影响硅橡胶涂层疏水性的因素

目的寻找影响硅橡胶涂层疏水性的因素,并找到相应的提升改进方法。方法以液体硅橡胶为基体,通过燃烧橡胶条熏附、添加纳米SiO2粉末混合和喷洒纳米SiO2粉末附着这三种不同方式,来制备超疏水表面涂层。通过改变纳米粉末的加入方式、加入质量,研究疏水性的最佳条件。并通过光学显微镜测量静态接触角评价表面疏水性能,寻找影响其疏水性的因素。结果最佳的方法为熏烧的烟尘附于液体硅橡胶涂层表面,大多数试验样本出现超疏水特性,静态接触角最高可达159°,平均值150°,静态接触角提高40°以上;次之为均匀喷洒纳米SiO2粉末,部分试验样本出现超疏水特性,静态接触角最高为145°,平均值135.5°,静态接触角提高30°~40°;简单搅拌混合的提升效果最差,没有试验样本出现超疏水特性,静态接触角最高可达124°,平均值108.5°,静态接触角只提高5°~15°。结论构建超疏水涂层的关键在于能否成功构建出微纳米的二级微观结构,简单的物理混合、搅拌会使纳米粉末被覆盖掉,无法表现出其特性。涂层的疏水能力与接触周围的实际微观长度有关。     

波前传感器电铸镍层应力实时检测精度评估

目的 搭建电铸应力实时检测平台，评估其测量精度，并探明电化学沉积过程中镍层平均内应力的变化规律。方法 采用横向剪切波前传感器搭建电铸应力实时检测平台，通过测量在铸层应力作用下电铸基底弯曲的曲率半径，利用Stoney公式计算铸层平均应力。采用参考球面反射镜评估横向剪切波前传感器曲率半径的测量精度，并在0.5 A/dm2电流密度下进行电铸应力实时检测实验，对铸层平均应力测量极限进行评估，同时对检测误差进行分析。结果 横向波前传感器曲率半径测量精度为99.22%，在0.5 A/dm2电流密度下，所搭建的铸层应力实时检测平台可测量的最小厚度为5.1 μm，由曲率测量波动带来的应力检测误差为1.3 MPa。实验测得铸层平均应力随铸层厚度的增加而变大，当铸层厚度达到30 μm左右，铸层平均应力趋于稳定，应力大小为79.7 MPa。同时发现，当铸层厚度小于30 μm时，沿电铸基底长度方向的铸层平均应力明显大于宽度方向铸层平均应力，随铸层厚度的增加，两个方向的应力大小趋于等值。结论 采用横向剪切波前传感器搭建的电铸应力检测平台，能有效对铸层应力进行高精度的实时测量，为精密电铸过程中应力变化规律的研究提供了检测技术基础。     

飞机蒙皮材料在醋酸钾型除冰液中腐蚀行为研究

目的 评价醋酸钾型除冰液能否用于飞机除冰以及对飞机蒙皮材料腐蚀性的影响。方法 采用AutoLab电化学工作站对飞机蒙皮材料在不同浓度缓蚀剂、无缓蚀剂醋酸钾型除冰液中的干湿交替腐蚀电化学行为进行分析，通过扫描电镜观察其腐蚀前后表面形貌及涂层/基体金属界面形貌。结果 无缺陷飞机蒙皮涂层在除冰液中的阻抗模值高达2.78×1010 Ω?cm2，而缺陷涂层的阻抗模值只有1.72×107 Ω?cm2，说明缺陷破坏了涂层的完整性，降低了涂层的阻抗模值，明显加速了飞机蒙皮材料的腐蚀。带缺陷飞机蒙皮试样经除冰液腐蚀不同周期后的低频区Rct存在较大变化，试样在高浓度无缓蚀剂除冰液中的Rct始终低于在低浓度溶液中的Rct；试验初期，试样在高浓度除冰液中的Rct较大，说明此时缓蚀剂浓度较高，缓蚀作用明显；但随着腐蚀周期的延长，Rct逐渐减小，说明缓蚀剂逐渐失效，高浓度除冰液的腐蚀性逐渐增强并高于低浓度除冰液。腐蚀实验后，飞机蒙皮涂层表面和涂层/基体金属界面处存在一定的腐蚀产物；人造缺陷破坏了涂层的完整性，降低了涂层的结合力，甚至产生局部剥离，造成除冰液浸入，在划痕处发生了较严重的膜下腐蚀。结论 醋酸钾型除冰液对飞机蒙皮材料存在一定的腐蚀性，尤其是当涂层存在缺陷时，腐蚀较为严重。     

纯镁表面硅烷/透明质酸钠复合涂层的结构及腐蚀性能研究

纯镁因较快的腐蚀速率使其用于手术移植材料成为了一个障碍。为了控制其降解速率,本研究采用BTSE(1,2-(三乙氧基硅基)乙烷)硅烷化处理和共键嫁接1-(3-二甲氨基丙基)-3-乙基碳二亚胺盐酸盐(EDC)/N-羟基丁二酰亚胺(NHS)交联改性的透明质酸钠涂层的两步制备工艺在纯镁上制备复合涂层。同时使用红外光谱(FTIR)、X射线光电子能谱(XPS)、原子力显微镜(AFM)和静态接触角方法(CA)分析涂层的物化性能,通过电化学行为分析涂层在模拟体液中的耐腐蚀性能。FTIR和XPS结果表明在纯镁表面上成功的制备出复合涂层;其他结果显示,交联透明质酸钠涂层表面较裸镁、硅烷表面更平整、光滑,且呈现出亲水性,提高了其生物活性;与未改性的纯镁相比,复合涂层的腐蚀电流密度减小了2个数量级,阻抗值提高3个数量级,表现出很好的耐腐蚀性能。表明这种复合涂层作为手术移植材料在医学上具有很大的应用前景。     

Zinc-doped hydroxyapatite—zeolite/polycaprolactone composites coating on magnesium substrate for enhancing in-vitro corrosion and antibacterial performance

This work is focused on developing zinc-doped hydroxyapatite—zeolite (ZnHA—Zeo) and polycaprolactone (PCL) composite coatings on magnesium (Mg) substrate to improve the corrosion resistance and antimicrobial properties. Dip-coating technique was used to coat ZnHA—Zeo/PCL on the Mg substrate at room temperature. The samples were subjected to field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), Fourier transform infrared (FTIR), energy dispersive X-ray spectroscopy (EDX) and antimicrobial potential. Results demonstrated that composite coatings consist of HA, scholzite, zeolite, and PCL phases. EDX spectra indicated the presence of calcium (Ca), silicon (Si), aluminum (Al), zinc (Zn), phosphorus (P) and oxygen (O). The composite surface appeared in spherical-like microstructure on coating with thickness ranging 226–260 μm. Zinc-doped HA—Zeo composite coating had a high corrosion resistance and provided sufficient protection to the Mg surface against galvanic corrosion. Doped ZnHA—Zeo coating samples exhibited superior disc inhibition by confirming antimicrobial activity against the E. coli as compared to HA—Zeo sample. Altogether these results showed that the ZnHA—Zeo coatings not only improved the corrosion resistance, but also enhanced the antimicrobial property and hence they can be used as suitable candidates for implant applications.     

Design,synthesis, and characterization of hybrid micro-nano surface coatings for enhanced heat transfer applications

Metal particles coating is extensively used for surface coating a wide range of application including thermal management of electronics, concentrating photovoltaics, sensors and nuclear power plants. Both micro and nano-scale surfaces have been proven to show an enhanced two-phase heat transfer performance by varying surface properties like area, wettability, and roughness. To combine the unique features of both micro and nano-scale surface coatings, this study presents the design, synthesis, and characterization of new hybrid micro-nano scale surface coating by a new two steps approach. Five different types of surfaces; namely, plain nanocoated (PNC), uniform micro-porous (UMP), uniform hybrid micro-nano porous (UHMNP), 2-D modulated microporous (MMP) and modulated hybrid micro-nano (MHMNP) surfaces were fabricated. A new two steps approach of hot-pressing followed by nucleate boiling is used for the fabrication of these surfaces. Successful coating of hybrid micro-nano scale coating was achieved. Considering the critical surface properties of micro and nanoscale coatings, new hybrid micro-nano surfaces have been characterized for SEM, wettability, roughness test. The comparative analysis of these new hybrid coating is also performed with micro coated and uncoated surfaces. With the coating of nanoparticles, the average roughness of PNC surface increased by 4.67 times and that of hybrid micro-nano particle surface by 2.3 times. The deposition of nanoparticles resulted in an increase in contact angle for PNC surface, while the contact angle of hybrid micro-nano surfaces decreases from 126.4° to 82.1°.     

Significant hydrogen isotopes permeation resistance via nitride nano-multilayer coating

This work demonstrated a significant hydrogen isotopes permeation resistance in nitride nano-multilayer coatings. Dense and homogeneous CrN/AlTiN nano-multilayer coatings with different period-thicknesses were fabricated as hydrogen isotopes permeation barriers (HIPB) to highlight the effect of interface on hydrogen isotopes permeation resistance. Deuterium permeation measurement found that the nano-multilayer coatings had much higher permeation reduction factors (PRF) than the corresponding monolayer coatings, and more importantly there was an interface-number-dependent deuterium permeation resistance where the nano-multilayer coating containing more interfaces had higher PRF. Interfaces in the nano-multilayer coatings play a key role in the significant improved deuterium permeation resistance which was explained from three aspects. Ceramic nano-multilayer coatings offer a promising alternative for the design and preparation of HIPB in the hydrogen related fields.     

机械涂覆技术在光催化材料制备中的应用进展

机械球磨技术因工艺简单、成本低廉而受到广泛关注,特别在粉体材料的混合、细化及合金化等领域有着广阔的应用前景。综述了由机械球磨原理发展而成机械涂覆技术的应用现状,包括用于材料表面改性的功能涂层和光催化降解的薄膜材料制备。分析了工艺参数、涂覆材料及涂覆基底等因素对涂覆效果（厚度）的影响规律,并对该技术在薄膜制备中表现出的简便、廉价且可在球形等形状复杂基底上成膜的独特优势做了讨论。基于当前机械涂覆技术制备的薄膜形貌、厚度不可控且成膜基底材质受限等现状,指出今后应该向拓展成膜基底材料类型和加快推进光催化薄膜材料的实际应用方向发展。     

超音速火焰喷涂WC-10Co-4Cr涂层的摩擦腐蚀性能研究

目的研究不同喷涂距离下WC-10Co-4Cr涂层的摩擦腐蚀性能,探究其机理并优化工艺参数,以提高涂层性能。方法通过超音速火焰喷涂技术在304不锈钢基体上制备WC-10Co-4Cr防护涂层,通过扫描电子显微镜和X射线衍射仪研究涂层的微观结构及相组成,采用维氏显微硬度计测量涂层的显微硬度。采用装配有电化学工作站的摩擦磨损测试仪,对浸没于3.5%NaCl盐溶液中的涂层进行摩擦腐蚀实验,测量涂层在静态及滑动条件下的磨损率、摩擦系数和极化曲线。结果喷涂距离提高时,涂层孔隙率降低,硬度提高,达到1100～1400 HV。在腐蚀介质中滑动摩擦时,WC-10Co-4Cr涂层的磨损率较304不锈钢低2个数量级,磨损率为1.7×10~(-7)mm~3/(N·m),而304不锈钢的磨损率为2.6×10~(-5)mm~3/(N·m)。结论 WC-10Co-4Cr涂层良好的摩擦腐蚀性能归因于承受负载的WC相与产生钝化的金属粘结相之间的协同作用,其抵抗涂层受摩擦腐蚀破坏。     

热处理工艺对22MnB5钢铝硅镀层氧化层厚度和组织演变的影响

目的探究奥氏体化工艺对铝硅镀层氧化层厚度和微观组织的影响规律及其演变机理。方法以热浸镀Al-10%Si的22MnB5为研究对象,采用扫描电子显微镜(SEM)、辉光放电光谱仪(GD-OES)和X射线衍射仪(XRD)等仪器,观察镀层在奥氏体化过程中氧化层厚度的变化和微观组织的演变规律。结果当试样以15℃/s的速率升温到900℃后立即水淬,镀层氧化层最薄,当试样升温到900℃保温5 min后水淬,镀层氧化层出现了不同程度的开裂,镀层表面出现孔洞和脱落的现象,氧化层厚度明显增加。结论奥氏体化保温时间比奥氏体化升温速率对镀层氧化层厚度的影响更大,保温时间越长,氧渗入镀层的深度越深,氧化层越厚,奥氏体化时间的延长不利于镀层氧化层保持完整性,影响镀层对钢基体的保护功能。镀层及其氧化层的微观组织演变规律为:镀层中首先形成Al2Fe3Si3(τ1)和Fe2Al5相,随后Fe2Al5相生长并伴随FeAl2相形成,而后FeAl2+Fe2Al5相生长且有FeAl析出,随后FeAl相生长,氧化层出现孔洞,最后氧化层破裂,镀层表面孔洞增加,最终组织为FeAl2+Fe2Al5+FeAl。