The microstructures, friction and wear behavior under dry sliding condition of electrodeposited amorphous Fe-Co-W alloy deposits heat treated at different temperatures were studied. A comparative study of hard chrome ...The microstructures, friction and wear behavior under dry sliding condition of electrodeposited amorphous Fe-Co-W alloy deposits heat treated at different temperatures were studied. A comparative study of hard chrome deposit under the same testing condition was also made. The experimental results show that the hardness and wear resistance of amorphous Fe-Co-W alloy deposits are improved with the increasing of heat treatment temperature, and reach the maximum value at 800 ℃, then decrease above 800 ℃. Under 40 N load, the wear resistance properties of the alloy deposits heat treated at 800 ℃ are superior to those of hard chrome deposit. The main wear mechanisms of amorphous Fe-Co-W alloy deposits heat treated below 600 ℃ are peeling, plastic and flowing deformation; when the deposits are heat treated above 700 ℃, they are plastic and flowing deformation. While the main wear mechanisms of hard chrome are abrasive wear, fatigue and peeling.展开更多
Nickel-carbon nanotube(CNT) composite coatings with a Zn-Ni interlayer were prepared by electrodeposition technique on aluminum substrate. The effects of CNT concentration in plating bath on the volume fraction of CNT...Nickel-carbon nanotube(CNT) composite coatings with a Zn-Ni interlayer were prepared by electrodeposition technique on aluminum substrate. The effects of CNT concentration in plating bath on the volume fraction of CNTs in the deposits and the coating growth rate were investigated. The friction and wear behavior of the Ni-CNT composite coatings were examined using a pin-on-disk wear tester under dry sliding conditions at a sliding speed of 0.062 3 m/s and load range from 12 N to 150 N. Because of the reinforcement of CNTs in the composite coatings, at lower applied loads, the wear resistance was improved with increasing volume fraction of CNTs. Since cracking and peeling occur on the worn surface, the wear rates of composite coatings with high volume fraction of CNTs increase rapidly at higher applied loads. The friction coefficient of the composite coatings decreases with the increasing volume fraction of CNTs due to the reinforcement and self-lubrication of CNTs.展开更多
Formation of pyrite (FeS 2) films through electrodeposition from aqueous solutions which contain different source materials has been investigated. Na 2S 2O 3·5H 2O is used as sulfur source material, FeSO 4·7...Formation of pyrite (FeS 2) films through electrodeposition from aqueous solutions which contain different source materials has been investigated. Na 2S 2O 3·5H 2O is used as sulfur source material, FeSO 4·7H 2O, FeCl 2·4H 2O and FeCl 3·6H 2O are used as iron source materials respectively. The samples are annealed in N 2 atmosphere at 400 ℃ and 500 ℃ respectively. From XRD (X-ray diffraction) patterns of the films, it is found that there are peaks of FeS 2, FeS and Fe 7S 8 in all films, but there are sharp and more peaks characterizing FeS 2 in the film from Na 2S 2O 3 +FeSO 4 than other films, and 400 ℃ is the more suitable temperature than 500 ℃ for annealing the samples in N 2 atmosphere. In addition, one solution can be used repeatedly.展开更多
文摘The microstructures, friction and wear behavior under dry sliding condition of electrodeposited amorphous Fe-Co-W alloy deposits heat treated at different temperatures were studied. A comparative study of hard chrome deposit under the same testing condition was also made. The experimental results show that the hardness and wear resistance of amorphous Fe-Co-W alloy deposits are improved with the increasing of heat treatment temperature, and reach the maximum value at 800 ℃, then decrease above 800 ℃. Under 40 N load, the wear resistance properties of the alloy deposits heat treated at 800 ℃ are superior to those of hard chrome deposit. The main wear mechanisms of amorphous Fe-Co-W alloy deposits heat treated below 600 ℃ are peeling, plastic and flowing deformation; when the deposits are heat treated above 700 ℃, they are plastic and flowing deformation. While the main wear mechanisms of hard chrome are abrasive wear, fatigue and peeling.
文摘Nickel-carbon nanotube(CNT) composite coatings with a Zn-Ni interlayer were prepared by electrodeposition technique on aluminum substrate. The effects of CNT concentration in plating bath on the volume fraction of CNTs in the deposits and the coating growth rate were investigated. The friction and wear behavior of the Ni-CNT composite coatings were examined using a pin-on-disk wear tester under dry sliding conditions at a sliding speed of 0.062 3 m/s and load range from 12 N to 150 N. Because of the reinforcement of CNTs in the composite coatings, at lower applied loads, the wear resistance was improved with increasing volume fraction of CNTs. Since cracking and peeling occur on the worn surface, the wear rates of composite coatings with high volume fraction of CNTs increase rapidly at higher applied loads. The friction coefficient of the composite coatings decreases with the increasing volume fraction of CNTs due to the reinforcement and self-lubrication of CNTs.
文摘Formation of pyrite (FeS 2) films through electrodeposition from aqueous solutions which contain different source materials has been investigated. Na 2S 2O 3·5H 2O is used as sulfur source material, FeSO 4·7H 2O, FeCl 2·4H 2O and FeCl 3·6H 2O are used as iron source materials respectively. The samples are annealed in N 2 atmosphere at 400 ℃ and 500 ℃ respectively. From XRD (X-ray diffraction) patterns of the films, it is found that there are peaks of FeS 2, FeS and Fe 7S 8 in all films, but there are sharp and more peaks characterizing FeS 2 in the film from Na 2S 2O 3 +FeSO 4 than other films, and 400 ℃ is the more suitable temperature than 500 ℃ for annealing the samples in N 2 atmosphere. In addition, one solution can be used repeatedly.
