By the sessile drop technique, the wettability of Cu/W systems with the additions of Ni and Cr has been studied under vacuum atmosphere. Effects of Ni and Cr contents and wetting temperatures on the wettability and th...By the sessile drop technique, the wettability of Cu/W systems with the additions of Ni and Cr has been studied under vacuum atmosphere. Effects of Ni and Cr contents and wetting temperatures on the wettability and the wetting mechanisms of copper on W substrate have been investigated in detail. The results show that the wetting angles of Cu on the W substrate are decreased with an increase in the content of Ni or Cr, and also decrease with raising the wetting temperatures. SEM, EPMA, and X-ray diffraction have been used to analyze the interracial characteristics of the CuNi/W and CuCr/W systems. The results reveal that there is a transition layer about 2- 3μm in the interface of Cu-4.0 wt pct Ni/W, in which the interrnetallic phase Ni4W is precipitated. As to CuCr/W system, no reaction occurs at the interface. The two factors are that the contents of Cr and Ni and the infiltration temperature must be chosen appropriately in order to control the interfacial dissolution and reaction when the Cu- W alloys are prepared by the infiltration method.展开更多
The thermal barrier coatings with NiCrAlY alloy bonding layer, NiCrAlY Y 2O 3 stabilized ZrO 2 transition layer and Y 2O 3 stabilized ZrO 2 ceramic layer are prepared on nickel alloy substrates using the plasma spray ...The thermal barrier coatings with NiCrAlY alloy bonding layer, NiCrAlY Y 2O 3 stabilized ZrO 2 transition layer and Y 2O 3 stabilized ZrO 2 ceramic layer are prepared on nickel alloy substrates using the plasma spray technique. The relationship among the composition, structure and property of the coatings are investiga ted by means of optical microscope, scanning electronic microscope and the experiments of thermal shock resistance cycling and high temperature oxidation resistance. The results show that the structure design of introdu cing a transition layer between Ni alloy substrate and ZrO 2 ceramic coating guarantees the high quality and properties of the coatings; ZrO 2 coatings doped with a little SiO 2 possesses better thermal shock resistance and more excellent hot corrosion resistance as compared with ZrO 2 coating materials without SiO 2 ;the improvement in performance of ZrO 2 coating doped with SiO 2 is due to forming more dense coating structure by self closing effects of the flaws and pores in the ZrO 2 coatings.展开更多
The surface infiltrated composite （Ni/WC） layers on gray iron substrate were fabricated through a vacuum infiltration casting technique （VICT） using Ni-based composite powder with different WC particles content as...The surface infiltrated composite （Ni/WC） layers on gray iron substrate were fabricated through a vacuum infiltration casting technique （VICT） using Ni-based composite powder with different WC particles content as raw materials.The microstructures of surface infiltrated composite layer,the interface structures between surface composite layer and the substrate,the changes of macro-hardness with the increasing of WC content and the micro-hardness distribution are investigated.The infiltrated composite layer includes a surface composite layer and a transition layer,and the thickness of the transition layer decreases with the increasing content of WC.The thickness of transition layer with 20%WC content in the surface infiltrated composite layer was 170 μm which was the thickest for all transition layers with different WC content.The surface composite layer was mainly composed of WC,W2C,FeB and NiB,along with Ni-Cr-Fe,Ni （Cr） solid solution,Ni （Si） solid solution and Ni （Fe） solid solution.The transition layer was composed of Ni （Cr） solid solution,Ni （Fe） solid solution,Ni （Si） solid solution,Fe （Ni） solid solution and eutectic.The surface macro-hardness and micro-hardness of the infiltrated layer had been evaluated.The macro-hardness of the surface composite layer decreases with the WC content increasing,and the average macro-hardness is HRC60.The distribution of micro-hardness presents gradient change.The average micro-hardness of the infiltrated layer is about HV1000.展开更多
The surface segregation of substrate elements through the Au layer in the Au-Ni-Kovar sys- tem specimens heated at 250—350℃ for 0.5—1.5 h has been studied by SAM and XPS. Visual evidence of the mechanism for Ni and...The surface segregation of substrate elements through the Au layer in the Au-Ni-Kovar sys- tem specimens heated at 250—350℃ for 0.5—1.5 h has been studied by SAM and XPS. Visual evidence of the mechanism for Ni and Co surface segregation of the complicated sys- tem has been given,i.e.Ni and Co penetrated the gold layer mainly by grain boundary diffu- sion and then covered the Au layer by surface diffusion.The strdy results of the chemical states of surface segregation elements not only indicate that oxygen adsorption and oxidation reaction are the driving force for the surface segregation of Ni and Co,but also show that the above segregation can result in water absorption on surfaces.展开更多
The buffer layer CeO2 films were grown on cube textured metallic Ni substrates by using reactive magnetrun sputtering. Ar/H2 mixed atmosphere, which effectively inhibited the formation of NiO, was used as pre-depositi...The buffer layer CeO2 films were grown on cube textured metallic Ni substrates by using reactive magnetrun sputtering. Ar/H2 mixed atmosphere, which effectively inhibited the formation of NiO, was used as pre-depositing gas before CeO2 films were grown in Ar and 02. At 700 ℃ under the total pressure of 26 Pa,the pure c-axis orientation tilm was obtained. X-ray θ-2θscan, pole figure and φ-scan were used to observe the microstructure of the buffer layer. The resuits show that CeO2 film has strong cube texture and the FWHM is 9°. In addition, the CeO2 film is dense and crack-free.展开更多
CeO2/YSZ/CeO2 buffer layers were deposited on biaxially textured Ni substrates by pulsed laser deposition. The influence of the processing parameters on the texture development of the seed layer CeO2 was investigated....CeO2/YSZ/CeO2 buffer layers were deposited on biaxially textured Ni substrates by pulsed laser deposition. The influence of the processing parameters on the texture development of the seed layer CeO2 was investigated. Epitaxial films of YBCO were then grown in situ on the CeO2/YSZ （yttria-stabilized ZrO2）/CeO2-buffered Ni substrates. The resulting YBCO conductors exhibited self-fleld critical current density Jc of more than 1 MA/cm^2 at 77K and superconducting transition temperature Tc of about 91K.展开更多
Highly cube textured Ni tapes are produced by heavy cold rolling and recrystallization annealing. The textured nickel tapes have been proven to be suitable substrates for YBCO superconducting tape. Nevertheless, rolli...Highly cube textured Ni tapes are produced by heavy cold rolling and recrystallization annealing. The textured nickel tapes have been proven to be suitable substrates for YBCO superconducting tape. Nevertheless, rolling damage and grain boundary grooves on Ni influence the epitaxial growth of highly textured buffer and YBCO layers. The polishing of the Ni substrate surface may play a crucial role in making it beneficial to epitaxial film deposition. In our work, several polishing methods were adopted on Ni to reduce the depth of rolling damage and grain boundary grooves. On the polished Ni substrates, textured Y2O3 buffer layers were deposited using RF sputtering. XRD results show that in-plane texture of Y2O3 films will minish with the decreasing of the Ni substrate surface roughness. AFM results show that average grain size of the Y2O3 film is biggest and surface is coarse in film on flatter Ni surface.展开更多
The direct deposition of diamond films on copper substrate has been suffered fromadhesion problems due to the mismatch of the thermal expansion coefficients of diamond andcopper. In this paper nuclei with valuable den...The direct deposition of diamond films on copper substrate has been suffered fromadhesion problems due to the mismatch of the thermal expansion coefficients of diamond andcopper. In this paper nuclei with valuable density were directly introduced thirough a submicrondiamond powder layer. The diamond grits partially were buried in the copper substrate leadingto better adhesion. Another method with nickel intermediate layer for enhancing the adhesionwas studied here in detail. It was suggested that Cu-Ni eutectic between the copper substrate andNi interlayer might contribute to the adhesion improvement. The quality of the diamond filmsdeposited wlth rnckel interlayer was investigated by scanning electron microscopy and Ramanspectroscopy.展开更多
为改善Ni-5%W合金基带表面质量,以磷酸-硫酸和添加剂为电解液,采用均匀实验设计方法进行电解抛光,利用原子力显微镜对样品表面形貌进行表征,并用DPS(Data Process System)软件对抛光结果进行逐步回归优化。结果表明,在室温下,采用磷酸(8...为改善Ni-5%W合金基带表面质量,以磷酸-硫酸和添加剂为电解液,采用均匀实验设计方法进行电解抛光,利用原子力显微镜对样品表面形貌进行表征,并用DPS(Data Process System)软件对抛光结果进行逐步回归优化。结果表明,在室温下,采用磷酸(85%)、硫酸(98%)和有机添加剂,以体积比为4∶3∶3的抛光液抛光效果较好,抛光后基带表面均方根粗糙度在25μm×25μm范围内可降低到5nm以下。展开更多
基金the National Natural Science Foundation of China(No.50474012)Program for New Century Excellent Talents in University (GrantNo.NCET-05-0873).
文摘By the sessile drop technique, the wettability of Cu/W systems with the additions of Ni and Cr has been studied under vacuum atmosphere. Effects of Ni and Cr contents and wetting temperatures on the wettability and the wetting mechanisms of copper on W substrate have been investigated in detail. The results show that the wetting angles of Cu on the W substrate are decreased with an increase in the content of Ni or Cr, and also decrease with raising the wetting temperatures. SEM, EPMA, and X-ray diffraction have been used to analyze the interracial characteristics of the CuNi/W and CuCr/W systems. The results reveal that there is a transition layer about 2- 3μm in the interface of Cu-4.0 wt pct Ni/W, in which the interrnetallic phase Ni4W is precipitated. As to CuCr/W system, no reaction occurs at the interface. The two factors are that the contents of Cr and Ni and the infiltration temperature must be chosen appropriately in order to control the interfacial dissolution and reaction when the Cu- W alloys are prepared by the infiltration method.
文摘The thermal barrier coatings with NiCrAlY alloy bonding layer, NiCrAlY Y 2O 3 stabilized ZrO 2 transition layer and Y 2O 3 stabilized ZrO 2 ceramic layer are prepared on nickel alloy substrates using the plasma spray technique. The relationship among the composition, structure and property of the coatings are investiga ted by means of optical microscope, scanning electronic microscope and the experiments of thermal shock resistance cycling and high temperature oxidation resistance. The results show that the structure design of introdu cing a transition layer between Ni alloy substrate and ZrO 2 ceramic coating guarantees the high quality and properties of the coatings; ZrO 2 coatings doped with a little SiO 2 possesses better thermal shock resistance and more excellent hot corrosion resistance as compared with ZrO 2 coating materials without SiO 2 ;the improvement in performance of ZrO 2 coating doped with SiO 2 is due to forming more dense coating structure by self closing effects of the flaws and pores in the ZrO 2 coatings.
基金Funded by"Xi-Bu-Zhi-Guang" Foundation of Chinese Academy of Sciences(No.XBZG-2007-5)Gansu Natural Science Foundation of China(No.0806RJYA004)Outstanding Youngth of Lanzhou University of Technology (No.Q200910)
文摘The surface infiltrated composite （Ni/WC） layers on gray iron substrate were fabricated through a vacuum infiltration casting technique （VICT） using Ni-based composite powder with different WC particles content as raw materials.The microstructures of surface infiltrated composite layer,the interface structures between surface composite layer and the substrate,the changes of macro-hardness with the increasing of WC content and the micro-hardness distribution are investigated.The infiltrated composite layer includes a surface composite layer and a transition layer,and the thickness of the transition layer decreases with the increasing content of WC.The thickness of transition layer with 20%WC content in the surface infiltrated composite layer was 170 μm which was the thickest for all transition layers with different WC content.The surface composite layer was mainly composed of WC,W2C,FeB and NiB,along with Ni-Cr-Fe,Ni （Cr） solid solution,Ni （Si） solid solution and Ni （Fe） solid solution.The transition layer was composed of Ni （Cr） solid solution,Ni （Fe） solid solution,Ni （Si） solid solution,Fe （Ni） solid solution and eutectic.The surface macro-hardness and micro-hardness of the infiltrated layer had been evaluated.The macro-hardness of the surface composite layer decreases with the WC content increasing,and the average macro-hardness is HRC60.The distribution of micro-hardness presents gradient change.The average micro-hardness of the infiltrated layer is about HV1000.
文摘The surface segregation of substrate elements through the Au layer in the Au-Ni-Kovar sys- tem specimens heated at 250—350℃ for 0.5—1.5 h has been studied by SAM and XPS. Visual evidence of the mechanism for Ni and Co surface segregation of the complicated sys- tem has been given,i.e.Ni and Co penetrated the gold layer mainly by grain boundary diffu- sion and then covered the Au layer by surface diffusion.The strdy results of the chemical states of surface segregation elements not only indicate that oxygen adsorption and oxidation reaction are the driving force for the surface segregation of Ni and Co,but also show that the above segregation can result in water absorption on surfaces.
文摘The buffer layer CeO2 films were grown on cube textured metallic Ni substrates by using reactive magnetrun sputtering. Ar/H2 mixed atmosphere, which effectively inhibited the formation of NiO, was used as pre-depositing gas before CeO2 films were grown in Ar and 02. At 700 ℃ under the total pressure of 26 Pa,the pure c-axis orientation tilm was obtained. X-ray θ-2θscan, pole figure and φ-scan were used to observe the microstructure of the buffer layer. The resuits show that CeO2 film has strong cube texture and the FWHM is 9°. In addition, the CeO2 film is dense and crack-free.
文摘CeO2/YSZ/CeO2 buffer layers were deposited on biaxially textured Ni substrates by pulsed laser deposition. The influence of the processing parameters on the texture development of the seed layer CeO2 was investigated. Epitaxial films of YBCO were then grown in situ on the CeO2/YSZ （yttria-stabilized ZrO2）/CeO2-buffered Ni substrates. The resulting YBCO conductors exhibited self-fleld critical current density Jc of more than 1 MA/cm^2 at 77K and superconducting transition temperature Tc of about 91K.
文摘Highly cube textured Ni tapes are produced by heavy cold rolling and recrystallization annealing. The textured nickel tapes have been proven to be suitable substrates for YBCO superconducting tape. Nevertheless, rolling damage and grain boundary grooves on Ni influence the epitaxial growth of highly textured buffer and YBCO layers. The polishing of the Ni substrate surface may play a crucial role in making it beneficial to epitaxial film deposition. In our work, several polishing methods were adopted on Ni to reduce the depth of rolling damage and grain boundary grooves. On the polished Ni substrates, textured Y2O3 buffer layers were deposited using RF sputtering. XRD results show that in-plane texture of Y2O3 films will minish with the decreasing of the Ni substrate surface roughness. AFM results show that average grain size of the Y2O3 film is biggest and surface is coarse in film on flatter Ni surface.
文摘The direct deposition of diamond films on copper substrate has been suffered fromadhesion problems due to the mismatch of the thermal expansion coefficients of diamond andcopper. In this paper nuclei with valuable density were directly introduced thirough a submicrondiamond powder layer. The diamond grits partially were buried in the copper substrate leadingto better adhesion. Another method with nickel intermediate layer for enhancing the adhesionwas studied here in detail. It was suggested that Cu-Ni eutectic between the copper substrate andNi interlayer might contribute to the adhesion improvement. The quality of the diamond filmsdeposited wlth rnckel interlayer was investigated by scanning electron microscopy and Ramanspectroscopy.
文摘为改善Ni-5%W合金基带表面质量,以磷酸-硫酸和添加剂为电解液,采用均匀实验设计方法进行电解抛光,利用原子力显微镜对样品表面形貌进行表征,并用DPS(Data Process System)软件对抛光结果进行逐步回归优化。结果表明,在室温下,采用磷酸(85%)、硫酸(98%)和有机添加剂,以体积比为4∶3∶3的抛光液抛光效果较好,抛光后基带表面均方根粗糙度在25μm×25μm范围内可降低到5nm以下。
