抗划伤剂对聚碳酸酯/晶须硅体系性能的影响

利用抗划伤剂对质量分数为5 %的晶须硅改性后的聚碳酸酯/晶须硅体系进行抗划伤改性,通过铅笔硬度计、维卡仪、电子万能试验机和高压流变仪分别测定其改性后的抗划伤性能、热力学性能、力学性能和流变性能。结果表明,抗划伤剂对聚碳酸酯/5 %晶须硅体系抗划伤改性的最佳配方为：聚碳酸酯/5 %晶须硅/1.2 %抗划伤剂,此时的铅笔硬度达到2H。     

Scratch resistant polyimide coatings for aluminosilicate glass surfaces

Several polyimide resins were tested as possible scratch resistant coatings for aluminosilicate glass centrifuge tubes. Tubes with siloxane pretreatments provided the best adhesion between the polyimide and glass surface. Resins synthesized with an alkoxysilane group incorporated into the polyimide chain also showed improved adhesion, but the results were not as significant as when the pretreatment was used. Elastic recovery and effective Young's modulus of the polyimide coatings were calculated from nano-scratching. The results indicate that polyimides with a lower modulus, and higher elastic recovery, protected the glass surface best, exhibiting compression of the coating layer. An example was poly-4-4′-oxydiphenylene pyromellitimide (PMDA-ODA), whereas the coatings with a high effective Young's modulus and low elastic recovery ruptured. An example of a failed coating was poly-4,4′-carbonyldiphenylene 3,3′,4,4′-biphenylenetetracarboximide (BPDA-DABP) which had low amount of elastic recovery, high effective Young's modulus and a large amount of flaking during macroscratch testing.     

The influence of substrate absorbency on coating surface chemistry

The composition of the top surface of a coating layer can influence its functional properties or subsequent processing steps. The effect of the substrate absorbency on the coating surface chemistry is reported. Different coating systems containing a kaolin clay pigment, fine or coarse precipitated calcium carbonates, and a common latex binder were examined. The influence of a soluble polymer added into the coating was characterized. The surface chemistry was measured with attenuated total internal reflectance (ATR) and X-ray photoelectron spectroscopy (XPS).

Absorbent substrates generate bulky coatings with high voids and low gloss. Rapid dewatering by the absorbent substrate pulls the small particles, like latex binder, away from the top layers causing a low latex concentration at the surface. On non-absorbent substrates, the addition of the soluble polymer generates coating layers with higher void volume, lower gloss, and lower latex concentrations at the coating surface. However, on absorbent substrates, polymer addition causes coatings with lower void volumes and higher gloss. In this case, the rapid dewatering and mobility of particles is reduced by the polymer, which helps to retain the small particles at the surface. As a result, latex concentration at the surface increases with polymer addition on absorbent substrates.     

粘接低表面能材料的新型胶粘剂研究

详述了用于低表面能材料粘接的新型胶粘剂的制备过程,探讨了低表面能胶粘剂的粘接机理,并讨论了弹性体、三乙基硼烷胺络合物、丙烯酸单体等对低表面能材料胶粘强度的影响.     

辊式涂布法构建纸基牢固超疏水表面

采用辊式涂布的方法在纸基材料上构建超疏水表面,并对超疏水表面的牢固性、自清洁性和疏水性能进行评价。用γ-氨丙基三乙氧基硅烷和1H,1H,2H,2H-全氟辛基三乙氧基硅烷（POTS）对微米级和纳米级两种尺寸的TiO₂粒子进行疏水改性处理,然后将改性后的微/纳米TiO₂涂布在纸基材料表面。采用红外光谱（FTIR）对改性后的微/纳米TiO₂的化学组成进行了分析,采用扫描电镜（SEM）对涂布纸表面结构进行了表征,通过接触角、耐磨性和自洁净测试评价了涂层表面的超疏水性、牢固性和自清洁性。改性TiO₂的FTIR分析显示在1000～1500cm^-1之间出现多个C—F键的伸缩振动峰,表明POTS通过化学键与TiO₂表面发生了结合。涂布纸表面的SEM分析可以看出,纸基材料表面上均匀分布了微米和纳米尺寸的TiO₂颗粒,具备了类似荷叶表面微-纳结构的粗糙表面。涂层表面的水接触角为153°±1.5°,滚动角为3.5°±0.5°,水滴在涂层表面呈球形,极易滑落,涂层在水中浸泡7天后,接触角没有发生明显变化,表明纸张表面具备了优异的超疏水性能,且疏水稳定性较好。涂层表面经过10次循环磨损试验后,接触角仍能达到150°,滚动角为9°,表明机械摩擦没有对涂布纸表面的化学成分和粗糙结构造成明显的破坏,超疏水表面的牢固性较好。自洁净测试表明,涂布纸表面具有良好的自清洁和防污性能。该工艺过程操作简单,易于实现工业化生产,为在纸基表面构建综合性能优异的超疏水表面提供了一种新的便利途径。     

钢结构防火涂料配方的响应面法优化

引言钢结构建筑的防火历来是备受业界关注的领域,在众多保护措施当中,防火涂料因其施工方便,不受钢结构形状、面积限制,防火性能优异等优点而在钢结构建筑中广泛使用。其中超薄膨胀型钢结构防火涂料具有粒度细、涂层薄、施工方便和装饰性好等特点,能在满足钢结构防火要求的同时     

耐热涂料用颜料的选择

综述了耐热涂料用颜料的特性要求 ,提出了颜料的选择方法和颜料在耐热涂料中的应用     

Preparation and properties of low friction silicon carbide ceramic seals by pore creation

Abstract

Low friction silicon carbide (SiC) ceramic seals were prepared by combining liquid phase sintering (LPS) with pore creation, the effects of polyethylene oxide (PEO) as pore former on the sintering and mechanical properties, microstructure, and friction properties of LPS–SiC ceramic seals were investigated. The PEO firstly forms cross-linking aggregates with loose structure in SiC granules, which uniformly creates macropores on the surface and inside of LPS–SiC ceramic seals during the sintering. The addition of PEO decreases the sintering and mechanical properties of LPS–SiC ceramic seals obviously, while significantly reduces the dry friction coefficient of LPS–SiC ceramic seals. When the PEO content increases from 0 to 15 wt-%, the dry friction coefficient drops from 0·403 to 0·126. The pore creation of PEO improves the friction performances of SiC ceramic seals in sliding wear applications.     

Growth of low temperature silicon nano-structures for electronic and electrical energy generation applications

This paper represents the lowest growth temperature for silicon nano-wires (SiNWs) via a vapour-liquid–solid method, which has ever been reported in the literature. The nano-wires were grown using plasma-enhanced chemical vapour deposition technique at temperatures as low as 150°C using gallium as the catalyst. This study investigates the structure and the size of the grown silicon nano-structure as functions of growth temperature and catalyst layer thickness. Moreover, the choice of the growth temperature determines the thickness of the catalyst layer to be used.The electrical and optical characteristics of the nano-wires were tested by incorporating them in photovoltaic solar cells, two terminal bistable memory devices and Schottky diode. With further optimisation of the growth parameters, SiNWs, grown by our method, have promising future for incorporation into high performance electronic and optical devices.     

Gradient HfB2-SiC multilayer oxidation resistant coating for C/C composites

The gradient HfB₂ modified SiC coating was prepared on the surface of SiC-coated C/C composites by in-situ synthesis. Anti-oxidation behaviors of the coated C/C samples at 1773, 1873 and 1973?K were investigated. The results show that the gradient HfB₂ modified SiC coatings possess excellent oxidation resistance, which can protect C/C substrates from oxidation for 800, 305 and 100?h at 1773, 1873 and 1973?K, respectively. In addition, with the oxidation temperature increasing, the evaporation of the Hf-Si-O glass layer and the active oxidation of SiC were accelerated, which is the reason for the worst oxidation resistance of the sample at 1973?K among the three temperatures.     

船舶用低表面能防污涂料的性能研究

以一种有机硅弹性体作基料,制备了低表面能船舶防污涂料,研究了该涂料在不同温度条件下的复涂间隔、与环氧树脂涂料的配套性和防污性能。结果表明,有机硅弹性体漆与环氧防锈漆之间的复涂间隔非常窄,在环氧底漆上喷涂有机硅弹性体时必须严格控制复涂时间;有机硅弹性体漆在高温高湿下,可更好的快速固化;该涂料可以有效防止海洋生物的生长繁殖,且不释放任何重金属有害物质。     

Scratch resistant clear coats: development of new testing methods for improved coatings

More and more car manufacturers are now demanding clear coats with improved scratch resistance from their paint suppliers. Some motor companies have developed their own tests, some have chosen a test developed by a paint supplier and others are still looking for their optimum test. The opinion prevails that there should be one test which covers all aspects of realistic damage. However, microscopic photographs and reflow experiments show that two kinds of scratches occur in reality, abrasive as well as non-abrasive, renewable ones. Different standard clear coat systems have different sensitivities to both scratch types. In the scratch tests the rating of the clear coats is divergent, because the ratio of both sorts of scratches differs. We have developed a set of two tests, where each test mainly generates one scratch type. These tests, together with physico-chemical measurements (glass transition onset temperature T_g, laser optical profile scanning, indentation depths) lead to a deeper insight into scratch phenomena. One way to develop a clear coat which is resistant against all kinds of scratching damage is described.     

微电子工艺中硅衬底的清洗技术

通过研究硅片表面颗粒的吸附原理,提出了优先吸附模型,并提出改进SC-1的配方,不仅能去除颗粒,而且能有效去除有机物。介绍一些操作方法更加简单、去除更加彻底以及更加环保的清洗新技术。通过分析微电子技术的发展要求,指出今后硅片清洗工艺的发展趋势。     

Aluminum borophosphate glaze-coated aluminum alloy substrate: Coating properties and coating/substrate coupling

Thermal fatigue can cause irreversible damage in aluminum alloys restricting their use in the automotive industry, despite their excellent mechanical and technological properties. The application of ceramic coating is an alternative to obtain a protective barrier to improve the wear resistance at high temperatures. However, the low melting point and high coefficient of thermal expansion (CTE) of aluminum alloys limit the coating options. Thus, a suitable coupling feature can be obtained between aluminum alloys and a glazed coating. A glazed coating based on the aluminum borophosphate system was developed and applied onto an aluminum-silicon-copper commercial alloy. The coating was characterized by X-ray diffractometry, scanning electron microscopy, hardness tests, and thermal analysis. The coupling between the glazed coating and the aluminum alloy surface was studied employing optical dilatometry and optical fleximetry. A dense, good adhesion coating and presenting adequate dilatometric coupling (effective coupling temperature of 345 °C) related to the investigated aluminum alloy was obtained at 500 °C. The good compatibility of CTE between the layers (24.54 × 10^?6 °C^-1 for the substrate and 14.56 × 10^?6 °C^-1 for the coating) led to a crack-free material. For this reason, microhardness increased from 136 (aluminum alloy) to 325 HV (glazed aluminum alloy). The glazed coating can expand the use of this alloy, improving its performance and thermal efficiency. This result suggests an enormous potential of applications in the automotive industry, for instance.     

船舶低表面能防污涂料研究进展

本文论述了低表面能防污涂料的机理和研究进展,展望了仿生技术在低表面能防污涂料研究中的应用前景。     

粗糙度对彩色涂层与基体间附着力的影响

研究粗糙度对基体和涂层之间的附着力的影响,其一,是因为基体表面的凸凹不平导致漆膜在其上附着时产生互相咬合的现象,增大了附着力;另外,基体表面粗糙度越大其真实表面积越大,在基体表面发生腐蚀时腐蚀产物不易扩散,因此涂层附着力不易下降。     

Polymer-derived silicon nitride aerogels as shape stabilizers for low and high-temperature thermal energy storage

This work presents a new skeleton material for thermal energy storage (TES), a silicon nitride aerogel obtained through the pyrolysis of a pre-ceramic polymer. Silicon nitride offers a good combination of thermal conductivity, high-temperature resistance, and chemical inertness. The aerogel porosity can be spontaneously infiltrated with molten NaNO₃, which is a typical phase change material (PCM) in high-temperature TES. The Si₃N₄/NaNO₃ composite exhibits excellent thermal properties with a thermal energy storage efficiency of 82 %, a limited molten salt leakage, and good stability to thermal cycling. The aerogel withstands oxidation up to high temperature and is chemically inert even in contact with salts. This novel aerogel shows also a notable paraffin absorption ability (used in room temperature TES) with negligible leakage even when in contact with absorbent paper. The so-obtained composite reached ≈ 82.4 vol % of organic PCM and a thermal energy storage efficiency of ≈ 62 % compared to neat paraffin.     

Painting method for hydroxyapatite coating on titanium substrate

Coating on prostheses and implantable devices is one of the ways to increase the osseointegration of these products. However, plasma spray techniques, that are normally used, present high complexity and high cost. In this work, a new methodology for coating with nanometric hydroxyapatite is presented, with a low cost and ease of production. The technique proposed involves the formation of a suspension of hydroxyapatite (HAp) and oil of turpentine (OT) and its application, with a paintbrush, on the titanium substrate. In order to qualify the process for medical devices, the properties of the titanium substrate, before and after the coating process, the calcium phosphate phases present and the adhesive bond of the coating were evaluated. The results indicated that thermal treatment does not affect the properties of ASTM F67 titanium in order to compromise the properties and the analyses, by X-ray diffraction and Raman spectroscopy, proved that no formation of second phases of calcium phosphate occurred. The adhesive bond assay showed that the coating behaved according to ISO 13779–2, i.e., it had adhesive bond values higher than 15 MPa. The proposed new coating method proved promising for the titanium coating and is an alternative to the complex and high cost processes normally used in metal implants.     

Stainless steel as new substrate for coil coating

Increasing needs of very high resistance to cosmetic corrosion, of more extended service life and reduced maintenance costs for infrastructures, civil and industrial buildings open new fields of application for coil coated stainless steel. This paper describes the adhesion and corrosion properties of new coil coated stainless steel materials produced in industrial coil coating lines. The use of an electrochemical test (electrochemical impedance spectroscopy) can give detailed information on the reactivity of the system and allow the performance of different substrates (AISI 409, 430, 316 and 304) coated with different polymers (polyvinylidene and polyester) to be compared. The results obtained show the interesting properties of this new class of coil coated products. The materials were tested for a long time (about 200 days) in an aggressive environment (3.5% sodium chloride solution) also in the presence of macrodefects. In particular, VIVINOX 430, 304 and 316 revealed no reactivity, corrosion or disbonding, thus supporting the expectancy of very long trouble free exposure also in very aggressive natural environments. (VIVINOX is the brand name of the AST (Acciali Speciali Terni) line of coil coated stainless steel.)