环氧树脂涂层的耐冲蚀磨损性能

配制了3种环氧树脂涂层配方,测试其耐冲蚀磨损性能。结果发现,以纳米蒙脱土为填料、203#聚酰胺为固化剂的环氧树脂涂层的耐冲蚀磨损性能最佳:随着磨料粒度、磨料质量分数、试验机主轴转速的增大,冲蚀磨损率增加,攻角为45°时冲蚀磨损率最大,60°时最小;推荐最佳耐磨涂层的配方为:w(环氧树脂E-44):w(环氧树脂E一51):w(203#聚酰胺):w(纳米蒙脱土)为30:70:80:7。     

Effects of thickness and substrate on the mechanical properties of hard coatings

Nanoindentation technique was employed to characterize the mechanical properties of TiN coatings deposited on high-speed steel and stainless steel substrates. Effects of thickness and substrate on-the mechanical properties were investigated. The results show that TiN coatings exhibit different mechanical properties corresponding to the variation in thickness and substrate.     

氯化橡胶涂料在重防腐涂装中的应用

氯化橡胶涂料属于重防腐涂料。在C4严重腐蚀大气环境条件下,氯化橡胶配套涂层有5~15 a的使用寿命,性价比高。介绍了氯化橡胶涂料的优缺点,在生产及应用中存在的问题以及改性方法。建议采用水相法、非四氯化碳溶剂法生产氯化橡胶树脂,发展高固含量氯化橡胶涂料,并扩大氯化橡胶涂料在船舶制造、非标集装箱、水利电力、化工和航标制造等行业的应用。     

硅烷在油漆与涂料中的应用

介绍了硅烷在涂料中的各种最新应用,包括各种硅烷改性水性丙烯酸酯涂料、硅烷增粘底漆、硅烷溶胶-凝胶涂料及硅烷富锌底漆等。对涂料工程师在各种涂料配方中应用硅烷来提高涂料性能具有一定的借鉴作用。     

The flow of paint coatings: a hydrodynamic analysis

The flow of a viscous liquid film on a plane surface, under the influence of gravity and surface tension, is analysed mathematically, taking into account the initial surface profile of the liquid and any inclination of the underlying surface. The approach adopted is suitable for liquids such as paint where the Reynolds number is extremely low and the viscosity may be shear or time dependent. The surface profile is represented by a complex Fuorier Series and the hydrodynamic analysis centres on the biharmonic equation for the stream function. Two velocity components are derived for each point on an arbitrary initial grid and the displacements are obtained on multiplying by a short time interval from which the next grid is obtained. In this way the progress of the surface profile can be followed. Such a numerical method is eminently suitable for computer graphic simulation.     

Development of iodopropynyl carbamates as preservatives for paint and coatings

Over the last 100 years, there have been many developments in terminal iodinated acetylene chemistry. Within the iodopropynyl derivatives, it appears that over the last 30 years iodopropynyl carbamates have attracted the most attention in research, development, and industrial applications as preservatives for material protection. This article provides an overview of the chemistry and antimicrobial profiles of specific iodopropynyl derivatives suitable for use in paint and coatings as fungicides, bactericides, and algaecides. Recent chemical and antimicrobial developments of these very effective and broad spectrum 3-iodo-2-propynyl carbamate preservatives for in-can preservation, dry film protection, and marine paint are discussed. P.O. Box 165, Basking Ridge, NJ 07920.     

The effect of substrate roughness on air entrainment in dip coating

Dynamic wetting failure was observed in the simple dip coating flow with a series of substrates, which had a rough side and a comparatively smoother side. When we compared the air entrainment speeds on both sides, we found a switch in behaviour at a critical viscosity. At viscosity lower than a critical value, the rough side entrained air at lower speeds than the smooth side. Above the critical viscosity the reverse was observed, the smooth side entraining air at lower speed than the rough side. Only substrates with significant roughness showed this behaviour. Below a critical roughness, the rough side always entrained air at lower speeds than the smooth side. These results have both fundamental and practical merits. They support the hydrodynamic theory of dynamic wetting failure and imply that one can coat viscous fluids at higher speeds than normal by roughening substrates. A mechanism and a model are presented to explain dynamic wetting failure on rough surfaces.     

Solution combustion of spinel CuMn2O4 ceramic pigments for thickness sensitive spectrally selective (TSSS) paint coatings

A series of spinel-type CuMn₂O₄ ceramic pigments were prepared by a facile and low-cost sol-gel solution combustion method and used as cost-effective materials to fabricate thickness sensitive spectrally selective (TSSS) paint coatings by a convenient spray-coating technique. The chemical component, crystalline morphology, and optical property of the copper manganese oxide ceramic pigment could be accurately controlled by altering the annealing temperature. X-ray diffraction (XRD) analysis confirmed that the ceramic pigments annealed at 500 °C for 1 h coincided well with the XRD patterns of crystalline CuMn₂O₄ in the JCPDS database, and there were segregated phases of CuO and Mn₂O₃. Furthermore, the pure spinel CuMn₂O₄ phase could be achieved at 900 °C for 1 h. The copper manganese oxide ceramic pigments could serve as an effective pigment for fabricating the TSSS paint coating, and the TSSS paint coatings based on ceramic pigments calcined at 900 °C showed solar absorptance of 0.895–0.905 and thermal emittance of 0.186–0.310. In addition, the accelerated thermal stability test revealed that the TSSS paint coating exhibited good thermal stability when it was exposed to air at a temperature of 300 °C for 300 h. Hence, the fabricated TSSS paint coating could be used as a solar absorber coating in the low-to-mid temperature domain.     

Crack-bridging ability of organic coatings for concrete: influence of the method of concrete cracking, thickness and nature of the coating

Some concern about the determination of a standardised test for crack-bridging ability (CBA) measurements exists. The present work focuses on the analysis of the results of experimental tests performed to simulate the mechanical behaviour of a coating when a crack in the beneath concrete opens and grows. The influence of the method of concrete cracking, thickness and nature of the coating on the CBA are studied. Experimental results suggest that: (i) the same coating has higher CBA when the crack in the beneath concrete is produced through slight bending rather than through tensile loading; (ii) the CBA clearly depends on the nature (then mechanical properties) of the applied coating; (iii) power law relationships between CBA and thickness of the coating exist.     

水性新颜色油漆投罐及外观调试

介绍了汽车生产中涂装车间水性新颜色的投罐准备、投罐过程,外观调试与验证方法,以及遇到各种问题时的参数调整思路,以实现在非常短的时间内投入最低的调试成本,而达成理想的油漆外观水平.     

Tensile bonding strength of epoxy coatings to concrete substrate

In this study, four commercially available epoxy coatings were selected to investigate their tensile bonding characteristics to dry and wet concrete with and without 105-kPa backwater pressure. The CIGMAT CT-2 (modified ASTM D4541-95e1) and CIGMAT CT-3 (modified ASTM C321-00) tests were used to determine the tensile bonding strength of the coatings with curing time. The tests were conducted over a period of 2 years. Fifty-three CIGMAT CT-2 tests and 26 CT-3 tests were performed for the four epoxy coatings. Five failure types were identified for both the test methods based on the failure mechanisms observed during the tests. In situ bonding tests (CIGMAT CT-2, full-scale test with back pressure on) were also performed on coatings that were tested under a hydrostatic (back) pressure of 105 kPa (simulating 10 m of groundwater) for at least 6 months (full-scale test). All the coatings investigated were epoxy based, but their bonding strength and failure modes to dry and wet concrete surfaces were different. For all the coatings investigated, in situ bonding strength with dry concrete was higher than wet concrete. Epoxy-A and Epoxy-D (fiber-mat-reinforced epoxy) had good bonding strength (>1.3 MPa, 190 psi) to both dry and wet concrete surfaces during the 2 years of testing period. The bonding strength of Epoxy-B and Epoxy-C varied with time for both dry and wet concrete surfaces. Although for coatings with higher bonding strength, better correlations between the two test methods were observed, in general, the bonding strength from CIGMAT CT-3 test was higher than that from CIGMAT CT-2 test for the coatings tested.     

UV-cured fluorinated coatings for plastics: effect of the photoinitiator and of the substrate filler on adhesion

A high-performance fluorinated acrylic coating, containing perfluoropolyether chains, was applied to polyethylene and polypropylene by means of the UV-curing technique. The conditions for a good adhesion onto the plastic substrates were studied. A chemical bonding between the cured network and both the substrates was achieved when the photopolymerization was performed in the presence of benzophenone as a photoinitiator: by hydrogen abstraction from the substrate, polymer radicals were formed and could then initiate the polymerization of the acrylic species; grafting experiments of hydroxyethylacrylate confirmed this mechanism. However, the grafting reaction did not take place when the plastic substrates contained carbon black as a filler, which acted as a radical scavenger. In this case, in fact the adhesion results are not good, similar to those obtained in presence of a cleavage-type photoinitiator.     

Model for thickness effect with impact testing of viscoelastic materials

Thickness effect on impact parameters is studied and a model is developed for flat‐ended drop weight impact testing of viscoelastic materials. The model represents a relationship of specimen thickness with impact force/stress and impact energy. A polymeric material, ethylene vinyl acetate (EVA), was used for experimental verification. Experimental results for a thickness range of 1–9 mm at impact energy levels of 0.42, 0.96, and 1.54 J have been found to be in reasonable agreement with predictions based on the model with some approximated parameters. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1762–1767, 2001     

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.     

Slot die coating of lithium-ion battery electrodes: investigations on edge effect issues for stripe and pattern coatings

An important step in the production of lithium-ion batteries is the coating of electrodes onto conducting foils. The most frequently used coating method in industry is slot die coating. This process allows the reproducible preparation of thin functional films at high velocities. A phenomenon that is often neglected in scientific studies and has attracted little attention, compared to film stability, is the inevitable presence of edge effects. Film elevations appear at the coating edges and at the start of each single patch during intermittent coating. These superelevations will cause problems at the downstream cell-assembling steps. In this study the influence of dynamic and geometric coating parameters on the shaping of coating edge effects was investigated. A quantitative measurement technique for edge profiles was developed and implemented. Film stretching has been identified in literature as a main reason for edge effects. We could show that varying the coating speed and the gap ratio did not lead to ideal edges, but affected the shape of the coating edges. The elevation height appeared to be independent from the varied process parameters, in the range of investigation. Also the gradient at the very edge of the film was not affected by these parameters. Only the edge width showed a disproportionately increasing trend towards higher applied gap ratios. The results indicate that the approach of film stretching is not sufficient to fully describe the cause of superelevations in lithium-ion battery coatings.     

From single particle impact behaviour to modelling of impact mills

An approach to quantify the impact grinding performance of different materials is presented. Based on a dimensional analysis and on fracture mechanical considerations two material parameters, f_Mat. and W_m,min, are derived from theoretical considerations. f_Mat. characterises the resistance of particulate material against fracture in impact comminution. W_m,min gives the mass specific energy which a particle can absorb without fracture. Using this approach various materials in a wide size range, e.g. different polymers, crystalline substances, glass and limestone, can be characterised quantitatively. The derived material parameters are applied to the systematic and multi-scale modelling of grinding in impact mills. A population balance model is presented and the results of the simulation for two different impact mills are shown. The developed model allows for a clear separation of the influence of material properties, mill specific features and operating conditions, thus enabling a deeper understanding of the impact grinding process.     

Hydroxyapatite-based nanoparticles as a coating material for the dentine surface: An antibacterial and toxicological effect

In this study, nano sized hydroxyapatite (nHAp) and Ag(I) doped hydroxyapatite (Ag-nHAp) particles were synthesized by the precipitation method and used as a coating material for remineralization on caries-affected dentine samples. Characterization studies of both the synthesized hydroxyapatite-based particles and the coated dentine samples were performed using instrumental techniques such as SEM and FTIR, and then toxicity and antibacterial properties were also evaluated. It was observed that dentine samples were effectively coated by both nHAp and Ag-nHAp particles which have no toxic effects. Furthermore, the coating of nano-hydroxyapatite on dentine samples positively contributed to the viability of L929 fibroblast cells and also provided an antibacterial effect against to bacteria such as S. mutants, C. albicans and E. coli bacteria that are most frequently caused caries in the teeth. While all type of bacteria was eliminated by the nHAp coated dentine samples at 24th, Ag-nHAp coated dentine samples removed to all bacteria type at 1st.