Imogolite: the Nanotubular Aluminosilicate. Synthesis, Derivatives, Analogues, General and Biological Applications

Imogolite is an aluminosilicate mineral originally found in volcanic ash derived soils. Through the use of chemical synthesis methods this mineral has been successfully synthesized and a number of modified...

Influence of the Processes Occurring in the Movable Interfaces of the Parts of Transport Machines Under the Action of the Components of the Geomodifier on the Efficiency of Tribotechnologies of Running-in and Recovery

It is shown that the effectiveness of the implementation of tribotechnologies for running-in and restoration of systems and assemblies of transport machines depends on the preparation of the working environment in which the running-in of tribocouplings of parts takes place. When using a geomodifier to add to engine and transmission oil, it is important to refine the particles of its components and obtain special properties of their surfaces. The properties of the main components of the KGMT-1 geomodifier: SiO2, MgO, Al2O3, Fe2O3 are considered. Their activation during grinding and feeding into the friction zone is substantiated. The change in the size of the particles of the components of the geomodifier on the duration of the test under various operating conditions and within the limits of the strength intervals was investigated. The course of various physical processes according to nonequilibrium thermodynamics and the realization of states and processes of self-organization are considered. It was found that, depending on the degree of fragmentation, the particles of the components exhibit different activity, and therefore, different conditions for the formation of protective coatings on the working surfaces of parts and tribomechanical and tribophysical effects on particles are realized. It is shown that the latter manifests itself during the formation of defects, specific surface area, and duration of mechanical activation. It was revealed that for the materials of the KGMT-1 geomodifier components with strongly homeopolar bonds, such as SiO2, SiC, and the aluminosilicate mineral kaolinite, an amorphization process is observed. The influence of the α-Si-k-Si phase transformation in the materials of the KGMT-1 additive on the efficiency of the implementation of tribotechnologies has been determined. It is shown how physical processes in a composite oil cause tribochemical reactions and formation of coatings on the working surfaces of interfaces of parts of systems and aggregates of transport machines.

Effect of Silane-Treated Mineral Fillers on Corrosion, Wettability, and Adhesion of Saturated Polyester Coated on Carbon Steel

Saturated polyester (PE) resin was modified with 0.5 and 1.0% (v/v) of epoxysilane-treated (aluminosilicate, muscovite, nepheline syenite, and wollastonite) and alkoxysilane-treated (aluminosilicate) mineral fillers before coating to carbon steel. The corrosion behavior of specimens was studied using potentiodynamic polarization method. Wetting behavior and adhesion of specimens were evaluated by static contact angle and cross-cut tape tests, respectively. The addition of silane-treated mineral fillers dramatically improved the corrosion resistance of saturated PE, with epoxysilane-treated wollastonite and alkoxysilane-treated aluminosilicate at 0.5% concentration significantly lowering the corrosion tendency and rate in 2 M HCl solution. Meanwhile, only epoxysilane-treated nepheline syenite significantly increased the water contact angle of saturated PE. The adhesion of saturated PE to carbons steel was increased after addition of fillers at 0.5%, with epoxysilane-treated wollastonite and alkoxysilane-treated aluminosilicate giving the lowest percent area removed after application of adhesive tape. Epoxysilane-treated wollastonite and alkoxysilane-treated aluminosilicate at 0.5% were found most suitable as fillers for saturated PE coating.

Synthesis of Zeolite A From Coal Fly Ash with Variation of Si/Al Molar Ratio

Fly ash containing 30-36% silica and 14,52-23,78% alumina can be potentially as raw material for synthetic zeolite such as zeolite A. Zeolite A is an aluminosilicate mineral which is rich in alumina so that this zeolite has a good cation exchange capability. Zeolite A has been synthesized by hydrothermal treatment after NaOH fusion. Fly ash has been fused with NaOH at 550 0C for 40 minutes and hydrothermally treated at 1000C for 5 hours. The hydrothermal treatment was conducted in some various Si/Al molar ratios from 0.90; 1.00.; 1.05; to 1.24. The zeolite A was then analyzed using XRD and XRF. The best zeolite A based on XRD result is zeolite with Si/Al molar ratio of 1.1 with crystallinity of 96,80%. The x-ray fluorescence result showed that the Si/Al molar ratios of the four zeolite samples were close to of Si/Al molar ratios of 1, 1.1, 1.21.3 respectively.Keywords: Fly ash, Zeolite A, Hydrothermal Fusion