基于线性离子束技术的镁合金表面类金刚石膜的制备与性能研究EI北大核心

为了提高AZ31镁合金的力学性能和耐蚀性能,采用线性离子束技术在其表面沉积了类金刚石薄膜。分别利用原子力显微镜和扫描电子显微镜观察了薄膜的表面形貌和截面形貌,利用X射线衍射分析了薄膜的相结构,利用X射线光电子能谱分析了薄膜中元素的价态。利用纳米压痕仪和显微硬度计考察了镁合金镀膜后的表面硬度。利用极化曲线考察了镀膜镁合金在3.5%(质量分数)氯化钠溶液中的耐腐蚀性能。结果表明,利用线性离子束可以获得光滑致密的类金刚石膜,镀膜后镁合金的表面硬度和耐蚀性能得到显著提高。     

AZ31镁合金表面多层膜的结构与性能研究

研究了在AZ31镁合金表面依次进行浸锌、化学镀镍、电镀铜、电弧离子镀Cr/CrN的复合镀膜工艺.利用x射线晶体分析仪、扫描电镜、显微硬度计、腐蚀测量系统及热震法等仪器和方法对复合镀层的显微组织及性能进行了研究.结果表明,在此复合镀工艺条件下,可以在AZ31镁合金表面形成致密度高、结合强度好、耐蚀性好且硬度高的复合合金镀层;AZ31镁合金镀膜后的显微硬度形成一个梯度,由71.1HK提高到2224.8HK;耐蚀性明显提高,腐蚀电位从-1481mV提高到-382mV.     

AM60镁合金表面功能纳米有机薄膜的制备及特性研究

通过有机镀膜方法,利用一种设计合成的三氮杂嗪硫醇有机化合物钠盐在AM60镁合金表面制备了有机薄膜。采用循环伏安法和X射线光电子能谱仪(XPS)分析了镁合金表面有机镀膜过程的反应机理,使用椭圆偏振光谱仪测量了薄膜的厚度、接触角测量仪表征了薄膜的浸润性,借助极化曲线和电化学阻抗谱评价了膜层的耐腐蚀性。结果表明,该有机薄膜为纳米尺度,且使镁合金表面发生亲水到疏水特性转变;经有机镀膜后镁合金的腐蚀电流从1840nA/cm2降低到540nA/cm2、腐蚀电位从-1.454V上升到-1.340V,且电荷传递电阻从2.24kΩ·cm2提高到16.88kΩ·cm2,从而有效地提高了镁合金基体的耐腐蚀性能。     

镁合金表面有机纳米薄膜的功能特性

采用有机镀膜技术和三嗪硫醇类有机单体在Mg-Mn-Ce镁合金表面生成了具有疏水特性的有机纳米薄膜。选取循环伏安法曲线中不同特征点研究了有机镀膜的反应机理,借助傅里叶变换红外光谱仪、X射线光电子能谱仪、椭圆偏振光谱仪和接触角测量仪表征了有机镀膜后镁合金表面薄膜的特性.结果表明,有机镀膜过程分为电化学反应成膜和膜层层间聚合反应增厚两个阶段;镁合金与有机物单体通过化学键发生结合;随着有机镀膜反应过程的进行薄膜的厚度由9.14 nm逐渐增加到64.51 nm,形成稳定的纳米薄膜;有机镀膜后镁合金表面的蒸馏水接触角从未镀膜的45.8°上升到117.9°,实现了由亲水到疏水的功能特性转换。     

具有不同浸润性功能有机表面薄膜的制备

通过开发的有机镀膜技术,选用具有不同功能基团的有机镀液对不锈钢表面进行改性.借助于红外光谱、接触角和表面自由能等测试对有机镀膜处理的不锈钢表面薄膜进行了表征.实验结果表明,经过TTN溶液有机镀膜后,不锈钢表面自由能升高、蒸馏水接触角减小,具有了亲水功能特性;而经过DHN和AF17N溶液有机镀膜处理后,其表面自由能降低、蒸馏水接触角增大,具有良好的疏水功能特性;其中经过AF17N镀液处理后表面自由能最小而接触角最大,即疏水效果最佳.该技术实现了不锈钢表面的亲/疏水表面改性,提供了一种制备具有不同浸润性的有机表面薄膜材料的方法.     

AZ31镁合金表面复合镀膜工艺研究

研究了在AZ31镁合金表面依次进行浸锌、化学镀镍、电镀铜、电弧离子镀Cr/CaN的复合镀膜工艺.结果表明,在此复合镀工艺条件下,可以在AZ31镁合金表面形成致密度高、结合强度好、耐蚀性好且硬度高的复合合金镀层.AZ31镁合金镀膜后的显微硬度形成一个梯度,由71 HK提高到2225 HK;耐蚀性明显提高,在3.5%NaCl溶液中腐蚀电位从-1481 mV提高到-382 mV.     

磁控溅射制备Al_2O_3薄膜及耐蚀性能研究

采用直流磁控溅射镀膜技术以高纯铝为靶材,氧气为反应气体,在304不锈钢基底上以不同溅射功率(60,90,120,150和180 W)沉积Al_2O_3薄膜。采用X射线衍射仪(XRD)和扫描电子显微镜(SEM)对薄膜晶体结构和表面形貌进行分析表征,使用电化学工作站考察Al_2O_3薄膜的耐蚀性能。结果表明:所制备的Al_2O_3薄膜表面平整、均匀致密,并且在(217)面具有较好的择优取向;溅射功率对薄膜耐蚀性有较大影响,随溅射功率增加,耐蚀性先增强后减弱,在功率为150 W时所制备薄膜的耐蚀性能最优。     

AZ91镁合金表面MgFe_2O_4薄膜的溶胶-凝胶法制备及其耐蚀性能

MgFe2O4耐酸耐碱,但目前还未见将其制成镁合金防腐蚀涂层的报道。采用溶胶-凝胶法在AZ91镁合金表面制备了MgFe2O4薄膜,利用正交试验研究了镀膜层数、溶胶中Mg2+与Fe3+的摩尔比、烧结温度、烧结时间对AZ91镁合金膜试样自腐蚀电流密度的影响,得出最优方案,并研究了优化条件制备的膜试样的组织结构及耐蚀性。结果表明:各因素对AZ91镁合金膜试样自腐蚀电流密度的影响程度由大到小依次是镀膜层数、烧结温度、nMg2+/nFe3+、烧结时间;最优条件是镀膜1层,nMg2+/nFe3+=0.35,烧结温度400℃,烧结时间5 h;与AZ91镁合金基体相比,优化条件制备的MgFe2O4薄膜的自腐蚀电流密度降低了1个数量级,自腐蚀电位正移了690 mV,耐腐蚀性能得到很大提高。     

物理气相沉积在镁合金表面防护领域的研究现状

镁合金表面耐腐蚀性能、耐磨性能较差,物理气相沉积(PVD)镀膜技术是一种提高镁合金表面性能的有效方法。总结了PVD镀膜防腐蚀层和耐磨层的特性,分析了涂层耐腐蚀耐磨的机理和存在的不足。综述了镁合金表面PVD膜层的研究进展,阐述了物理气相沉积技术对镁合金的表面改性的应用现状,并对该技术在镁合金上的发展进行了概括,指出了目前PVD技术在镁合金表面防护领域的新前景,为今后PVD技术对镁合金表面防护的研究与发展提供了相关参考。     

直流磁控溅射非晶碳膜的导电性和耐蚀性

用直流磁控溅射技术在304不锈钢基体上制备导电非晶碳膜,重点研究了基体偏压对非晶碳膜微结构、导电性和耐蚀性的影响。结果表明:与纯不锈钢双极板相比,经非晶碳膜表面改性的不锈钢表面的导电性和耐蚀性均大幅度提高。当基体偏压为-200V时在质子交换膜燃料电池组装典型压力(1.5MPa)下非晶碳膜的sp2含量最高,使改性不锈钢双极板具有最低的接触电阻(16.65mΩ·cm2);在模拟质子交换膜燃料电池工作环境的腐蚀溶液中镀膜后不锈钢板的腐蚀电位显著提高,腐蚀电流明显下降。尤其在偏压-200V下薄膜具有最佳的致密性,腐蚀电位为0.25V,腐蚀电流密度为1.22×10-8A/cm2,耐蚀性能最佳。     

Study of the characteristics and corrosion behavior for the Zr-based metallic glass thin film fabricated by pulse magnetron sputtering process

Two sets of source target which consist of ZrCuAlNiV and ZrTiAlNiV, respectively were selected as the target materials for preparing a series of thin film coatings on the 304 stainless steel substrate by DC pulse magnetron sputtering process. The microstructures of these as-prepared ZrCuAlNiV and ZrTiAlNiV thin films were examined by X-ray diffraction and TEM observation. In parallel, the characteristic analysis of these ZrCuAlNiV and ZrTiAlNiV alloy thin films including surface roughness, and corrosion resistance were analyzed by atomic force microscopy (AFM), and tested by electrochemical method as well as salt spray testing, respectively. The results showed that the ZrCuAlNiV thin film exhibits a typical amorphous microstructure and smooth surface with average roughness about 1 nm. The ZrCuAlNiV thin film performs similar corrosion resistance to 304 stainless steel according to the result of salt spray testing in 5% NaCl solution. Additionally, the AC impedance value of ZrCuAlNiV is 20 times than 316L stainless steel and 4 times than ZrTiAlNiV, implying that the ZrCuAlNiV thin film has better corrosion resistance than the others owing to its amorphous state.     

Mitigation of chloride driven stress corrosion cracking susceptibility of 316L austenitic stainless steel using plasma sprayed TiO2 coating

The present study proposes a protective TiO₂ coating against chloride driven stress corrosion cracking problem of 316L austenitic stainless steel. To test the performance of the proposed coating, the severe chloride-based boiling magnesium chloride solution at 155 °C was chosen. For experimentation, the constant strain-based U-bend specimens were coated with TiO₂ using atmospheric plasma spray method. The results indicated higher resistance by TiO₂ coated specimens against stress corrosion cracking problem, while the bare specimens experienced severe damage in the boiling magnesium chloride solution under various strain loading configurations. The coating-electrolyte system of TiO₂ coated sample demonstrated over seven times higher resistance, eventually led to reduction in corrosion rate over fifteen times compared to the bare 316L stainless steel in the boiling magnesium chloride solution. This improved performance of the coated 316L stainless steel is attributed to inhibition of outward diffusion of iron-chromium-nickel in the corrosive environment and the high chemical stability of TiO₂.     

Evaluation of the Corrosion Protection Performance of Epoxy-Coated High Manganese Steel by SECM and EIS Techniques

The corrosion protection performances of epoxy-coated Mn steel and carbon steel were evaluated by electrochemical impedance spectroscopy (EIS) and scanning electrochemical microscopy (SECM) analysis. EIS was performed on coated Mn steel with a scratch in a 0.1 M NaCl solution after a wet/dry cyclic corrosion test. The charge transfer resistance (R _ct) and film resistance (R _f) of the coated Mn steel displayed a higher value than the coated carbon steel. The increase in the charge transfer resistance and film resistance of the coated steel is due to the presence Mn in steel. SECM was conducted to estimate the corrosion protection performance of the epoxy-coated Mn steel immersed in a 0.1 M NaCl solution. It was found that dissolution of Fe²⁺ was suppressed at the scratch on the coated Mn steel due to the higher resistance for anodic dissolution of the substrate. SEM/EDX analysis showed that Mn was enriched in corrosion products at a scratched area of the coated steel after corrosion testing. FIB-TEM analysis confirmed the presence of the nanoscale oxide layer of Mn in the rust of the steel, which had a beneficial effect on the corrosion resistance of the coated steel by forming protective corrosion products in the wet/dry cyclic test.     

Surface interactions of a W-DLC-coated biomedical AISI 316L stainless steel in physiological solution

The corrosion stability of a W-DLC coated surgical AISI 316L stainless steel in Hanks’ solution has been evaluated. Particle induced X-ray emission (PIXE) measurements were performed to evaluate the incorporation of potentially bioactive elements from the physiological solution. The film structure was analyzed by X-ray diffractometry and micro-Raman spectroscopy. The wear behavior was assessed using the sphere-on-disc geometry. The in vitro biocompatibility of the W-DLC film was evaluated by cytotoxicity tests. The corrosion resistance of the stainless steel substrate decreased in the presence of the PVD layer. EIS measurements suggest that this behavior was closely related to the corrosion attack through the coating pores. PIXE measurements revealed the presence of Ca and P in the W-DLC film after immersion in Hanks’ solution. This result shows that the PIXE technique can be applied to identify and evaluate the incorporation of bioactive elements by W-DLC films. The film showed good wear resistance and biocompatibility.     

沉积扩散法制备含银抗菌不锈钢工艺研究

采用沉积扩散法制备含银抗菌不锈钢层,通过抗菌试验、盐干湿循环腐蚀试验、SEM、XPS等检测手段,研究了沉积扩散工艺制备含银抗菌不锈钢的抗菌性能、耐蚀性能及银在不锈钢基体中的分布状态和价态.结果表明,基材表面化学镀银后经离子轰击抗菌处理(工艺参数:电压1.25 kV,电流3 A,气流量20～60 mL/min,时间4 h),所得含银抗菌不锈钢的杀菌率达到99%以上,耐蚀性能没有降低,银在基体中呈弥散状态分布,其价态为零价态.     

不锈钢表面电化学合成导电聚苯胺膜的研究

在酸性电解液中分别用电化学恒电位法和恒电流法在不锈钢基材上成功制备了导电聚苯胺膜，该膜在空气中呈绿色，稳定、完整致密，为结晶态结构，与基体的结合情况较好。在氯化钠溶液中测定试样的阳极极化曲线后发现，表面覆盖聚苯胺膜后的不锈钢，其点蚀电位比无膜时升高1000mV左右，表明导电聚苯胺膜可显著提高不锈钢的抗点蚀性能，具有良好的点腐蚀防护效果。     

Mechanical and corrosion properties of Al/Ti film on magnesium alloy AZ31B

Preparation of titanium film on magnesium substrate faces a challenge due to non-Fickian inter-diffusion between titanium and magnesium. Aluminum can build a bridge between titanium and magnesium. Al/Ti duplex coatings were deposited on magnesium alloy AZ31B using magnetron sputtering (MS). The low temperature diffusion bonding behavior of the Mg/Al/Ti coating was investigated through SEM and its affiliated EDS. The phase structure and critical load of the coatings were examined by means of XRD and scratch tests, respectively. The results demonstrated that the bonding strength was significantly improved after a post heat treatment (HT) at a temperature of 210°C. The diffusion mechanism of the interfaces of Mg/Al and Al/Ti in the coating was discussed based on the analysis of formation energy of vacancies and diffusion rates. The Al/Ti dual layer enhanced the corrosion resistance of the alloy. And the HT process further increased the corrosion resistance of the coated alloy. This result implies that a post HT at a lower temperature after MS is an effective approach to enhance the bonding strength and corrosion resistance of the Al/Ti film on Mg alloys.     

不锈钢基Al2O3/SiC双层薄膜的制备和性能

用磁控溅射法在奥氏体不锈钢上分别制备了SiC单层膜和Al2O3/SiC双层膜,研究了溅射气压,溅 射功率以及退火温度对性能的影响.对比了二者的结构、硬度以及耐腐蚀性.结果表明,Al2O3缓冲层降低了SiC薄膜与奥氏体不锈钢基底的热失配和晶格失配,减少了因其而产生的缺陷,从而改善了奥氏体不锈钢上SiC薄膜的结晶质量.     

激光熔敷Co基合金的组织及涂盐热腐蚀性能

本文采用刷涂加激光重熔固化处理的方法,在1Cr18Ni9Ti 不锈钢表面激光熔敷 Co 基合金,显著提高了其耐高温腐蚀的性能。文中对激光熔敷 Co 基合金结晶的组织,高温腐蚀的机制及其腐蚀的产物进行了较详细的研究,为激光熔敷技术在实际生产中的推广应用提供理论依据。     

镍-钴合金镀钢带及其制成的锂电池钢壳的耐腐蚀性能

用于锂电池壳体制备的预镀镍工艺会使钢壳表面有大量裂纹,耐蚀性下降。通过3种方式在钢带上镀覆镍-钴合金层,并冲压制成电池钢壳,采用扫描电镜(SEM)、能谱、X射线衍射(XRD)、电化学测试、中性盐雾试验、硫酸铜点滴试验研究了镀覆钢带和电池钢壳的组织结构和耐腐蚀性能。结果表明:电镀2μm镍-钴合金层经700℃热处理3 h后再加镀2μm镍-钴合金层制备的钢带表层致密均匀,加镀的薄膜封闭了热处理后晶粒间存在的位错等缺陷产生的针孔,具有良好的耐腐蚀性能;电镀4μm镍-钴合金层经700℃热处理3 h制备的钢带冲压而成的电池钢壳表面裂纹少且细小,裂纹处为镍/钴/铁固溶体,耐腐蚀性能明显优于其他2种方式制备的钢壳。