Kemas Ahmad Zaini Thosin

National Research and Innovation Agency

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Toto Sudiro

National Research and Innovation Agency

Eni Sugiarti

Indonesian Institute of Sciences

Hamdan Akbar Notonegoro

Sultan Ageng Tirtayasa University

Naila Mubarok

Universitas Prima Indonesia

Ahmad Yusuf Afandi

Indonesian Agency for Agricultural Research and Development

Azwar Manaf

University of Indonesia

Hubby Izzuddin

National Research and Innovation Agency

Hubby 'Izuddin

Indonesian Institute of Sciences

Kusnandar Kusnandar

Universitas Pancasakti Tegal

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Hubby ‘Izzudin

Indonesian Institute of Sciences

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Indonesian Institute of Sciences

National Research and Innovation Agency

National Nuclear Energy Agency of Indonesia

University of Indonesia

Universitas Pamulang

IPB University

Surya University

University of North Sumatra

Hokkaido University

Material Physics Center

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The effect of mechanical deformation to the magnetic properties of stainless steel 304

Journal of Physics Conference Series (2016)

Naila Mubarok Hamdan Akbar Notonegoro Kemas Ahmad Zaini Thosin Azwar Manaf

A study of a non-magnetic 304 austenitic stainless steel alloy through mechanical deformation has been done. These specimens are pipe usually used to deliver gas which contains corrosive oil fields. The metallographic observation of a 20% deformation shows the increase in the value of the magnetization, as compensation for the formation of martensite phase as a result of a mechanical treatment. Martensitic phase formed due to a shift in the structure of the z-axis due to the effects of pressure and shear from the cold rolled. The existence of martensite phase and magnetic properties conducted through x-ray diffraction and permagraf investigation. An identified x-ray diffraction pattern shows the presence of a new peak between 10°-30° angle indicate the mechanical deformation in crystallite structure. Furthermore, at in 20% distortion, the value of magnetization is increased above 0.2 T in small coercivity value and caused decreased the ability of corrosion resistant.

Austenitic stainless steel

10.1088/1742-6596/776/1/012014

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The engineering of soft ferromagnetic plane by AISI 304 hardening process

AIP conference proceedings (2017)

Naila Mubarok Hamdan Akbar Notonegoro Kemas Ahmad Zaini Thosin Azwar Manaf

Austenitic stainless steels AISI 304 are widely used in engineering applications for various industrial applications. In basic condition, AISI 304 is non-magnetic. Shifting the structure through the hardening process will affect the magnetic properties. This technique makes it possible to produce soft ferromagnetic material through mechanical processes. A percentage of thinning rate correlated linearly with the thickness of the sample. Sizeable changing occurred at 21-30 HVC. The hysteresis curve shows the soft ferromagnetic property with small coercivity. The magnetic value significantly increased found at 344 HVC to 371 HVC and maximum when reaching 425 HVC. We suggest a 60% of thinning as a better hardening process for manufacturing soft ferromagnetic material from AISI 304.

Hardening (computing)

Ferromagnetic material properties

Austenitic stainless steel

10.1063/1.4968306

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Effect of Electrolyte Composition on Corrosion Resistance in Nickel Plating Process for Coating Bonded Magnet PrFeB

Advanced materials research (2014)

Candra Kurniawan Hayati M.A. Sholihat Kemas Ahmad Zaini Thosin Muljadi Muljadi Prijo Sardjono

Despite of its excellence magnetic quality, one of the critical properties of PrFeB based permanent magnet is a low corrosion resistance so it can be oxidized easily which can reduce its magnetic properties. In this study, Nickel coating has been performed for bonded PrFeB magnet by the electroplating method using Nickel-Watts bath-type as the electrolyte to improve the corrosion resistance. The varying amount of the electrolyte compounds used to have the optimized composition indicated by the corrosion resistance measurement. The solution composition used was NiSO 4 (230-380 g/L), NiCl 2 (30-60 g/L), and H 3 BO 3 (30 and 45 g/L) with a fixed value of other parameters. Characterization used including the immersion corrosion test, microstructure analysis, and magnetic properties. Based on the corrosion rate measurement, the highest corrosion resistant of Nickel coated PrFeB magnet achieved from the electrolyte composition of NiSO 4 : NiCl 2 : H 3 BO 3 = 380: 60: 30 g/L with a plating time and current density (J) of 60 minutes and 40 mA/cm 2 respectively. The corrosion rate data showed that the Nickel metal coating can improve the corrosion resistance of bonded PrFeB magnet up to 29 times than of the substrate. The SEM images showed that the thickness of the Nickel coating on the optimum electrolyte composition was in average value of 35.1 µm. The overall samples has a magnetic remanence value (B r ) reached ≥ 6 kG, so it has enough properties to be applied in devices such as generators and electric motors.

Plating (geology)

10.4028/www.scientific.net/amr.896.245

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Pengaruh Proses Pelapisan NiCoCrAl Terhadap Flexural Strength & Modulus Flexural Pada Baja ST-37

Rio Simatupang Frida Ulfah Ermawati Kemas Ahmad Zaini Thosin

Abstrak Telah dilakukan sintesis pelapisan lapisan NiCo dan CrAl pada baja ST-37 dengan menerapkan metode elektroplating NiCo 5% pada temperatur ± 50 °C, kemudian dilanjutkan dengan metode pack cementation pada temperatur ± 800 °C guna mendifusikan chromium (Cr) dan aluminium (Al) pada baja ST-37 sehingga diperoleh lapisan FeNiCoCrAl dengan sifat mekanik yaitu flexural strength dan modulus flexural yang lebih baik. Untuk keperluan tersebut maka uji tekuk ( bending test ) dilakukan terhadap 4 sampel yang berbeda, yaitu Fe- base , FeNiCo, FeNiCoCr, dan FeNiCoCrAl. Diperoleh hasil flexural strength dan modulus flexural terbesar berturut-turut sebesar 681,96 MPa dan 12.855,0 MPa yang dimiliki lapisan FeNiCo, sedangkan f lexural strength terkecil sebesar 483,48 MPa yang dimiliki lapisan FeNiCoCrAl, serta modulus flexural terkecil sebesar 4.434,8 MPa yang dimiliki lapisan FeNiCoCr. Simpulan dari penelitian ini ialah dengan dilakukannya proses pelapisan NiCoCrAl pada baja ST-37 yang meliputi proses elektroplating NiCo 5% dan pack cementation Cr dan Al, maka diperoleh sifat mekanik ( flexural strength dan modulus flexural ) yang justru menurun bukan meningkat seperti yang diharapkan. Hal diakibatkan karena pengaruh pemanasan yang cukup tinggi pada pack cementation sehingga dapat mempengaruhi mikrostruktur dari logam dasarnya (Fe- base ) menjadi semakin lunak dan tidak stabil fasenya. Kata Kunci : Elektroplating, Pack Cementation , NiCoCrAl, Flexural Strength , Modulus Flexural , Baja ST-37, Uji Tekuk ( bending test ). Abstract Synthesis on coating of NiCo and CrAl layer to ST-37 steel type was carried out by using electroplating and pack cementation methods. The first coating method was aimed to add NiCo layer to the surface of steel at 50 °C, while the second was addressed to diffuse CrAl layer into the FeNiCo substrate and this was carried out at 800 °C. The aim of coating is to improve mechanical properties (flexural strength and modulus flexural) of the steel. To do that, bending test was carried out to 4 different samples, namely Fe-base, FeNiCo, FeNiCoCr, and FeNiCoCrAl. The result are flexural strength and modulus flexural, respectively for the largest are 681.96 MPa and 12855.0 MPa is owned by FeNiCo layer, while the smallest flexural strength is 483.48 MPa owned by FeNiCoCrAl layer, and the smallest modulus flexural is 4434.8 MPa owned by FeNiCoCr layer. It was obtained that the thicker the NiCo coated onto the surface of the steel, then the higher the flexural strength and modulus flexural. On the other hand, the thicker the CrAl layer diffused into the FeNiCo, then the thinner the flexural strength and modulus flexural. So, by doing NiCoCrAl coating process on ST-37 steel that include electroplating NiCo 5% process and pack cementation Cr and Al can decrease the mechanical properties (flexural strength and modulus flexural) which is instead of increasing as expected. It is caused by the effect of heating is high enough so that the pack cementation can affect the microstructure of basic metals (Fe-base) become soft and unstable phase. Keywords : Electroplating, Pack Cementation, NiCoCrAl, Flexural Strength, Modulus Flexural, ST-37 Steel, Bending Test.

Cementation (geology)

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Fe-Si-Al Alloys Prepared by a Spark Plasma Sintering Technique

Materials science forum (2015)

Toto Sudiro Kemas Ahmad Zaini Thosin Didik Aryanto Agus Sukarto Wismogroho Kazuya Kurokawa

Fe-Si alloys with various concentration of Al (0, 1, 3 and 5 % by mass) were synthesized by a spark plasma sintering technique. The specimens were prepared in an evacuated chamber of less than 4 Pa and under compressive stress of 40 MPa. During spark discharge, the heating rate was fixed at 10°C/min. After the SPS process was completed, the specimen surfaces were ground with silicon carbide papers. The metallographic characterization was performed by mean of X-ray diffraction (XRD) and scanning electron microscope (SEM) equipped with energy dispersive X-ray (EDX) spectroscopy. According to sintering curves, all samples seem to have a similar sintering behavior. The densification of specimens was completed in the temperature range of about 1020-1050°C. Microstructure and phase characterization revealed that the alloys were mainly composed of FeSi 2 and FeSi phases containing oxide inclusions. The SEM images indicated that the fraction of FeSi phase and oxide inclusions appears to decrease with increase in Al concentration in the Fe-Si alloy.

Spark Plasma Sintering

10.4028/www.scientific.net/msf.827.300

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STUDI INTER-DIFUSI ALUMINIUM PADA HASTELLOY DAN LAPISAN ELECTROPLATING NIKEL

Dwi Oktarina Kemas Ahmad Zaini Thosin Ramlan Ramlan

study has been carried out on Al-Ni coating on a substrate with a plate-shaped hastelloy pack cementation method and electroplating Ni-Strike and electroplating Ni-watts.. In the method pack cementation metals Al deposited at a temperature of 800°C for 7 hours in an inert gas (argon) in a mixture powder composed of 15% Al which serves as a source of coating, 80% Al2O3 serves as an activator and 5% NH4Cl serves as an inert filler Electroplating method and Ni Nistrike- watts performed with a current of 500 mA / cm2 at a temperature of 25 ℃ in the hood for 30 seconds, to form a Ni layer of adhesive on the substrate . For electroplating Ni - watts using a current of 20 mA / cm2 a temperature of 50 ° C in a water bath for 60 minutes. During the electroplating process, the electrolyte solution kept stirred using magnetic stirerr maintain solution homogeneity. Source electrolyte solution obtained from 165 g NiSO4, 22,5 NiCl2, and 20 g H3BO3 Heat Treatment carried out at a temperature of 900oC for 10 hours in an inert gas (Argon) so that diffusion between Al in hastelloy and layer electroplating nickel lining, so hastelloy and a layer of Al-Ni can bind to form a compound that is strong and get the value of hardness (Vickers Hardness Test) and a higher power. Test analysis by SEM (Scanning Electron Microscopy) and EDS (Energy Dispersive Spectroscopy) was performed to analyze the phenomenon that is formed between the layers and find out the various elements contained in each layer

Cementation (geology)

Inert gas

Inert

Source

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Iron aluminide coating on Al by mechanical alloying

Surface Engineering (2009)

Agus Sukarto Wismogroho Wahyu Bambang Widayatno Suryadi Suryadi Kemas Ahmad Zaini Thosin Nurul Taufiqu Rochman

The formation of iron aluminide coating on an Al surface by mechanical alloying with Al–Fe powder of various compositions was investigated. When the amount of Fe powder in the starting powder is >50 at.‐%, an FeAl containing coating layer is formed. As the mass ratio of the balls and substrate to the powder in the pot is small, the formation of FeAl phase is achieved in a short time. The obtained FeAl containing coating layer has high hardness and fracture toughness. When the amount of Fe powder in starting powder is <50 at.‐%, a coating layer consisting of FeAl and Fe 2 Al 5 is formed. The coexistence of Fe 2 Al 5 in the coating layer causes the coating layer to be more brittle.

FEAL

Aluminide

Brittleness

Powder coating

10.1179/026708410x12506873242949

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Citations (14)

Development of 410S-Y2O3 oxide dispersion strengthened steel prepared by a powder metallurgy technique

IOP Conference Series Materials Science and Engineering (2018)

Toto Sudiro Ronaldus Ekaputra Kemas Ahmad Zaini Thosin Adhitya Trenggono Ahmad Yusuf Afandi

In the present study, the Oxide Dispersion Strengthened (ODS) steels were synthesized by adding various concentration of Y2O3 (0, 0.25, 0.35 and 1 wt. %) into 410S steel. The sample preparation was carried out using a powder metallurgy technique. The steel-Y2O3 powders were wet mechanically alloyed for 3 h, dried and then compacted into green body. The samples were sintered in a vacuum furnace at elevated temperatures of 1000 °C and 1100 °C for 3 h. The phase analysis and structural characterization were carried out by XRD and SEM-EDX, respectively. The bulk density and hardness of the samples were measured using Archimedes principle and Vickers hardness tester, respectively. According to the results of metallographic characterization, ODS steels are composed mainly by (Fe,Cr) phase. The SEM observations indicate the presence of precipitates in the sintered steels. The density and hardness of the sample sintered at 1000 and 1100 °C increase with the increase of Y2O3 concentration. At 1100 °C, however, the density and hardness of ODS steel containing 1 wt. % Y2O3 have a tendency to decrease due to the formation of a compound consisting of Fe, Cr, Mn, Si and O.

Powder Metallurgy

Vickers hardness test

10.1088/1757-899x/432/1/012021

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The influence of Cr and Al pack cementation on low carbon steel to improve oxidation resistance

AIP conference proceedings (2012)

Didik Prasetya Eni Sugiarti Fredina Destyorini Kemas Ahmad Zaini Thosin

Pack chromizing and aluminizing has been widely used for many years to improve hot temperature oxidation and corrosion resistance of metals. The coating process involves packing the steel in a powder mixture which contain aluminum and chromium source, and inert filler (usually alumina), and halide activator NH4Cl. Al and Cr were deposited onto carbon steel by pack cementation process using elemental Al and Cr powder as Al and Cr source, whereas NiCo alloys codeposited by electrodeposition. The position of Al and Cr could be under or over Ni-Co alloys deposited. Pack cementation was heated on dry inert gas at temperature 800 °C about 5 hours and 20 minute for Cr and Al respectively. Al and Cr was successfully deposited. Laying down effect of Al and Cr onto carbon steel whether up and down toward NiCo alloys coating have affected to oxidation resistance. The pack aluminizing as top layer given best resitance to restrain excessive oxide scale, in contrast pack chromizing reveal bad oxidation resistance, moreover occured spallation on layer.

Cementation (geology)

Inert gas

Inert

Carbon steel

Carbon fibers

10.1063/1.4730729

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Synthesis of alumina ceramic encapsulation for self-healing materials on thermal barrier coating

Journal of Physics Conference Series (2018)

Obert Golim Niki Prastomo Hubby ‘Izzudin Sri Hastuty R Sundawa

Durability of Thermal Barrier Coating or TBC can be optimized by inducing Self-Healing capabilities with intermetallic materials MoSi2. Nevertheless, high temperature operation causes the self-healing materials to become oxidized and lose its healing capabilities. Therefore, a method to introduce ceramic encapsulation for MoSi2 is needed to protect it from early oxidation. The encapsulation process is synthesized through a simple precipitation method with colloidal aluminum hydroxide as precursor and variations on calcination process. Semi-quantitative analysis on the synthesized sample is done by using X-ray diffraction (XRD) method. Meanwhile, qualitative analysis on the morphology of the encapsulation was carried out by using Scanning Electron Microscope (SEM) and Field Emission Scanning Electron Microscope (FESEM) equipped with dual Focus Ion Beam (FIB). The result of the experiment shows that calcination process significantly affects the final characteristic of encapsulation. The optimum encapsulation process was synthesized by colloidal aluminum hydroxide as a precursor, with a double step calcination process in low pressure until 900 °C.

Encapsulation

Alumina ceramic

10.1088/1742-6596/985/1/012036

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