紫外光固化自修复剂的微胶囊化及智能防腐蚀涂层的制备

利用在水相中原位生成的聚脲甲醛沉淀吸附在可见紫外光固化组份构成的油相表面,制备了包覆自修复剂的脲醛树脂(PUF)微胶囊. 光学显微镜及SEM表明,PUF微胶囊尺寸为118～663 μm,与PUF 形成过程中的搅拌速度有关. 在中等搅拌速度(600 r/min)时,可以得到最高的包覆率(97.52wt%)和产率(65.23wt%). 将此微胶囊掺入水性聚氨酯乳胶中制成的涂层表面受损后,在紫外光照射下可以进行自修复,具有优异的金属防腐蚀性能.     

环氧树脂对封端型水性聚氨酯树脂的改性研究

以聚醚多元醇、甲苯二异氰酸酯和二羟甲基丙酸为主要原料,丙烯酸单体封端,加入改性剂环氧树脂E-44,制备出稳定的水性聚氨酯分散体.红外光谱分析表明反应得到了水性聚氨酯结构;随着环氧树脂含量的增加,水性聚氨酯树脂粒径,黏度逐渐增大,乳液贮存稳定性下降,低温柔韧性变差,吸水率逐渐减小;甲基丙烷酸羟乙酯(HEMA)作为封端剂水性聚氨酯乳液高温稳定性优于季戊四醇三丙烯酸酯(PETA)封端剂乳液;环氧树脂改性增加了水性聚氨酯树脂的热稳定性.     

含片状金属粒子复合涂层辐射特性研究

含金属片状粒子复合涂层的涂料通常是由粘结剂(树脂类材料)、金属颗粒和其他功能助剂组成,广泛的应用于能源、建筑、航空航天和军事等诸多领域。将复合涂料涂覆于目标物体表面所形成的涂层,可实现光谱选择性调控的功能。目前的理论计算模型,主要是基于几何光学理论、经典K-M理论以及有效介质理论,大部分工作集中在含球形颗粒涂层的研究.本文将基于几何光学理论,使用蒙特卡洛射线追踪(MCRT)模型,研究片状平行随机分布铝颗粒及丙烯酸树脂复合涂层的光谱辐射特性,分析了粒子的体积分数、粒子尺寸参数对涂层光谱发射率的影响。     

磁场辅助激光熔覆制备Ni60CuMoW复合涂层

采用磁场辅助激光熔覆技术,在Q235钢表面制备了Ni60CuMoW复合涂层,借助SEM,EDS 和XRD 等表征手段对涂层进行了微观组织和物相分析,利用维氏硬度计测试了复合涂层截面的显微硬度分布,通过摩擦磨损实验和电化学测试系统研究了复合涂层的磨损性能和耐腐蚀性能。研究结果表明:涂层主要由-Ni,Cu）固溶体、硅化物和硼化物组成,Cr3Si晶粒细化且均匀致密;磁场辅助作用下,激光熔覆涂层平均显微硬度达到913HV0.5,为无磁场辅助涂层的1.5 倍,磨损失重仅为无磁场涂层的36%,自腐蚀电位上升了100 mV,腐蚀电流密度降低了70%,耐磨耐蚀性能得到了显著改善。     

邻甲酚醛环氧丙烯酸光敏树脂的合成研究

用丙烯酸对邻甲酚醛环氧树脂进行改性,合成了邻甲酚醛环氧丙烯酸光敏树脂(OCAFEE),考察了反应温度、催化剂种类和反应时间对丙烯酸转化率的影响,并提出最佳反应条件.在烯丙基/环氧基的摩尔比为0.3:1时,温度控制在95C,采用N,N-二甲苯胺作为催化剂(用量为1%),反应3h后,丙烯酸转化率可达到98.80%.     

碳化钨对激光熔覆高熵合金的影响

为了获得高性能的涂层材料,采用激光熔覆的方法,在Q235钢基体上制备了FeSiCrCoMo高熵合金涂层,并研究了WC对高熵合金涂层的组织和性能的影响。通过金相、X射线衍射、扫描电镜、硬度计、磨损试验机分别研究了添加WC前后涂层的微观形貌、相结构、硬度及磨损性能。结果表明:高熵合金FeSiCrCoMo涂层组织为粗大枝状晶,主要由BCC相和金属间化合物构成,添加WC后,涂层中形成了致密细小的胞状晶,同时BCC相增多,金属间化合物明显减少;添加WC后涂层的硬度明显增强,平均硬度提升了23%,涂层表面平均硬度达到了687HV0.2;WC的添加使得涂层的摩擦系数减小,磨损率减小,耐磨性能提高。     

激光熔覆FeCrNiMnMoxB0.5高熵合金涂层组织与耐蚀性能

为了获得性能优异的涂层材料,采用激光熔覆的方法在Q235钢基体上制备了不同Mo含量的FeCrNiMnMoB0.5系高熵合金涂层,着重探究Mo对高熵合金组织与性能的影响。通过金相、X射线衍射、扫描电镜、硬度计、电化学工作站分别研究了高熵合金涂层的显微组织、相结构、显微硬度及耐蚀性能。结果表明:FeCrNiMnMoB0.5系高熵合金组织为树枝晶,主要由fcc相和少量金属间化合物构成。当添加少量Mo时,涂层的硬度较低,为290 HV,随着Mo的增加,晶格畸变加剧,出现少量金属化合物,涂层硬度最大增加到658 HV。在模拟饱和盐水泥浆溶液中FeCrNiMnMo0.4B0.5表现出较好的耐腐蚀性。     

Si,Al对激光熔覆MoFeCrTiW高熵合金涂层组织性能的影响

为了提高材料表面的耐磨性和高温抗氧化性,利用激光熔覆技术在Q235钢表面制备了MoFeCrTiW高熵合金涂层,并采用X射线衍射仪(XRD)、扫描电镜(SEM)和磨损试验机等研究了Si,Al添加对高熵合金涂层组织、相结构、耐磨性和高温抗氧化性能的影响。结果表明:激光熔覆MoFeCrTiW高熵合金涂层组织为等轴晶,单独添加等物质的量的Si或Al时,涂层分别为共晶组织或树枝晶,同时添加等物质的量的Si和Al时,涂层组织为细小的等轴晶。各高熵合金涂层的主体相均为BCC相,随着Si,Al的添加,BCC相的晶格常数减小。添加等物质的量的Al有助于抑制涂层中金属间化合物的形成,使涂层耐磨性降低;添加等物质的量的Si则会形成含Si的金属间化合物和一些未知相,提高涂层耐磨性。激光熔覆MoFeCrTiW高熵合金涂层在800℃的抗氧化性较高,Si、Al的添加可使涂层的高温抗氧化性进一步提高。     

颜料含量对复合涂层红外发射率的作用机制研究

以聚氨酯(PU)为粘合剂,某片状金属粉为颜料,采用刮涂法制备了PU/片状金属复合涂层。对不同颜料含量条件下涂层的红外发射率进行了测试,并采用扫描电镜对涂层的微结构进行了观察。发射率测试结果表明,涂层发射率随金属粉含量增加呈“∪”型变化。微结构观察结果表明,PU/片状金属复合涂层由PU和片状金属粉交错堆叠而成,具有类似一维光子结构特征。基于涂层的微结构特征,对具有转折变化特征的4个金属粉含量点状态下涂层中一维光子结构的反射光谱进行了模拟计算,结果表明：PU/片状金属复合涂层的发射率随金属粉含量变化呈“∪”型变化关系特征主要是由涂层中一维光子结构的主反射峰中心波长随颜料含量增加所产生的蓝移现象引起的。     

6-硝基-7-二异丙基香豆素磷酸酯的结构确定

以7-羟基香豆素为原料,与硝酸在乙醇中反应得到了其硝化产物,发现硝化后的香豆素不能通过传统的Atherton-Todd反应实现磷酰化,通过改进反应条件即加入少量碳酸钾,顺利得到其相应的磷酰化产物.利用核磁共振(NMR)技术,确认得到的磷酰化产物是6-硝基-7-二异丙基香豆素磷酸酯.通过2D NMR对目标化合物的1H和13C NMR数据进行了全归属和较详细的解析,其结构进一步被X-ray晶体结构所证实.     

Comparison of anti-corrosion properties of polyurethane based composite coatings with low infrared emissivity

Four polyurethane resins, pure polyurethane (PU), epoxy modified polyurethane (EPU), fluorinated polyurethane (FPU) and epoxy modified fluorinated polyurethane (EFPU), with similar polyurethane backbone structure but different grafting group were used as organic adhesive for preparing low infrared emissivity coatings with an extremely low emissivity near 0.10 at 8-14 μm, respectively. By using these four resins, the effect of different resin matrics on the corrosion protection of the low infrared emissivity coatings was investigated in detail by using neutral salt spray test, SEM and FTIR. It was found that the emissivity of the coatings with different resin matrics changes significantly in corrosion media. And the results indicated that the coating using EFPU as organic adhesive exhibited excellent corrosion resistance property which was mainly attributed to the presence of epoxy group and atomic fluorine in binder simultaneously.     

Corrosion Evaluation of Very Rapid High-Current Vacuum Arc Coatings

The corrosion resistance of Al alloy, Ni, and stainless steel coatings deposited on 1010 steel sample anodes using pulsed high-current vacuum arcs was investigated as a function of the arc parameters. Coating thicknesses of up to 30 ?m were obtained from a sequence of six 70-ms pulses, indicating effective coating rates of up to 72 ?m/s. The thicker coatings, and the best corrosion protection, were obtained at higher currents (600-900 A) and short gaps (3 mm). The coatings were generally well bonded to the substrate. The composition of the coatings was approximately that of the source electrode. With optimal arc parameters, all three coating materials gave full corrosion protection during a 5-h salt-spray test, and Al and Ni coatings showed no signs of corrosion after a 48-h test.     

In situ formation of low friction ceramic coatings on carbon steel by plasma electrolytic oxidation in two types of electrolytes

In situ formation of ceramic coatings on Q235 carbon steel was achieved by plasma electrolytic oxidation (PEO) in carbonate electrolyte and silicate electrolyte, respectively. The surface and cross-section morphology, phase and elemental composition of PEO coatings were examined by means of scanning electron microscopy (SEM), X-ray diffraction (XRD) and energy-dispersive X-ray spectroscopy (EDS). The bond strength of the coating was determined using a direct pull-off test. The hardness as well as tribological properties of the ceramic coating was primarily studied. The results indicated that the coating obtained in carbonate electrolyte was Fe₃O₄, while the coating achieved from silicate electrolyte was proved to be amorphous. Both kinds of coatings showed coarse and porous surface. The Fe₃O₄ coatings obtained in carbonate electrolyte showed a high bonding strength to the substrate up to 20 ± 2 MPa and the value was 15 ± 2 MPa for the amorphous coatings obtained in carbonate electrolyte. The micro hardness of the amorphous coating and the Fe₃O₄ coating was 1001 Hv and 1413 Hv, respectively, which was more than two and three times as that of the Q235 alloy substrate (415 Hv). The friction coefficient exhibited by amorphous coating and Fe₃O₄ coating was 0.13 and 0.11, respectively, both lower than the uncoated Q235 substrate which ranged from 0.17 to 0.35.     

Waterborne crackle decorative coatings and crack patterns

A preparation method of waterborne crackle decorative coatings was reported in this paper and the factors that influence crack patterns were investigated. The crackle coating consisted of a waterborne basecoat and a waterborne topcoat. The basecoat was made from two-component epoxy emulsion and the topcoat was made from fluorine-containing acrylic emulsion, silicone-acrylic emulsion or styrene-acrylic emulsion. Three junction types of crack patterns were prepared by the three top coatings, which were T-junction, Y-junction and mixed junction. T-junction type with long and straight cracks was prepared from styrene-acrylic emulsion 296DS. Y-junction type with curve and short cracks was prepared from fluorine-containing acrylic emulsion A603C and mixed junctions type was made from silicone-acrylic emulsion. Crack patterns with different spacing were prepared by controlling the thickness of topcoat, dryness of basecoat or conditions of film forming. The characterize methods of type and spacing for crack pattern were developed and properties of coating film including adhesion, water resistance, scrub resistance and so on were tested. The results showed that the crackle coatings possessed satisfactory properties for practical application.     

Comparison of the protection effectiveness of acrylic polyurethane coatings containing bark extracts on three heat-treated North American wood species: Surface degradation

High temperature heat-treatment of wood is a very valuable technique which improves many properties (biological durability, dimensional stability, thermal insulating characteristics) of natural wood. Also, it changes the natural color of wood to a very attractive dark brown color. Unfortunately, this color is not stable if left unprotected in external environment and turns to gray or white depending on the wood species. To overcome this problem, acrylic polyurethane coatings are applied on heat-treated wood to delay surface degradations (color change, loss of gloss, and chemical modifications) during aging. The acrylic polyurethane coatings which have high resistance against aging are further modified by adding bark extracts and/or lignin stabilizer to enhance their effectiveness in preventing the wood aging behavior. The aging characteristic of this coating is compared with acrylic polyurethane combined with commercially available organic UV stabilizers. In this study, their performance on three heat-treated North American wood species (jack pine, quaking aspen and white birch) are compared under accelerated aging conditions. Both the color change data and visual assessment indicate improvement in protective characteristic of acrylic polyurethane when bark extracts and lignin stabilizer are used in place of commercially available UV stabilizer. The results showed that although acrylic polyurethane with bark extracts and lignin stabilizer was more efficient compared to acrylic polyurethane with organic UV stabilizers in protecting heat-treated jack pine, it failed to protect heat-treated aspen and birch effectively after 672 h of accelerated aging. This degradation was not due to the coating adhesion loss or coating degradation during accelerated aging; rather, it was due to the significant degradation of heat-treated aspen and birch surface beneath this coating. The XPS results revealed formation of carbonyl photoproducts after aging on the coated surfaces and chain scission of CN of urethane linkages.     

NiCrBSi涂层在酸性介质中耐腐蚀性能

研究了NiCrBSi涂层在沸腾的H2SO4和HCl溶液中的耐腐蚀性能,分析了其腐蚀过程.实验结果表明,NiCrBSi涂层具有良好的耐腐蚀性能,腐蚀过程主要为腐蚀剂通过涂层中的通孔进入涂层,引起腐蚀,腐蚀一定时间后,在涂层与基体之间产生腐蚀产物,涂层鼓泡.     

Preparation and properties of ceramic coating on Q235 carbon steel by plasma electrolytic oxidation

Ceramic coating was achieved on Q235 carbon steel by PEO (plasma electrolytic oxidation, PEO) without any pretreatment in sodium aluminate system. The discharge process as well as the accompanied surface morphology evolution was analyzed. The phase and elemental composition of the coatings were also investigated. The corrosion, mechanical and tribological properties of the ceramic coating were primarily studied. It is found that the coating surface was porous and the thickness of the coating was about 120 μm. The coating mainly consisted of FeAl₂O₄, Fe₃O₄ and a little γ-A1₂O₃. The corrosion current of the coated sample was 3.082 × 10⁻⁷ A/cm², which was decreased by two orders of magnitude compared with the uncoated one. The micro hardness of the ceramic coating was 1210 Hv, which was about three times as that of the uncoated sample. The friction coefficient of coated sample was also well improved. Investigations revealed that PEO provided a promising technique for preparation of protective ceramic coatings on steels.     

Development of electroless Ni-Zn-P/nano-TiO2 composite coatings and their properties

Ni-Zn-P-TiO₂ composite coatings were successfully obtained on low carbon steel by electroless plating technique. Deposits were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy-dispersive analysis (EDS) studies. The hardness and microstructure of as plated and heat treated Ni-Zn-P and Ni-Zn-P-TiO₂ composite coatings were analyzed. The change in microstructure and higher hardness was noticed for heat treated composite. The corrosion resistance behavior of as plated and heat treated Ni-Zn-P and Ni-Zn-P-TiO₂ coatings was investigated by anodic polarization, Tafel plots and electrochemical impedance spectroscopic (EIS) studies in 3.5 wt% NaCl solution. The composite coating exhibited enhanced corrosion resistance property over Ni-Zn-P coating.