The titanic 80 years later: initial observations on the microstructure and biogeochemistry of corrosion products

Author(s):  
Patricia Stoffyn ◽  
Dale E. Buckley

The “Titanic 91” Expedition, carried out from the Russian Academy of Science vessel “Akademik Keldysh”, recovered artifacts from the wreck of the Titanic using the manned submersible “MIR-2”. Conspicuous corrosion products are iron rusticles resembling stalactites. These rusticles can reach lengths of several tens of cm and grow from various parts of the ship (Fig. 1). The origin of the rusticles and their relation to other corrosion products was investigated using a scanning electron microscope equipped with an x-ray energy dispersive spectrometer and a separate x-ray diffraction system.Rusticles are formed of a brittle iron oxy-hydroxide shell approximately 100 to 200 μm thick, with a smooth dark red outer surface (toward seawater) and an orange rough inner surface (toward the centre of the rusticle). The core of the rusticle and the inner surface of the shell is made of a reticular framework of spherical aggregates. The small needle-like crystals forming these aggregates (Fig. 2) are goethite (α- FeO(OH)).

2009 ◽  
Vol 416 ◽  
pp. 553-557 ◽  
Author(s):  
Zeng Dian Zhao ◽  
Yu Hong Huang ◽  
Yu Gang Zhao ◽  
Xian Jin Yu

The silicon-coated iron powder was evenly mixed with corundum powder and high temperature binder. After tabletting and sintering, followed by crushing and screening, the magnetic abrasive with a certain size was obtained. Scanning electron microscope (SEM), Energy dispersive spectrometer (EDS) and X-ray diffraction (XRD) were respectively used to characterize the morphology, elemental composition and the crystalloid structures of magnetic abrasive. The ferromagnetic phase and abrasive phase were combined firmly. The magnetic abrasive prepared showed a good grinding ability, whose durable time was up to 24 min. Irregular particles was obtained by smashing the magnetic abrasive, mainly composed of Al2O3, Fe2O3, α-Fe, AlFeO3, (Al, Fe)7BO3(SiO4)3O3.


2016 ◽  
Vol 703 ◽  
pp. 112-118
Author(s):  
Chuang Lu ◽  
Fa Qin Xie ◽  
Li Ping Zhu

Microarc oxidation(MAO) was used to prepare the coatings on the surface of Al-Si alloy. Besides, scanning electron microscope (SEM), energy dispersive spectrometer (EDS) and X-ray diffraction (XRD) were utilized to research the microstructure characteristics, the components distribution, and the phase compositions, for the microarc oxidation coatings on Al-Si alloys. Furthermore, the growth process and wear properties of the coatings were explored. Results indicated that:the phase compositions of microarc oxidized coating consisted of mullite (3Al2O3·2SiO2), α- Al2O3 and γ- Al2O3. With the increase of load, the friction coefficient of the coating decreased, however it was greater than that of Al-Si alloy substrate. The wear resistance of the coating were one time higher than that of the substrate.


Arena Tekstil ◽  
2013 ◽  
Vol 28 (1) ◽  
Author(s):  
Maya Komalasari ◽  
Bambang Sunendar

Partikel nano TiO2 berbasis air dengan pH basa telah berhasil disintesis dengan menggunakan metode sol-gel dan diimobilisasi pada kain kapas dengan menggunakan kitosan sebagai zat pengikat silang. Sintesis dilakukan  dengan prekursor TiCl4 pada konsentrasi 0,3 M, 0,5 M dan 1 M, dan menggunakan templat kanji dengan proses kalsinasi pada suhu 500˚C selama 2 jam. Partikel nano TiO2 diaplikasikan ke kain kapas dengan metoda pad-dry-cure dan menggunakan kitosan sebagai crosslinking agent. Berdasarkan hasil Scanning Electron Microscope (SEM),diketahui bahwa morfologi partikel TiO2 berbentuk spherical dengan ukuran nano (kurang dari 100 nm). Karakterisasi X-Ray Diffraction (XRD) menunjukkan adanya tiga tipe struktur kristal utama, yaitu (100), (101) dan (102) dengan fasa kristal yang terbentuk adalah anatase dan rutile. Pada karakterisasi menggunakan SEM terhadap serbuk dari TiO2 yang telah diaplikasikan ke permukaan kain kapas, terlihat adanya imobilisasi partikel nano TiO2 melalui ikatan hidrogen silang dengan kitosan pada kain kapas. Hasil analisa tersebut kemudian dikonfirmasi dengan FTIR (Fourier Transform Infra Red) yang hasilnya memperlihatkan puncak serapan pada bilangan gelombang 3495 cm-1, 2546 cm-1, dan 511 cm-1,  yang masing-masing diasumsikan sebagai adanya vibrasi gugus fungsi O-H, N-H dan Ti-O-Ti. Hasil SEM menunjukkan pula bahwa kristal nano yang terbentuk diantaranya adalah fasa rutile , yang berdasarkan literatur terbukti dapatberfungsi sebagai anti UV.


Minerals ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 533 ◽  
Author(s):  
Xin Zhang ◽  
Guanghui Li ◽  
Jinxiang You ◽  
Jian Wang ◽  
Jun Luo ◽  
...  

Ludwigite ore is a typical low-grade boron ore accounting for 58.5% boron resource of China, which is mainly composed of magnetite, lizardite and szaibelyite. During soda-ash roasting of ludwigite ore, the presence of lizardite hinders the selective activation of boron. In this work, lizardite and szaibelyite were prepared and their soda-ash roasting behaviors were investigated using thermogravimetric-differential scanning calorimetry (TG-DSC), X-ray diffraction (XRD), and scanning electron microscope and energy dispersive spectrometer (SEM-EDS) analyses, in order to shed light on the soda-ash activation of boron within ludwigite ore. Thermodynamics of Na2CO3-MgSiO3-Mg2SiO4-Mg2B2O5 via FactSage show that the formation of Na2MgSiO4 was preferential for the reaction between Na2CO3 and MgSiO3/Mg2SiO4. While, regarding the reaction between Na2CO3 and Mg2B2O5, the formation of NaBO2 was foremost. Raising temperature was beneficial for the soda-ash roasting of lizardite and szaibelyite. At a temperature lower than the melting of sodium carbonate (851 °C), the soda-ash roasting of szaibelyite was faster than that of lizardite. Moreover, the melting of sodium carbonate accelerated the reaction between lizardite with sodium carbonate.


2012 ◽  
Vol 525-526 ◽  
pp. 277-280
Author(s):  
Guo Jin ◽  
Xiu Fang Cui ◽  
Er Bao Liu ◽  
Qing Fen Li

The effect of the neodymium content on mechanical properties of the electro-brush plated nanoAl2O3/Ni composite coating was investigated in this paper. The microstructure and phase structure were studied with scanning electron microscope (SEM) and X-ray diffraction (XRD). The hardness and abrasion properties of several coatings with different neodymium content were studied by nanoindentation test and friction / wear experiment. Results show that the coatings are much finer and more compact when the neodymium was added, and the hardness and abrasion property of the coatings with neodymium were improved obviously. Besides, the small cracks conduced by the upgrowth stress in the coatings were ameliorated when the rare earth neodymium was added. The improvement mechanism was further discussed.


2014 ◽  
Vol 881-883 ◽  
pp. 1049-1052 ◽  
Author(s):  
Nai Peng ◽  
Cheng Ji Deng ◽  
Hong Xi Zhu

In this paper, the effects of briquetting pressure on the performance of in-situ formed Sialon in Al2O3-C refractory bricks are investigated. The phase compositions and microstructure of the Al2O3-C refractory were investigated by X-ray diffraction (XRD) and scanning electron microscope (SEM).The results show the briquetting pressure hardly has effect on the phase of the sintered specimens, two new phases of Sialon with a Z value of 2 and SiC formed. The micrographs of Sialon crystals have the shape of both column and tabular column, but with a cone tip in the specimens sintered at 200MPa and 300MPa and smooth tip in specimens sintered at 400MPa and 500MPa.


2011 ◽  
Vol 236-238 ◽  
pp. 1712-1716 ◽  
Author(s):  
Hai Tao Liu ◽  
Jun Dai ◽  
Jia Jia Zhang ◽  
Wei Dong Xiang

Bismuth selenide (Bi2Se3) hexagonal nanosheet crystals with uniform size were successfully prepared via a solvothermal method at 160°C for 22 h using bismuth trichloride(BiCl3) and selenium powder(Se) as raw materials, sodium bisulfite(NaHSO3) as a reducing agent, diethylene glycol(DEG) as solvent, and ammonia as pH regulator. Various techniques such as X-ray diffraction (XRD), field-emission scanning electron microscope (FESEM), high-resolution transmission electron microscope (HRTEM), and selected area electron diffraction (SAED) were used to characterize the obtained products. Results show that the as-synthesized samples are pure Bi2Se3 hexagonal nanosheet crystals. A possible growth mechanism for Bi2Se3 hexagonal nanosheet crystals is also discussed based on the experiment.


2011 ◽  
Vol 306-307 ◽  
pp. 961-965
Author(s):  
Chao Nan Yin ◽  
Ling Chao Lu ◽  
Shou De Wang

The influence of P2O5on the properties of alite-calcium strontium sulphoaluminate cement was researched by means of X-ray diffraction, scanning electron microscope-energy dispersive spectroscopy (SEM-EDS) and petrographic analysis. The results show that the optimal content of P2O5is 0.3% and the compressive strength of the cement at 1, 3, 28d are 27.0, 59.1, 110.9MPa when the calcining temperature is 1350°C. P2O5mainly exists in the belite and a suitable amount of P2O5can promote the formation of C1.5Sr2.5A3and alite. When the content of P2O5is higher than 0.3%, the formation of C1.5Sr2.5A3and alite can be hindered. P2O5can enhance the hydration heat evolution rate in the acceleration period and the hydrate heat of cement containing P2O5increases slightly.


2012 ◽  
Vol 620 ◽  
pp. 384-388
Author(s):  
Sharifah Aishah Syed Salim ◽  
Julie Juliewatty Mohamed ◽  
Zainal Arifin Ahmad ◽  
Zainal Arifin Ahmad

Numerous methods have been used to produce high purity TiC. There is no previous study has been reported on the formation using single elemental powders of Titanium (Ti) and Carbon (C) with addition Nickel (Ni) by tungsten inert gas (TIG) weld method. In this work, TiC was synthesized via TIG method by arc melting elemental powder mixture of Ti and C at ~5 second (s) and 80 ampere (A). The effect Ni contents on TiC formation was investigated. The mixed raw material was ball milled for 24 hours followed by synthesis via TIG method. The arced samples were characterized by X-ray diffraction (XRD) and Scanning electron microscope (SEM). It was revealed, that small amount of Ni additive to the metal powder allows the production of dense and tough TiC.


2007 ◽  
Vol 43 (2) ◽  
pp. 141-150 ◽  
Author(s):  
G.P. Vassilev ◽  
K.I. Lilova ◽  
J.C. Gachon

Phase equilibria were studied in the system Ni-Sn-Bi. Special attention has been paid to the identification of the recently found ternary phase. For this purpose samples were synthesized using intimately mixed powders. After annealing and quenching, all alloys were analyzed by scanning electron microscope and by X-ray diffraction. The results give evidences about the existence of a ternary compound with approximate formula Ni6Sn2Bi to Ni7Sn2Bi. Overlapping of some neighboring diffraction peaks of this phase with NiBi and Ni3Sn_LT is the reason for the difficulties related to the X-ray diffraction identification of the ternary phase.


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