K. Y Ma
,
Z.C. Guo
,
M.F. Wen
,
X. W Yang and F. Han ( Kunming University of Science and Technology
,
Kunming 650093
,
China China National Nonferrous Metals Imp. & Exp. Corp.
,
Shanxi Company
,
Xi'an 710000
,
China )
金属学报(英文版)
The effects of electroplating conditions on the composition of N-W-SiC composite coating were studied; the znfiuence of heat-treatment and nitrocarburization on the microstructure, hardness and wear resistance of the coating were discussed. The results showed that an amorphous composite coating, containing(wt%) 50-55Ni, 42-45.IW and 3.0-7.6SiC, could be electroplated on the matrix. Afier heat-treatment or nitrocarburization the coating crystallized to form some new phases, and the haordness and wear resistance of the composite coating were enhanced retmarkably.
关键词:
electroplating
,
null
,
null
,
null
QIAO Lijie LIU Rui XIAO Jimei University of Science and Technology Beijing
,
Beijing
,
China
金属学报(英文版)
The effects of stress components on nucleation sites and propagation directions of stress cor- rosion cracks in brass were investigated with specimens under mode Ⅱ and mode Ⅲ loadings. The results indicated that under mode Ⅱ loading,stress corrosion cracks nucleated on the site with maximum normal stress component and propagated along the plane perpendieular to the maximum normal stress,under mode Ⅲ loading,the stress corrosion crack was not evident on the 45°plane due to the general corrosion in aqueous solution with high NH_4OH concentra- tion,while stress corroded in aqueous solution with low NH_4OH concentration, numerous cracks with spacings of 10—150μm were found on the 45°plane with maximum normal stress and no stress corrosion cracks was observed on the plane with maximum shear stress.
关键词:
stress corrosion cracking
,
null
,
null
,
null
Superconductor Science & Technology
It is shown that the superconductivity in Ce(1-x)Gd(x)FeAsO(0.84)F(0.16) compounds can be modulated by internal (chemical) pressure. The internal pressure is induced by Gd substitution for Ce in CeFeAsO(0.84)F(0.16), which compresses the crystal lattice. The temperature dependences of resistivity and magnetization show that the superconducting-transition temperature T(c) is enhanced from 40 K for CeFeAsO(0.84)F(0.16) to 47.5 K for Ce(0.6)Gd(0.4)FeAsO(0.84)F(0.16). The increase and subsequent decrease of Tc upon application of external pressure, as observed previously in LaFeAsO(0.89)F(0.11), is entirely confirmed by the modulation of Tc of the Ce(1-x)Gd(x)FeAsO(0.84)F(0.16) superconductors by internal pressure.
关键词:
layered quaternary compound;43 k;iron
