Ti-doped graphite-like carbon （Ti-GLC） films were synthesized successfully by magnetron sputtering technique. The compositions, microstructures and properties of the Ti-doped GLC films dependent on the parameter of ...Ti-doped graphite-like carbon （Ti-GLC） films were synthesized successfully by magnetron sputtering technique. The compositions, microstructures and properties of the Ti-doped GLC films dependent on the parameter of Ti target current were systemically investigated by Raman spectra, X-ray photoelectron spectroscopy （XPS）, X-ray diffraction （XRD）, scanning electron microscopy （SEM）, atomic force microscopy （AFM）, nanoindentation and ball-on-disk tribometer. With the increase of the Ti target current, the ratio of sp2 bond and the content of Ti as well as the film hardness and compressive internal stress increase, but the high content of the Ti would result in the loose film due to the formation of the squamose structure. Less incorporated Ti reduces the friction of the GLC film in dry-sliding condition, while pure GLC film exhibits the lowest friction coefficient in water-lubricated condition. Ti-GLC film deposited with low Ti target current shows high wear resistance in both dry-sliding and water-lubricated conditions.展开更多
Amorphous carbon films with high sp2 concentrations are deposited by unbalanced magnetron sputtering with a narrow range of substrate bias voltage. Field emission scanning electron microscopes （FESEMs）, high resolut...Amorphous carbon films with high sp2 concentrations are deposited by unbalanced magnetron sputtering with a narrow range of substrate bias voltage. Field emission scanning electron microscopes （FESEMs）, high resolution transmission electron microscopes （HRTEMs）, atomic force microscopes （AFMs）, the Raman spectrometers, nano- indentation, and tribometers are subsequently used to characterize the microstructures and the properties of the resulting films. It is found that the present films are dominated by the sp2 sites. However, the films demonstrate a moderate hardness together with a low internal stress. The high hardness of the deposited film originates from the crosslinking of the sp2 clusters by the sp3 sites. The presence of the graphite-like clusters in the film structure may be responsible for the low internal stress. What is more important is that the resulting films show excellent tribological properties with high load capacity and excellent wear resistance in humid atmospheres. The relationship between the microstructure determined by the deposition condition and the film characteristic is discussed in detail.展开更多
Graphite-like amorphous carbon film was fabricated by unbalanced magnetron sputtering technique.Raman spectroscopy,atomic force microscopy(AFM)and tribometer were subsequently used to investigate the microstructure an...Graphite-like amorphous carbon film was fabricated by unbalanced magnetron sputtering technique.Raman spectroscopy,atomic force microscopy(AFM)and tribometer were subsequently used to investigate the microstructure and tribological properties of the resultant film.It is found that the deposited carbon film is dominated by sp 2 sites,and the intensity ratio of the D and G peaks is as high as 4.0,which is one order of magnitude larger than that of diamond-like carbon films with high sp 3 content,indicating a more graphite-like structure.However,the as-deposited carbon film exhibits moderately high hardness(13.7 GPa),low internal stress(0.38 GPa)and superior tribological properties with high load bearing capacity(Hertz contact stress about 3.2 GPa)and low wear rate(2.73×10-10 cm3/N.m)in ambient atmosphere.Although it displays a poor wear resistance in water lubricated condition,a superior wear resistance is achieved in oil lubricated condition.Its inherent physical property,the formation of transfer layer and the friction induced chemical reactions may be commonly responsible for its tribological properties.展开更多
Carbon/carbon （C/C） composites were deposited with graphite-like carbon （GLC） coating, and then, Arg-Gly- Asp acid （RGD） peptides were successfully immobilized onto the functionalized GLC coating. GLC coating wa...Carbon/carbon （C/C） composites were deposited with graphite-like carbon （GLC） coating, and then, Arg-Gly- Asp acid （RGD） peptides were successfully immobilized onto the functionalized GLC coating. GLC coating was utilized to prevent carbon particles releasing and create a uniform surface condition for C/C composites. RGD peptides were utilized to improve biocompatibility of GLC coating. Surface chemical characterizations of functionalized GLC coating were detected by contact angle measurement, X-ray photoelectron spectroscopy and Raman spectra. Optical morphology of GLC coatings was observed by confocal laser scanning microscopy. In vitro biological performance was determined using samples seeded with MC3T3-E1 osteoblast-like cells and cultured for 1 week. Surface characterizations and morphological analysis indicated that C/C composites were covered by a dense and uniform GLC coating. Contact angle of GLC coating was reduced to 27.2° when it was functionalized by H202 oxidation at 40 ℃ for 1 h. In vitro cytological test showed that the RGD peptides immobilized GLC coating had a significant improvement in biocompatibility. It was suggested that RGD peptides provided GLC coating with a bioactive surface to improve cell adhesion and proliferation on C/C composites.展开更多
Diamond-like carbon(DLC)and graphite-like carbon(GLC)coatings have good prospects for improving the surface properties of engine parts.However,further understanding is needed on the effect of working conditions on tri...Diamond-like carbon(DLC)and graphite-like carbon(GLC)coatings have good prospects for improving the surface properties of engine parts.However,further understanding is needed on the effect of working conditions on tribological behaviors.In this study,GLC and two types of DLC coatings were deposited on GCr15 substrate for investigation.The friction and wear properties of self-mated and steel-mated pairs were evaluated.Two temperatures(25 and 90℃),three lubrication conditions(base oil,molybdenum dithiocarbamate(MoDTC)-containing oil,MoDTC+zinc dialkyldithiophosphate(ZDDP)-containing oil),and high Hertz contact stress(2.41 GPa)were applied in the experiments.The results showed that high temperature promoted the effect of ZDDP on steel-mated pairs,but increased wear under base oil lubrication.The increased wear for steel-mated pairs lubricated by MoDTC-containing oil was due to abrasive wear probably caused by MoO_(3) andβ-FeMoO_(4).It was also found that in most cases,the tribological properties of self-mated pairs were better than those of steel-mated pairs.展开更多
基金Project (50905178) supported by the National Natural Science Foundation of ChinaProject (2011CB706603) supported by the National Basic Research Program of China
文摘Ti-doped graphite-like carbon （Ti-GLC） films were synthesized successfully by magnetron sputtering technique. The compositions, microstructures and properties of the Ti-doped GLC films dependent on the parameter of Ti target current were systemically investigated by Raman spectra, X-ray photoelectron spectroscopy （XPS）, X-ray diffraction （XRD）, scanning electron microscopy （SEM）, atomic force microscopy （AFM）, nanoindentation and ball-on-disk tribometer. With the increase of the Ti target current, the ratio of sp2 bond and the content of Ti as well as the film hardness and compressive internal stress increase, but the high content of the Ti would result in the loose film due to the formation of the squamose structure. Less incorporated Ti reduces the friction of the GLC film in dry-sliding condition, while pure GLC film exhibits the lowest friction coefficient in water-lubricated condition. Ti-GLC film deposited with low Ti target current shows high wear resistance in both dry-sliding and water-lubricated conditions.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.50705093 and 50575217)the Innovative Group Foundation of the National Natural Science Foundation of China(Grant No.50421502)the National Basic ResearchProgram of China(Grant No.2007CB607601)
文摘Amorphous carbon films with high sp2 concentrations are deposited by unbalanced magnetron sputtering with a narrow range of substrate bias voltage. Field emission scanning electron microscopes （FESEMs）, high resolution transmission electron microscopes （HRTEMs）, atomic force microscopes （AFMs）, the Raman spectrometers, nano- indentation, and tribometers are subsequently used to characterize the microstructures and the properties of the resulting films. It is found that the present films are dominated by the sp2 sites. However, the films demonstrate a moderate hardness together with a low internal stress. The high hardness of the deposited film originates from the crosslinking of the sp2 clusters by the sp3 sites. The presence of the graphite-like clusters in the film structure may be responsible for the low internal stress. What is more important is that the resulting films show excellent tribological properties with high load capacity and excellent wear resistance in humid atmospheres. The relationship between the microstructure determined by the deposition condition and the film characteristic is discussed in detail.
基金National Natural Science Foundation of China(50705093,50575217)Innovative Group Foundation from NSFC(50421502)National"973"Project(2007 CB607601)
文摘Graphite-like amorphous carbon film was fabricated by unbalanced magnetron sputtering technique.Raman spectroscopy,atomic force microscopy(AFM)and tribometer were subsequently used to investigate the microstructure and tribological properties of the resultant film.It is found that the deposited carbon film is dominated by sp 2 sites,and the intensity ratio of the D and G peaks is as high as 4.0,which is one order of magnitude larger than that of diamond-like carbon films with high sp 3 content,indicating a more graphite-like structure.However,the as-deposited carbon film exhibits moderately high hardness(13.7 GPa),low internal stress(0.38 GPa)and superior tribological properties with high load bearing capacity(Hertz contact stress about 3.2 GPa)and low wear rate(2.73×10-10 cm3/N.m)in ambient atmosphere.Although it displays a poor wear resistance in water lubricated condition,a superior wear resistance is achieved in oil lubricated condition.Its inherent physical property,the formation of transfer layer and the friction induced chemical reactions may be commonly responsible for its tribological properties.
基金supported by the National Natural Science Foundation of China under Grant Nos.51202194 and 51221001the Programme of Introducing Talents of Discipline to Universities(‘‘111’’project of China)under Grant No.B08040
文摘Carbon/carbon （C/C） composites were deposited with graphite-like carbon （GLC） coating, and then, Arg-Gly- Asp acid （RGD） peptides were successfully immobilized onto the functionalized GLC coating. GLC coating was utilized to prevent carbon particles releasing and create a uniform surface condition for C/C composites. RGD peptides were utilized to improve biocompatibility of GLC coating. Surface chemical characterizations of functionalized GLC coating were detected by contact angle measurement, X-ray photoelectron spectroscopy and Raman spectra. Optical morphology of GLC coatings was observed by confocal laser scanning microscopy. In vitro biological performance was determined using samples seeded with MC3T3-E1 osteoblast-like cells and cultured for 1 week. Surface characterizations and morphological analysis indicated that C/C composites were covered by a dense and uniform GLC coating. Contact angle of GLC coating was reduced to 27.2° when it was functionalized by H202 oxidation at 40 ℃ for 1 h. In vitro cytological test showed that the RGD peptides immobilized GLC coating had a significant improvement in biocompatibility. It was suggested that RGD peptides provided GLC coating with a bioactive surface to improve cell adhesion and proliferation on C/C composites.
基金This work was supported by the Beijing Municipal Natural Science Foundation(3182032)the National Natural Science Foundation of China(41772389)+1 种基金the Pre-Research Program in National 13th Five-Year Plan(61409230603)Joint Fund of Ministry of Education for Pre-research of Equipment for Young Personnel Project(6141A02033120).
文摘Diamond-like carbon(DLC)and graphite-like carbon(GLC)coatings have good prospects for improving the surface properties of engine parts.However,further understanding is needed on the effect of working conditions on tribological behaviors.In this study,GLC and two types of DLC coatings were deposited on GCr15 substrate for investigation.The friction and wear properties of self-mated and steel-mated pairs were evaluated.Two temperatures(25 and 90℃),three lubrication conditions(base oil,molybdenum dithiocarbamate(MoDTC)-containing oil,MoDTC+zinc dialkyldithiophosphate(ZDDP)-containing oil),and high Hertz contact stress(2.41 GPa)were applied in the experiments.The results showed that high temperature promoted the effect of ZDDP on steel-mated pairs,but increased wear under base oil lubrication.The increased wear for steel-mated pairs lubricated by MoDTC-containing oil was due to abrasive wear probably caused by MoO_(3) andβ-FeMoO_(4).It was also found that in most cases,the tribological properties of self-mated pairs were better than those of steel-mated pairs.
