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Development of high temperature and corrosion-resistant materials is one of the key issues for the deployment of advanced nuclear reactors and also to accommodate the problem that occurred in the conventional reactor as the lesson-learned from Fukushima Daiichi nuclear reactor power plant accident. One of the high performance materials for that purpose is austenitic stainless steel such as AISI 316L that widely used for power plant. In this study we investigate the characteristics of AISI 316L austenitic phase transformation if cold working is applied. In general, during the cold working process the mechanical characteristic and the phase of the austenitic steel will change. It is expected that the characteristic of AISI 316L austenitic steel will be improved by optimum cold working mechanism. Cold working of AISI 316L austenitic steel at various percentage reduction of 5%, 15%, 25% and 38% have been done. Afterward, the sample was characterized using X-Ray Diffraction and Optical Microscope to analyze the microstructure characteristics and phase transformation. The results showed that the phase transformation in AISI 316L austenitic steel occurred from austenite – gamma (FCC: Face-Centered Cubic lattice) to martensite – alpha prime (BCC: Body Centered Cubic lattice). The percentage of martensite phase was increasingly growth related to the increasing of the percentage of cold working value i.e. 8.3%, 21.6%, 29.6% and 37.1%, respectively. The hardness of AISI 316L austenitic steel increased with the increasing of the cold working percentage. AISI 316L double phases which covers of austenite-martensite intermix phase structure with higher hardness mechanical properties has been successfully developed.

Hydroxyapatite is synthesized by precipitation-sonification using calcium from field snail shell and powder phosphorus from (NH 4 ) 2 HPO 4. The calcium value was measured by atomic absorption spectrophotometer was 82.82%.The temperatures were varied on 600, 800, and 1000 o C to determine the best temperature of the coating. The best temperature was used to superimpose the HAp on the CoCrMo-TiN metal alloy using the modified sol-gel method. The layer on the metal alloy was identified with x-ray diffraction (XRD) and corrosion test. The XRD result showed that most of the CoCrMo-TiN metal alloy surface was coated by HAp. Beside HAp, there were several other phases such as calcium phosphate, carbonate apatite type A and type B. The best result of the corrosion test was showed in CoCrMo-TiN metal alloy coated with HAp with the smallest corrosion rate 0.0082 mpy. Keywords: hydroxyapatite, CoCrMo-TiN, precipitation-sonification, sol-gel modified

SYNTHESIS AND CHARACTERIZATION OF HPMC/HAp/Fe3O4 COMPOSITE FOR HYPERTHERMIA APPLICATION. Magnetic material become subject of intense research for hyperthermia application, and injectable magnetic hyperthermia for bone cancer is one of this research interest. In this study, composite of hydroxyapatite (HAp) and Fe3O4 in Hydroxypropyl-methyl cellulose (HPMC) matrix (HPMC/HAp/Fe3O4) has been synthesized in gel form that are expected can be applied for injectable bone substitute (IBS) in hyperthermia therapy. Composites were made using conventional methods by mixing HAp powder with ferrofluid Fe3O4 in HPMC solution. The composition of the composites were varied with the mass comparison of HPMC: HAp: Fe3O4 was 1: 0: 0; 1: 3: 0; 1: 2: 0.5; 1: 1: 0.25; and 1: 0: 3. The physical, chemical, and magnetic properties of the composites were characterized using X-Ray Diffractometer (XRD), Fourier Transform Infrared Spectrometry (FT-IR), Particle Size Analyzer (PSA), and Vibrating Sample Magnetometer (VSM). The XRD characterization results of the HPMC/HAp/Fe3O4 composite showed the crystalline phase of the constituent components. Saturation magnetization of the HPMC/HAp/Fe3O4 composite was 2.72 emu/g and 1.79 emu/g for the composition of 1: 2: 0.5 and 1:1:0.25 respectively. HPMC/HAp/Fe3O4 composite has superparamagnetic and biocompatible properties, so that can be applied as IBS in hyperthermia therapy for bone cancer.

Nanoparticles (NP) have been studied because of their unique physical and chemical properties compared with their bulk counterparts. The ferrite colloids, magnetite (Fe3O4) are the main representatives of the magnetic nanoparticles (MNPs). These ferrite colloids are characterized by a spinel crystal structure with oxygen ions forming a close-packed cubic lattice and iron ions located at the interstices. Fe3O4 has been attracting in biomedical applications due to their biocompatibility and their biodegradability. In this research, Fe3O4 nanoparticles has been successfully synthetized by using coprecipitation method by using Natrium hydroxide (NaOH) as precipitant agent, Ferrous Chloride Tetrahydrate (FeCl2.4H2O) and Ferric Chloride Anhydrous (FeCl3.6H2O) were used as precursor. Fe3O4 were characterized with X-Ray Diffraction (XRD), Vibrating Sample Magnetometer (VSM), and Particle Size Analysis (PSA). The results of synthesized Fe3O4 shown that the crystallite size 7.664 nm and the XRD pattern was match with the reference magnetite Fe3O4 pattern (JCPDS card number 19-0629). From PSA measurement, it shown that the average particles size was 228.9 nm with Polidispersity Index (PdI) 0.402 and the magnetic saturation value 80 emu/gram.

Perekayasa material BATAN telah berhasil mensintesis serial baja superaloi tipe Austenitik (A2) dan tipe Feritik (F1). Beberapa bahan telah dilakukan treatments dengan memvariasi waktu penyinaran menggunakan arc plasma sintering (APS). Dalam studi ini dilakukan pengukuran difraksi sinar-X untuk menginvestigasi bentuk bangun struktur kristal dan parameter kisi dari baja feritik F1, baja austenitik A2 dan baja austenitik A2 yang disintering APS selama 2 detik penyinaran. Perhitungan dilakukan menggunakan formula Bragg dengan membandingkan deret aritmetika (hitung) S2 dan jarak interplanar dhkl. Diketahui bahwa: baja feritik F1 berstruktur body centered cubic (BCC) dengan parameter kisi a = 2,87 Å. Baja austenitik A2 berstruktur  face centered cubic (FCC) dengan parameter kisi a = 3,59 Å. Baja austenitik A2 yang disintering APS selama 2 detik berstruktur  face centered cubic (FCC) dengan parameter kisi a = 3,60 Å. Pengamatan struktur mikro permukaan bahan menggunakan Mikroskop Optik (OM) dan Mikroskop Elektron (SEM) memperlihatkan mikrografi yang menarik. Mengasumsikan kondisi proses peleburan (casting) sama, kedua tipe bahan uji memiliki struktur cor yang mirip. Baja feritik F1 menampakkan batas butir (grain boundary) yang lebih halus jika dibandingkan dengan batas butir dalam baja austenitik A2 yang cenderung terlihat lebar garis batasnya. Sedang baja austenitik A2 yang disintering APS selama 2 detik, menampakkan pola butiran yang semula memanjang berubah struktur butiran (grain)-nya menjadi agak bulat-bulat (globular). Uji SEM memetakan sebaran presipitat pada baja feritik F1 di batas butir dan di dalam butir, sedangkan pada baja autenitik A2 tersebar di batas butir saja. Spektrum EDX menunjukkan komposisi presipitat pada baja feritik F1 meliputi C, Cr, dan Fe. Sedangkan pada baja austenitik A2: C, Cr, Fe, dan Ni. Dimungkinkan, krom karbida (Cr23C6) terbentuk sebagai precipitat di batas butir, karena bahan didominanasi konten unsur Cr dan C.Kata Kunci : feritik F1, austenitik A2, XRD, aritmetika, formula Bragg, struktur mikro.

Mg-Ca-Zn alloys are promising candidate metal cellular material for biocompatible and biodegradable implant. This is due to its corrosion behavior which enables well controlled degradation, as well as due to the fact that the corrosion product shows no cytotoxicity at all. In this present work, the characteristics of Mg-Ca-Zn alloy metallic foam prepared by the foaming of a powder compact based on Mg-2Zn-Ca and CaH2 system were investigated. Mg-Zn-CaH2 powders with various compositions of 67-96 wt.% Mg, 1.2-30 wt.% CaH2, 9 wt.% Ca and 2 wt.% Zn constant were studied. The prepared powders were then pressed under a load of 26 MPa at room temperature. Sintering process of green compacts was conducted at 350 °C for 2 h continued to 520 °C for 1 h. The sintered green compacts were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive analysis (EDS). The XRD results showed the sintering process affects the phase formation of Mg, Ca, Mg2Ca, and MgCaZn. Mg2Ca binary phase to be avoided because its leading to reduce mechanical properties of the final product.

The synthesis and characterization of both structural and microstructure of hydroxyapatite (HAp) nanoparticles by using precipitation method have been performed. Orthophosphoric acid solution (H3PO4) 0.3 M was dropped into the suspension of Ca(OH)2 from tutut (Bellamya javanica) shells at pH 10 and added by NH4OH 1 M at the final deposition process. The precipitate was filtered and then heated in a furnace at temperature of 1000 °C for 3 hours. The result of elemental analysis showed that the Ca/P ratio of HAp sample was 1.71. X-ray diffraction patterns showed that the sample was a single phase of Ca10(PO4)6(OH)2 with hexagonal structure (P63/m) and lattice parameters of a = b = 9.418(3) Å, c = 6.885(2) Å, a = b = 90o, g = 120o, V = 528.9(4) Å3, and r = 3.084 g cm-3. The as-synthesized HAp has crystallite and particle sizes of 16.1055 and 89.15 nm, respectively. The TEM image revealed that the HAp particles have spherical-polygonal shape with an average diameter particles of around 10-20 nm. It was concluded that the synthesis of HAp nanoparticles from tutut (Bellamya javanica) shells by using a wet precipitation method has been successfully carried out and the as-synthesized HAp was potential to be applied as materials for artificial bone engineering.

In recent years, development of magnesium (Mg) as biodegradable implant very rapidly in orthopedic applications . This is due to its young’s modulus close to young modulus of natural bone . However, Mg implants demonstrate higher biological activity which could cause high degradation rate in human bio-environment. Consequently, needed to develop Mg-based alloys with superior corrosion performance. In the present study, it has been attempted to develop biocomposite of Magnesium Zinc-5% Hydroxyapatite (MgZn-5%HAp) as biodegradable bone implant. The biocomposites were prepared by adding 5 wt. % powders to MgZn powder and then were sintered at temperature 350 o C in vacuum furnace for holding an hour. The characterization of MgZn-5 wt %HA p biocomposite was examined by Scanning Electron Microscopy with Energy Dispersive Spectroscopy ( SEM/EDS ) and X-ray diffraction ( XRD ) while corrosion test ed by potensiostat. The SEM / EDS and XRD results indicate d that some of the Zn atoms have dissolved in Mg to form a MgZn solid solution. The SEM results also showed that the MgZn-5%HAp biocomposite has a microstructure with a matrix Mg and HAp at the grain boundary. The presence of HAp in the sample resulted in a smaller crystallite size and corrosion rate compared to the one with MgZn alloy.

Paduan Co-Cr merupakan material tahan suhu tinggi dan tahan korosi. Penelitian ini bertujuan mensistesis serbuk paduan Co-Cr dengan metode ultrasonik, kemudian dilanjutkan dengan proses sintering dalam kapsul kaca kuarsa. Iradiasi ultrasonik yang digunakan pada frekuensi 20 kHz dan amplitudo 40 % dengan komposisi Co : Cr sebesar 80 : 20.Waktu perlakuan sonikasi adalah selama 0 jam, 3 jam, 6 jam, 12 jam, 24 jam, dan 48 jamdalam larutan etanol. Setelah sonikasi selama 48 jam, fasa FCC dari Co mulai bertransformasi menjadi fasa HCP. Perlakuan ultrasonik terhadap campuran Co-Cr juga memberikan efek pengurangan ukuran partikel. Parameter kisi serbuk setelah ultrasonikasi 48 jam adalah: untuk HCP-Co a = b = 0,25074 nmdan c = 0,40699 nm, untuk FCC-Co a = b = c = 0,35411nm, dan untuk BCC-Cr a=b=c=0.28827 nm. Perlakuan ultrasonik selama 48 jam menhasilkan pembentukan paduan Co-Cr dengan persentasi berat sebesar 25,2124. Hasil sintering padatan Co-Cr menunjukkan parameter kisi HCP-Co memiliki nilai yaitu a = b = 0,25230 nm dan c=0,41223 nm, dan FCC-Co a = b = c = 0,35232 nm. Terbentuknya microalloying CoCr diindikasikan dari hasil EDS, teramati partikel yang mempunyai komposisi Co : Cr = 71,25 : 24,45. Paduan Co-Cr yang terbentuk setelah sintering pada 1300 oC adalah sebesar 15,33416 %berat.

Biomaterials are materials from which medical devices are made. Based on their chemical composition, they can be polymers, metals, ceramics or composites. Metals are still the most used biomaterials mostly due to their superior mechanical properties and can be found in orthopedic, cardiovascular and dental implants. However, many type of implants can only work properly when polymers or ceramics are also used in pair with metals such as in total knee or hip arthroplasties. Nowadays, biomaterials are no longer seen as inert substances supporting or replacing dysfunctional tissues or organs. They are now required to promote the healing process and self-disintegrate once the process is completed. All the efforts in searching ideal biomaterials are paid to improve the wellness and health of human beings. This chapter is intended to give a brief introduction to the structure and property of biomaterials.

Indonesia is an emerging country with population about 255 million in 2015 and 40 % of this population is in their productive age. The country’s nominal GDP for 2015 is about 900 billion USD with 5 % annual growth and general government debt stays at 26 % of GDP. The government has put healthcare service as one of the strategic program in the 2015–2019 National Development Plan along with a new effective national healthcare financing scheme. Indonesia is a big market for medical products with a market value about 800 million USD in 2015 and estimated to reach 1.2 billion USD in 2019. The government has set policies and a clear roadmap for assuring the availability and distribution of medical devices by fostering local production, improving the quality of local products and tightening the surveillance to the pre- and post-market devices. The challenge lies on unifying the country’s experts to mutually collaborate under a strong leadership on the same interest toward the national independency in producing effective yet low cost medical devices.

Thin tantalum oxide (Ta 2 O 5 ) films were prepared on Si(100) substrates using the chemical solution deposition (CSD) method. X-ray diffraction (XRD), scanning electron microscopy (SEM), spectrophotometric UV-VIS and ellipsometric measurements were employed to characterize these films. High-quality films of Ta 2 O 5 were obtained by spin coating at 2000, 2250, 2500, 2750 and 3000 rpm during 30 s, and subsequently annealed at 900°C for 15 h. The microstructure and crystallinity of the thin films were analyzed by XRD in preferred (001), (010), (200) orientations, the surface morphology was examined by SEM, and the film thickness was determined by profilometric and ellipsometric measurements, the thin films were heterogeneous. The orthorhombic structure and crystallinity of Ta 2 O 5 thin films on Si(100) substrates were characterized by XRD. The obtained lattice constants are a = 6.117 A, b = 3.716 A, c = 4.114 A. The optical spectrophotometric measurements at λ = 400 nm yielded refractive index values n of 1.81-1.93; from ellipsometric analysis the refractive index values are 1.8-1.94.

Ketahanan Korosi Temperatur Tinggi Baja Super Austenitik 15%Cr-25%Ni Pada Temperatur 850 °C. Ketahanan korosi temperatur tinggi atau ketahanan oksidasi merupakan prasyarat penting bahan logam yang akan diterapkan dilingkungan operasi bertemperatur tinggi. Pengujian ketahanan oksidasi baja super austenitik 15%Cr-25%Ni pada temperatur 850 °C selama 5 jam lebih telah dilaksanakan. Satu sampel as-cast sebagai acuan awal yang tidak diperlakukan panas dan dua (2) kelompok sampel (masing-masing 3 buah) disiapkan dalam eksperimen. Satu kelompok sampel as-cast setelah dipanaskan (pada 850 °C /5 jam lebih) dan didinginkan perlahan kemudian ditimbang. Satu kelompok sampel quench yang dilakukan penurunan cepat temperatur (dari 850 °C / 5 jam lebih) ke dalam air, kemudian ditimbang. Percobaan dilakukan selama 15 jam lebih pada masing-masing kelompok. Hasil memperlihatkan bahwa walaupun terjadi kenaikan berat sangat kecil pada sampel as-cast dan quench, tetapi foto morfologi mikroskop elektron (SEM) pada kedua sampel tersebut tidak memperlihatkan perubahan yang signifikan. Demikian pula hasil analisis fasa menggunakan difraksi sinar-X, tidak memperlihatkan pertumbuhan fasa produk oksidasi. Hasil pengamatan struktur mikro permukaan bahan menggunakan mikroskop optik (MO), juga tidak memperlihatkan kerusakan dan perubahan ukuran butir oleh proses oksidasi. Kebolehjadian pada fenomena ini adalah selain pembentukan spinel unsur Ni diperkuat juga oleh kemampuan unsur Cr untuk membentuk lapisan pasif (Cr2O3) dipermukaan bahan yang sangat besar dengan mengikat unsur O, sehingga bahan mampu menanggulangi produk oksidasi yang sangat kecil. Disimpulkan bahwa baja super austenitik memiliki ketahanan oksidasi yang baik pada temperatur 850°C. ABSTRACT High Temperature Corrosion Resistance of Super Austenite 15%Cr-25%Ni Steel at Temperature 850 °C. High temperature corrosion resistance so called oxidation resistance is an important prerequisite of a metal material that may be applied in a high-temperature operating environment. An oxidation test of super austenite steel 15% Cr-25% Ni at 850 °C for more than 5 hours has been performed. One as-cast specimen as an initial reference is not treated any heat and two (2) specimen groups (each of 4 pieces) were prepared in the experiments. One group of as-cast specimens after being heated at 850 °C for more than 5 hours and cooled slowly then weighed. Another group of quench specimens performed a rapid decrease of temperature (850 °C for more than 5 hours) into water, then weighed. The experiment was conducted for more than 15 hours in each group. The results show that there is a very small slight increase in weight on as-cast and quench specimens. However, electron microscope morphology (SEM) images on both specimens showed no significant changes. Similarly, the results of phase analysis using X-ray diffraction techniques also do not show the phase growth of oxidation products. In accordance with the observation of surface microstructures of materials by using optical microscope (OM), also did not show damage and changes in grain size by oxidation process. The likelihood of this phenomenon is that in addition to the formation of Ni element of spinels, it is also strengthened by the ability of Cr-elements to form a passive layer (Cr2O3) on a very large material surface by binding O-elements, so that the material can cope with very small oxidation products. It is concluded that the super austenitic steels has good oxidation resistance at 850°C.

Oil palm empty fruit bunches (OPEFB) was one of the solid waste produced by the palm oil factory and were totally plentiful in biomass. OPEFB fiber used as reinforcement of polymer matrix acrylonitrile butadiene styrene (ABS). The use of FTIR is to see that there is no changes in the molecules of the constituent biocomposite ABS and OPEFB. The reactivity of butadiene and styrene through the double bond- π conjugated system, contributed to the bond reaction with the maleic acid as compatibilizer witch is grafted to the system. It is concluded that the posible grafting reaction occurs by the addition of the MAH to the double bond of the butadiene and styrene. The hydroxyl group of cellulose can interact with this maleic acid to form a bond through the carboxyl group.

Bone implants is a way to cure broken bones which is being developed. The implants can be made of metals, ceramics and polymers. Metallic materials commonly used are titanium (Ti), stainless steel, and metal alloys. This study used Co-based alloys, i.e. CoCrMo coated with titanium nitride (TiN) which was then coated on hidroxyapatite (HAp). The HAp coating on the surface of CoCrMo alloy was done by biomimetic methods, first by soaking the metal alloys in simulated body fluid (SBF) solution for 18, 24, and 36 hours. The immersion in the SBF solution produced white coat on the surface of the metal alloy. The layers formed were analyzed by scanning electron microscope (SEM) and characterized by x-ray diffractometer (XRD). Based on the SEM results of 36 hours treatment, the morphology of apatite crystal formed fine grains. According to XRD result, there were HAp peaks at angles 2θ 31.86, 32.25, dan 39.48. However, there were also CaCO3 peaks at angles 2θ 29.46, 36.04, and 46.79. It indicated the pure HAp is not yet formed.

Metoda pemaduan mekanik adalah reaksi padatan dari beberapa logam dengan memanfaatkan proses deformasi untuk membentuk suatu paduan. Pada penelitian ini dibuat paduan Co-Cr-Mo dengan proses wet milling dengan variasi waktu milling selama 3, 5, 10, 20, dan 30 jam. Proses wet milling sangat efektif untuk mencegah terjadinya oksidasi dan juga memicu pembentukan paduan Co-Cr-Mo dengan baik. Hasil XRD menunjukkan bahwa telah terjadi pertumbuhan fasa γ pada durasi milling 3, 5, 10, 20, dan 30 jam, berturut-turut sebesar 42,80 %; 67,61 %; 82,94 %, 84,63 % dan 88,92 %. Ukuran kristalit fasa γ sebesar 25,9 nm; 12,5 nm; 5,1 nm dan 4,9 nm seiring dengan meningkatnya waktu milling. Disimpulkan bahwa telah berhasil dilakukan pembuatan paduan nanokristalin Co-Cr-Mo dengan metode pemaduan mekanik lebih dari 85 % dengan waktu milling minimum selama 30 jam. Kata kunci : Co-Cr-Mo, pemaduan mekanik, nano-kristalin Abstract Synthesis of Co-Cr-Mo nano-crystalline by mechanical alloying has been carried out. Mechanical alloying is a solid state reaction of some metals by utilizing the deformation process to form an alloy. In this research, parameter milling time used for making Co-Cr-Mo alloy by wet milling process is 3, 5, 10, 20 and 30 h. Wet milling process is very effective to prevent oxidation and triggers the formation of fine Co-Cr-Mo alloys. Results of XRD pattern refinement shows that Co-Cr-Mo alloys was growth by percentage approximately around 42.80%, 67.61%, 82.94%, 84.63% and 88.92% for milling time 3, 5, 10, 20, and 30 h, respectively. Otherwise, crystalline size measurement after milling time 5, 10, 20, and 30 h obtained around 25.9 nm, 12.5 nm, 5.1 nm and 4.9 nm, respectively. This research concluded that the optimum milling time could obtained synthesizes nano-crystalline of Co-Cr-Mo alloy more than 85% is 30 h. Keywords: Co-Cr-Mo alloy, mechanical alloying, nano-crystalline

Dalam ortopedi UHMWPE sering digunakan sebagai bantalan materi (tibial tray) pada sendi lutut buatan. Namun dalam penggunaannya, keausan bahan UHMWPE merupakan salah satu faktor utama yang memperpendek umur pakai sendi lutut buatan sehingga diperlukan metode untuk meningkatkan sifat mekanik UHMWPE. Tujuan penelitian ini adalah untuk mengetahui pengaruh radiasi sinar gamma terhadap sifat mekanik dan tingkat keausan dari UHMWPE sehingga dapat memenuhi kualifikasi bahan baku pembuatan tibial tray serta mengetahui dosis optimum yang diperlukan UHMWPE agar diperoleh bahan yang tahan terhadap keausan dan memiliki sifat mekanik yang lebih baik. Pembuatan tibial tray dilakukan dengan metode molding pressure dengan radiasi gamma. Pembuatan film UHMWPE dilakukan dengan hot press pada 170 °C selama 3 menit dan tekanan 200 kg/cm2. Kemudian film tersebut dipanaskan ke dalam furnace pada 128 oC selama 100 menit dan diradiasi dengan irradiator karet alam (IRKA) pada dosis 0 kGy, 50 kGy, 100 kGy, 125 kGy dan 150 kGy. Berdasarkan hasil karakterisasi sifat tibial tray dengan XRD, FT-IR, alat uji tarik, alat uji kekerasan, dan alat uji keausan, dapat disimpulkan bahwa efek radiasi terhadap polimer UHMWPE adalah terbentuknya ikatan silang dan degradasi bahan. Sehingga, semakin tinggi dosis radiasi dihasilkan sifat bahan yang semakin keras serta tahan terhadap aus. Selain itu, dapat diketahui bahwa dosis 100 kGy merupakandosis optimal untuk meningkatkan sifat mekanik bahan.