Hydroxyapatite （HA）-zirconium （ZrO2） composite coating was produced by magnetic sputtering on Ti6Al4V titanium alloy substrate, the coatings of 50HA-50ZrO2 and 75HA-25ZrO2 （mass fraction, %） were characterized b...Hydroxyapatite （HA）-zirconium （ZrO2） composite coating was produced by magnetic sputtering on Ti6Al4V titanium alloy substrate, the coatings of 50HA-50ZrO2 and 75HA-25ZrO2 （mass fraction, %） were characterized by scanning electron microscopy, energy disperse spectroscopy, X-ray diffraction and scratch test, respectively, and the effects of HA contents in the coating on residual stress were analyzed. The experimental results show that the phases of HA-ZrO2 composite coatings are HA, ZrO2 and Y2O3, and the HA has a certain decomposition in the combination process, producing TCP and CaO impurity phases. The porous surface of coating is conducive to the growth of bone tissue, and the surface roughness values of 50HA-50ZrO2 and 75HA-25ZrO2 are 1.61 μm and 2.92 μm, respectively. The coating interface is of mechanical integration, the bonding strength values of 50HA-50ZrO2 and 75HA-25ZrO2 are 30 N and 17.5 N, respectively, showing a downward trend with the HA contents increasing. The residual stress values in the coating of 50HA-50ZrO2 and 75HA-25ZrO2 are （-399.1±3.0） MPa, （-343.2±20.3） MPa, respectively, as a result, the appropriate increase of HA contents in the coating will reduce its residual stress.展开更多
The X80 pipeline steel was welded with the way of submerged arc welding. The SST （slow strain test） of the welded joint samples in the air, NACE （National Association of Corrosion Engineers） solution （no H2S）, N...The X80 pipeline steel was welded with the way of submerged arc welding. The SST （slow strain test） of the welded joint samples in the air, NACE （National Association of Corrosion Engineers） solution （no H2S）, NACE solution （saturated H2S） was performed to research the sensibility index of SCC （stress corrosion cracking） Iscc. The morphologies of the welded joint fractures and the fracture modes were observed with SEM （scanning electron microscope）, and the fracture chemical compositions were analyzed with EDS （energy dispersive spectrometer）, respectively. The fracture mechanisms of the welded joints were discussed. The results show that sensibility index of SCC in the air is not obvious, the fracture is dimple, and the mode of fracture is ductile fracture. The sensibility index of SCC in NACE solution （no H2S） is 13.21%, the stress corrosion is not obvious. The sample fracture shows quasi cleavage＋dimple, and the fracture mode is toughness＋brittle rupture. The sensibility index of SCC in NACE solution （saturated H2S） is 56.94%, the plastic loss is the most serious, appearing an obvious stress corrosion tendency, and there is no obvious necking phenomenon. The fracture mode is brittle fracture, and the sample fracture has a high sulfur concentration, prompting S to a aliquation of crisp crystal in the welded zone, and making its mechanical properties worsen.展开更多
基金Project (08KJB430002) supported by the Natural Science Foundation of the Higher Education Institutions of Jiangsu Province, ChinaProject (CJ20110019) supported by the Applied Basic Research Programs of Changzhou City, China
文摘Hydroxyapatite （HA）-zirconium （ZrO2） composite coating was produced by magnetic sputtering on Ti6Al4V titanium alloy substrate, the coatings of 50HA-50ZrO2 and 75HA-25ZrO2 （mass fraction, %） were characterized by scanning electron microscopy, energy disperse spectroscopy, X-ray diffraction and scratch test, respectively, and the effects of HA contents in the coating on residual stress were analyzed. The experimental results show that the phases of HA-ZrO2 composite coatings are HA, ZrO2 and Y2O3, and the HA has a certain decomposition in the combination process, producing TCP and CaO impurity phases. The porous surface of coating is conducive to the growth of bone tissue, and the surface roughness values of 50HA-50ZrO2 and 75HA-25ZrO2 are 1.61 μm and 2.92 μm, respectively. The coating interface is of mechanical integration, the bonding strength values of 50HA-50ZrO2 and 75HA-25ZrO2 are 30 N and 17.5 N, respectively, showing a downward trend with the HA contents increasing. The residual stress values in the coating of 50HA-50ZrO2 and 75HA-25ZrO2 are （-399.1±3.0） MPa, （-343.2±20.3） MPa, respectively, as a result, the appropriate increase of HA contents in the coating will reduce its residual stress.
基金Item Sponsored by Natural Science Foundation of Jiangsu Province of China(BK2009104)Innovation Program of Graduated Student of Jiangsu Province China(CXZZ12-731,CXLX11-0388)
文摘The X80 pipeline steel was welded with the way of submerged arc welding. The SST （slow strain test） of the welded joint samples in the air, NACE （National Association of Corrosion Engineers） solution （no H2S）, NACE solution （saturated H2S） was performed to research the sensibility index of SCC （stress corrosion cracking） Iscc. The morphologies of the welded joint fractures and the fracture modes were observed with SEM （scanning electron microscope）, and the fracture chemical compositions were analyzed with EDS （energy dispersive spectrometer）, respectively. The fracture mechanisms of the welded joints were discussed. The results show that sensibility index of SCC in the air is not obvious, the fracture is dimple, and the mode of fracture is ductile fracture. The sensibility index of SCC in NACE solution （no H2S） is 13.21%, the stress corrosion is not obvious. The sample fracture shows quasi cleavage＋dimple, and the fracture mode is toughness＋brittle rupture. The sensibility index of SCC in NACE solution （saturated H2S） is 56.94%, the plastic loss is the most serious, appearing an obvious stress corrosion tendency, and there is no obvious necking phenomenon. The fracture mode is brittle fracture, and the sample fracture has a high sulfur concentration, prompting S to a aliquation of crisp crystal in the welded zone, and making its mechanical properties worsen.
