whereas the surface morphology was observed by SEM image. Compared to the untreated sample, the hardness of the treated samples was significantly high.

Activated zinc sulfide (ZnS) is a semiconductor material which able to emit photon in the form of visible light when expose to external energy. The capability of activated ZnS, mainly doped with silver (Ag) and copper (Cu), to convert radiation become light to make it potentially applicable as the radioluminescent thin film for alphaphotovoltaic-type nuclear battery. One of the important specifications of the radioluminescence layer that influences the fluorescence efficiency is the thickness. This work presents a study on the thickness optimization for ZnS:Ag:Cu as the radioluminescent film for alpha particles using Monte Carlo model. Simulation to study alpha particles’ energy deposited by using Stopping and Range of Ions in Matter/TRansport of Ions in Matter (SRIM/TRIM) code. The model examined the transport of 5.485 MeV alpha particles emitted by to determine the best thickness based on energy deposition depth. Based on TRIM module simulation, the optimal thickness for radioluminescence film is approximately 19-22 µm. Most energy from 5.485 MeV alpha particles is deposited in 18.92 µm depth activated zinc sulfide. The results from SRIM/TRIM model then compare with analytical calculation using Bragg-Kleman rule. The alpha particles stop at 22 µm from the SRIM/TRIM simulation while using Bragg-Kleman formula the alpha particles stop at 23.51 µm.

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.

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.

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.

During operation, shaft steel always contacts with other components, so this material will erode gradually and will be accelerated if this component used in corrosive environment. Finally, the performance of the components to be worse. To improve the quality of the surface components, an ion nitriding technique can be applied. In this research, ion nitriding process was carried out at 300°C, 350°C, 400°C, 450°C and 1.6 mbar for 4 hours. It can be concluded that generally by increasing the temperature, the hardness increases and at 450°C reached the highest value in order of 297.86 VHN, while the hardness of raw materials is 98.66 VHN or increases by factors 3, the wear decreases from 60.3 × 10−9 mm2/kg to 26.8 × 10−9 mm2/kg or there is an increasing in wear resistance by factor 2.25, and corrosion rate decreases from 4.2465 mpy to 0.6748 mpy.From XRD analysis, it is observed the formed phase are Fe2N and Fe3N. The formation of new phase contributes in improving of hardness, wear, and corrosion resistance.

Telah dilakukan penelitian mengenai penentuan nilai breakdown voltage pada nitridasi plasma dan aplikasinya pada surface treatment. Surface treatment dilakukan menggunakan metode nitridasi ion, agar terbentuk lapisan tipis di permukaan aluminium AA 7075 untuk meningkatkan sifat kekerasan. Perubahan sifat kekerasan sebelum maupun sesudah proses nitridasi diuji dengan menggunakan metode vickers. Penentuan nilai breakdown voltage bertujuan untuk mengetahui besar tegangan yang diperlukan untuk membangkitkan nitridasi plasma (breakdown voltage) dengan variasi tekanan gas nitrogen sebesar 1,0; 1,2; 1,4; 1,6; 1,8; dan 2,0 mbar. Sedangkan pada proses surface treatment untuk meningkatkan kekerasan aluminium AA 7075 dilakukan dengan variasi tekanan gas nitrogen sebesar 0,8; 1,0; 1,2; dan 1,4 mbar. Dari hasil eksperimen, didapatkan nilai breakdown voltage sebesar 529; 562,7; 588,3; 629,3; 664,3 dan 683 volt. Pada nilai tegangan tersebut, arus yang dihasilkan sebesar 171,3; 186; 332; 402,6; 635; dan 689,7 mA. Dari proses surface treatment diketahui bahwa peningkatan kekerasan optimum terjadi pada tekanan 1,2 mbar dengan nilai kekerasan 112,8 VHN atau meningkat sebanyak 131,62%.

Penelitian bertujuan menentukan breakdown voltage karburasi plasma dan pemanfaatannya untuk meningkatkan kekerasan stainless steel 316L. Proses penentuan breakdown voltage karburasi plasma dilakukan dengan menggunakan gas CH4 dengan variasi tekanan 1; 1,2; 1,4; 1,6; 1,8; 2 mbar. Selain itu juga dilakukan proses surface treatment menggunakan gas CH4 dengan teknik karburasi plasma pada stainless steel 316L untuk meningkatkan kekerasan dengan variasi tekanan 1,2; 1,4; 1,6; 1,8 mbar. Breakdown voltage yang diperoleh dari perlakuan variasi tekanan berturut-turut sebesar 512; 540 ; 572,3; 602; 654,3; dan 655,7 volt, sedangkan nilai arus yang diperoleh berturut-turut 256; 457; 547; 708,3; 947,7; 986,7 mA. Hasil uji kekerasan menunjukkan nilai kekerasan optimum terjadi pada variasi tekanan 1,6 mbar dengan nilai kekerasan meningkat dari 109,4 VHN menjadi 228,6 VHN, atau meningkat sebanyak 108,88%.

This paper presents the research on the growth of ZnS:Ag:Cu thin film on a glass substrate as a radio-luminescent material. The SRIM/TRIM software is used to determine the optimum thickness based on an energy deposition depth of 5.485 MeV Am 241 alpha radiation source on ZnS:Ag:Cu material. To increase the adhesive strength of the coating, initially, the glass substrate is etched using a plasma glow discharged at 280°C for 15 minutes. Multiple coatings of ZnS:Ag:Cu were etched on the glass substrate; this was carried out using a thermal evaporation technique to achieve the optimal thickness (based on SRIM/TRIM simulation). The thin film thickness was observed using a scanning electron microscope (SEM). The optical properties of the un-etched, etched glass substrate and thin-film were characterized using UV-Vis spectrometer. Based on SRIM/TRIM simulation, the optimal thickness is 22 mm which can be achieved by coating three times. From optical properties of ZnS:Ag:Cu thin film and after being analysed using Taue plot method, it is found that the energy gap of ZnS:Ag:Cu thin film is 2.48 eV. It can be concluded that the addition of Ag and Cu doped decrease the energy gap of ZnS (3.66 eV).

Plasma nitriding is a treatment process of metals by depositing nitrogen into metal that considered to be nitrided by mean of increasing the mechanical, physical, and chemical properties of the metal. This treatment will form a hard layer compund of Al-N on the surface of the sample. In this study, aluminium alloy 7075 was nitrided which the application of it to structural part of aircraft makes it vulnarable to not only corrosion and wear attack but also decreasing the hardness of the material. One method to overcome these issues is plasma nitriding. The purpose of of this research is to do the characterizations of plasma nitrided aluminium alloy 7075 regarding its microstructure, mechanical, and chemical properties. The characterizations that had been done were microhardness Vickers testing, SEM-EDX, and electrochemical corrosion testing Potensiostat. The hardness of the sample increased 55% from 75,88 VHN (raw material) to 117,68 VHN (at optimum parameter). The depth of the white layer of plasma nitriding is approximately 6 µm, while the EDX result reported carbon, oxygen, and nitrogen presence. Corrosion testing showed that the highest corrosion rate is on the raw material, 0,15393 mpy. While the optimum one is 0,07184 mpy.

316L stainless steel is widely used as an orthopedic implant due to its high corrosion resistance and biocompatibility, but the weakness of these materials is low hardness and high wear. The surface must be modified to improve the material. For the purpose, a titanium nitride (TiN) thin film was deposited on the surface of SS 316L using DC sputtering technique. The sputtering process was carried out for various of a gas mixture of argon (Ar) and nitrogen (N 2 ) such as 90 Ar: 10N 2 , 80 Ar: 20 N 2 , 70 Ar: N 2 , and 60 Ar: 40 N 2 , while the other parameters kept constant. The objective of the gas mixture variation is to find out the optimum condition of ratio Ar: N 2 gas mixture with the highest hardness and lowest wear resistance. From experiment done it’s found that the highest hardness in order of 232.02 VHN, while before being coated the hardness is 133.61 VHN, or there is an increasing hardness by factor 1.73, while the wear resistance reduces from 11.6 × 10 -8 mm 2 /kg to 1.17 × 10 -8 mm 2 /kg or there is reducing in wear resistance by factor 9.9. The optimum conditions were achieved at Ar: N 2 ratio = 70:30. From XRD analysis, it can be concluded that the crystal structure of TiN thin film is cubic with the peaks (111), (200), (202), (311) and (222). From cross-section microstructure analysis using Scanning Microscope Electron (SEM), it’s found the thickness of the thin film is 744 nm.

Aplikasi LPG untuk pelapisan permukaan logam menggunakan teknik lucutan pijar. Surface treatment adalah proses ionisasi yang dimanfaatkan untuk deposisi atom gas pada permukaan benda untuk dapat merubah sifat suatu benda terutama dalam perubahan sifat mekanik, akibat mengalami proses deposisi atom gas. Kegiatan surface treatment suatu material dengan menggunakan teknik plasma lucutan pijar dapat diawali pada kondisi breakdown voltage (BV). Fenomena ini akibat suatu kondisi ketika pelepasan muatan/discharge mulai terjadi sehingga gas yang awalnya bersifat isolator berubah menjadi konduktor. BV terjadi iakibat dari sumber tegangan tinggi yang dinaikkan secara terus menerus dalam sutu tabung vakum hingga terjadi plasma. Penelitian dengan cara memasukkan gas LPG kedalam tabung vakum. Jarak elektrode, tekanan gas merupakan parameter terjadinya plasma. Kurva Paschen gas LPG, digunakan untuk acuan pada saat pengoperasian mesin plasma lucutan pijar untuk kegiatan surface treatment tersebut. Hasil penelitian diperoleh variasi jarak elektroda sebagai nilai acuan untuk melakukan surface treatment LPG, berdasarkan kurva Paschen antara 0,7cm sampai 2,8 cm. Kata-kata kunci: breakdown voltage, surface treatment, plasma lucutan pijar, LPG. Abstract Measurement of breakdown voltage LPG for metal surface applications using plasma. The surface treatment is an ionization process utilized for deposition of gas atoms on the surface of an object to change the properties of an object, especially in the change of mechanical properties, due to the process of atom gas deposition. Surface treatment of materials using plasma begins during breakdown voltage (BV). This phenomenon is due to a condition when discharge/discharge starts to occur so that the initially insulating gas turns into a conductor. BV occurs as a result of a high voltage source that is raised continuously in a vacuum tube until plasma occurs. Research by putting LPG into a vacuum tube. Electrode distance, the gas pressure is the parameter of plasma occurrence. The Paschen LPG curve, used for reference at the time of operation of the incandescent plasma machine for such surface treatment activities. The result of the research shows that the optimum distance of the electrode for reference to surface treatment using LPG ranges from 0.7cm-2.8 cm. Keywords: breakdown voltage, surface treatment, plasma discharge incandescent, LPG.

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.

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.

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 as CH4/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 made DC 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 byusing Vickers hardness test, wear test, corrosion test and microstructure test (SEM-EDS and XRD). The optimum hardness and wear resistance are 225.3 VHN and 1.7 × 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 × 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 forming DLC 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.

In this study, the mechanical properties and corrosion properties of plasma nitrocarburized 304 stainless steel at various processing times was investigated. Plasma nitrocarburizing was carried out at different processing time durations which varied from 60 min to 300 min at fixed temperature of 500 °C in an atmosphere of 78 vol.% N2, 19 vol.% H2 and 3 vol.% CH4. An Optical microscope and SEM coupled with EDS have been used to characterize the microstructural and the elemental depth profiles in which the thickness of the modified layers is derived. Microindentation method is used for the study of mechanical performance of the nitrocarburized material. Corrosion properties were investigated using potentiostat method in a 1 wt% NaCl solution. The result shows that the microhardness increases to a maximum value of more than two times compared to that of the untreated one. The corrosion performance was found being treatment time duration dependent.

The oxidation kinetics and microstructure characteristics of oxide scales thermally grown on the surface of developed FeCr alloy were investigated at 900 °C. The influence of difference sintering technique, i.e. spark plasma sintering and hot pressing, to improve nanostructured alloy performance was studied. The La-implantation was also considered in this study. It was found that the SPS sintered sample showed better performance than the HP sintered sample. Moreover, it also found that a combining of La-implantation and nanostructured alloy was most beneficial. While nanostructured alloy reduced the oxidation rate, the La-implantation increased the Cr2O3 scale conductivity.

The fatigue and corrosion fatigue behaviours of commercially pure titanium (CpTi) have been particularly studied because the requirements of titanium (Ti) base materials are widely used for biomedical applications. The optimal properties of CpTi surface can be preserved by nitrogen ion implantation at a certain dose and energy. Still the fatigue and corrosion fatigue behaviours of nitrogen ion implanted CpTi (Nii-Ti) must be verified. This study performs the fatigue tests for CpTi and Nii-Ti specimens in a laboratory air and the corrosion fatigue tests for Nii-Ti specimens in a saline solution. Effects of nitrogen ion implantation on surface properties can improve the fatigue strength, fatigue life and corrosion fatigue life of Ti base materials. The corrosion pit growth law has been established on the basis of empirical data for predicting the corrosion penetration rate to estimate to the service life of Nii-Ti.

AISI 4340 is known as super strength steel and widely applied in military equipment, aircraft components, automotive components, drilling device and so on because of its excellent behavior in wear, corrosion, fatigue, high temperature, and high-speed operating conditions. However, due to continuing work which reduced the performance of that component surface during their service life, an effort to improve the surface properties for a longer service life should be carried out. This paper presents the research result of the influence of diamond-like carbon coating deposited using home-made DC Chemical Vapor Deposition (DC-CVD) on the surface of AISI 4340 steel. As a carbon source, a mixture of argon (Ar) and methane (CH4) with a ratio of 24%: 76% was used in this experiment. The conditions of the experiment were 400°C of temperature at various gas pressures (1.2 mbar, 1.4 mbar, 1.6 mbar, 1.8 mbar, and 2.0 mbar) for 5 hours of coating time. Investigated surface properties are hardness, fatigue strength, and surface morphology. It was found that the optimum conditions in enhancing fatigue strength at 1.4 mbar of pressure. At these conditions, the fatigue strength increase from 401 MPa to 514 MPa, the microhardness increase from 327 VHN to 625 VHN. Based on surface morphology observation of the fracture surfaces, it shows that for raw material, an initiation crack starting from the surface. However, after being coated for 1.2 mbar, 1.4 mbar, and 1.6 mbar, the initial crack begins from the inside. The high hardness layer hinders the fatigue crack initiation.

The weakness of aluminium and its alloys are relative low hardness and wear resistance. To improve this weakness a nitrogen ion implantation technique has been carried out. For the purpose, an ion implantation process was carried out for various of dose such as 0.578×1016 ion/cm2, 0.706×1016 ion/cm2, 0.842×1016 ion/cm2, 0.970×1016 ion/cm2, and 1.106×1016 ion/cm2 at a certain energy and beam current, 60 keV and 75 μA, respectively. Hardness test was performed using microhardness tester, the corrosion resistance was tested using the electrochemical method, and the crystal structure was analyzed using X-ray diffraction. From the hardness test result, it can be concluded that the optimum hardness in order of 37.5 VHN was achieved at an ion dose of 0.83×1017 ion/cm2. While the hardness for the untreated sample was 18.70 VHN. It meant, there is an increasing hardness by a factor of 100,53%. At these conditions, the corrosion rate reduces from 0.012 mmpy to 0.011 mmpy or reduce by a factor of 8.3%. Based on the XRD analysis, it can be obtained the AlN phase is formed through the peaks at 2-theta was 39.37° (111), 45.76° (200), and 66.88° (202).

Plasma nitriding (also known as ion nitriding, plasma ion nitriding, or glow-discharge nitriding) is a method of surface hardening using glow-discharge technology to introduce nascent (elemental) nitrogen to the surface of a metal part subsequent diffusion into the material. Because of the formation of high compressive residual stresses in the case region, increasing surface hardness and depth parameters cause remarkable improvement in the mechanical properties of steels. In this study, the properties of a nitrided local disc brake were investigated. For that purpose, the material was nitrided at 400°C of temperature, 1.6 mbar of pressure, and 4 hours of time then followed by post-treatment in Argon (Ar) environment for various of holding time such as 10, 20, 30, 40, and 50 minutes. At these conditions the hardness increased in the range 123.1 - 223.3 VHN, the wear rate decreased in the range 21.7 × 10-9 - 3.1 × 10-9 mm3/mm kg, while before being nitrided the hardness and the wear rates were 113.5 VHN and 22.8 × 10-9 mm3/mm kg, respectively. The optimum condition for holding time during post treatments was 20 minutes. Besides that, the effect of various of N2: Ar mixture such as 90%: 10%, 80%: 20%, 70%: 30%, and 60%: 40% on the properties of local disc brake was studied. For various of gas mixing, the optimum hardness in the order of 252.7 VHN and wear rate in the order of 2.8 × 10-9 mm3/mm kg were achieved at 90%N2: 10%Ar of a gas mixture.

Weaknesses of local disc brakes are cover several conditions such as low hardness, wear, and corrosion resistance. To improve this weakness, it is necessary to modify the surface properties of the material. The aim of this research is to study the influences of nitrogen ion implantation on the surface properties of a disc brake material. The implantation process was carried out for various of ions dose such as 3.107×1016 ions/cm2, 3.148×1016 ions/cm2, 3.728×1016 ions/cm2, 4.039×1016 ions/cm2, 4.350×1016 ions/cm2 at a certain energy and beam current of 60×1016 ions/cm2, 30 μA respectively. Hardness and wear properties were tested using microhardness tester and wear testing machine, respectively. Meanwhile, the crystalline structure for un-implanted (raw) and implanted materials at the optimum dose was analyzed using XRD. From the hardness test results, it can be obtained that the hardness of raw material is 59.82 VHN and after implantation it reached the highest value of 109.78 VHN or increases by factor 83%, while the wear test results is 22.9×10-9 mm2/kg for raw material and after implantation it reaches the highest value of 2.5×10-9 cm2/kg or decreases by factor 88%. These conditions were obtained at 3.728×1016 ions/cm2 of dose. Based on the XRD analysis, 45.5% Fe2N and 54.55% Fe3N compounds are formed.

Commercially pure (cp) titanium has a relative soft hardness property. In particular usage such as sliding, the improvement of the surface hardness will be required. In this study, surface hardness improvement of cp titanium by Plasma Nitrocarburizing and Ion Implantation are compared. Plasma Nitrocarburizing processes are conducted at different elevated temperatures with different duration processes, i.e. at 350 °C for 3, 4, and 5 hours, and at 450 °C for 2, 3, and 4 hours respectively, while Ion Implantation processes are conducted at room temperature and process durations are varied as 2.3 hours, 4.7 hours, and 9.3 hours. Nitrogen ions are used to implant the material. Hardness tests are then performed on each specimen by using Micro Vickers Hardness Tester. The surface hardness number (HV) for specimens of the Plasma Nitrocarburizing processes at temperature of 350 °C for process duration of 3 hours, 4 hours, and 5 hours are 74.16, 92.25 and 94.41, respectively while those at temperature of 450 °C for duration process of 2 hours, 3 hours, and 4 hours are 103.70, 121.31 and 126.17, respectively. The processes of Ion Implantation produce the surface hardness number (HV) of 88.97, 125.51, and 130.2, for duration processes of 2.3 hours, 4.7 hours, and 9.3 hours. The process of Ion Implantation produce higher surface hardness number than the Plasma Nitrocarburizing process at temperature 350 °C but the surface hardness number is lower when compared to the Plasma Nitrocarburizing at a temperature of 450 °C. For the duration processes 4 hours and more, the process of Ion Implantation produces the same surface hardness number with the Plasma Nitrocarburizing at temperature of 450 °C.

Prediction of fatigue life has become an interesting issue in biomaterial engineering and design for reliability and quality purposes, particularly for biometallic material with modified surfaces. Commercially pure titanium (Cp-Ti) implanted with nitrogen ions is a potential metallic biomaterial of the future. The effect of nitrogen ion implantation on fatigue behavior of Cp-Ti was investigated by means of axial loading conditions. The as-received and nitrogen-ion implanted specimens with the energy of 100 keV and dose of 2 × 1017 ions cm-2, were used to determine the fatigue properties and to predict the life cycle of the specimens. The effect of nitrogen ion implantation indicated revealed improved the tensile strength due to the formation of nitride phases, TiN and Ti2N. The fatigue strength of Cp-Ti and Nii-Ti was 250 and 260 MPa, respectively. The analytical results show good agreement with experimental results.

Commercially pure (cp) titanium is a relative soft metal and easily broken on friction-wear applications. To improve the hardness of the surface while maintaining the original properties, plasma nitrocarburizing process has been conducted. The effects of the treatment in different temperatures to the surface harness are then studied. In this study, cp titanium plasma nitrocarburizing process is conducted at different temperatures with different process time, i.e. at 350 °C for 3, 4, and 5 hours, and at 450 °C for 2, 3, and 4 hours respectively. Hardness tests are then performed on each specimen by using Micro Vickers Hardness Tester. The hardness values for the plasma specimens nitrocarburizing processes at temperature of 350 °C for process duration of 3 hours, 4 hours, and 5 hours are 74.16 HV, 92.25 HV and 94.41 HV, respectively, while for processes at temperature of 450 °C, the hardness values are 103.70 HV, 121.31 HV, and 126.17 HV for process duration of 2 hours, 3 hours, and 4 hours respectively. Hardness value of specimens which are resulted from the plasma nitrocarburizing process at temperature of 450 °C is higher compared with specimens that are processed at temperature of 350 °C.

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 characteri...

The oxidation behaviour of developed Fe80Cr20 alloy and commercial ferritic steel at 1173 - 1373 K in air is studied. Effects of crystallite size and titanium implantation on the oxidation behaviour of specimens were analyzed based on oxide morphologies and microstructures. Oxide scales characterisations of specimen after oxidized were identified by X-ray diffraction (XRD). The surface morphology of oxide scales were examined with scanning electronic microscope (SEM) and energy dispersive X-ray analysis (EDX). The rate constant of oxidation were determined using Wagner method. The results show that crystallite size and titanium implantation has remarkably enhanced the oxidation resistance. The oxidation kinetics indicate that the developed Fe80Cr20 as the finer crystallite size both unimplanted and implanted specimens show better performance.

The cross-sectional examinations of oxide scales formed by oxidation on the surface of FeCr alloys and Ferritic Steel that implanted with lanthanum and titanium dopants were observed and investigated. Scanning electron microscopy (SEM) coupled with energy dispersive X-ray spectroscopy (EDS) has been used to study the cross-sectional oxides produced by specimens after oxidation process. X-ray diffraction (XRD) analysis was used to strengthen the analysis of the oxide scale morphology, oxide phases and oxidation products. Cross-sectional observations show the effectiveness of La implantation for improving thinner and stronger scale/substrate interface during oxidation process. The result shows that the thickness of oxide scales formed on the surface of La implanted FeCr alloy and ferritic steel was found less than 3 μm and 300 μm, respectively. The oxide scale formed on the surface of La implanted specimens consisted roughly of Cr2O3 with a small amount of FeO mixture, which indicates that lanthanum implantation can improve the adherence, reduce the growth of the oxide scale as well as reduce the Cr evaporation. On the other side, the oxide scale formed on the surface of FeCr alloys and ferritic steel that implanted with titanium dopant was thicker, indicating that significant increase in oxidation mass gain. It can be noticed that titanium implantation ineffectively promotes Cr rich oxide. At the same time, the amount of Fe increased and diffused outwards, which caused the formation and rapid growth of FeO.

PERLAKUAN PERMUKAAN PADA ROLLER RANTAI DENGAN METODE PLASMA CARBURIZING DARI CAMPURAN GAS He DAN CH4 PADA TEKANAN 1,8 mbar. Transmisi daya mekanik antara dua roda gigi dapat menggunakan rantai. Bagian dari mata rantai yang bergesekan langsung dengan roda gigi adalah roller rantai. Permukaan roller rantai harus memiliki sifat yang keras agar tidak mudah aus. Pengerasan permukaan roller rantai dapat dilakukan dengan pembentukan lapisan DLC pada permukaan tersebut. Lapisan DLC dapat dibentuk dengan metode plasma carburizing. Plasma carburizing dalam penelitian ini memanfaatkan lucutan pijar DC dari campuran gas helium dan gas metana pada tekanan 1,8 mbar dan temperatur 573 K, sedangkan waktu perlakuan bervariasi 1, 2, 3, 4, dan 5 jam. Hasil penelitian menunjukkan bahwa kekerasan permukaan roller rantai naik dari 276,05 VHN menjadi 403,56 VHN atau terjadi kenaikan sebesar 46,19% setelah dilakukan perlakuan plasma carburizing selama 4 jam.

KAJIAN TEKNO EKONOMI APLIKASI NITRIDASI PLASMA UNTUK PENGUATAN LAPISAN PERMUKAAN KOMPONEN OTOMOTIF. Telah diselesaikan rancang bangun Perangkat Nitridasi Ion untuk penguatan lapisan permukaan komponen mesin dengan bantuan dana oleh Kementerian Riset dan Teknologi. Pemanfaatan hasil litbangyasa ini di bidang industri perlu didahului dengan kajian ekonomi teknik untuk mendukung kelayakannya. Telah dilakukan kajian tekno-ekonomi pemanfaatan Perangkat Nitridasi Ion untuk perbaikan kualitas permukaan komponen mesin di bidang otomotif. Kajian ekonomi/kelayakan finansial yang meliputi biaya modal tetap, modal kerja, biaya produksi dan analisis Break Event Point, Payback Period dan Rate of Return telah dilakukan. Hasii anal isis ekonomi menunjukkan bahwa aplikasi Perangkat Nitridasi Ion untuk meningkatkan mutu permukaan komponen otomotif cukup potensial dan mempunyai prospek positif, dimana nilai perhitungan BEP untuk estimasi keuntungan dari 10% s/d 75% berkisar antara 52% sampai dengan 12,9% atau Payback Period antara 137 buIan sampai dengan 23,5 bulan. Analisis Rate of Return menunjukkan pencapaian tingkat suku bunga proyek (i*) sebesar 17,75%/tahun jauh lebih besar dari tingkat suku bunga simpanan di Bank sebesar 7,2%/tahun. Jika mengambil tingkat keuntungan bisnis yang wajar (50%), diperoleh nilai BEP 17,9% dan PP = 34,5 bulan, nilai yang sangat bagus. Dengan demikian dapat disimpulkan Teknologi Nitridasi Ion sangat prospektif secara ekonomi dan diharapkan mampu memacu pertumbuhan ekonomi lndustri Kecil Menengah di Indonesia.

EFEK IMPLANTASI ION Mg DAN Y TERHADAP SIFAT KETAHANAN OKSIDASI MATERIAL MA 956. Dalam makalah ini disajikan hasil penelitian tentang pengaruh implantasi ion Magnesium dan Yttrium terhadap sifat ketahanan oksidasi material MA 956. Untuk maksud tersebut material MA 956 diimplantasi dengan ion Magnesium dan Yttrium pada doses Ion 1 x 1017 ion/cm2 dan pada energi 100 keV. Untuk mengetahui pengaruh sifat ketahanan oksidasinya, sampel dipanasi pada temperatur 1100 oC dalam udara yang mengandung oksigen selama 100 jam dengan menggunakan TGA (Thermogravitymetry). Disamping itu juga telah dilakukan analisa struktur mikro menggunakan SEM dan analisa komposisi kimia menggunakan EDX, dari pengujian yang telah dilakukan diperoleh hasil bahwa untuk benda uji yang tanpa diimplantasi, untuk benda uji yang diimplantasi dengan ion Magnesium dan dengan ion Yttrium dengan waktu oksidasi 100 jam, laju oksidasinya masing-masing sekitar 0.54 mg/cm2., 0,48 mg/cm2 dan 0,40 mg/cm2. Sedangkan dari analisa struktur mikro potongan melintang terlihat bahwa ketebalan lapisan oksida masing-masing adalah sekitar 0 67μm. 0,3μm dan 0,25μm. Dari hasil tersebut dapat disimpulkan bahwa dengan adanya implantasi elemen reakif Magnesium maupun Yttrium mampu menghambat laju oksidasi dari 0,54 mg/cm2 menjadi 0,48 mg/cm2 untuk material yang diimplantasi dengan ion Magnesium dan dari 0,54 mg/cm2, meyadi 0,40 mg/cm2 untuk materialyang diimplantasi dengan ion Yttrium.

ANALISA PERMUKAAN MATERIAL ALUMINIUM PADUAN (AlSiCu) HASIL NITRIDASI ION. Paduan aluminium (AlSiCu) merupakan material yang banyak digunakan untuk komponen mesin misalnya piston dan pully karena ringan dengan kekuatan spesifiknya yang tinggi. Kelemahan utama dari paduan ini adalah kekerasan dan kehandalan aus yang rendah. Untuk mengatasi masalah tersebut dilakukan perlakuan permukaan dengan teknik nitridasi ion untuk meningkatkan kekerasan permukaan maupun kehandalan ausnya. Proses nitridasi ion ini dilakukan dengan berbagai variasi parameter meliputi: lamanya proses, tekanan dan temperatur. Untuk mengetahui hasil proses nitridasi dilakukan analisa struktur mikro dan komposisi unsur, uji keras maupun uji aus baik untuk sampel awal maupun yang telah di nitridasi. Dari hasil pengujian diperoleh bahwa kondisi optimum dari parameter proses dicapai pada lamanya proses 3 jam, tekanan 1,2 mbar dan temperatur 150 °C. Berdasarkan analisa struktur mikro dan unsur untuk hasil nitridasi pada kondisi optimun diperoleh perubahan struktur permukaan akibat terbentuknya senyawa AlN dan Al 2 O 3 dan terdeksi kandungan unsur nitrogen serta oksigen masing masing sebesar 3.95 %/berat dan 29.93%/berat. Untuk uji keras dan aus diperoleh kekerasan permukaan meningkat dari 60,24 VHN untuk material awal menjadi 120,88 V setelan dinitridasi yaitu 2,01 kalinya, keausan turun (ketahan aus meningkat) dari 4,1 × 10 -5 mm 2 /kg menjadi 3 × 10 -6 mm 2 /kg atau terjadi peningkatan ketahan aus sebesar 13.67 kalinya. Dari data tersebut dapat disimpulkan bahwa peningkatan kekerasan maupun ketahanan aus kemungkinan besar disebabkan oleh terbentuknya senyawa AlN maupun Al 2 O 3 . Dari data tersebut juga dapat disimpulkan bahwa dengan meningkatnya kekerasan maupun ketahan aus maka umur pemakaiaan komponen juga meningkat (umur pemakaian lebih lama)