PENGARUH WAKTU KALSINASI TERHADAP SIFAT FISIKA-KIMIA HIDROKSIAPATIT DARI CANGKANG GELOINA COAXANS

Hidroksiapatit (HAp) merupakan salah satu senyawa biokeramik yang digunakan dalam berbagai aplikasi. Pada penelitian ini telah dilakukan sintesis hidroksiapatit (HAp) dengan metode pengendapan menggunakan cangkang lokan (Geloina coaxans) dan H3PO4 sebagai prekursor. Analisis menggunakan X-Ray Flourocence (XRF) menunjukkan bahwa komposisi kimia utama pada cangkang lokan (Geloina coaxans) adalah CaO. Produk terbaik diperoleh melalui waktu kalsinasi pada suhu 900 oC selama 180 menit yang ditunjukkan dengan puncak yang memiliki intensitas tertinggi pada 2θ = 31,7o dan puncak spesifik lainnya untuk hidroksiapatit pada 2θ = 32,89o, 32, 17o, 25,86o dan 49,46o. Difraktogram dibandingkan dengan JCPDS (No 09-0432). Berdasarkan perhitungan menggunakan persamaan Scherrer, didapatkan ukuran kristal dari hidroksiapatit (HAp) adalah 26,62 nm. Analisis menggunakan FTIR juga telah dilakukan untuk mengidentifikasi gugus fungsi pada hidroksiapatit yang diperoleh. Dari spektrum FTIR menunjukkan adanya pita serapan yang khas untuk gugus OH‒, CO32- dan PO43-pada hidroksiapatit. Morfologi partikel berbentuk granular seperti bola dan gumpalan yang tidak seragam diperoleh melalui analisis menggunakan SEM.. ABSTRACT Hydroxyapatite (HAp) is a bioceramic compound that is used in various applications. In this research, hydroxyapatite (HAp) synthesis has been carried out by precipitation method using Geloina coaxans shell and H3PO4 as precursors. Analysis using X-Ray Flourocence (XRF) showed that the main chemical composition of Geloina coaxans shell was CaO. The best product was obtained by calcination at 900 oC for 180 minutes indicated by a peak having the highest intensity at 2θ = 31.7o and other specific peaks for hydroxyapatite at 2θ = 32.89o, 32 ,17o, 25.86o and 49.46o. The difractogram was compared to JCPDS (No 09-0432). Based on calculations using the Scherrer equation, the crystallite size of hydroxyapatite was 26.62 nm. Analysis using FTIR has also been carried out to identify the functional groups of the hydroxyapatite obtained. The FTIR spectrum showed that there were unique absorption bands for OH‒, CO32- and PO43- groups on hydroxyapatite. Analysis using SEM showed that the morphology was granular like balls and non-uniform aggregate

SYNTHESIS OF CdS NANOPARTICLES BY CHEMICAL Co-PRECIPITATION METHOD AND ITS COMPARATIVE ANALYSIS OF PARTICLE SIZE VIA STRUCTURAL AND OPTICAL CHARACTERIZATION

CdS is an important wide bandgap chalcogenides most popularly studied for various optoelectronics and biosensing applications. In this study, CdS Nanoparticles (NPs) have been prepared successfully by chemical co-precipitation method, using cadmium acetate and sodium sulphide as precursors. A comparative study of average particle size calculated by Scherrer Plot, Uniform Deformation Model (UDM), Dynamic Light Scattering (DLS) analysis and Brus Model has been done here. The structural and optical behaviour of synthesized samples were investigated via X-ray diffraction (XRD), DLS and UV–Visible Spectroscopy. The XRD spectra of the prepared CdS NPs revealed the crystalline phase having cubic structure. The average particles size has been studied via Debye Scherrer equation and Scherrer Plot. For the theoretical calculations of particle size along with the induced lattice strain, considering the broadening effect of lattice strain, Williamson-Hall analysis was employed. Assuming the lattice strain to be isotropic in nature, UDM was applied for calculation. The particles size distribution profile in terms of volume as well as intensity was recorded using DLS analysis in ethanol medium at room temperature. Besides this, the energy bandgap was obtained by applying Tauc model in the recorded absorption spectra. The obtained value of bandgap was used in Brus model for estimating the average particle size. The obtained comparative results show that the average particle size of the prepared CdS NPs estimated from Scherrer equation, Scherrer plot, UDM plot and Brus model are almost similar and lies in the range of 2-5 nm whereas the results of DLS showed wide variation in the range of 40-600 nm.

Structural and Magnetic Properties of NiZn Ferrite Nanoparticles Synthesized by a Thermal Decomposition Method

Ni1−xZnxFe2O4 (x = 0.5, 0.6, 0.7) nanoparticles were synthesized by a thermal decomposition method. The synthesized particles were identified as pure spinel ferrite structures by X-ray diffraction analysis, and they were calculated to be 46–51 nm in diameter by the Scherrer equation, depending on the composition. In the FE-SEM image, the ferrite nanoparticles have spherical shapes with slight agglomeration, and the particle size is about 50 nm, which was consistent with the value obtained by the Scherrer equation. The lattice parameter of the ferrite nanoparticles monotonically increased from 8.34 to 8.358 Å as the Zn concentration increased from 0.5 to 0.7. Initially, the saturation magnetization value slowly decreases from 81.44 to 83.97 emu/g, then quickly decreases to 71.84 emu/g as the zinc content increases from x = 0.5, through 0.6, to 0.7. Ni1−xZnxFe2O4 toroidal samples were prepared by sintering ferrite nanoparticles at 1250 °C and exhibited faceted grain morphologies in the FE-SEM images with their grain sizes being around 5 µm regardless of the Zinc content. The real magnetic permeability (μ′) of the toroidal samples measured at 5 MHz was monotonically increased from 106, through 150, to 217 with increasing the Zinc content from x = 0.5, through 0.6, to 0.7. The cutoff frequency of the ferrite toroidal samples was estimated to be about 20 MHz from the broad maximum point in the plot of imaginary magnetic permeability (μ″) vs. frequencies, which seemed to be associated with domain wall resonance.

Analisis Ukuran Kristal Dan Sifat Magnetik Melalui Proses Pemesinan Milling Menggunakan Metode Karakterisasi Xrd, Mechannical Alloying, Dan Ultrasonik Tekanan Tinggi Pada Material Barium Hexaferrite (Bafe12o19)

ABSTRAKSintesa terhadap ukuran kristal dan sifat magnet dari material Barium Hexaferrite (BHF) hasil proses pemesinan milling selama 60 jam, setiap 10 jam proses pemesinan di lakukan analisa untuk mengetahui ukuran partikel. Setelah proses pemanasan 1100o C dan penahanan selama 2 jam, dikarakterisasi XRD dan PSA. Dengan pendekatan persamaan Scherrer di dapat di sintesa ukuran kristal, dan partikel dari material BHF menggunakan pengolahan melalui perangkat lunak Match diperoleh material satu fasa dengan nilai FWHM dengan parameter kisi a = b = 5,8920 Å, c= 23,1830 Å, struktur kristal berbentuk hexagonal, space group P63/mmc dan masa jenis 5,926 g/cm3. Ukuran kristal (crystallite size) dihitung berdasarkan puncak-puncak difraksi. Hasil perhitungan persamaan Scherrer diperoleh puncak indeks bidang kristal [hkl] dengan posisi puncak sudut 2q³30° dan nilai rata-rata ukuran kristal yang terbentuk pada setiap bidang kisi dari BHF sebesar 57, 63639 nm. Kata kunci : XRD, Milling, Ukuran Kristal, Persamaan Scherrer, Parameter kisi, FWHM. ABSTRACTSynthesis of the crystal size and magnetic properties of the Barium Hexaferrite (BHF) material resulting from the milling machining process for 60 hours, every 10 hours the machining process is analyzed to determine the particle size. After 1100o C heating and detention for 2 hours, XRD and PSA were characterized. With the Scherrer equation approach it can be synthesized in crystal size, and particles from BHF material using processing through Match software obtained single phase material with FWHM values with lattice parameters a = b = 5.8920 Å, c = 23.1830 Å, crystal structure hexagonal shape, P63 / mmc space group and density of 5,926 g / cm3. Crystallite size is calculated based on diffraction peaks. The calculation result of the Scherrer equation obtained the peak of the crystal field index [hkl] with an angle peak position of 2q³30° and the average value of the crystal size formed in each lattice plane of the BHF of 57,63639 nm.Keywords : XRD, Milling, Crystal Size, Scherrer Equation, Lattice Parameters, FWHM.

KARAKTERISASI BATU KAPUR ALAM BUKIT JIMBARAN BALI

This research is about the characterization of naturar limestone in the Bukit Jimbaran area of Bali. The aim of this research was to learn chemical composition and micromorphology of Bukit Jimbaran limestone. The research was conducted in sequential steps as described below i.e. the limestone was grinded and sieved in size of 0.25-0.50 mm. Fine limestone, then was heated by using oven at 1000 C for 24 hours and analyzed by FTIR, XRD and SEM. The Spectra of FTIR showed that O-H, C-H, and C-O were dominantly functional groups, which composed CaCO3 and CaO. The results of CaO crystal measurements using Scherrer equation is 51,39 nm. Micromorphology observation by using SEM showed size shaped (vaterite) of Bukit Jimbaran limestone

Determining Crystallite Size Using Scherrer Formula, Williamson-Hull Plot, and Particle Size with SEM

It has been determined the crystallite size by XRD technique using Scherrer equation and Williamson-Hull Plot method. While the particle size is determined by SEM using Image-J software. For this purpose, synthesized samples of compound Gd0,95La0.05Ba2Cu3O7-d phase. From the calculation results, obtained the crystallite size in nanometers order, however the crystallite size resulting from the Scherrer equations and Scherrer Modified is different, i.e. 63.1675 nm and 67.0005 nm. The results of the crystallite size calculation by the scherrer equation directly and modified differed from that of the Williamson-Hull Plot method (97,3040 nm). Meanwhile, the results of the Williamson-Hull Plot methods and SEM show almost the same value (98.7297nm).

STUDY OF SYNTHESIS FEATURES OF NANOCRYSTALLINE ZINC FERRITE

In work the process of formation of nanocrystal zinc ferrite was studied. The samples obtained were characterized with XPS, BET and SEM. The received samples have the developed surface. The average size of crystallites determined by Debye-Scherrer equation was 3 nm.

The limit of application of the Scherrer equation

The Scherrer equation is a widely used tool to obtain crystallite size from polycrystalline samples. Its limit of applicability has been determined recently, using computer simulations, for a few structures and it was proposed that it is directly dependent on the linear absorption coefficient (μ0) and Bragg angle (θB). In this work, a systematic study of the Scherrer limit is presented, where it is shown that it is equal to approximately 11.9% of the extinction length. It is also shown that absorption imposes a maximum value on it and that this maximum is directly proportional to sin θB/μ0.