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2. UTILISATION OF NATURAL HYDROXYAPATITE FROM LATES CALCARIFER SCALES TO INCREASE THE BIOACTIVITY IN SS 316L WITH THE DIP COATING METHOD FOR BONE IMPLANTS

Author

Nurfitri Rahmi Sari, Riza Verdian, Putra Iqbal Yunanda, Affi Jon, Indra Ade, Nanda Is Prima, and Gunawarman

Subjects
ss 316l, hydroxyapatite, lates calcarifer scales, dip coating, withdrawal speed, Clay industries. Ceramics. Glass, TP785-869
Abstract

Hydroxyapatite (HA) from Lates calcarifer scales was used as a coating material for 316L Stainless Steel (SS 316L) to determine the influence of the thickness and withdrawal speed on the morphology of the layer. The dip coating method was used with variations in the mass of the HA in the coating suspension at a constant immersion time and carried out at 2 withdrawal speeds. The withdrawal speed used was 2 mm/s and 4 mm/s with variations in the HA content in the suspension of 4 g, 8 g, and 12 g at a constant immersion time of 10 seconds. Analysis of morphological characteristics and thickness were observed with a Stereo Microscope, Scanning Electron Microscopy (SEM) and a Sanfix Thickness Gauge. Based on the data obtained from this study, the optimal layer morphology is at a withdrawal speed of 2 mm/s with a mass of HA as much as 12 g in suspension because it has a uniform thickness value according to the biomedical standards and a coated surface area of 91.8%.

Published
2023
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4. UTILISATION OF NATURAL HYDROXYAPATITE FROM WHITE BARRAMUNDI FISH (LATES CALCARIFER) SCALES FOR COATING TITANIUM ALLOY (Ti6Al4V ELI) USING DIP COATING METHOD TO IMPROVE BIOACTIVITY IN BIOMEDICAL APPLICATION

Author

Riza Verdian, Nurfitri Rahmi Sari, Ferbriansyah Fikri, Affi Jon, Ridwan Firman, and Gunawarman

Subjects
ti6al4v eli, hydroxyapatite, white barramundi fish scales, dip coating, coating time, Clay industries. Ceramics. Glass, TP785-869
Abstract

Ti6Al4V ELI is a titanium alloy that is quite widely used in medical applications for prosthesis implants. Ti6Al4V ELI has high corrosion resistance and good biocompatibility, but is less bioactive for new bone growth sites. Improving the bioactive properties of titanium alloys can be undertaken by coating them with hydroxyapatite. In this study, the type of hydroxyapatite used is a natural hydroxyapatite which is processed from local Indonesian ingredients, namely white barramundi fish scales (Lates calcarifer). White barramundi scales are a type of waste that contains high calcium, so they have the potential to be a source of hydroxyapatite. The purpose is to determine the characteristics of the natural hydroxyapatite layer on the mechanical properties and surface properties of the Ti6Al4V ELI titanium alloy. The hydroxyapatite coating was conducted by the dip coating method with a coating time of 10, 14, 24, and 30 seconds. The characterisation was carried out using a Stereo Microscope and SEM. The results showed that the hydroxyapatite layer met the thickness parameters in biomedical applications in 14 minutes with a layer thickness of 199 μm. This result is better than previous studies using the electrophoretic deposition method at a voltage of 7 V for 10 seconds where the layer thickness was 72 μm. This indicates that such a simple method of dip coating with an optimum parameter is applicable for coating titanium alloys with a natural hydroxyapatite.

Published
2022
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5. ADHESION BONDING OF HYDROXYAPATITE WITH ADDITION OF ZIRCONIUM OXIDE ON Ti-6Al-4V ELI FOR ORTHOPAEDIC IMPLANT

Author

Sanny Ardhy, Gunawarman, Affi Jon, and Yetri Yuli

Subjects
cross-cut, dip coating, hydrophilic, osseointegration, titanium alloy, Clay industries. Ceramics. Glass, TP785-869
Abstract

The lack of adhesion bonding of a hydroxyapatite (HA) coating layer on the surface of an implant material can cause the coating layer to peel off during implantation and will increase the risk of metallic ion release into the human body and may also to increase the inflammatory effect and slow down the osseointegration process. In order to increase the adhesion of HA coated Ti-6Al-4V ELI, zirconia (ZrO₂) was added into the coating layer. The coating process of the HA suspension with addition of ZrO₂ on Ti-6Al-4V ELI sample surfaces was conducted by using dip-coating method. The samples were then heated to 800, 900, and 950 °C. The coating layer properties were then examined using a light microscope. The improvement in the adhesion bonding was correlated by calculating the removed area on the layer using the cross-cut tape test method and calculating the contact angle of the coating. The low value of the removed area and contact angle of the coating indicated the adhesion coating is good. The test specimen with the ZrO₂ addition has a lower removed area than the test specimen without the ZrO₂ addition. The value of the removed area also correlates with the obtained layer contact angle. The test specimen with the ZrO₂ addition has a lower contact angle (hydrophilic coating) than the test specimen without the ZrO₂ addition. The adhesion of this strong hydroxyapatite layer is good for improving the osseointegration.

Published
2022
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10. Effect of type and number of grinding balls on physical characteristics of chicken egg shells powder using ball mill.

Author

Sari, Nurfitri Rahmi, Verdian, Riza, Martha, Tomi, Affi, Jon, Indra, Ade, Nanda, Is Prima, and Gunawarman

Subjects
BALL mills, POWDERS, METALS in surgery, EGGSHELLS, EGGS, CRAB shells, SNAIL shells, METAL coating, CERAMIC materials
Abstract

Bio-ceramic powder from chicken egg shells has been made using a planetary ball mill with varied numbers and types of grinding balls and gradual heating. Chicken egg shells powder is used as a precursor for manufacturing Hydroxyapatite (HA) bio-ceramic material. HA is used as a scaffold, bone filler, and metal implant coating. The manufacture of HA powder with a fine size is very well used for making bone grafts. HA, which consists of calcium and phosphate, is the main component of bone. HA sourced from organic materials such as bovine bones, pig bones, fish bones, goat bones, clam shells, egg shells, snail shells, crab shells, and so on. The research was conducted using a ball mill with variations in the number and ball milling. The balls used are agate and stainless steel. Milling will be carried out in two stages in each variation, namely grinding without gradual heating and grinding followed by gradual heating to a temperature of 900°C. Milling was carried out at 200 rpm for 2 hours. Furthermore, the chicken egg shells powder was characterized using a Scanning Electron Microscope (SEM). The results showed that milling using 45 balls effectively reduced powder size. The powder size decreased in the first stage by 175 µm in the second stage to 32 µm. The Stainless Steel grinding ball type is more effective in reducing powder size than the Agate ball type. The difference in powder size between the two types of balls in the first stage was 133 µm and in the second stage was 80 µm. [ABSTRACT FROM AUTHOR]

Published
2024
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13. Contribution of hydroxyapatite layer on corrosion and bioactivity properties of Ti-12Cr in simulated body fluid.

Author

Gunawarman, Affi, Jon, Ilhamdi, Idris, Irfan, Akahori, Toshikazu, and Niinomi, Mitsuo

Subjects
*BODY fluids, *HYDROXYAPATITE, *BIOACTIVE glasses, *SCANNING electron microscopes, *COATING processes, *SURFACES (Technology), *TITANIUM alloys
Abstract

Biomaterial implant is a material use for biomedical applications such as for fixing bone fractures. One of materials used in this application is titanium and its alloys because they have a better biocompatibility and biomechanical properties than other metals. However, titanium and its alloys are less bioactive to induce bone osseointegration with living tissue as compared with the other bioactive materials. Therefore, it is necessary to conduct a coating treatment on the material using bioactive substances such as hydroxyapatite (HA). In this study, a coating process of HA on Ti-12Cr surface was carried out by using an electrophoretic deposition (EPD) method and subsequently sintered at a temperature of 700°C. The sample was then immersed into simulated body fluid (SBF) solution using an incubator shaker at a temperature of 36.5°C for 1, 2, 3 and 4 weeks. The surface of the material was examined using a light microscope and a scanning electron microscope (SEM). The weight loss method was used to determine the corrosion rate by comparing the weight of the material before immersion and after immersion in SBF solution. The SEM micrographs shows the presence of apatite growth in the second week to the fourth week on the surface of the hydroxyapatite-coated materials. The surface is covered by tapered hydroxyapatite cells that increases along with increasing immersion time. This indicates the improvement of bioactivity of the material surfaces. While, uncoated materials have several cavities in the surface indicating initial corrosion process. The corrosion rate of the uncoated material is much higher than that of the coated material indicating that HA coating improves not only bioactivities but also corrosion resistance. [ABSTRACT FROM AUTHOR]

Published
2023
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14. Zirconium oxide contribution for cracking reduction of the hydroxyapatite-based coating layer on Ti-6AL-4V ELI surface through dip-coating method.

Author

Ardhy, Sanny, Gunawarman, Affi, Jon, and Yetri, Yuli

Subjects
ZIRCONIUM oxide, HYDROXYAPATITE, HYDROXYAPATITE coating, SURFACE coatings, CALCIUM phosphate, ORTHOPEDIC implants, SCANNING electron microscopes
Abstract

Ti-6Al-4V Extra Low Interstitials (ELI) is one of the most widely used titanium alloys for orthodontic and orthopedic implants. However, several studies revealed that cracks are often found in the surface of the hydroxyapatite coating layer, possibly can trigger implant failure. This study aimed to minimize the cracks and also to strengthen the coating layer on Ti-6Al-4V ELI, by adding zirconium oxide (ZrO2) into the composites. The results were expected to provide advantages, especially for biomedical applications in accelerating the growth of new bones during the implantation process. This study used the dip-coating method, which is quite inexpensive and easy to perform to obtain an even layer of hydroxyapatite over the entire surface of the implant material. The hydroxyapatite used was commercial nano-sized hydroxyapatite, which would later be mixed with zirconium oxide (wt%: 16,67% and 20%) to strengthen the coating. After the specimens were coated, the sintering process was carried out at temperatures of 800 °C, 900 °C, and 950 °C. Microstructure examination was then carried out using a scanning electron microscope (SEM) to observe the morphology of the coating layers; whether or not the coating had been evenly distributed over the entire surfaces and whether or not there were cracks. The results showed that the addition of zirconium oxide could minimize cracks in the Ti-6Al-4V ELI surface. Optimal results were obtained with the addition of ZrO2 (wt%: 20) at a sintering temperature of 900 °C; the surface of the implant material was evenly coated and no cracks were found. [ABSTRACT FROM AUTHOR]

Published
2023
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20. Improvement in Bioactivity Properties of Hydroxyapatite Coated Ti-6Al-4V ELI with Addition of Zirconium Oxide for Orthopaedic Implant

Author

Ardhy, Sanny, Gunawarman, Affi, Jon, and Yetri, Yuli

Abstract

One of factor causing the failure of Ti-6Al-4V Extra Low Interstitial (ELI)-based material implants, does not have bioactive properties in the implantation process, thus not supporting the osseointegration process in the body. For this reason, coating with hydroxyapatite (HA) suspension is necessary. This research used the dip-coating method and added Zirconium Oxide (ZrO2) into nanosized commercial HA to be suspensions (17%wt and 20%wt) to strengthen the adhesion of the coating. The specimens were heated at 800, 900, and 950°C to densify the layers. Bioactivity increased along with the increasing calcium/phosphate (Ca/P) ratio of the HA layers in the test specimens. The specimens were immersed in Simulated Body Fluid (SBF), namely Hank’s Solution, for 1, 2, 3, and 4 weeks. ZrO2 added to the HA suspensions of Ti-6Al-4V ELI can increase the Ca/P ratio from 1.51 in the first immersion week to 1.62 in the fourth. The bioactivity level is also proven by the accumulation of calcium and phosphate on the surface of the coating. The Ca/P value close to the Ca/P ratio of HA of 1.67 is good for improving the osseointegration process in the body.

Published
2023
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21. Pengaruh Waktu dan Temperatur Larutan Terhadap Ketebalan dan Kekerasan Permukaan Lapisan Hasil Elektroplating Kuningan Pada Baja

Author

Yetri, Yuli, Marsedi, Ultra, Affi, Jon, and Leni, Desmarita

Abstract

Telah dilakukan analisa proses elektroplating kuningan pada permukaan baja terhadap ketebalan dan kekerasan hasl lapisannya. Proses elektroplating dilakukan terhadap baja karbon rendah ST 37 dengan memvariasikan waktu (10 menit, 15 menit, 20 menit, dan 25 menit), dan temperatur larutan( 40°C, 45°C, 50°C, dan 55°C. Untuk mengetahui kualitas hasil lapisan diamati dengan menggunakan mikroskop stereo dan alat uji keras Vicker untuk mengukur ketebalan dan kekerasannya. Hasil pengujian menunjukan bahwa peningkatan waktu dan suhu sebanding dengan ketebalan dan nilai kekerasan. Nilai rata-rata ketebalan dan kekerasan terendah 11,323 μm 182,4 VHN pada 40°C dengan waktu pewarnaan 10 menit. Sedangkan nilai rata-rata ketebalan dan kekerasan tertinggi 29,333 μm dan 218,8 VHN yang diperoleh pada temperatur 55°C selama 25 menit. Hasil pengamatan menunjukan peningkatan nilai ketebalan dan kekerasan secara signifikan setelah waktu 20 menit. Hal ini menunjukan semakin tinggi suhu larutan, akan mengurangi penyerapan hidrogen ke endapan sehingga terjadi peningkatan kekerasan permukaan dari lapisan yang dihasilkan akibat dari semakin banyak sedimen yang menempel pada katoda. Peningkatan waktu dan temperatur larutan yang diberikan berbanding lurus dengan ketebalan dan nilai kekerasan yang dihasilkan di permukaan logam., Brass electroplating process has been analyzed on the steel surface for the thickness and hardness of the coating. The electroplating process was carried out on low carbon steel ST 37 by varying the time (10 minutes, 15 minutes, 20 minutes and 25 minutes), and the temperature of the solution (40 °C, 45 °C, 50 °C, and 55 °C). To determine the quality of the coating results were observed using a stereo microscope and Vicker hard test equipment to measure the thickness and hardness. The test results show that the increase in time and temperature is proportional to the thickness and hardness value obtained. The lowest average thickness and hardness value was 11,323 μm 182.4 VHN at 40 °C with 10 minutes coloring time. While the highest average thickness and hardness values were 29.333 μm and 218.8 VHN were obtained at a temperature of 55 °C for 25 minutes. The observations showed a significant increase in thickness and hardness values after 20 minutes. This shows that the higher the solution temperature, it will reduce the absorption of hydrogen into the sludge resulting in an increase in the surface hardness of the resulting layers due to more sediment attached to the cathode. The increase in time and temperature of the solution given is directly proportional to the thickness and hardness value produced on the metal surface.

Published
2020
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24. Improvement of the Corrosion Resistance and Potential for Metal Ion Release of Titanium Alloy Ti-6Al-4V ELI in Hanks Balanced Salt Solution (HBSS) after Thermomechanical

Author

Anderson, Sir, Al-Bayummy, Tansri Ayub, Affi, Jon, Yetri, Yuli, and Gunawarman

Abstract

Ti-6Al-4V ELI is one of the titanium alloys commonly used as an implant material for its good biocompatibility. However, it has problems related to its corrosion behavior, especially when it is used for a long time. This study aimed to analyze the corrosion behavior of the implant material Ti-6Al-4V ELI in Hanks’ Balanced Salt Solution (HBSS) for a certain period, using the weight loss method in HBSS as the corrosive medium at 37°C. The immersion time was varied from two, four, until six weeks. Before immersion, the sample was thermomechanically treated with a combination of solution heat treatment at a temperature of 950°C and a holding time of 1 hour, water quenching, plastic deformation with deformation variations of 10%, 15%, and 20%, and, finally, aging heat treatment at a temperature of 550°C and holding time for 1.5 hours. The study results show that thermomechanical treatment and increased plastic deformation could reduce the corrosion rate and the metal ions released into the solution. These findings were evidenced by the corrosion rates of the pre-thermomechanical and the thermomechanical Ti-6Al-4V ELI with deformations of 10%, 15%, and 20% at the 6-week immersion of 6.57 x 10-6 mmpy, 4.27 x 10-6 mmpy, 3.89 x 10-6 mmpy, and 2.76 x 10-6 mmpy, respectively, and the metal ions released of 7.3 μg/L, 7 μg/L, 6.3 μg/L, and 6 μg/L, respectively. The corrosion rate of Ti-6Al-4V ELI under thermomechanical treatment, namely 2.76 x 10-6 mmpy, was the lowest compared to other materials in HBSS, while the highest one was that of Ti-6Al-7Nb of 3.05 x10-2 mmpy. In addition, the study results show that Ti-6Al-4V ELI under thermomechanical treatment is the best material compared to others for biomedical applications, based on corrosion resistance and metal ions released into HBSS.

Published
2022
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25. Shear strength and microstructure of joints processed with free vacuum diffusion bonding.

Author

Affi, Jon, Diaz, Rahmad, Nugraha, Teguh, Gunawarman, Aji, Daisman Purnomo Bayyu, Triyono, Triyono, and Nor, Fethma

Subjects
*SHEAR strength, *METALWORK, *MECHANICAL behavior of materials, *LAMINATED metals, *GRINDING & polishing
Abstract

A sequence experiments were performed to clarify the influence of material combination on the mechanical properties of bonding dissimilar metals. The strength of bonding of three combinations of dissimilar metal was compared in this work i.e., Aluminium AA 5052-Copper C10100 (AC), Copper C10100-Steel AISI 1045 (CS) and Steel AISI 1045 and Aluminium AA 5052 (SA). Prior to joining proses, the surfaces of both material involved were prepared by grinding and polishing. During the joining process, both materials were clamped and held in the chamber of conditioned heat treatment furnace at elevated temperature to facilitate migration atom occurred at the interface. The initial results showed that all of the combinations of dissimilar metal investigated in this work success to form the joint. However, the joint between AISI 1045 and Al AA5052 has the lowest strength value. The joints were peeled during its preparation for the shear test specimen. Conversely, joint between Copper C10100-Steel AISI 1045 (CS) and Steel AISI 1045 and Aluminium AA 5052 (SA) have a better strength compared to that of steel and aluminium. In the case of steel to copper bimetal, the highest joint strength was achieved without the formation of the intermetallic phase at the interphase. On the other hand, copper-aluminium bimetal bonding has a lower shear strength, which is probably caused by the brittle intermetallic phase. [ABSTRACT FROM AUTHOR]

Published
2020
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27. Comparative Study of the Physical and Tensile Properties of Jicama (Pachyrhizus erosus ) Starch Film Prepared Using Three Different Methods

Author

Abral, Hairul, primary, Soni Satria, Riyan, additional, Mahardika, Melbi, additional, Hafizulhaq, Fadli, additional, Affi, Jon, additional, Asrofi, Mochamad, additional, Handayani, Dian, additional, Sapuan, Salit M., additional, Stephane, Ilfa, additional, Sugiarti, Eni, additional, and Muslimin, Ahmad Novi, additional

Published
2019
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32. Corrosion behavior of new beta type Ti-29Nb-13Ta-4.6Zr alloy in simulated body fluid solution

Author

Ilhamdi Ilhamdi, Refieska Andrew, Cho Ken, Hermawan Hendra, Gunawarman Gunawarman, Niinomi Mitsuo, Affi Jon, and Nakai Maasaki

Subjects
Histology, Materials science, Simulated body fluid, Alloy, Biomedical Engineering, Bioengineering, 02 engineering and technology, 010501 environmental sciences, engineering.material, 021001 nanoscience & nanotechnology, 01 natural sciences, engineering, Composite material, Beta type, 0210 nano-technology, Corrosion behavior, 0105 earth and related environmental sciences, Biotechnology
Published
2016
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33. Electrophoretic Deposition (EPD) of Natural Hydroxyapatite Coatings on Titanium Ti-29Nb-13Ta-4.6Zr Substrates for Implant Material

Author

Fajri, Hidayatul, Ramadhan, Fuad, Nuswantoro, Nuzul Ficky, Juliadmi, Dian, Tjong, Djong Hon, Manjas, Menkher, Affi, Jon, Yetri, Yuli, and Gunawarman

Abstract

This study aims to investigate the effect of the electrophoretic deposition process (EPD) of natural HA (extracted from bovine bones) with various particle size on Ti-29Nb-13Ta-4.6Zr (TNTZ) coating surfaces. HA particles were refined from bovine bone powders using planetary ball mill and then sieving to separate the particle based on its size. The maximum size according to sieving mesh size is #25 µm, #63 µm and #125 µm. The coating process was conducted by using EPD apparatus with voltage and time process 10V and 5 minutes, respectively, for each sample. The coating layer morphology was observed with Stereo Microscopy, Scanning Electron Microscopy (SEM) and the thickness was measured with Thickness Gauge. The result shows that the size of the particle determines the coating layer characteristics. The best of HA coating quality according to the implant coating standard is obtained for the 25 µm particle size with the surface coverage is 99%. The thickness is 121 µm and the ratio of chemical composition Calcium and Phosphor Ca/P) is 1,49%. These may be concluded that, on the point of view physical characteristics, natural HA from bovine bone has potential enough as a coating layer to improve the bioactivity implant for biomedical application. However, the mechanical characteristic of the layer is still needed to determine the strength of coating layer for avoiding delamination during application.

Published
2020

34. Electrophoretic Deposition Performance of Hydroxyapatite Coating on Titanium Alloys for Orthopedic Implant Application

Author

Nuswantoro, Nuzul Ficky, Juliadmi, Dian, Fajri, Hidayatul, Manjas, Menkher, Suharti, Netti, Tjong, Djong Hon, Affi, Jon, and Gunawarman

Abstract

Hydroxyapatite (HA) is potentially used as a coating material for titanium alloys to improve their bioactivity and then enhancing the osseointegration characteristic of metal implants for orthopedic application. Electrophoretic Deposition (EPD), one of the coating methods that is widely applied for coating metal because of its simplicity and relatively low cost, is chosen for coating metal implants. HA coating layer quality can be controlled by adjusting applied voltages and coating time of the EPD process. However, the optimum voltage and exposing time has not yet been known for new type titanium implant such as Ti-12Cr and TNTZ. This work is, therefore, focusing on the effect of applied voltage and coating time on the mass growth, HA coating thickness, and surface coverage that can be produced on the surfaces of both alloys, and also on the conventional titanium alloy, Ti6Al4V, for comparison. The result of this work showed that there is a significant influence of the titanium alloy type on the HA layer performances. However, it is necessary to choose a suitable voltage and to expose time for producing a sufficient coating layer that meets the standard of orthopedic implants.

Published
2020

35. The Coating of Bovine-Source Hydroxyapatite on Titanium Alloy (Ti-6Al-4V ELI) Using Electrophoretic Deposition for Biomedical Application

Author

Juliadmi, Dian, Nuswantoro, Nuzul Ficky, Fajri, Hidayatul, Indriyani, Irma Yulia, Affi, Jon, Manjas, Menkher, Tjong, Djong Hon, and Gunawarman

Abstract

Research about the utilization of titanium alloy (Ti-6Al-4V ELI) as implant material in the treatment of orthopedic cases had been increasing. Health problems appear due to the drawbacks of using titanium. The lack of titanium using is bio-inertness characteristic, which decreasing its bioactivity and results in low bone growth and effect for implant failure. The titanium can be modified with coating on the surface using a bioactive substance that is natural-source hydroxyapatite. Bovine-source hydroxyapatite (bovineHA) contains apatite component that is similar to human bone apatite. The coating process was carried out using particle size variation (25 μm, 63 μm, and 125 μm) of bovineHA. The electrophoretic deposition (EPD) method was applied to coat hydroxyapatite with 10 volt for 5 minutes onto the titanium surface. The result showed that different size particles have an effect on coating properties. The coating composed by particle-sized 25 μm has better surface coverage (95.89%), indicating more particle mass (particle weight 6.97x103 μg) attached to surface material, thus resulting thick coating. The good coating characteristic using bovine-source hydroxyapatite with small particle size was expected can be used in biomedical applications due to fulfill the prerequisite of the bone implant.

Published
2020

36. PENGARUH LAPISAN OKSIDA TAMBAHAN PADA ELEKTRODA E 6013 TERHADAP SIFAT MEKANIK DAN STRUKTUR MIKRO LASAN BAJA KARBON RENDAH

Author

Affi, Jon and Gunawarman, Gunawarman

Subjects
TJ Mechanical engineering and machinery
Abstract

Elektroda stick pada pengelasan SMAW adalah logam isisan yang dibungkus fluks. Jenis elektroda E 6013 merupakan jenis yang banyak digunakan dengan harga yang cukup murah. Komposisi fluks secara detail dari elektroda stick ini tidak diketahui secara pasti. Fluks pada elektroda stick mempunyai banyak fungsi seperti penambah unsur paduan, terbakar sebagi gas pelindung dan pemantap busur. Penelitian ini dilakukan karena adanya keinginan untuk meningkatkan kualitas sambungan las menggunakan elektroda E 6013 dengan biaya yang relatif murah untuk jenis baja yang lain seperti baja karbon medium dan baja paduan rendah. Pengelasan dilakukan pada plat baja karbon rendah ST 37setebal 10 mm. Elektroda yang digunakan adalah E 6013 berdiameter 2.6mm. Alur sambungan dibuat bersudut 90o dengan jarak akar 1.6 mm. Elektroda dilapisi dengan variasi jenis fluks tambahan yang dilarutkan dalam aseton. Sebanyak 3 sampel plat dilas dengan masing menggunakan fluks tambahan yaitu Al2O3, TiO2, dan MnO serta satu sampel plat tanpa fluks tambahan. Keempat plat dilas dengan parameter pengelasan yang sama untuk mengetahui pengaruh masing-masing fluks terhadap sifat mekanik dan struktur mikro sambungan. Hasil pengujian tarik menunjukkan adanya peningkaan kekuatan pada daerah HAZ untuk semua jenis fluks dibanding tanpa plat tanpa tambahan fluks. Fluks dari jenis TiO2 mempunyai efek yang lebih besar dari fluks lainnnya. Pengujian bending dan pengujian kekerasan mikro juga menunjukkan kecendrungan yang sama. Hal ini dibuktikan dengan kemapuan ketiga fluks dalam mereduksi penyusupan hidrogen dan oksigen selama pengelasan. Jumlah Void dan inklusi ditemukan lebih sedikit pada pengelasan menggunakan fluks Al2O3, TiO2, dan MnO dibanding tanpa fluks tambahan. Jumlah void dan inklusi yang paling sedikit diperoleh dari penggunaan fluks TiO2. Pengamatan fasa-fasa pada sampel las yang dietsa juga menunjukkan penurunan ukuran butir( grain refinement) yang tampak pada weld metal. Pengaruh yang lebih dominan antara penurunan void/inklusi dan penurunan ukuran butir pada weld metal terhadap peningkatan sifat mekanik tidak bisa ditentukan. Tetapi kedua sebab ini punya kontribusi masingmasing. Keyword: Fluks Al2O3, TiO2, MnO, Elektroda E6013, Sifat Mekanik, Void, Grain refinement.

Published
2014

38. Potensi Penyambungan Antara AA 5052 dengan AISI 1045 Menggunakan Free Vacuum Diffusion Bonding

Author

Eriend, Robby, Affi, Jon, Gasni, Dedison, Amin, Zulkifli, Eriend, Robby, Affi, Jon, Gasni, Dedison, and Amin, Zulkifli

Abstract

Penyambungan untuk logam-logam yang berbeda jenis telah banyak digunakan untuk komponen–komponen yang membutuhkan kedua sifat dari logam yang disambung. Friction welding merupakan salah satu contoh dari proses pengelasan padat yang digunakan untuk penyambungan logam yang berbeda jenis. Beberapa kelemahan dari hasil sambungan friction welding ini masih ditemui diantaranya, terjadinya perubahan dimensi dari hasil sambungan, perlunya proses penyelesaian lanjutan setelah proses penyambungan, terdapatnya logam yang terbuang pada proses penyambungan, serta tidak fleks ibel pada beberapa kondisi sambungan yang membutuhkan ketelitian tinggi. Penyambungan presisi untuk komponen-komponen yang membutuhkan ketelitian tinggi hanya bisa dilakukan dengan penyambungan dif usi. Berhubung proses penyambungan difusi membutuhkan peralatan yang mahal serta biaya produksi yang tinggi (listrik dan waktu proses), maka penyambungan difusi dengan tungku perlakuan panas menjadi menarik untuk digunakan. Perlindungan proses pada penyambungan difusi menggunakan tungku perlakuan panas bisa dilakukan dengan mengalirkan gas pelindung argon untuk menekan induksi oksigen ke daerah sambungan. Proses penyambungan ini biasa dikenal sebagai free vacuum diffusion bonding. Ketersambungan logam berbeda jenis dengan free vacuum diffusion bonding telah diamati dan dikarakterisasi. Material yang digunakan pada penelitian ini adalah aluminium AA 5052 – baja AISI 1045. Tekanan kontak pada sambungan diber ikan me lalui hydraulic press sebesar 94 MPa dengan temperatur pemanasan yang diatur pada tungku perlakuan panas sebesar 490oC. Debit aliran gas pelindung digunakan sebagai variasi pengujian yaitu tanpa argon, argon aliran 1 liter/menit (lpm), dan argon aliran 3 liter/menit (lpm). Hasil sambungan yang didapatkan antara AA 5052–AISI 1045 menggunakan metode free vacuum diffusion bonding dengan tiga buah variasi aliran gas argon masih belum baik, dimana hanya pada variasi argon aliran 1 liter/menit (lpm) dan argon

Published
2014

39. Karakterisasi Sambungan Logam-Logam Berbeda Jenis Hasil Penyambungan Difusi dengan Tungku Tanpa Vakum

Author

Affi, Jon, Gasni, Dedison, Amin, Zulkifli, Diaz, Rahmad, Danniel, Muhammad, Eriend, Robby, Affi, Jon, Gasni, Dedison, Amin, Zulkifli, Diaz, Rahmad, Danniel, Muhammad, and Eriend, Robby

Abstract

Pengelasan difusi adalah penyambungan padat untuk logam-logam yang tidak mungkin diproses dengan metoda penyambungan lain. Logam-logam disatukan pada temperatur tertentu di dalam tungku vakum sehingga kontak kedua permukaan logam menjadi media untuk migrasi atom-atom dari konsentrasi tinggi ke konsentrasi rendah. Untuk mereduksi waktu proses yaitu dengan meniadakan proses pemakuman telah digunakan tungku perlakuan panas untuk penyambungan logam-logam. Fungsi pemakuman digantikan dengan mengalirkan gas inert ke dalam tungku sehingga induksi oksigen ke daerah sambungan bisa dikurangi. Tiga kombinasi logam telah digunakan yaitu baja AISI 1045-Tembaga C10100, Baja AISI 1045-Alumnium AA5052 dan Baja AISI 1045-Tembaga C10100. Permukaan yang disambung telah disiapkan dengan amplas hingga #2000 yang dilanjutkan dengan pemolesan menggunakan pasta alumina. Ketersambungan logam menggunakan tungku tanpa vakum ini telah diamati. Kekuatan sambungan telah dievaluasi menggunakan uji geser serta pengamatan sisi sambungan dilakukan menggunakan scanning electron microscope. Analisis komposisi atom dekat sisi sambungan dikarakterisasi dengan menggunakan EDX. Ketiga kombinasi sambungan bisa disambung dengan proses difusi menggunakan tungku tanpa vakum. Dua kombinasi sambungan baja-tembaga dan tembaga-alumnium cukup kuat sehingga bisa diuji geser. Sedangkan ketersambungan baja-aluminium tidak begitu sempurna dan terlepas saat akan dipotong. Ketersambungan ketiga kombinasi logam sangat dipengaruhi oleh laju gas pelindung yang dialirkan. Gas gas argon dengan laju tertinggi memberikan ketersambungan terbaik. Kombinasi sambungan tembaga-alumnium membentuk 3 inter layer dengan ketebalan 10 hingga 20 µm per layer. Masing-masing inter layer membentuk bidang pisah yang nyata sesamanya dan dengan logam induknya. Bidang pisah yang nyata ini memberikan kemudahan untuk retak merambat saat sambungan diuji geser. Sebaliknya untuk sambungan kombinasi baja-tembaga, tidak terbentuk inter layer. Ketebalan

Published
2014

40. INVESTIGATION OF WEAR MECHANISM IN BALL BEARINGS LUBRICATED BY A BIO-LUBRICANT.

Author

Gasni, Dedison, Mulyadi, Ismet Hari, Affi, Jon, and Miswar, Andrea Yulandra

Subjects
FRETTING corrosion, BALL bearing lubrication, COCONUT oil
Abstract

Due to increased environmental sensitivity, renewable-based lubricants, and food grade lubricants are being considered potential alternatives to petroleum-based lubricants. Understanding of bio-lubricant in relation to abrasive wear is essential for using ball bearings in industrial implementation. This study focused on wear mechanism on ball bearings lubricated by bio-lubricants. Palm oil and coconut oils were used in this study. Coconut oils were made by two processes, namely dry and wet processing, resulting in three types of oil (virgin coconut oil [VCO], refined coconut oil [RCO], and hydrogenated coconut oil [HCO]). Full-scale bearing life tests were conducted with 300 N load with 2,840 rpm for 6 hours. Method of lubrication was circulating oil by using pump injection to the self-aligning ball bearings. The results show that the main wear mechanism, which impacted on the surfaces of inner race, outer race, and ball for different bio-lubricants, were abrasive and adhesive wear. It found that the abrasion rate was the least severe for VCO. The discrepancies of worn surfaces are thought to be as a result of the physical and chemical properties of bio-lubricants. [ABSTRACT FROM AUTHOR]

Published
2017
Full Text
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41. Penggunaan Gas Argon sebagai Pelindung Proses pada “Free Vacuum Diffusion Bonding'. Studi Kasus Sambungan Aluminium AA 5052 dan Tembaga Murni Komersil

Author

Affi, Jon, Febriyandi, Febriyandi, Gasni, Dedison, Amin, Zulkifli, Affi, Jon, Febriyandi, Febriyandi, Gasni, Dedison, and Amin, Zulkifli

Abstract

Penyambungan dua material logam secara permanen biasanya dilakukan dengan cara pengelasan fusi. Sebagian kecil dari kedua logam dicairkan dan disatukan sehingga terbentuk sambungan saat pembekuan kedua logam tersebut. Pencairan sebagian logam ini akan berakibat terjadi perubahan struktur mikro dari logam yang disambung baik pada bagian yang mencair ataupun pada sisi didekatnya (HAZ). Disamping itu, secara makro akan terjadi perubahan dimensi dan distorsi akibat panas pengelasan yang digunakan. Untuk dua material logam yang memiliki perbedaan temperatur leleh yang berbeda jauh, pengelasan fusi ini akan sangat sulit dilakukan. Penyambungan difusi merupakan alternatif untuk menyambung kedua material tersebut secara padat (solid state welding) Penyambungan difusi bisa dilakukan di ruangan vakum atau tanpa vakum. Difusi terjadi saat berkontaknya dua logam yang ditekan di ruangan vakum pada temperatur tertentu. Kondisi vakum bertujuan menekan pertumbuhan oksida di antara kedua logam yang disambung sehingga proses difusi bisa berlangsung lebih baik antar logam. Ruang tungku yang terkondisi ini bisa digantikan dengan tungku perlakuan panas komersil menggunakan gas pelindung argon. Namun, laju pemberian gas argon yang optimal terhadap kualitas sambungan perlu diteliti. Pada penelitian ini, gas argon 3 liter permenit, 5 liter permenit telah digunakan selama proses difusi berlangsung. Sebagai pembanding, proses difusi tanpa gas pelindung juga telah diamati. Preparasi permukaan sambungan dilakukan dengan mengunakan mesin poles dan alumina terlarut dalam air. Proses difusi dilakukan dengan tungku perlakuaan panas induksi skala laboratorium. Kekuatan sambungan telah dievaluasi menggunakan uji geser menggunakan universal testing machine. Pengamatan struktur mikro sambungan dan migrasi atom-atom telah diamati dengan mikroskop optik logam, scanning electron microscope yang dilengkapi dengan electron dispersive X-Ray microanalizer. Hasil pengujian menunjukkan bahwa kekuatan geser ter

Published
2013

50. Corrosion Behavior Of New Type Titanium Alloy As Candidate For Dental Wires In Artificial Saliva On Fluctuating Temperatures

Author

Affi, Jon, Ihsan, Fadhli, and Fajri, Hidayatul

Abstract

Titanium alloys are widely used for implant material due to high biocompatibility properties. It is well known that the corrosion resistance of titanium alloys is better than other metallic materials. However, if the alloys are applied for unknown condition such as wire in orthodontic application, the fluctuating temperature is important to be considered as parameter which influences on corrosion rate. In this study, the effect of fluctuating temperature on corrosion behavior of TNTZ was investigated. Two conditions of TNTZ were used in this study, i.e., Ti-29Nb-13Ta-4.6Zr aging treatment (AT) and TNTZ solution treatment (ST). For comparison, the commercial Ti6Al4V ELI was also used in this study. The corrosion rates of the samples were characterized in artificial saliva on fluctuating temperatures range between 10degC and 50degC by immersion testing. The results showed that the lowest corrosion rate for each variation of temperature was TNTZ ST. The corrosion process seems to decrease the hardness of TNTZ up to 26 VHN. The result also showed that the corrosion rate of TNTZ is much lower than that of Ti6Al4V in all cycles. Moreover, the hardness of Ti6Al4V decreases more significantly i.e., up to 77.2 VHN. The artificial saliva with fluctuating temperature induces corrosion process and decreases the hardness of the alloys.

Published
2019

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