6.0 mm 304H不锈弹簧钢丝生产的弹簧放置一段时间后,部分弹簧表面岀现红色锈斑。采用扫描电镜观察304H不锈钢弹簧局部锈蚀酸洗前、后表面正常区和锈蚀区微观形貌,并用能谱仪检测不同区位的化学成分。结果表明:生产不锈钢丝的原材料热...6.0 mm 304H不锈弹簧钢丝生产的弹簧放置一段时间后,部分弹簧表面岀现红色锈斑。采用扫描电镜观察304H不锈钢弹簧局部锈蚀酸洗前、后表面正常区和锈蚀区微观形貌,并用能谱仪检测不同区位的化学成分。结果表明:生产不锈钢丝的原材料热轧线材表面局部存在麻面或麻坑,拉拔过程中麻坑中残留的润滑剂在制簧回火时和空气中的氧发生化学反应,形成带有孔隙的多元复合物,这些物质和弹簧表面基体经漫长的电化学反应,生成红色的锈蚀物。展开更多
Salicylic acid(SA)is used as a preservative in food and a biocide in some consumer products.However,in some countries its use is prohibited.The main problem in the electroanalytical determination of SA is the formatio...Salicylic acid(SA)is used as a preservative in food and a biocide in some consumer products.However,in some countries its use is prohibited.The main problem in the electroanalytical determination of SA is the formation of a passive film during the electro-oxidation of SA.To alleviate the passivation during SA measurement,the experiment was conducted by screen-printed carbon electrode(SPCE).While,differential pulse voltammetry(DPV)was essential for oxidation process to provide better sensitivity.Under conditions of optimized pH and electrolyte concentration,we have calibrated SA in the range of 0.001-0.2 mM,with and LOD of 1.6μM.The relative standard deviation of the sensor responses to 40μM and 100μM SA(n=20)was<3%.SA recoveries in samples such as pickled green mustard,pickled bamboo shoots,pickled mango,pickled lime,pickle ginger and apple juice were found to be in the range of 84-113%.展开更多
通过酸洗、浸泡法和电化学腐蚀测试分析了烧结Nd Fe B永磁体在不同浓度的H2SO4溶液、HCl溶液和HNO3溶液中的腐蚀行为。结果表明,烧结Nd Fe B磁体在HNO3溶液中的腐蚀机制为均匀腐蚀,而在H2SO4溶液和HCl溶液中的腐蚀机制为选择性的晶间腐...通过酸洗、浸泡法和电化学腐蚀测试分析了烧结Nd Fe B永磁体在不同浓度的H2SO4溶液、HCl溶液和HNO3溶液中的腐蚀行为。结果表明,烧结Nd Fe B磁体在HNO3溶液中的腐蚀机制为均匀腐蚀,而在H2SO4溶液和HCl溶液中的腐蚀机制为选择性的晶间腐蚀。烧结Nd Fe B磁体在酸溶液中的腐蚀速率随着酸溶液浓度的增加而增加。在浸泡试验和电化学腐蚀试验中,烧结Nd Fe B磁体在HNO3溶液中的腐蚀速率均最小。因此,HNO3溶液更适合作为烧结Nd Fe B磁体的酸洗液。展开更多
文摘6.0 mm 304H不锈弹簧钢丝生产的弹簧放置一段时间后,部分弹簧表面岀现红色锈斑。采用扫描电镜观察304H不锈钢弹簧局部锈蚀酸洗前、后表面正常区和锈蚀区微观形貌,并用能谱仪检测不同区位的化学成分。结果表明:生产不锈钢丝的原材料热轧线材表面局部存在麻面或麻坑,拉拔过程中麻坑中残留的润滑剂在制簧回火时和空气中的氧发生化学反应,形成带有孔隙的多元复合物,这些物质和弹簧表面基体经漫长的电化学反应,生成红色的锈蚀物。
基金support provided by Agricultural Research Development Agency(Grant no.CRP5507010820)the King Mongkut’s University of Technology Thonburi through the“KMUTT 55th Anniversary Commemorative Fund”(Grant number 60000331).
文摘Salicylic acid(SA)is used as a preservative in food and a biocide in some consumer products.However,in some countries its use is prohibited.The main problem in the electroanalytical determination of SA is the formation of a passive film during the electro-oxidation of SA.To alleviate the passivation during SA measurement,the experiment was conducted by screen-printed carbon electrode(SPCE).While,differential pulse voltammetry(DPV)was essential for oxidation process to provide better sensitivity.Under conditions of optimized pH and electrolyte concentration,we have calibrated SA in the range of 0.001-0.2 mM,with and LOD of 1.6μM.The relative standard deviation of the sensor responses to 40μM and 100μM SA(n=20)was<3%.SA recoveries in samples such as pickled green mustard,pickled bamboo shoots,pickled mango,pickled lime,pickle ginger and apple juice were found to be in the range of 84-113%.
基金National Science and Technology Key Support Projects of China(2012BAE02B01)Major Science and Technology Special Projects of Jiangxi Province(2010AZX00200)+1 种基金Science and Technology Plan Projects of Jiangxi Province(20121BBE50001)Science and Technology Plan Projects of Department of Education of Jiangxi Province(KJ201109132281)
文摘通过酸洗、浸泡法和电化学腐蚀测试分析了烧结Nd Fe B永磁体在不同浓度的H2SO4溶液、HCl溶液和HNO3溶液中的腐蚀行为。结果表明,烧结Nd Fe B磁体在HNO3溶液中的腐蚀机制为均匀腐蚀,而在H2SO4溶液和HCl溶液中的腐蚀机制为选择性的晶间腐蚀。烧结Nd Fe B磁体在酸溶液中的腐蚀速率随着酸溶液浓度的增加而增加。在浸泡试验和电化学腐蚀试验中,烧结Nd Fe B磁体在HNO3溶液中的腐蚀速率均最小。因此,HNO3溶液更适合作为烧结Nd Fe B磁体的酸洗液。
