The high-temperature oxidation behavior of arc-sprayed aluminum bronze coatings on steel substrate was studied during isothermal exposures in air at 900 ℃. The surface morphologies and interface of the coatings after...The high-temperature oxidation behavior of arc-sprayed aluminum bronze coatings on steel substrate was studied during isothermal exposures in air at 900 ℃. The surface morphologies and interface of the coatings after isothermal oxidation at 900 ℃ for different times were observed. The experiments showed that the coatings on steel substrate were not deteriorated and the substrate was protected well, being exposed to high temperatures up to 900 ℃ . The coatings withstood more than ten times thermal shock tests without any coating separation. The thermal expansion coefficient of the coatings was measured, revealing not much difference between it and that of steel substrate. After exposure at high temperature, the coatings were still adhered to steel substrate well. Isothermal mass gain of the coatings at elevated temperature in dry air was measured by means of a thermal balance and the oxidation behavior was evaluated by oxidation kinetic curves, exhibiting the oxidation kinetics curve accorded with a parabolic law. The parabolic rate constant of the oxidation kinetic curve is 1.02×10?9 g2·cm?4·s?1 for the first 60 min and from 150 min to 2 880 min the constant is 5.1×10?12 g2·cm?4·s?1.展开更多
The High Velocity Arc Spraying （HVAS） technology was used to prepare Fe-Al composite coatings by the adding of different elements into cored wires to obtain different Fe-Al coatings. The added compounds do great eff...The High Velocity Arc Spraying （HVAS） technology was used to prepare Fe-Al composite coatings by the adding of different elements into cored wires to obtain different Fe-Al coatings. The added compounds do great effect on the properties of the composite coatings. The microstructures and abrasive wear performances of the coatings were assessed by transmission electron microscopy （TEM）, scanning electron microscopy （SEM）, and THT07-135 high temperature wear equipment. It was found that the adding of Cr3C2 can greatly increase the room temperature wear behavior, and Fe-Al/WC coatings have adapting periods at the beginning of wear experiment. With the rise of temperature, the wear resistance of Fe-AI/Cr3C2 coatings becomes bad from room temperature to 250℃, and then stable from 250℃ to 550℃; the wear resistance of Fe-Al/WC becomes well with the rise of temperature. The adding of Cr and Ni can also improve wear performances of Fe-Al composite coatings.展开更多
Three kinds of single layer coatings of Zn,Zn15Al,316L stainless steel and two kinds of double layer coatings with inner layer of Zn or Zn15Al and outer layer of 316L stainless steel by arc spraying were developed to ...Three kinds of single layer coatings of Zn,Zn15Al,316L stainless steel and two kinds of double layer coatings with inner layer of Zn or Zn15Al and outer layer of 316L stainless steel by arc spraying were developed to protect the metal ends of prestressed high-strength concrete(PHC)pipe piles against soil corrosion.The corrosion behaviors of the coated Q235 steel samples in the simulated Dagang soil solution were investigated by potentiodynamic polarization,electrochemical impedance spectroscopy(EIS) and natural immersion tests.The results show that the corrosion of the matrix Q235 steel is effectively inhibited by Zn,Zn15Al, Zn+316L and Zn15Al+316L coatings.The corrosion rate value of Zn15Al coated samples is negative.The corrosion products on Zn and Zn15Al coated samples are compact and firm.The corrosion resistance indexes of both Zn and Zn15Al coated samples are improved significantly with corrosion time,and the latter are more outstanding than the former.But the corrosion resistance of 316L coated samples is decreased quickly with the increase in immersion time.When the coatings are sealed with epoxy resin,the corrosion resistance of the coatings will be enhanced significantly.展开更多
文摘The high-temperature oxidation behavior of arc-sprayed aluminum bronze coatings on steel substrate was studied during isothermal exposures in air at 900 ℃. The surface morphologies and interface of the coatings after isothermal oxidation at 900 ℃ for different times were observed. The experiments showed that the coatings on steel substrate were not deteriorated and the substrate was protected well, being exposed to high temperatures up to 900 ℃ . The coatings withstood more than ten times thermal shock tests without any coating separation. The thermal expansion coefficient of the coatings was measured, revealing not much difference between it and that of steel substrate. After exposure at high temperature, the coatings were still adhered to steel substrate well. Isothermal mass gain of the coatings at elevated temperature in dry air was measured by means of a thermal balance and the oxidation behavior was evaluated by oxidation kinetic curves, exhibiting the oxidation kinetics curve accorded with a parabolic law. The parabolic rate constant of the oxidation kinetic curve is 1.02×10?9 g2·cm?4·s?1 for the first 60 min and from 150 min to 2 880 min the constant is 5.1×10?12 g2·cm?4·s?1.
基金This work was financially supported by the National Natural Science Foundation of China (No.50235030, 50005024)
文摘The High Velocity Arc Spraying （HVAS） technology was used to prepare Fe-Al composite coatings by the adding of different elements into cored wires to obtain different Fe-Al coatings. The added compounds do great effect on the properties of the composite coatings. The microstructures and abrasive wear performances of the coatings were assessed by transmission electron microscopy （TEM）, scanning electron microscopy （SEM）, and THT07-135 high temperature wear equipment. It was found that the adding of Cr3C2 can greatly increase the room temperature wear behavior, and Fe-Al/WC coatings have adapting periods at the beginning of wear experiment. With the rise of temperature, the wear resistance of Fe-AI/Cr3C2 coatings becomes bad from room temperature to 250℃, and then stable from 250℃ to 550℃; the wear resistance of Fe-Al/WC becomes well with the rise of temperature. The adding of Cr and Ni can also improve wear performances of Fe-Al composite coatings.
基金Projects(20080440043)supported by China Postdoctoral Science FoundationProject supported by Guangdong Sanhe Pipe-pile Co.Ltd.,China
文摘Three kinds of single layer coatings of Zn,Zn15Al,316L stainless steel and two kinds of double layer coatings with inner layer of Zn or Zn15Al and outer layer of 316L stainless steel by arc spraying were developed to protect the metal ends of prestressed high-strength concrete(PHC)pipe piles against soil corrosion.The corrosion behaviors of the coated Q235 steel samples in the simulated Dagang soil solution were investigated by potentiodynamic polarization,electrochemical impedance spectroscopy(EIS) and natural immersion tests.The results show that the corrosion of the matrix Q235 steel is effectively inhibited by Zn,Zn15Al, Zn+316L and Zn15Al+316L coatings.The corrosion rate value of Zn15Al coated samples is negative.The corrosion products on Zn and Zn15Al coated samples are compact and firm.The corrosion resistance indexes of both Zn and Zn15Al coated samples are improved significantly with corrosion time,and the latter are more outstanding than the former.But the corrosion resistance of 316L coated samples is decreased quickly with the increase in immersion time.When the coatings are sealed with epoxy resin,the corrosion resistance of the coatings will be enhanced significantly.
