The aim of the present investigation is to develop mechanochemically synthesized nano-crystalline hydroxyapatite (nHAp) bioceramics using clam seashells and phosphoric acid by varying the CaO:H3PO4 acid at different wt% ratios, i.e. 1:0.75, 1:1.0, 1:1.25, 1:1.5 and 1:1.75. The synthesized powders were characterized using X- ray diffraction ( XRD), scanning electron microscope and high resolution transmission

ABSTRACT With spalling and corrosion during thermal cycles, the castable composites used in injecting lance are easily damaged. In order to solve this problem, we used carbon fibers as additives in the matrix, and prepared mullite- based castables with the addition of anti-oxidant silicon. It was found that the addition of carbon fibers could significantly improve the mechanical properties; the maximum

In this investigation, powder metallurgy route was employed to synthesize SiO2 (5, 10 and 15 vol%) coated aluminium borate whisker (ABOw) reinforced aluminium composites. Commercial pure aluminium powder was used as matrix material and SiO2 coated ABOw was used as reinforcements. M icrostructures of the composites were characterized using scanning electron microscopy and high resolution scanning electron

ABSTRACT To investigate the effect of synthesis approach on the structural and catalytic properties, CoAl2O4/CuFe2O4/CeO2/Ti O2 ceramic nanocomposite was synthesized by four liquid phase routes: mixing of components in the liquid phase ( method 1), mixing of CoAl2O4 precursor with other components (method 2), mixing of CoAl2O4 and CuFe2O4 precursors with other components ( method 3) and mixing of Cu

Abstract Ferroelectric ceramic compositions SrBi2–xYxNb2O9 (x = 0.0, 0.2, 0.4, 0.6 and 0.8) were prepared via conventional solid-state route with high density (92-99%) establishing the sintering conditions. X-ray diffraction studies confirmed the orthorhombic structure. The micrographs obtained from scanning electron microscopy showed the presence of well packed and randomly oriented needle-shaped

Based on the oxidation kinetics of C/SiC composites at 900o-1200oC in stress-oxidation environment, a non-uniform model of oxidation has been suggested in this paper. Combined with fiber notch model, Curtin’s strength model and BHE model, the non-uniform model is able to predict the failure time and residual strength of C/SiC composites accurately. Besides, the initial defects of the model (matrix

Abstract MgAl2O4:M (M = Ti, Mn, Co, Ni) phosphors were successfully prepared by a modified polyacrylamide gel method. Calcination temperature and metal particle has significant effects on the phase transition, optical and color properties of Mg Al2O4: M phosphors. Ti, M n, Co and Ni metal particles introduced into the MgAl2O4 system can produce a variety of colours from white, grayish black, blue to

The present work is based on investigation of mechanical behavior of green ceramic parts fabricated in scanning based ceramic microstereolithography (CM SL). This study is essential as many times green ceramic bodies fabricated by microstereolithography (MSL) can be directly incorporated in microelectromechanical systems (MEMS). These green parts are fabricated from ceramic suspensions obtained by

In this paper, a novel method of preparing porous alumina with alumina powder and boric acid is firstly proposed and experimented, and its mechanism of the fabricating process is also investigated. Unlike traditional methods of manufacturing porous alumina including electrochemical anodization of aluminium and chemical etching, ordered porous alumina has been directly fabricated through synthesis and

ABSTRACT Nanocrystalline boron carbide was synthesized using a precursor. The precursor was prepared by the thermal decomposition of a condensed product formed by boric acid and mannitol. The condensed product was formed by microwave-assisted heating of the aqueous solution of boric acid and mannitol. The condensed product was thermally decomposed at various temperatures, viz. 400°, 500° and 600°C

Abstract MgAl2O4:M (M = Ti, Mn, Co, Ni) phosphors were successfully prepared by a modified polyacrylamide gel method. Calcination temperature and metal particle has significant effects on the phase transition, optical and color properties of Mg Al2O4: M phosphors. Ti, M n, Co and Ni metal particles introduced into the MgAl2O4 system can produce a variety of colours from white, grayish black, blue to

ABSTRACT A promising Aurivillius layered pervoskite ceramics, namely, the title compound has drawn interest in recent days owing to its figure of merit (magnetoelectric coupled properties). General formula of the compound is expressed as (Bi2O2)2+(A n–1 B nO3n+ 1)2–, where A represents Bi/Nd and B represents Ti/Fe/Co. However, no reports are available on impedance measurement of this compound. In the

Nanocrystalline LiCoO2 particles have been surface modified with La2O3 by a simple and cost effective resin coating process. The synthesized pure and La2O3 coated samples were characterized by thermogravimetric analysis / differential scanning calorimetry (TGA/DSC), X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) and transmission electron

Tribological behavior of hot pressed HfB2-5%TiSi2 composite was studied under reciprocative sliding condition using cemented tungsten carbide (WC-Co) ball as counter body. Coefficient of friction (COF) for HfB2 composite sample was obtained in the range of 0.43 to 0.63 at different loads. It was observed that enhancement of load from 5 to 15 N resulted in decrease of COF of HfB2. Specific wear rate

Calcium phosphate is widely used as an implant material in the biomedical field, mainly because they are chemically similar to the inorganic components of bones. In many applications, dimensional accuracy is critical, and implants need to be shaped, sized and machined as needed. However, as ceramic materials with strong atomic bonding forces, they have high hardness and brittleness, so the ability

ABSTRACT Dry sliding wear experiments were carried out at constant normal load and sliding speed on electrodeposited Ni and Ni-α-nano Al2O3 coatings. The coating surfaces were worn against EN-32 HRc hardened steel in pin-on-disc test rig. The work was concentrated on the pin temperature, frictional force and specific wear rate of the coating which were measured as the function of sliding distance.

ABSTRACT Substitution in A or/and B sites of the perovskite lattice, or strain engineering is known to influence the properties of piezoelectric ceramics. Cerium (Ce) has been identified as a substituent to investigate the properties of lead-free (Ba0.85Ca0.15)(Zr0.1Ti0.9)O3 (BCZT) ceramics. Structural, ferroelectric, piezoelectric and dielectric properties of Ce substituted BCZT ceramics were investigated

Alumina and monel superalloy was successfully joined by active metal brazing technique using Ticusil (68.8Ag-26.7Cu-4.5Ti in wt%) filler alloy in a vacuum furnace at 910°C for 10 min under a vacuum of 5×10–6 Torr. Phase analysis of the monel-filler alloy and alumina-filler alloy interfaces was conducted by X-ray diffraction analysis. Interfacial and cross-sectional microstructural investigation and

Determination of local atomic structure at nanoscale for both amorphous and nanocrystalline materials is very difficult and challenging. Local arrangement of atoms needs to be studied for understanding the local or short-range structural information. Pair distribution function (PDF) analysis is a technique used to study the short-range structure of the materials based on local atomic arrangement of

In order to improve the corrosion resistance of magnesium-lithium (Mg-Li) alloy, a micro-arc oxidation (MAO) ceramic layer was first prepared on LA103Z Mg-Li alloy, and then the MAO coating on LA103Z Mg-Li alloy was sealed by layered double hydroxide (LDH) hydrothermal treatment. The obtained samples were subjected to immersion test in 3.5% NaCl solution for 8 days. The growth characteristics of different

To improve the corrosion resistance of the ceramic layer prepared by micro-arc oxidation (MAO) on magnesium alloy, a hydrophobic Mg-Al-Co layered double hydroxide (LDH) coating was fabricated on MAO coated AZ31 magnesium (Mg) alloy by using a simple in-situ growth method. The results showed that the LDH film covered the MAO coating tightly, and it sealed the micro-pores and cracks in the MAO coating

The effects of gamma irradiation in the dose rate of 25 kGy on the structural and optical properties of ZrO2 doped sodium borate glasses were studied. Glassy nature confirmed by XRD and all the physical parameters were calculated. IR spectra revealed the characteristic vibrational and stretching bands due to trigonal and tetrahedral borate network. Slight changes were caused by gamma irradiation in

The influence of calcium bentonite addition on the compressive strength, efflorescence extent and drying shrinkage of fly-ash based geopolymer mortar was investigated. The results showed that appropriate amount (e.g. 15 wt%) of calcium bentonite addition favoured the enhancement of compressive strength mainly because its addition allowed the geopolymer to tolerate more water glass addition and therefore

Suitable sintering ability and excellent densification are important factors for forsterite (Mg2SiO4) ceramics and refractories when used in glass furnaces, continuous casting tundishes, non-ferrous metal smelters, etc. Here, a dense and fine-grained structure has been obtained in the forsterite ceramics prepared by two-step sintering process. Results show that combination of grinding and second step

The work presented in this article deals with the synthesis of a cordierite ceramics, using a natural Algerian kaolin named DD3 of black colour, located in the region of Djbel Dbagh in Guelma. A synthesis was also carried out on bleached DD3 kaolin obtained by activation of hydrochloric acid on natural kaolin in order to eliminate the manganese oxide (which is responsible for the blackish colour) while

The aim of this investigation is to study the UV/Visible absorption and infra-red transmission characteristics due to Cu+/Cu2+ redox in silica glass. The glass composition 18Na2O-2MgO-8CaO-72SiO2 (mol%) containing different concentrations of CuO were prepared by melting route. The optical absorption spectra of the glasses were recorded on an UV/Visible/NIR spectrophotometer in the wavelength range

XRD results show that diffraction peak of M3B is gradually apparent with the increase of annealing temperature and time, which indicates that annealing can promote the formation of M3B phase. The increase of annealing temperature and time leads to transformation of inter dendritic microstructure from long strip Cr3B phase to granular Cr3B phase. Particularly, after annealing at 1100oC for 20 h, the

Based on the attribute of asbestos tailings rich in silicon and magnesium, the powder of asbestos tailings was pre-calcined followed by MgO addition in the green body and finally sintered to develop refractory ceramics containing phases of forsterite, magnesioferrite and merwinite. The effects of pre-calcining treatment, MgO content and sintering temperature on crystallization, phase transition, microstructure

Eu3+ doped M3La2Si3O12 (M = Mg2+, Ca2+, Sr2+, Ba2+) materials were prepared using sol-gel technique. The samples were prepared at a temperature of 950oC using 0.01-0.05 mole of Eu3+ ion to examine worth of amount of activator ion on luminous intensity. Photoluminescence characteristics of these Eu3+ incorporated inorganic fluorescent materials were explored using photoluminescence (PL) emission spectroscopy

High voltage bushing is one of the key components of Indian Test Facility. It is designed to provide 100 kV electrical isolation to all high voltage feedlines from the electrically grounded vessel. It also forms vacuum boundary between the vessel and the outer atmosphere. Conventional vacuum compatible porcelain insulator is selected for this purpose. However, to accommodate several high voltage feedlines

Indian natural magnesite containing silica and lime as main impurities was beneficiated using reverse froth flotation technique. Pine oil was used as frother, Flotigam EDA as collector and sodium hexametaphosphate as depressant of carbonate group. Operating parameters were optimized using response surface methodology and a quadratic model equation was formulated for the experiment. The effect of different

High strength ceramic proppants are a significant factor during the hydraulic fracturing process. Although many system ceramic proppants have been developed, their strength remained relatively low. In this work high strength ceramic proppants have been successfully prepared by solid state sintering at 1450°C using low grade bauxite and varying contents of feldspar; XRD analysis revealed that the prepared

The present work reports a convenient way to evaluate the photocatalytic activity of anatase TiO2 films by monitoring the degradation of methylene blue (MB) directly on the TiO2 coated tiles under simulated solar light (1 sun condition; AM 1.5G simulator) using Raman spectroscopy. For this purpose, nanocrystalline TiO2 films of aesthetic quality (thickness ∼80±5 nm) were deposited by the sol-gel method

The present work is focused on the development and characterization of low-cost flat microfiltration ceramic membranes from West Cameroonian kaolin, cassava starch and bovine bone ash as pore-forming agents, and comparative study of porogens’ influence on membranes properties. These materials were chosen due to their abundance in the country and their beneficial properties. The proportion of porogens

Two series of semi-conducting glazes based on cassiterite phase were prepared and characterized after application on electrical porcelain bodies. In one series, semi-conducting fraction of the final glazes was calcined, then added to the base glaze. In another series, semi-conducting fraction of the studied glazes was precipitated in-situ during firing. Morphology of cassiterite and its optimized content

Novel Eu3+ doped MGdAl3O7 (M = Mg, Ca, Sr and Ba) phosphors were synthesized and examined. The samples were prepared at 600°C using solution-combustion procedure and investigated at 0.01 to 0.05 mole of dopant ion concentration. The optimal concentration of Eu3+ ions was 0.03 mole for MGdAl3O7 host matrix. On 393 nm excitation, the materials exhibited sharp red emission at 608-614 nm because of 5D0

Thermal barrier coatings (TBCs) typically have low thermal conductivity and high resistance to oxidation at elevated temperatures. TBCs are used to protect the turbine blades of aircraft engines operating at high temperature. The commonly used YSZ (8 wt% Y2O3-stabilized ZrO2) cannot function at temperatures higher than 1200°C for an extended period of time, which hinders the necessary improvement in

In this study, lithium and magnesium ferrites have been synthesized using EDTA/EG assisted sol-gel method. Based on X-ray diffraction data, it is identified that a spinel-type structure of Li ferrite with space group of P4332 and Mg ferrite with space group of Fd3m has been successfully formed. The estimated value of crystallite size falls within 33-42 nm range. The microstructure of the as-produced

Microstructures, mechanical properties, thermal shock resistance, as well as oxidation resistance of short carbon fiber (Cf) and nano ZrB2 enhanced SiC-BN ceramics were investigated systematically. Results showed that ZrB2 induced the structure developments of BN, graphite plates and SiC particles. Consequently, flexural strength reached 378.2 MPa and fracture toughness reached 5.80 MPa.m1/2. Mechanical

Cleaning of coal resulted in ash reduction, heat value enhancement, increased reactive maceral content and change in ash composition influencing combustion performance. With washed fractions, trends of improved combustion behavior were observed in thermo-gravimetric analyser, which was not always reflected correspondingly in bench scale combustor, i.e. drop tube furnace (DTF). Lower burnout efficiency

Dispersion of zirconia powder in aqueous suspension using suitable dispersant for coating application was studied. Zeta potential experiments were conducted in search of stable suspensions. Sedimentation tests were carried out in both acidic and basic pH range, i.e. from 2 to 11. Zirconia slurry as coating material was used for coating on clay-alumina tubular ceramic support. The slurry was composed

Porous silicon carbide ceramics were prepared by an in situ reaction bonding process using clay and alumina as additives. The effects of alumina additive, pore former on phase composition, microstructure, flexural strength and thermal shock resistance of the ceramics were studied. Thermal shock resistance of porous SiC ceramics due to cooling was evaluated as a function of quenching temperatures and

In this study, production of alumina and steatite containing ceramic insulators as thermostat material was realized by investigating the composition, pressing pressure and sintering temperature. 90 bar of pressing pressure was employed to give a ring shape to thermostat insulators by mixing with 3% kerosene. Alumina based samples were sintered at 1400°C, while 1300°C sintering temperature was determined

In this work, the corrosion behavior of titanium composites of titanium-titanium boride composites for marine applications was investigated by conducting electrochemical polarization experiments in neutral chloride (3.5% NaCl) at room temperature. The composites with two different volume fractions (20% and 40%) of TiB were processed by three powder metallurgical techniques such as spark plasma sintering

In this present investigation, AA6082-T6 thin aluminium alloy plates of 2 mm thickness were friction stir welded using fine ceramic Al2O3 nanoparticles as the reinforcing materials between the adjoining plates. The joining was done by hexagonal pin profile tool of tungsten carbide material with tool rotational speeds 710 rpm and 900 rpm. The number of passes of the welds was 2 and 3 with constant tool

Ceramic industry generates a large amount of wastes, which pollutes and damages the environment. This paper presents the effects of concrete waste incorporating dolomite aggregate on ceramic-based geopolymer pastes in terms of microstructure and compressive strength. Recently, attention has been drawn to the use of geopolymer technology in the production of building units. Geopolymers were prepared

Nickel-cobalt ferrite (NCF) without Sn-dopant and with (x = 0 to 0.1%), (Ni0.7Co0.3)(Fe2–xSnx)O4+ d, have been synthesized through solid-state route. Calcination of oxides at 900°C yielded spinel phase as confirmed by X-ray diffraction. Sn doping does not show much variation in lattice constants, but slightly increases crystallite size. Green compacts have been well sintered in 1150°-1200°C for 10

In this study, local mineral (silica sand) obtained from Hazara division, Khyber Pakhtunkhwa, Pakistan was fabricated into soda-lime silicate glass. Titanium dioxide (TiO2) concentration in the range of 1-3 wt% was added as a nucleating agent to investigate its effect on crystallization phase, density, hardness, thermal expansion coefficient (α), glass transition temperature (Tg), micro hardness and

The influence of grain size (7-16 nm) on electrical conductivity, dielectric properties and magnetic field dependent I–V characteristics along with magnetoresistance have been studied for zinc ferrite ( ZnFe 2O4). ZnFe2O4 was prepared by co-precipitation technique. Ball milling on the chemical routed material was carried out to control the particle size. The effect of particle size on the conduction

The structural, ferroelectric, piezoelectric and dielectric properties of lead-free 0.45Ba0.92Ca0.08TiO3-0.55BaTi0.96Zr0.04O3 (BCT8-BZT4) ceramics synthesized by conventional solid state reaction method have been reported. Structural analyses by X-ray diffraction (XRD) and Raman spectroscopic measurements indicate that the BCT8-BZT4 ceramics possesses both tetragonal (space group P4mm) and orthorhombic

Strontium bismuth niobate (SrBi2Nb2O9 (SBN), K0.025Sr0.95Gd0.025Bi2Nb2O9 (KSGBN1), K0.05Sr0.9Gd0.05Bi2Nb2O9 (KSGBN2) and K0.1Sr0.8Gd0.1Bi2Nb2O9 (KSGBN3)) ceramics were prepared by two stage solid state reaction method. Calcination was done at 850oC for 4 h. Structural property of calcined samples was studied by powder X-ray diffraction (XRD) technique at room temperature. XRD patterns of the samples

Dual mixed slurry for AA6061/Al2O3-Al powder was formed under argon gas protection and used to fabricate composite due to the effect of free vortex flow in semi-solid stage. Initially, Al2O3 reinforcement was mixed with aluminium powder via ball milling process and then converted into reinforcement slurry. Simultaneously, primary slurry for AA6061 alloy was prepared in closed coiled sprue. Semi-solid

Biphasic calcium phosphate (BCP) ceramics was synthetically prepared by ex-situ method using hydroxyapatite (HAp) and beta tricalcium phosphate (β-TCP) powders. Both HAp and β-TCP were prepared by wet chemical co-precipitation and calcination method and were then mixed at two different weight ratios of 60:40 and 70:30. The mixed BCPs were then pressed and sintered at 1200o and 1250oC. Sintered pure

Lead-iron phosphate (LIP) glasses are a promising new waste form for safe immobilization of both high level defence and high level commercial radioactive waste for long term disposal. LIP glasses have several advantages such as lower aqueous corrosion rate, lower processing temperature, etc. The durability test for LIP glasses showed that the alkaline earth oxides BaO, SrO and CaO decrease the durability

The effects of sintering temperature, heating rate, holding time and sintering additive on the properties of single-phase indium tin oxide (ITO) target, prepared by normal pressure sintering method, were studied systematically. The results showed that target sintered at 1550°C for 10 h with a heating rate of 9°C/min had a higher relative density of 98.7% and a lower resistivity of 4×10–4 Ω.cm. When

Thermal shock resistance of precursor derived Si-Hf-C-N(O) foams at temperatures varying from 800o-1000oC subjected to multiple thermal cycles was investigated. The as-synthesized foams possessed interconnected pores with an average cell size of 1.09 mm. The X-ray diffractograms of the foams before and after thermal cycling showed that the amorphous nature of the foams was retained. FTIR spectra exhibited

Enthalpy increments of the ternary compounds of rare earth uranium oxides, RE6UO12 (RE = La, Nd, Sm, Eu, Gd) were measured by inverse drop calorimetry in the temperature range 533-1738K. These compounds (RE6UO12) were prepared by gel combustion synthesis and characterized by XRD. From the measured enthalpy increment values, thermodynamic functions, viz. heat capacity, entropy, Gibb's energy functions

In this study, light-weight insulation materials were prepared with calcined flint clay as the main material and sawdust was infused by sols as a pore forming agent. Micro-porosity and properties of the prepared insulation materials were investigated and were found to have better comprehensive properties. Apparent porosity, bulk density and cold crushing strength of the compositions containing 40 wt%

Rare-earth aluminate (ReAlO3, Re = La, Gd, Nd, Y) powders were successfully synthesized from a mixture of Re2O3 (Re = La, Gd, Nd, Y) and Al2O3 powders using microwave assisted synthesis which consists of two steps: microwave heat treatment and high-energy milling process. X-ray diffraction, laser particle size analyzer, nitrogen adsorption technique (BET) and scanning electron microscopy were employed

In this work, the effect of microwave sintering on the properties of scandia doped zirconia (10 mol% scandia in zirconia) was investigated. The sample was prepared by mixed oxide method and the sintering was done at the temperature of 1400oC for 20 min using a 2.45 GHz microwave furnace. Sintering behavior of this microwave sintered ceramics was compared with the corresponding conventional sintered