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Fe-Cr-Ni-Mn-Mox-Si0.5-B0.5 (x=0.0, 0.3, 0.5, 0.8, 1.0) alloy systems with close-to-equiatomic ratios were fabricated by laser surface alloying onto Q235 steel substrates, aiming to obtain excellent coatings. The experimental results indicate that the phase composition consists of face-centred cubic (FCC) phase with a few intermetallic FeMoSi as a result of adding Si and Mo into FeNiCrMn alloy system. It makes lattice constant increase and lattice expansion. The coatings also shows excellent corrosion resistance in the simulated saturated brine slurry, especially FeCrNiMnMo0.8Si0.5B0.5 coating is the best. [ABSTRACT FROM AUTHOR]

To obtain high performance coating materials a Fe5Cr5SiTiCoNbMoW high entropy alloy coating was prepared for deposition onto 6542# and Q235 tool steel by CO2 laser cladding. The microstructure, microhardness, corrosion resistance and wear resistance of the coatings were investigated. The experimental results showed that the Fe5Cr5SiTiCoNbMoW high entropy alloy is mainly composed of body-centred cubic (BCC) phase accompanied with a few metal carbides. The microstructure was dendritic crystal. The hardness and wear resistance of the Fe5Cr5SiTi-CoNbMoW high entropy alloy coated 6542# tool steel with high C content was higher than those of the Fe5Cr5SiTiCoNbMoW high entropy alloy coated Q235 tool steel. [ABSTRACT FROM AUTHOR]

To improve anti-corrosion and wear resistance, a new kind of Fe5Cr5SiTiCoNbMoW high-entropy alloy (HEA) coating was fabricated successfully on Q235 by laser cladding technology. The microstructure, phase structure, microhardness, anti-corrosion and wear resistance were researched using metallographic microscope, scanning electron microscope, X-ray diffraction, microhardness tester, electrochemical workstation as well as friction and wear testing machine, respectively. The experimental results show that the microstructure of cladding coating is composed of dendrite and eutectic crystal. The main phase in the coating is single body-centered cubic solid solution. The anti-corrosion of HEA coating is better than that of 304 stainless steel in NaCl solution. Moreover, the average microhardness of HEA coating is nearly 600 HV0.2, which is almost five times higher than that of Q235 substrate. The HEA coating is of low friction coefficient and mass loss, exhibiting excellent wear resistance. [ABSTRACT FROM AUTHOR]

Single domain YBCO bulk superconductors with different additions of ZnO have been successfully fabricated by RE011 TSIG process with a new solid phase of [(100-)(Y2OBaCuO2)+ZnO] and a new liquid phase of (Y2O3+6CuO+10BaCuO2). The effects of ZnO additions on the growth morphology, microstructure, critical temperature (), the levitation force and trapped field of the YBCO bulks have been investigated. It is found that within the range of ZnO additions =0-1.0 wt.%, all the samples are of the typical characteristic of single-domain YBCO bulk; the of the samples decreases from 92 K to 80 K when the ZnO addition increases from =0 wt.% to =1.0 wt.%; the levitation force and trapped field of the samples firstly increase and then decrease with increase of ZnO additions after going through a maximum, which is closely related with the ZnO addition and the resulting flux pinning force caused by lattice distortion due to the substitution of Zn for Cu site in the YBCO crystal; the largest levitation force 36.8 N (77 K, 0.5 T) and trapped field 0.416 T (77 K, 0.5 T) of the samples are obtained when =0.1 wt.%, respectively. This result is significantly important and helpful for us to improve the properties of YBCO bulk superconductors. [ABSTRACT FROM AUTHOR]

The purpose of this study was to investigate the degree of pozzolanic reaction and active ion dissolution of fly ash in different concentrations of Ca(OH)2 solution dissolving in 48 hours. The active ion concentration and conductivity of filtrate were measured by inductively coupled plasma optical emission spectrometer and conductivity metre. The micromorphology of residue in different dissolving times was analysed by field emission transmission electron microscopy. The results indicate the following: (a) the fly ash has pozzolanic activity and it has similar variation of active Al3+, Fe3+, Si4+ ion concentration in 1 mol L−1 Ca(OH)2 solutions compared with 0·1 mol L−1 Ca(OH)2 solutions with an increase in dissolving time: the concentration of Al3+, Si4+ ions appears to have two peaks at 6 and 24 hours, whereas Fe3+ ion concentration appears declining. (b) Conductivity of 1 and 0·1 mol L−1 fly ash-Ca(OH)2 solution shows decreasing tendency, the degree of pozzolanic reaction in 1 mol L−1 Ca(OH)2 solution appears to be higher than in 0·1 mol L−1 Ca(OH)2 solution. [ABSTRACT FROM AUTHOR]