The isothermal sections of the Co-Nb-Ni ternary system at 1373 K and the Ni-Mo-Re ternary system at 1473 K were determined by means of diffusion triple and electron probe microanalysis（EPMA）.The results indicate tha...The isothermal sections of the Co-Nb-Ni ternary system at 1373 K and the Ni-Mo-Re ternary system at 1473 K were determined by means of diffusion triple and electron probe microanalysis（EPMA）.The results indicate that there are three three-phase regions found in the Co-Nb-Ni ternary system at 1373 K：（Ni,Co） ＋ NbCo3 ＋ Ni3Nb,NbCo3 ＋ NbCo2 ＋ Ni3Nb,and NbCo2 ＋ μ ＋ Ni3Nb;and four three-phase regions found in the Ni-Mo-Re ternary system at 1473 K：Re ＋ Ni ＋ χ,Ni ＋ NiMo ＋ σ,σ ＋ χ ＋ Ni,and σ ＋ Mo ＋ NiMo.No ternary compound is observed in the two isothermal sections.The isothermal sections are contrasted with the previous study.展开更多
化学复合镀RE Ni Mo P WC合金镀层具有良好的硬度、耐蚀、耐磨、抗氧化性能 ,但沉积速度对镀层性能有很大的影响。采用增重法研究了稀土元素、镀液温度、pH值、钼酸钠浓度对化学复合镀RE Ni Mo P WC合金镀层沉积速度的影响 ,并探讨了稀...化学复合镀RE Ni Mo P WC合金镀层具有良好的硬度、耐蚀、耐磨、抗氧化性能 ,但沉积速度对镀层性能有很大的影响。采用增重法研究了稀土元素、镀液温度、pH值、钼酸钠浓度对化学复合镀RE Ni Mo P WC合金镀层沉积速度的影响 ,并探讨了稀土元素的作用机理。结果表明 ,稀土元素的加入增大了复合镀层的沉积速度 ,其中混合稀土的作用最为明显 ;稀土元素的加入能促进反应离子在金属基体表面的吸附 ,增大阴极极化 ,改变界面双电层结构 ,从而使沉积速率加快。RE Ni Mo P WC最佳工艺条件为 :混合稀土浓度 4 g/L ,镀液温度 80℃ ,pH值 7.0～ 7 5 ,钼酸钠浓度≤ 0 .3g/L。展开更多
The Terreneuvian Epoch（541-521 Ma）is also an important period for metallogenesis in South China, as was represented by the widespread occurrences of Ni-Mo polymetallic layers on the antecedent shallow platform margi...The Terreneuvian Epoch（541-521 Ma）is also an important period for metallogenesis in South China, as was represented by the widespread occurrences of Ni-Mo polymetallic layers on the antecedent shallow platform margin and the V-enriched black shales in deeper slope-basin settings. In this study, we have measured Re-Os isochron ages of Ni-Mo polymetallic layers（Songlin, Niuchang, Sancha, Chuanpengwan）, V-rich black shales（Bahuang）, and non-metalliferous black shales（Shuidong） in the basal Niutitang Formation in Guizhou and Hunan province, South China. The Ni-Mo polymetallic layers and V-enriched black shales have similar Re-Os isochron ages, suggesting concurrent deposition of these two types of metalliferous ores. This suggestion is consistent with the traditional stratigraphic correlation by using the nodular phosphorite bed directly underlying these metalliferous layers as a stratigraphic marker. Furthermore, the metalliferous ores and non-metalliferous black shales have similar initial ^（187）Os/^（188） Os ratios of 0.8-0.9, arguing for a dominant seawater origin with minor contribution of hydrothermal activity. Furthermore, Re-Os isotopic data also imply that Ni-Mo and V ore might have derived from the same source. We suggest that the spatial distribution of metalliferous ores can be explained by the development of non-sulfidic anoxic-suboxic wedge（NSASW） in the slope-basin and sulfidic wedge in the previous platform margin. Upwelling of deep water first transects the mildly reduced, organic rich NSASW, in which V（V） is reduced to V（IV）, and is preferentially removed from seawater by organometallic complex formation. As a result, V-rich black shale deposits in the slope-basin of Yangtze Platform. Further movement of deep water into the sulfidic platform margin results in Ni-Mo polymetallic layer formation.展开更多
The high temperature oxidation resistance of RE Ni W B B 4C MoS 2 composite coating, the effects of electrodeposition conditions on the morphologies of the coating and the effect of heat treatment temperature on its h...The high temperature oxidation resistance of RE Ni W B B 4C MoS 2 composite coating, the effects of electrodeposition conditions on the morphologies of the coating and the effect of heat treatment temperature on its hardness, abrasion resistance and phase structure were investigated by using scanning electron microscope(SEM), X ray diffractometer, microhardness tester and abrasion machine. The results show that the oxidation degree of RE Ni W B B 4C MoS 2 composite coating is small when the temperature is lower than 700 ℃, but it increases sharply when the temperature is higher than 700 ℃. The hardness of RE Ni W B B 4C MoS 2 composite coating increases with increasing heat treatment temperature, it comes up to the maximum value at 400 ℃,but it decreases gradually if the temperature rises continuously. The most favourable abrasion resistance was attained after RE Ni W B B 4C MoS 2 composite coating being heat treated at 400 ℃. Without heat treating, it is mainly amorphous and partially crystallized, but wholly crystallized after being heat treated at 500 ℃. RE in the composite coating is in the form of CeO 2 and additions of CeO 2 and B 4C can enhance the thermostability of RE Ni W B B 4C MoS 2 composite coating.展开更多
The thermal fatigue property of Cr-W-Mo-Ni-Mn-RE ferric-base hardfacing layer was investigated. The results show that the generation and propagation of thermal fatigue cracks prefer the parts of oxidation and etching ...The thermal fatigue property of Cr-W-Mo-Ni-Mn-RE ferric-base hardfacing layer was investigated. The results show that the generation and propagation of thermal fatigue cracks prefer the parts of oxidation and etching of the grain boundary, the joint efforts of cycle stress and oxidation at high temperatures are the main factors in the generation and propagation of thermal fatigue cracks. When the temperatures is below 600 ℃, the Cr-W-Mo-Ni-Mn-RE ferric-base hardfacing layer has higher ability of thermal fatigue resistance. The function of the alloy and rare earth elements was discussed.展开更多
文摘The isothermal sections of the Co-Nb-Ni ternary system at 1373 K and the Ni-Mo-Re ternary system at 1473 K were determined by means of diffusion triple and electron probe microanalysis（EPMA）.The results indicate that there are three three-phase regions found in the Co-Nb-Ni ternary system at 1373 K：（Ni,Co） ＋ NbCo3 ＋ Ni3Nb,NbCo3 ＋ NbCo2 ＋ Ni3Nb,and NbCo2 ＋ μ ＋ Ni3Nb;and four three-phase regions found in the Ni-Mo-Re ternary system at 1473 K：Re ＋ Ni ＋ χ,Ni ＋ NiMo ＋ σ,σ ＋ χ ＋ Ni,and σ ＋ Mo ＋ NiMo.No ternary compound is observed in the two isothermal sections.The isothermal sections are contrasted with the previous study.
文摘化学复合镀RE Ni Mo P WC合金镀层具有良好的硬度、耐蚀、耐磨、抗氧化性能 ,但沉积速度对镀层性能有很大的影响。采用增重法研究了稀土元素、镀液温度、pH值、钼酸钠浓度对化学复合镀RE Ni Mo P WC合金镀层沉积速度的影响 ,并探讨了稀土元素的作用机理。结果表明 ,稀土元素的加入增大了复合镀层的沉积速度 ,其中混合稀土的作用最为明显 ;稀土元素的加入能促进反应离子在金属基体表面的吸附 ,增大阴极极化 ,改变界面双电层结构 ,从而使沉积速率加快。RE Ni Mo P WC最佳工艺条件为 :混合稀土浓度 4 g/L ,镀液温度 80℃ ,pH值 7.0～ 7 5 ,钼酸钠浓度≤ 0 .3g/L。
基金supported by the National Natural science Foundation of China (Nos. 41203037, 41272017, 41472089, 41402025)the Chinese Geological Survey Program (Nos. 12120113015500, 12120114039701, 1212010633903, 1212011120622, J(2010)KP010705)+2 种基金Laboratory of Paleontology and Stratigraphy Open-lab grant (133103)the Science and Technology Foundation of Guizhou (No. QKHJZ(2012)2163)the Talents Introduction Foundation of Guizhou University (No. GDRJHZ(2011)17)
文摘The Terreneuvian Epoch（541-521 Ma）is also an important period for metallogenesis in South China, as was represented by the widespread occurrences of Ni-Mo polymetallic layers on the antecedent shallow platform margin and the V-enriched black shales in deeper slope-basin settings. In this study, we have measured Re-Os isochron ages of Ni-Mo polymetallic layers（Songlin, Niuchang, Sancha, Chuanpengwan）, V-rich black shales（Bahuang）, and non-metalliferous black shales（Shuidong） in the basal Niutitang Formation in Guizhou and Hunan province, South China. The Ni-Mo polymetallic layers and V-enriched black shales have similar Re-Os isochron ages, suggesting concurrent deposition of these two types of metalliferous ores. This suggestion is consistent with the traditional stratigraphic correlation by using the nodular phosphorite bed directly underlying these metalliferous layers as a stratigraphic marker. Furthermore, the metalliferous ores and non-metalliferous black shales have similar initial ^（187）Os/^（188） Os ratios of 0.8-0.9, arguing for a dominant seawater origin with minor contribution of hydrothermal activity. Furthermore, Re-Os isotopic data also imply that Ni-Mo and V ore might have derived from the same source. We suggest that the spatial distribution of metalliferous ores can be explained by the development of non-sulfidic anoxic-suboxic wedge（NSASW） in the slope-basin and sulfidic wedge in the previous platform margin. Upwelling of deep water first transects the mildly reduced, organic rich NSASW, in which V（V） is reduced to V（IV）, and is preferentially removed from seawater by organometallic complex formation. As a result, V-rich black shale deposits in the slope-basin of Yangtze Platform. Further movement of deep water into the sulfidic platform margin results in Ni-Mo polymetallic layer formation.
文摘The high temperature oxidation resistance of RE Ni W B B 4C MoS 2 composite coating, the effects of electrodeposition conditions on the morphologies of the coating and the effect of heat treatment temperature on its hardness, abrasion resistance and phase structure were investigated by using scanning electron microscope(SEM), X ray diffractometer, microhardness tester and abrasion machine. The results show that the oxidation degree of RE Ni W B B 4C MoS 2 composite coating is small when the temperature is lower than 700 ℃, but it increases sharply when the temperature is higher than 700 ℃. The hardness of RE Ni W B B 4C MoS 2 composite coating increases with increasing heat treatment temperature, it comes up to the maximum value at 400 ℃,but it decreases gradually if the temperature rises continuously. The most favourable abrasion resistance was attained after RE Ni W B B 4C MoS 2 composite coating being heat treated at 400 ℃. Without heat treating, it is mainly amorphous and partially crystallized, but wholly crystallized after being heat treated at 500 ℃. RE in the composite coating is in the form of CeO 2 and additions of CeO 2 and B 4C can enhance the thermostability of RE Ni W B B 4C MoS 2 composite coating.
文摘The thermal fatigue property of Cr-W-Mo-Ni-Mn-RE ferric-base hardfacing layer was investigated. The results show that the generation and propagation of thermal fatigue cracks prefer the parts of oxidation and etching of the grain boundary, the joint efforts of cycle stress and oxidation at high temperatures are the main factors in the generation and propagation of thermal fatigue cracks. When the temperatures is below 600 ℃, the Cr-W-Mo-Ni-Mn-RE ferric-base hardfacing layer has higher ability of thermal fatigue resistance. The function of the alloy and rare earth elements was discussed.
