把TiBCN陶瓷粉末和Mn粉末混合(其中TiCB含量分别是100 wt%、95 wt%、90wt%、80 wt%和60 wt%)作为熔覆材料,用5 k W CO_2激光对Ti6-Al4-V(TC4)合金进行激光熔覆处理。用扫描电子显微镜(SEM)、能谱仪(EDS)和X-射线衍射仪(XRD)分析熔覆层中...把TiBCN陶瓷粉末和Mn粉末混合(其中TiCB含量分别是100 wt%、95 wt%、90wt%、80 wt%和60 wt%)作为熔覆材料,用5 k W CO_2激光对Ti6-Al4-V(TC4)合金进行激光熔覆处理。用扫描电子显微镜(SEM)、能谱仪(EDS)和X-射线衍射仪(XRD)分析熔覆层中TiBCN颗粒的形貌和反应产物。观察发现,激光熔覆层没有形成裂纹,TiBCN颗粒发生部分熔化,并和金属发生反应生成TiN_(0.2)、Al_3Ti、TiAl和MnB等新相。TiBCN颗粒之间连接紧密,自动组装成枝晶状组织,与基体呈冶金结合状态。TiBCN颗粒和基体发生传质,基体中的Al元素扩散到TiBCN,形成多元Ti(Al)BCN固溶体。测试表明,熔覆层硬度明显提高达到HV1300,耐磨性比基体提高了4倍。展开更多
TiBCN nanocomposite coatings were deposited on cemented carbide and Si （100） by a cathode arc plasma system, in which TiB2 cathodes were used in mixture gases of N2 and C2H2. X-ray diffraction shows that TiB2 and Ti...TiBCN nanocomposite coatings were deposited on cemented carbide and Si （100） by a cathode arc plasma system, in which TiB2 cathodes were used in mixture gases of N2 and C2H2. X-ray diffraction shows that TiB2 and Ti2B5 peaks enhance at low flow rates of C2H2, but they shrink when the flow rate is over 200 sccm. An increase of deposition rate was obtained from different TiBCN thicknesses for the same deposition time measured by scanning electron microscopy. Atomic force microscopy shows that the surface roughnesses are -10 nm and ,-20 nm at C2H2 flow rates of 0-100 sccm and of 150-300 sccm, respectively. High resolution transmis- sion electron microscopy and X-ray photoelectron spectroscopy show that the coatings consist of nanocrystal phases Ti2Bh, TiB2 and TiN, and amorphous phase carbon and BN. The average crystal sizes embedded in the amorphous matrices are 200 nm and 10 nm at C2H2 flow rates of 200 sccm and 300 sccm, respectively. In Raman spectra, the D- and G-bands increase with C2H2 flows at low flow rates, but weaken at high flow rates. The microhardness of the coatings decreases from 28.6 GPa to 20 GPa as the C2H2 increases from 0 sccm to 300 sccm, and the ball-on-disk measurement shows a dramatic decrease of the friction coefficient from 0.84 to 0.13. The reason for the reduced hardness and friction coefficient with the change of C2H2 flow rates is discussed.展开更多
TiBCN films were deposited on Si(100) and cemented carbide substrates by using multi-cathodic arc ion plating in C_2H_2 and N_2atmosp^here. Their structure and mechanical properties were studied systematically under d...TiBCN films were deposited on Si(100) and cemented carbide substrates by using multi-cathodic arc ion plating in C_2H_2 and N_2atmosp^here. Their structure and mechanical properties were studied systematically under different N_2 flow rates. The results showed that the Ti BCN films were adhered well to the substrates. Rutherford backscattering sp^ectroscopy was employed to determine the relative concentration of Ti, B, C and N in the films.The chemical bonding states of the films were explored by X-ray photoelectron sp^ectroscopy, revealing the presence of bonds of Ti N, Ti(C,N), BN, pure B, sp^2C–C and sp^3C–C, which changed with the N_2 flow rate. Ti BCN films contain nanocrystals of Ti N/Ti CN and Ti B_2/Ti(B,C)embedded in an amorphous matrix consisting of amorphous BN and carbon at N_2 flow rate of up to 250 sccm.展开更多
Evolution of the TiB0.71C3.32N0.79 quaternary nanocomposite structure at 600,700,800,900,and 1000℃ is investigated by high-resolution transmission electron microscopy,X-ray diffraction,X-ray photoelectron spectrometr...Evolution of the TiB0.71C3.32N0.79 quaternary nanocomposite structure at 600,700,800,900,and 1000℃ is investigated by high-resolution transmission electron microscopy,X-ray diffraction,X-ray photoelectron spectrometry,and micro-hardness indentation.The nc-Ti(C,N)nanocrystallites exhibit the(200)preferential orientation and the amorphous carbon(a-C)phase gradually transforms into the crystallite graphite phase as the temperature is increased.At 1000℃,the nc-Ti(C,N)nanocrystallites increase to a size of 13 nm but the microhardness diminishes to 18-19 GPa.The corresponding mechanism is discussed.展开更多
文摘把TiBCN陶瓷粉末和Mn粉末混合(其中TiCB含量分别是100 wt%、95 wt%、90wt%、80 wt%和60 wt%)作为熔覆材料,用5 k W CO_2激光对Ti6-Al4-V(TC4)合金进行激光熔覆处理。用扫描电子显微镜(SEM)、能谱仪(EDS)和X-射线衍射仪(XRD)分析熔覆层中TiBCN颗粒的形貌和反应产物。观察发现,激光熔覆层没有形成裂纹,TiBCN颗粒发生部分熔化,并和金属发生反应生成TiN_(0.2)、Al_3Ti、TiAl和MnB等新相。TiBCN颗粒之间连接紧密,自动组装成枝晶状组织,与基体呈冶金结合状态。TiBCN颗粒和基体发生传质,基体中的Al元素扩散到TiBCN,形成多元Ti(Al)BCN固溶体。测试表明,熔覆层硬度明显提高达到HV1300,耐磨性比基体提高了4倍。
基金supported by National Natural Science Foundation of China(Nos.11350110206,11375133)the Fundamental Research Funds for the Central Universities of China(No.11275141)
文摘TiBCN nanocomposite coatings were deposited on cemented carbide and Si （100） by a cathode arc plasma system, in which TiB2 cathodes were used in mixture gases of N2 and C2H2. X-ray diffraction shows that TiB2 and Ti2B5 peaks enhance at low flow rates of C2H2, but they shrink when the flow rate is over 200 sccm. An increase of deposition rate was obtained from different TiBCN thicknesses for the same deposition time measured by scanning electron microscopy. Atomic force microscopy shows that the surface roughnesses are -10 nm and ,-20 nm at C2H2 flow rates of 0-100 sccm and of 150-300 sccm, respectively. High resolution transmis- sion electron microscopy and X-ray photoelectron spectroscopy show that the coatings consist of nanocrystal phases Ti2Bh, TiB2 and TiN, and amorphous phase carbon and BN. The average crystal sizes embedded in the amorphous matrices are 200 nm and 10 nm at C2H2 flow rates of 200 sccm and 300 sccm, respectively. In Raman spectra, the D- and G-bands increase with C2H2 flows at low flow rates, but weaken at high flow rates. The microhardness of the coatings decreases from 28.6 GPa to 20 GPa as the C2H2 increases from 0 sccm to 300 sccm, and the ball-on-disk measurement shows a dramatic decrease of the friction coefficient from 0.84 to 0.13. The reason for the reduced hardness and friction coefficient with the change of C2H2 flow rates is discussed.
基金supported by the National Natural Science Foundation of China(Nos.11375135 and 11275141)International Cooperation Program of the Ministry of Science and Technology of China(No.2015DFR00720)Fundamental Research Funds for the Central Universities
文摘TiBCN films were deposited on Si(100) and cemented carbide substrates by using multi-cathodic arc ion plating in C_2H_2 and N_2atmosp^here. Their structure and mechanical properties were studied systematically under different N_2 flow rates. The results showed that the Ti BCN films were adhered well to the substrates. Rutherford backscattering sp^ectroscopy was employed to determine the relative concentration of Ti, B, C and N in the films.The chemical bonding states of the films were explored by X-ray photoelectron sp^ectroscopy, revealing the presence of bonds of Ti N, Ti(C,N), BN, pure B, sp^2C–C and sp^3C–C, which changed with the N_2 flow rate. Ti BCN films contain nanocrystals of Ti N/Ti CN and Ti B_2/Ti(B,C)embedded in an amorphous matrix consisting of amorphous BN and carbon at N_2 flow rate of up to 250 sccm.
基金Doctorial Subject Special Foundation of Chinese University(20070698087)Hongkong Research Grants Council(RGC)General ResearchFunds(CityU 112608)
文摘Evolution of the TiB0.71C3.32N0.79 quaternary nanocomposite structure at 600,700,800,900,and 1000℃ is investigated by high-resolution transmission electron microscopy,X-ray diffraction,X-ray photoelectron spectrometry,and micro-hardness indentation.The nc-Ti(C,N)nanocrystallites exhibit the(200)preferential orientation and the amorphous carbon(a-C)phase gradually transforms into the crystallite graphite phase as the temperature is increased.At 1000℃,the nc-Ti(C,N)nanocrystallites increase to a size of 13 nm but the microhardness diminishes to 18-19 GPa.The corresponding mechanism is discussed.
