In vitro Study on a New High Nitrogen Nickel-free Austenitic Stainless Steel for Coronary Stents

Most commercialized coronary stents are made of 316L stainless steels due to its good combination of properties,and currently some new stents are made of cobalt-based alloy owing to its higher mechanical properties. However,the presence of high quantity of nickel and/or cobalt elements in these materials,which are known to trigger the toxic and allergic responses,has caused many concerns.Nickel-free austenitic stainless steels have been developed in order to solve these problems.In this paper,based on the development of a new Fe-Cr-Mn-Mo-N type high nitrogen nickel-free austenitic stainless steel,properties such as mechanical property,corrosion resistance in Hank s solution,and in vitro blood compatibility including the kinetic clotting time and the platelets adhesion,were investigated in comparison to the above two conventional materials,a 316L stainless steel and a Co-28Cr-6Mo alloy.The results showed that the new high nitrogen steel possessed better combination of mechanical properties,corrosion resistance and blood compatibility than those of 316L steel and the Co-28Cr-6Mo alloy,and can be a promising alternative material for manufacture of coronary stents.     

Nickel-free austenitic stainless steels for medical applications

Abstract

The adverse effects of nickel ions being released into the human body have prompted the development of high-nitrogen nickel-free austenitic stainless steels for medical applications. Nitrogen not only replaces nickel for austenitic structure stability but also much improves steel properties. Here we review the harmful effects associated with nickel in medical stainless steels, the advantages of nitrogen in stainless steels, and emphatically, the development of high-nitrogen nickel-free stainless steels for medical applications. By combining the benefits of stable austenitic structure, high strength and good plasticity, better corrosion and wear resistances, and superior biocompatibility compared to the currently used 316L stainless steel, the newly developed high-nitrogen nickel-free stainless steel is a reliable substitute for the conventional medical stainless steels.     

氮势对奥氏体不锈钢离子渗氮性能的影响

对AIS1304奥氏体不锈钢进行了不同氮势的离子渗氮,利用金相显微镜、轮廓仪、摩擦磨损试验机、X射线衍射仪和显微硬度计测试了经渗氮处理后试样改性层的截面形貌、微观结构、相组成和力学性能,并与未渗氮的试样进行了比较。结果表明：随着氮势的增加,试样表面的渗层深度、磨损程度、显微硬度呈规律性变化;X射线衍射分析表明：低氮势容易形成S相,高氮势有利于氮化物的形成。     

奥氏体不锈钢在三种深冷储罐中的应用

本文介绍了子母型储罐、双层球罐、组合储罐各自的特点以及优缺点;结合三种不同结构的储罐,表明了奥氏体不锈钢可以良好用于深冷储罐。最后提出了选型的建议。     

医用不锈钢的研究与发展

不锈钢由于具有优异的力学性能、耐蚀性能和加工性能而被广泛应用于各种医疗器械及手术工具的制造。概述了医用不锈钢的特点和临床应用,以及存在的主要问题,并以高氮无镍奥氏体不锈钢、不锈钢表面改性、抗菌不锈钢为重点,介绍了医用不锈钢近年来在国内外的主要研究进展。表明医用不锈钢的研究与发展,进一步提高或改善了不锈钢的生物安全性、力学性能、耐蚀性能,甚至带来了一些生物功能化,为医用不锈钢的临床应用带来了新的机遇。     

Fatigue and Corrosion Fatigue of High-Nitrogen Austenitic Stainless Steel

High nitrogen contents in solid solution as well as appropriate strengthening mechanisms in austenitic stainless steels can result in very high corrosion resistance. This is true in both air environment and in simulated human body fluids (corrosion fatigue). High cycle corrosion fatigue data are listed and compared with similar data for titanium base and cobalt base implant materials. Thus high nitrogen austenitic stainless steels are candidates to replace other stainless steels as implant materials.     

不锈钢化学抛光工艺研究

研究了以硫酸为主的不锈钢化学抛光工艺。通过改变温度考察其对不锈钢抛光效果的影响，从而确定最佳温度范围；通过改变不锈钢化学抛光工艺中各组成的含量，考察其对抛光效果的影响，筛选出既有较好抛光效果、抛光成本也较低的最佳化学抛光工艺为：H2SO4 20％-30％，HNO3 3％-6％，添加剂3％-6％，水余量，温度60-70℃，时间3-5min。     

高强度奥氏体不锈钢的发展

工程应用对奥氏体不锈钢的强度、韧性、低磁性和耐蚀性的要求不断提高。本文综述了高强度奥氏体不锈钢(RP0.2≥400MPa)的发展趋势,以及几种高强度奥氏体钢的化学成分和力学性能。     

焊接不锈钢的电化学抛光

研究了一种焊接不镑钢的电化学抛光工艺，确定了电化学去氧化铁及电化学抛光液的化学成分和工艺参数为：H3PO4(85％)740～770mL／L，H2SO4(98％)180～210mL/L,CrO350g/L，明胶8～10mL/L，抛光液密度1．70～1．78g／cm^3，温度55～65℃，JA＝35～45A／dm^2，槽电压10～20V，时间4～5min，阴极为铅板。该工艺不会使不锈钢基体产生点蚀，能使不锈钢表面及焊缝达镜面光亮。     

双相不锈钢研究进展

从新钢种开发和工程应用中可靠性预测两方面,综述了国内外铁素体+奥氏体双相不锈钢近年来研究的进展情况,并对双相不锈钢未来的研究方向作了初步探讨。     

不锈钢中15个元素的ED—XRF分析

不锈钢是应用十分广泛的合金钢,成份的含量对性能有重要影响,湿式化学法材料消耗多,慢,采用ED—XRF同时分析其中15个元素,速度快,效率高,能满足分析要求。     

铁素体不锈钢焊接接头的再结晶现象

考察了新型铁素体不锈钢焊接接头中的再结晶现象，分析了其形成特点及相关影响因素。     

耐浓硝酸泵用新型不锈钢的研究

设计了用于浓硝酸泵的新型不锈钢的组织及其化学成分，采用金相显微镜、扫描电子显微镜和腐蚀试验方法研究了钢的金相组织、断口形貌和耐蚀性能。试验结果表明，该钢经１０５０℃×１．５ｈ水冷（或空冷）固溶处理后，在浓硝酸介质中具有优良的耐蚀性与满意的韧性和铸造性能。     

不锈钢超精抛光蜡的研制

目前,国产不锈钢超精抛光蜡不能满足市场需求,对其配方研制报道较少。为此,对不锈钢粗抛光后,采用超精抛光蜡进行精抛光,对其组分进行了筛选：以仪型氧化铝粉为抛光磨料;以混合硬脂酸作抛光内脂;利用油酸的润滑作用降低不锈钢表面的抛光温度,利用三乙醇胺与有机酸的皂化反应生成物润滑和清洁不锈钢表面;利用松香和石油磺酸钡提高不锈钢表...     

不锈钢电解法快速着金色工艺的研究

通过试验确定了一种不锈钢电解法快速着金色溶液的配方和最佳工艺参数:40-g/L K2Cr2O7,20-g/L MnSO4,20-g/L (NH4)2SO4,20-g/L H3BO3 ,添加剂A 9～12g/L、添加剂B 10g/L,电解电压3～4V,阳极电流密度0.2～0.5A/dm2, pH值2.5～4.0,温度10～30℃,时间12～15min,着重讨论了该配方各组分的作用及其对着色膜质量的影响,初步分析了该电解着色液着色的可能机理.耐腐蚀性测试试验表明金色膜的腐蚀失重率仅为未着色的1/30.试验结果表明:该工艺具有着色时间短、金色膜附着力强、光泽性好、环境污染小等特点;同时该膜提高了不锈钢的耐磨性和耐蚀性.     

Microdeformation Behaviour of a Ferritic-Austenitic Duplex Stainless Steel

Microdeformation of ferritic and austeniticgrains in a ferritic-austenitic duplex stainless steelhave been observed in-situ by SEM with photoetch.The plastic deformation behaviour of austeniticgrains are similar to ferritic grains for hydrogenuncharged specimens,it follows Mileiko'sstrain-equal model.But it will be changed when thespecimens are hydrogen charged.     

不锈钢小孔腐蚀统计规律的研究

本文验证了不锈钢孔蚀最大深度的极值统计规律。采用极值分析方法,对不锈钢孔蚀盘管用小面积的测试数据推测了整根盘管上的泄漏孔数,极值分析推断结果与实际测定的情况符合得很好。同时,还应用了广义线性模型来处理了孔蚀失效率与时间的关系,发现失效率与时间的关系曲线具有“S”型特征。并且证明后勤模型与实验室测试数据之间拟合程度最好。     

不锈钢镀铬预处理新型活化液的电化学特性

不锈钢电镀铬的预处理--活化处理可有效去除不锈钢表面的钝化膜,解决镀层与基体的结合力问题.通过测定18-8不锈钢在各活化液中的稳态电位、腐蚀速度和阳极极化曲线,结合镀层综合性能的检验,获得最佳活化液配方:98～102 g/L (NH4)2SO4,85～90 g/L H2SO4(分析纯),5～6 g/L H3PO4(分析纯),5～6 g/L H2SiF6.该活化液的稳态电位为-0.55 V,腐蚀速率在12 h内为2 g/(m2·h),随后缓慢下降.它能有效去除不锈钢表面的钝化膜,且对不锈钢基体的腐蚀很小;用该配方活化的不锈钢电镀后,可获得光亮平滑、均匀致密、硬度较高、结合力好的镀铬层.