In this work,thin films of nickel oxide(NiO)were deposited by a simple and inexpensive technique,which is spray pyrolysis on ordinary glass substrates heated to a fixed temperature of500°C,from a solution contain...In this work,thin films of nickel oxide(NiO)were deposited by a simple and inexpensive technique,which is spray pyrolysis on ordinary glass substrates heated to a fixed temperature of500°C,from a solution containing nickel nitrate hexahydrate as a precursor dissolved in distilled water with deferent values of concentrations.The NiO thin films obtained were characterized to determine the structure with X-ray diffraction technique(XRD),the absorption domain(UV-Visible Spectroscopy),and the surface morphology(SEM).The X-ray diffraction patterns confirm the presence of NiO phase with preferential orientation along the(111)direction.The optical gap for nickel oxide calculated with a concentration of0.1M from the measurement of optical absorption is3.6eV,which is quite comparable to the value of the ratio.展开更多
The aim of this work is to study the influence of successive weld repairs on the microstructure and the mechanical behavior of the heat-affected zone（HAZ） of an HSLA X70 steel. Detailed microstructural examination c...The aim of this work is to study the influence of successive weld repairs on the microstructure and the mechanical behavior of the heat-affected zone（HAZ） of an HSLA X70 steel. Detailed microstructural examination combined to grain size measurement showed that beyond the second weld repair, the microstructure of the HAZ undergoes significant change in the grain morphology and grain growth. The results of the X-ray diffraction analyzed using MAUD software indicated an increase in the crystallite size and a decrease in the dislocation density according to the number of weld repair operations. Consequently, a loss of mechanical properties, namely the yield strength and the toughness with the number of weld repairs, was recorded. Beyond the second weld repair operation, the properties of the welded joint do not fulfill the standards applied in piping industry.展开更多
The multiferroic ceramics Bi_(0.8)Ba_(0.2)Fe_(1-x)Sb_(x)O_(3)with x=0,0.01,and 0.02 were synthesized using the solid-phase reaction technique.The samples were sintered at two different temperatures,850℃and 900℃.Scan...The multiferroic ceramics Bi_(0.8)Ba_(0.2)Fe_(1-x)Sb_(x)O_(3)with x=0,0.01,and 0.02 were synthesized using the solid-phase reaction technique.The samples were sintered at two different temperatures,850℃and 900℃.Scanning electron microscopy revealed the effect of antimony concentration on grain size and formation.The effect of Sb-doping on the crystal structure and ferroelectric properties of these ceramics was investigated using X-ray diffraction,Raman spectroscopy,and dielectric measurements.The dielectric constant was enhanced upon Fe^(3+)substitution by Sb^(3+)without affecting the dielectric loss of the ceramics.The tetragonal distortion of the rhombohedral symmetry of BiFeO_(3)caused by Ba-doping at Bi 3þsite was lifted by Sb-doping at Fe^(3+)site.展开更多
文摘In this work,thin films of nickel oxide(NiO)were deposited by a simple and inexpensive technique,which is spray pyrolysis on ordinary glass substrates heated to a fixed temperature of500°C,from a solution containing nickel nitrate hexahydrate as a precursor dissolved in distilled water with deferent values of concentrations.The NiO thin films obtained were characterized to determine the structure with X-ray diffraction technique(XRD),the absorption domain(UV-Visible Spectroscopy),and the surface morphology(SEM).The X-ray diffraction patterns confirm the presence of NiO phase with preferential orientation along the(111)direction.The optical gap for nickel oxide calculated with a concentration of0.1M from the measurement of optical absorption is3.6eV,which is quite comparable to the value of the ratio.
基金the Research Center in Industria Technologies(CRTI)for its financial supportMohamed Khider University,Biskra,for its help to accomplish this study
文摘The aim of this work is to study the influence of successive weld repairs on the microstructure and the mechanical behavior of the heat-affected zone（HAZ） of an HSLA X70 steel. Detailed microstructural examination combined to grain size measurement showed that beyond the second weld repair, the microstructure of the HAZ undergoes significant change in the grain morphology and grain growth. The results of the X-ray diffraction analyzed using MAUD software indicated an increase in the crystallite size and a decrease in the dislocation density according to the number of weld repair operations. Consequently, a loss of mechanical properties, namely the yield strength and the toughness with the number of weld repairs, was recorded. Beyond the second weld repair operation, the properties of the welded joint do not fulfill the standards applied in piping industry.
文摘The multiferroic ceramics Bi_(0.8)Ba_(0.2)Fe_(1-x)Sb_(x)O_(3)with x=0,0.01,and 0.02 were synthesized using the solid-phase reaction technique.The samples were sintered at two different temperatures,850℃and 900℃.Scanning electron microscopy revealed the effect of antimony concentration on grain size and formation.The effect of Sb-doping on the crystal structure and ferroelectric properties of these ceramics was investigated using X-ray diffraction,Raman spectroscopy,and dielectric measurements.The dielectric constant was enhanced upon Fe^(3+)substitution by Sb^(3+)without affecting the dielectric loss of the ceramics.The tetragonal distortion of the rhombohedral symmetry of BiFeO_(3)caused by Ba-doping at Bi 3þsite was lifted by Sb-doping at Fe^(3+)site.
