Laser cladding of preplaced Al ＋ Ir powders on a ZM5 magnesium alloy was performed to enhance the corrosion resistance of the ZM5 magnesium alloy. A metallurgical bond was obtained at the coating/substrate interface....Laser cladding of preplaced Al ＋ Ir powders on a ZM5 magnesium alloy was performed to enhance the corrosion resistance of the ZM5 magnesium alloy. A metallurgical bond was obtained at the coating/substrate interface. The corrosion potential （Ecorr） of the laser cladded sample was 169 mV positive to that of the untreated ZM5 substrate,while the corrosion current （Icorr） was some one order of magnitude lower. The laser cladded sample,unlike the untreated ZM5 substrate,showed a passive region in the polarization plot. Immersion tests confirmed that the corrosion resistance of the laser cladded ZM5 sample was significantly enhanced in 3.5 wt.% NaCl solution. The Al-rich phases of AlIr,Mg17Al12,and Al formed in the cladding layer and the rapid solid characteristics were contributed to the improved corrosion behavior of the coating.展开更多
The main problems caused by improper gating are entrained aluminum oxide films and entrapped gas.In this study,the slot gating system is employed to improve mold filling behavior and therefore,to improve the quality o...The main problems caused by improper gating are entrained aluminum oxide films and entrapped gas.In this study,the slot gating system is employed to improve mold filling behavior and therefore,to improve the quality of aluminum castings produced in permanent molds.An equipment as well as operation procedures for real-time X-ray radiography of molten aluminum flowing into permanent molds have been developed.Graphite molds transparent to X-rays are utilized which make it possible to observe the flow pattern through a number of vertically oriented gating systems.The investigation discovers that there are many influencing factors on the mold filling process.This paper focuses its research on some of the factors,such as the dimensions of the vertical riser and slot thickness,as well as roughness of the coating layer.The results indicate that molten metal can smoothly fill into casting cavity with a proper slot gating system.A bigger vertical riser,proper slot thickness and rougher coating can provide not only a better mold filling pattern,but also hot melt into the top of the cavity.A proper temperature gradient is obtainable,higher at the bottom and lower at the top of the casting cavity,which is in favor of feeding during casting solidification.展开更多
A new technique for separation of petroleum acids from crude oil was proposed. The method relates to processes for treating acidic oils or fractions thereof to reduce or eliminate their acidity by addition of effectiv...A new technique for separation of petroleum acids from crude oil was proposed. The method relates to processes for treating acidic oils or fractions thereof to reduce or eliminate their acidity by addition of effective amounts of crosslinked polymeric amines such as polypropylene amine and anionic exchange resins having amino-groups. Petroleum acids contained in the mixture can be extracted by a complex solvent. The results indicate that more than 80 % of the petroleum acids are removed and the process does not cause environmental pollution because all the solvents are recovered and reused in the test.展开更多
基金the National Natural Science Foundation of China (No. 50371093).
文摘Laser cladding of preplaced Al ＋ Ir powders on a ZM5 magnesium alloy was performed to enhance the corrosion resistance of the ZM5 magnesium alloy. A metallurgical bond was obtained at the coating/substrate interface. The corrosion potential （Ecorr） of the laser cladded sample was 169 mV positive to that of the untreated ZM5 substrate,while the corrosion current （Icorr） was some one order of magnitude lower. The laser cladded sample,unlike the untreated ZM5 substrate,showed a passive region in the polarization plot. Immersion tests confirmed that the corrosion resistance of the laser cladded ZM5 sample was significantly enhanced in 3.5 wt.% NaCl solution. The Al-rich phases of AlIr,Mg17Al12,and Al formed in the cladding layer and the rapid solid characteristics were contributed to the improved corrosion behavior of the coating.
文摘The main problems caused by improper gating are entrained aluminum oxide films and entrapped gas.In this study,the slot gating system is employed to improve mold filling behavior and therefore,to improve the quality of aluminum castings produced in permanent molds.An equipment as well as operation procedures for real-time X-ray radiography of molten aluminum flowing into permanent molds have been developed.Graphite molds transparent to X-rays are utilized which make it possible to observe the flow pattern through a number of vertically oriented gating systems.The investigation discovers that there are many influencing factors on the mold filling process.This paper focuses its research on some of the factors,such as the dimensions of the vertical riser and slot thickness,as well as roughness of the coating layer.The results indicate that molten metal can smoothly fill into casting cavity with a proper slot gating system.A bigger vertical riser,proper slot thickness and rougher coating can provide not only a better mold filling pattern,but also hot melt into the top of the cavity.A proper temperature gradient is obtainable,higher at the bottom and lower at the top of the casting cavity,which is in favor of feeding during casting solidification.
文摘A new technique for separation of petroleum acids from crude oil was proposed. The method relates to processes for treating acidic oils or fractions thereof to reduce or eliminate their acidity by addition of effective amounts of crosslinked polymeric amines such as polypropylene amine and anionic exchange resins having amino-groups. Petroleum acids contained in the mixture can be extracted by a complex solvent. The results indicate that more than 80 % of the petroleum acids are removed and the process does not cause environmental pollution because all the solvents are recovered and reused in the test.
