316L不锈钢支架表面EVAL涂层的制备及性能研究

采用超声-喷涂沉积的方法,在316L不锈钢表面制得聚乙烯-乙烯醇涂层。利用原子力显微镜、接触角测量仪及扫描电镜对涂层表面形貌及性能进行研究。结果表明,316L不锈钢基体、S-EVAL涂层和USEVAL涂层的表面粗糙度Ra分别为123.677,14.994和2.830 nm。S-EVAL涂层和US-EVAL涂层表面接触角分别为75.6和74.3°,均小于316L不锈钢基体接触角。超声-喷涂沉积US-EVAL涂层血小板粘附量最少。     

316L不锈钢表面聚氨酯多孔涂层的制备及其生物性能研究

利用湿法相转化原理在316L不锈钢表面制备聚氨酯涂层时，空气湿度和溶液浓度是影响涂层形貌的两个主要因素．涂层表面形貌的观察结果表明：空气湿度增大或者溶液浓度减少，都有增大涂层表面孔径的趋势，而且可以加深孔的深度．通过控制空气湿度和溶液浓度，孔径可以在几个微米到30多个微米的范围内变化．通过亲疏水性测量、血小板粘附试验和动态凝血试验考察了涂层的血液相容性．以316L不锈钢作为参照组进行对比分析，结果可知：PU多孔涂层表面为超疏水性，明显降低了血小板在材料表面的粘附，延长了动态凝血时间，表现出良好的血液相容性．     

建筑用316L不锈钢表面树脂固化涂层600℃氧化行为分析

为了提高建筑设备表面涂层的防腐能力,通过实验制得一种经纳米改性处理的有机硅固化涂层,并分析其耐高温氧化特性。研究结果表明:当加入35%以上PU时,经过24 h后全部完成了固化过程,将PU和SM配比设定在30%为最优。SM发生固化通过硅羟基脱水缩合来实现,最终获得相互交联的网型组织。从5 min开始直到210 h发生了少量失重,到达210 h时质量表现为相对平稳的状态,涂层可以对基体组织发挥良好保护效果,显著降低氧化速率。氧化前形成致密涂层结构,并未产生裂纹,将涂层升温到600℃氧化处理后形成了更加粗糙的表面组织。涂层和基体之间形成紧密结合,没有发生剥落。随着氧原子不断扩散到涂层中时,不断与铝粉结合转变为氧化铝,抑制了氧气的扩散过程,从而达到了更强的防护效果。     

316L不锈钢表面聚氨酯多孔涂层的制备及其生物性能的研究

利用湿法相转化原理在316L不锈钢表面制备聚氨酯涂层时，空气湿度和溶液浓度是影响涂层形貌的两个主要因素。涂层表面形貌的观察结果表明：空气湿度增大或者溶液浓度减少，都有增大涂层表面孔径的趋势，而且可以加深孔的深度。通过控制空气湿度和溶液浓度，孔径可以在几个微米到三十多个微米的范围内变化。通过亲疏水性测量、血小板粘附试验和动态凝血试验考察了涂层的血液相容性。以516L不锈钢作为参照组进行对比分析，结果可知：PU多孔涂层表面为超疏水性，明显降低了血小板在材料表面的粘附，延长了动态凝血时间，表现出良好的血液相容性。     

叶片用316L不锈钢表面激光合金化铬涂层性能及参数优化

采用激光合金化方法在叶片用316L不锈钢表面制备铬涂层性能,并进行组织性能测定以及参数优化。研究结果表明:铬涂层合金化层为月牙状的结构,是一种网状的柱状晶形态。在中形成了具有较大宽度的枝状晶组织形态。在X射线衍射谱图上形成了Fe-Cr与Cr_xFe_y对应的各个衍射峰。硬度表现为由合金化层往基体方向具有明显梯度分布的特征。当激光功率增大后,将会引起铬合金层硬度与厚度的上升;当增大激光扫描速率后,铬合金层发生了硬度先增大后减小的现象,而厚度表现为持续减小的情况;当涂层的厚度增大后,将会引起铬合金层的硬度发生减小的现象,厚度开始增大。确定316L不锈钢表面激光合金化铬涂层最优工艺:激光功率5.5 kW,扫描速率8.5 mm/s,涂层厚度0.15 mm。     

金属基表面Al2O3-SiO2涂层耐冲蚀性能的研究

结合炼钢转炉用风机因炉气而导致叶片磨蚀较快的实际情况，从改善叶片材料的角度出发，采用溶胶-凝胶法制备Al2O3-SiO2涂层用在金属基体上进行试验。结果表明在含3％（质量分数）Si02磨粒的水介质中，单一三层的SiO2涂层、SiO2-Al2O3-SiO2涂层及混合溶胶制备的复合涂层的耐冲蚀性相近，均比单一三层的Al2O3涂层及A12O3-Sio2-Al2O3涂层好。混合溶胶制备的复合涂层在3％（质量分数）SiO2磨粒的酸性介质中表现出了良好的耐冲蚀性。     

叶片用316L不锈钢表面激光合金化铬涂层性能及参数优化北大核心CSCD

采用激光合金化方法在叶片用316L不锈钢表面制备铬涂层性能,并进行组织性能测定以及参数优化。研究结果表明:铬涂层合金化层为月牙状的结构,是一种网状的柱状晶形态。在中形成了具有较大宽度的枝状晶组织形态。在X射线衍射谱图上形成了Fe-Cr与Cr_xFe_y对应的各个衍射峰。硬度表现为由合金化层往基体方向具有明显梯度分布的特征。当激光功率增大后,将会引起铬合金层硬度与厚度的上升;当增大激光扫描速率后,铬合金层发生了硬度先增大后减小的现象,而厚度表现为持续减小的情况;当涂层的厚度增大后,将会引起铬合金层的硬度发生减小的现象,厚度开始增大。确定316L不锈钢表面激光合金化铬涂层最优工艺:激光功率5.5 kW,扫描速率8.5 mm/s,涂层厚度0.15 mm。     

搪瓷涂层对316L不锈钢表面润湿性的研究

为进一步降低316L不锈钢在核反应堆中使用过程中氢和氢同位素渗透所导致的危害，欲通过制备致密的与基体结合良好的搪瓷涂层进行保护，介绍了涂层的制备过程。涂层的质量及其保护效应与涂层高温熔体对基体的润湿性能有密切的关系，本试验通过不同方式往搪瓷釉浆中加入一定量的低表面能氧化物A，结果表明涂层高温熔体对不锈钢基体的润湿性能得到不同程度的改善，且作为玻璃组份直接加入比后续磨加的效果要好。     

医用316L不锈钢表面Ta(Ti)N涂层的制备与表征

采用射频磁控溅射的方法制备了Ti含量不同的Ta(Ti)N涂层并研究了涂层的微观结构和性能.扫描电子显微镜(SEM)照片显示涂层结构致密无大的孔洞.XRD结果显示无Ti掺杂的涂层为面心立方结构的TaN,Ti掺杂的Ta(Ti)N涂层随着Ti掺杂量的增加TaN的衍射峰向高角度偏移,偏移的原因是形成了Ta(Ti)N固溶体.固溶体的形成使Ta(Ti)N涂层的纳米硬度明显高于TaN涂层的纳米硬度.Tafel外推结果表明在PBS溶液中,Ta(Ti)N涂层后的316L不锈钢的耐腐蚀性明显好于基体316L不锈钢的耐腐蚀性.血液相容性实验结果表明Ta(Ti)N涂层的血液相容性明显好于316L不锈钢基体的血液相容性.     

钼含量及水氛对电弧喷涂铝316L不锈钢高温氧化性能的影响

目前,有关高温含水气氛对金属材料高温氧化行为的影响认识不统一。采用电弧喷涂的方法在含钼量不同的316L不锈钢表面制备一层纯铝层进行改性,并通过热处理获得铝扩散层;采用光学显微镜(OM)、扫描电镜(SEM)和氧化增重(TG)等手段研究了钼含量及含水气氛对改性316L不锈钢在高温下氧化行为的影响。结果表明:低钼含量不锈钢在高温下(1 050℃)的抗氧化性能优于高钼不锈钢;同时,高温下表面铝改性低钼不锈钢在含水气氛中的抗氧化性能强于其在空气中的表现。     

Parylene coatings on stainless steel 316L surface for medical applications — Mechanical and protective properties

The mechanical and protective properties of parylene N and C coatings (2-20 μm) on stainless steel 316L implant materials were investigated. The coatings were characterized by scanning electron and confocal microscopes, microindentation and scratch tests, whereas their protective properties were evaluated in terms of quenching metal ion release from stainless steel to simulated body fluid (Hanks solution). The obtained results revealed that for parylene C coatings, the critical load for initial cracks is 3-5 times higher and the total metal ions release is reduced 3 times more efficiently compared to parylene N. It was thus concluded that parylene C exhibits superior mechanical and protective properties for application as a micrometer coating material for stainless steel implants.     

Electrochemical properties of TiN coatings on 316L stainless steel separator for polymer electrolyte membrane fuel cell

TiN films for metallic bipolar plates were synthesized by closed-field unbalanced magnetron sputtering (CFUBM) and the properties were controlled by adjusting the N₂ partial pressure. The corrosion behaviors of TiN films were investigated by potentiodynamic tests and electrochemical impedance spectroscopy (EIS) measurements under the condition of an aerated 1 M H₂SO₄ + 2 ppm HF solution at 70 °C with a constant potential of 600 mV_SCE. The results revealed that the variation of N₂ pressure had an influence on the corrosion resistance of TiN coating. N₂ partial pressure of 0.4 mTorr showed good corrosion resistance with the lowest corrosion current density and the highest charge transfer resistance due to the low porosity.     

Effect of high temperature aging on ferrite transformation kinetics and tensile properties of type 316L stainless steel weld metal

Abstract

Tensile samples of AISI type 316L weld metal, deposited by the gas tungsten arc welding process, were heat treated at 873,973, and 1073 K, before being subjected to tensile loading at an initial strain rate of 5·5 × 10^?5 S^?1 at a temperature of 427 K. The transformation kinetics of δ ferrite was studied in detail. The activation energy for the transformation of δ ferrite was found to be 272 kJ mol^?1. Theferrite transformation kinetics datafor the above three temperatures were thenfitted into a master plot using the Dorn parameter, and its validity in this temperature range was verified by superimposing the ferrite transformation kinetics data at 948 and 1023 K on to the master plot. From examinations by optical microscopy, the weld metal was found to undergo competing transformation reactions during high temperature aging, namely, dissolution of δ ferrite, precipitation of carbidesj carbonitrides and σ phase, changes in σ phase morphology, and spheroidisation of σ phase. The effect of the ferrite transformation kinetics and σ phase precipitation kinetics on the tensile properties of the weld metal were also studied in detail. The yield stresses of all the aged weld metals were lower than that of the as deposited weld metal. The σ phase had no direct influence on changes in the yield stress. The ultimate tensile strength was affected only by the quantity and morphology of σ phase. All the competing processes (except changes in σ phase morphology) significantly influenced ductility. The increase in work hardening exponent n was dependent only on the amount of σ phase and not on its morphology.

MST/1983     

Influence of sigma phase on corrosion behavior of 316L stainless steel in high temperature and high pressure water

In order to elucidate the impact of σ phase on the oxidation film formation and stress corrosion cracking (SCC) resistance of 316L stainless steel, corrosion, SCC and three-point bending tests were conducted and the microstructures of the σ phase in 316L safe-end pipes were characterized via optical microscopy, environmental scanning electron microscopy and scanning Kelvin probe force microscopy. The results indicated that the σ phase was detrimental to the SCC resistance of 316L in high temperature and high pressure environments and the existence of inherently hard and brittle σ phase could change the cracking mode.     

Mechanical properties of phosphate glass-ceramic-316 L stainless steel composites

Thermal, elastic and mechanical properties of phosphate glass-ceramic-316 L stainless steel particulate composites, prepared by flash-pressing, have been measured. Results have then been explained using various theoretical models. It is shown that particles partly shrink away from the matrix on cooling; this is due both to the slight thermal mismatch between glass-ceramic matrix and 316 L stainless steel particles and to poor bonding between both phases. This small partial shrinkage could explain both the fracture characteristics and the fair agreement between theoretical and experimental values of elastic moduli.     

表面纳米化对316L不锈钢性能的影响

对316L不锈钢进行表面机械研磨处理(SMAT),研究表面组织变化对其硬度和在0.5 mol/LNaCl介质中腐蚀性能的影响.结果表明:通过SMAT可以在316L不锈钢表面制备出纳米结构层,随着处理时间的增加,表面纳米晶组织逐渐由单一的奥氏体相过渡到奥氏体与马氏体两相共存;表面纳米化和马氏体相变能够明显地提高316L不锈钢的表层硬度,使表面粗糙度略有下降;表面机械研磨处理降低了316L不锈钢在0.5mol/L NaCl腐蚀介质中的耐蚀性能.因为316L不锈钢表面纳米晶组织容易钝化,形成的钝化膜不稳定,提高了溶解速度.