Moisture-proof and Enhanced Effect of Inorganic Coating on Porous Si_3N_4 Ceramic

Inorganic coating was fabricated on the surface of the porous Si3N4 ceramic by polymer derived（PD） and spraying technology, via using vinyl-polysilazane（PSN-1） as a preceramic polymer and Si3N4 and lithium aluminosilicate（LAS） powders as fillers. The phase and microstructure of the coatings were analyzed by X-ray diffraction（XRD） analysis and scanning electron microscopy（SEM）, respectively. The effect of the coatings on mechanical property and humidity resistance of the porous Si3N4 ceramic was investigated. The experimental results showed that we successfully fabricated the uniform and dense coating which preferably combined with the substrate upon the addition of fillers. The bending strength of the porous Si3N4 ceramic sprayed the coating increased by more than 18%, and the surface hardness increased by 1.7 times. The apparent porosity of the materials reduced by an average of 97.7%, and water absorption was below 0.5%. Therefore, the prepared coating with preferable density had an obviously moisture-proof and enhanced effect on the porous Si3N4 ceramic.

Effect of surface roughness on the surface lubrication performance of galvanized steel sheets with a self-lubricated coating

Four kinds of galvanized steel sheets having different surface roughness values were used to prepare the steel sheets with a self-lubricated coating. The effects of surface roughness on the surface lubrication performance of the steel sheets were examined using a friction coefficient tester. Results revealed large dynamic friction coefficients for the galvanized steel sheets, which increased remarkably with surface roughness. Once the self-lubricated coating was applied, significant drops in the dynamic friction coefficients were measured. After the first stage of the friction test,the coefficients were almost unchanged, which reflected a weak dependence on the surface roughness of the self-lubricated steel sheets. However, the dynamic friction coefficients gradually increased as the test progressed, where these increase clearly correlated with the surface roughness of the self-lubricated steel sheets.

The Production of Organic-Inorganic Compound Film-Coated Urea and the Characteristics of Its Nutrient Release

The effect of different concentrations of natural macromolecular compound on the characteristics of nutrient release in the membrane materials of organic-inorganic compound film-coated urea was discussed, and the optimal concentrations for better nutrient release was proposed. The characteristics of nutrient release of film-coated urea were evaluated by soil column leaching experiment. Organic-inorganic compound film-coated urea showed good characteristics of nutrient release, which could be well simulated by Logistic curve. The two parameters in this curve, a and r, can be used to present nutrient release of film-coated urea, and followed the order of B 〉 C 〉 A and C 〈 B 〈 A, respectively, indicating that the release was stronger with the increasing concentration of natural macromolecular compound in the membrane, which implied better controllability of nutrient release. The concentration of 5% of natural macromolecular compound showed better characteristic of nutrient release and can be utilized as a membrane material combined with inorganic mineral powders to develop film-coated slow-release fertilizer.

Preparation and tribological performances of Ni-P-multi-walled carbon nanotubes composite coatings

Multi-walled carbon nanotubes （MWNTs） were wet-milled in the presence of ammonia and cationic surfactant and then used as reinforcements to prepare Ni-P-MWNTs composite coatings by electroless plating. The tribological performances of the composite coatings under dry condition were investigated in comparison with 45 steel and conventional Ni-P coating, Micrographs show that short MWNTs with uniform length and open tips were obtained through the wet-milling process. The results of wear test reveal that the Ni-P-MWNTs composite coatings posses much better friction reduction and anti-wear performances when compared with 45 steel and Ni-P coating. Within the MWNTs content range of 0.74%-1.97%, the friction coefficient and the volume wear rate of the composite coatings decrease gradually and reach the minimum values of 0.08 and 6.22x10-15 m3/（N.m）, respectively. The excellent tribological performances of the composite coatings can be attributed to the introduction of MWNTs, which play both roles of reinforcements and solid lubricant during the wear process.

Effect of wear conditions on tribological properties of electrolessly-deposited Ni-P-Gr-SiC hybrid composite coating

The friction and wear properties of the electrolessly-deposited Ni-P-Gr-SiC composites were investigated. The effects of graphite content, load and rotation speed on the friction coefficient and wear resistance of the composite coatings were mainly investigated. The worn surface and cross section of the coatings were characterized by scanning electron microscopy and energy-dispersive X-ray analysis. The results show that the composite coatings reveal good antifriction and wear resistance due to the synergic effect of graphite and SiC particles. The formation of graphite-rich mechanically mixed layer （GRMML） on the surface of Ni-P-Gr-SiC coating contributes to the good tribological behavior of the wear counterparts and SiC particles play a load bearing role in protecting GRMML from shearing easily.

The Self-assembling and Application of Inorganic Anti-bacterial Material Made of Natural Nanoporous Carrier

The inorganic antimicrobial material was inhibited to the microbes with the added metal ion,Zn.The primary wet product carrying 5%-10% zinc ion was generated under the following conditions：temperature was 95 ℃,solution zinc concentration was 1.2-2.0 mol/L,and the ratio of Zn solution to zeolite weight was 5：1.The final stable product was manufactured after baking in an oven for 1-3 h at the temperature of 500-900 ℃.The baked material was tested for its disinfection effectiveness and coloring effect when mixed with paint coating.Based on the final batch of tests,the zinc content of this anti-microbial product was further optimized.

Fabrication of in-situ synthesized ceramic reinforced Ni-based alloy composite coatings by reactive braze coating processing

In-situ synthesized ceramic such as TiC,Cr7C3 and Cr5B3 reinforced Ni-based alloy composite coating was fabricated on the surface of mild steel substrate by reactive braze coating processing with colloidal graphite,Cr,Ni,ferro-boron,Si and titanium powders as the raw materials at low temperature of 1000℃,and a new kind of coating materials was developed.By means of SEM,EDS,XRD and surface hardness tester,the microstructures,phases,hardness and wear-resistance of the coating were analyzed,respectively.The results revealed that the coating was mainly composed of the ceramic in-situ synthesized reinforcement phases of TiC,Cr7C3 and Cr5B3 and the binder phases in-situ synthesized of Ni31Si12 and(Ni,Fe)solid solution;The ceramic reinforcement phases of TiC,Cr7C3 and Cr5B3 were randomly distributed in the binder phases of Ni31Si12 and(Ni,Fe)solid solution;The coating had about 15vol%pores and can possibly be applied as a self-lubrication coating;The coating and the substrate were integrated together by metallurgical bonding;The coating had a hardness up to 91-94HR15N.

Preparation and Characteristic of Self-regulation Water-transmitting Coating Fiber

Common clay, Kaolin and Bentonite were used as additives to prepare water-transmitting coating fiber, respectively, and the water-transmitting characteristic of coating fiber was studied. Different water-transmitting coating fibers were prepared by coating fiber using coating material with different mass proportions of additives to adhesive. And the coating materials were made from three kinds of inorganic clays as additives respectively and polyvinyl alcohol （PVA） as adhesive. Furthermore, the surface morphology and water-transmitting capacity of coating fiber were studied by SEM, Perkin Elmer Diamond SII thermal multi-analyzer and instrument for quick measurement moisture M30. The experimental results indicate that water-transmitting coating fibers made from three kinds of clays all have water-transmitting capacity. The surface of water-transmitting coating fiber prepared by common clay T is continuous and compact, and the water-transmitting effect is better than coating fibers made from other clays.

STUDY OF MIXED RARE EARTH METAL (REM) CONVERSIONCOATING ON ALUMINUM ALLOY LY12

The process of mixed rare earth metal (REM) conversion coating on aluminum alloy LY12 (2024) was introduced. The corrosion resistance of mixed REM conversion coating was examined by using weight loss test and electrochemical method. The results show that the mixed REM conversion coating increases the corrosion resistance of the alloy surface. Examination result of scanning electron microscope (SEM) shows that the coating exhibits honeycomb-like feature. X-ray diffraction (XRD) analysis reveals that the coating is amorphous. The result of X-ray photoelectron spectroscopy (XPS) indicates that mixed REM conversion coating consists predominantly of Ce and O. The contents of other rare earth elements (La, Pr) are relatively low.

Preparation of CuInSe_2 thin films by paste coating

Precursor pastes were obtained by milling Cu-In alloys and Se powders. CulnSe2 thin films were successfully prepared by precursor layers, which were coated using these pastes, and were annealed in a H2 atmosphere. The pastes were tested by laser particle diameter analyzer, simultaneous thermogravimetric and differential thermal analysis instruments （TG-DTA）, and X-ray diffractometry （XRD）. Selenized films were characterized by XRD, scanning electron microscopy （SEM）, and energy dispersive spectroscopy （EDS）. The results indicate that chalcopyrite CuInSe2 is formed at 180℃ and the crystallinity of this phase is improved as the temperature rises. All the CuInSe2 thin films, which were annealed at various temperatures, exhibit the preferred orientation along the （112） plane. The compression of precursor layers before selenization step is one of the most essential factors for the preparation of perfect CuInSe2 thin films.

Microstructures and Adhesive Strength of Three Kinds of Ceramic Coatings

In gas turbine engine, the study of ceramic thermal resistance coating has always been paid more attention because it can effectively reduce metal interface temperatures, improve corrosion and/or oxidation resistance and extend life. The microstructures, SEM microfractographs and adhesive strength of three kinds of zirconia plasma-sprayed ceramic coating were investigated. The results indicated that nanostructured zirconia coating have higher adhesive strength and better micro-cracking resistance properties compared with magnesia or yttria stabilized zirconia coating because its less quantities laminar internal structures and closed packed structures with less quantities and uniform distribution cavities. The sprayed power is also an important factor affecting adhesive strength of nanostructured zirconia coating.

In-situ preparation of robust self-lubricating composite coating from thermally sprayed ceramic template

The self-lubricating ceramic coatings that can control friction and wear have attracted researchers’widespread attention.However,the poor interfacial bonding between lubricants and ceramics and the deterioration of mechanical properties due to a tribological design limit their practical applications.Here,a robust self-lubricating coating was fabricated by an in-situ synthesis of MoS_(2)/C within inherent defects of thermally sprayed yttria-stabilized zirconia(YSZ)coatings.The edge-pinning by noncoherent endows hybrid coatings with excellent interfacial strength,increasing their hardness(HV)and cohesive strength.Furthermore,owing to the formation of a well-covered robust lubricating film at a frictional interface,a coefficient of friction(COF)can be reduced by 79.6%to 0.15,and a specific wear rate(W)drops from 1.36×10^(−3) to 6.27×10^(−7) mm^(3)·N^(−1)·m^(−1).Combining outstanding mechanical properties and tribological performance,the hybrid coating exhibits great application potential in controlling friction and wear.Importantly,this strategy of introducing the target materials into the inherent defects of the raw materials to improve the relevant properties opens new avenues for the design and preparation of composite materials.

油田管道防垢的超疏水涂层的制备和性能研究

为解决管道结垢带来严重的经济损失和安全隐患,将超疏水涂层喷涂在管道内壁表面形成一层保护膜,以阻止流体与管壁的直接接触,研究以环氧树脂为基体,通过添加二氧化硅和氧化铝来构建表面微纳米结构,设计制备了EP-SiO_(2)/Al_(2)O_(3)超疏水涂层,通过调控2种无极纳米粒子的添加量优化涂层配方,并考察EP-SiO_(2)/Al_(2)O_(3)复合涂层的疏水和防垢性能。结果表明,当各投入5.1%SiO_(2)和5.1%Al_(2)O_(3)时涂层附着力为1级,同时接触角可达154.6°,复合涂层的垢结量明显降低,仅为同等状态下环氧涂层的16.5%。为减少油田管道的结垢和腐蚀,提高油田的经济效益和安全效益提供可行途径。

影响无机涂料调色的因素

无机涂料调色受粉体的种类与数量、漆料中乳液的含量与种类、分散剂的种类、硅酸盐的种类的影响。选取不同的粉体、助剂、乳液、硅酸盐对无机涂料进行平行对照实验,目测其色彩变化情况。结果表明,不同的粉体、分散剂、乳液、硅酸盐均对无机颜料的调色有一定的影响,选用400目重钙做填料最佳,WJ-70做分散剂最好,J-504B做乳液最佳,硅溶胶8802做硅酸盐最好。

常见水性涂料的研究进展

水性涂料不仅环保健康,而且生产和使用安全。近年来,水性涂料的发展受到了越来越多研究者的关注,已经成为涂料工业的发展主流之一。介绍了环氧树脂涂料、聚氨酯涂料、聚丙烯酸酯涂料、醇酸树脂涂料和无机富锌涂料共5类常见水性涂料的研究现状及其应用情况,并讨论了水性涂料目前面临的挑战和未来良好的发展前景。

釉质防护涂层的湿化学法制备及劣化性能

防护涂层是提升室外工程结构耐久性的重要保障。本工作采用湿化学法在还原性气氛中制备出釉质涂层,并通过XRD、FTIR、SEM、EDS等表征手段对涂层的物相结构和微观形貌进行深入研究,同时测试涂层在冻融循环、氙灯和紫外辐照前后的形貌结构演变、铅笔硬度、附着力、光泽度及厚度变化。结果表明:涂层的微观结构为有机硅-无机硅复合网络体系,其他无机相通过有机基团及分子间的配位键共同形成致密化交联。无机相中,微细Ti和TiO_(2)粉在还原气氛中会通过高能机械化学反应生成TiO,TiO拥有较高的抗侵蚀能力。NaAlO_(2)和Al 2O 3容易包覆在未参加反应的TiO_(2)表面,屏蔽TiO_(2)光催化活性对自身耐候性劣化的影响。因此,釉质涂层耐久性优异,在冻融循环和氙灯辐照前后表面宏观/微观形貌、色泽、光泽度、铅笔硬度及附着力基本不变。釉质涂层的铅笔硬度为8H,附着力为1级,60°角光泽度为64.5GU,紫外辐照失光率为1.7%。所有劣化过程中,紫外辐照会削弱涂层的附着力,提升铅笔硬度,且减薄明显。这是由于紫外光子能量高,能促使活性的SiO_(2)发生交联反应生成有机硅,使涂层内部结构更加致密,并能断键产生CH_(2)基团,从而削弱涂层与基体的结合。本研究可为室外工程结构表面防护涂层的发展提供支持。

颜填料和膨胀防火助剂对无机膨胀型防火涂料性能的影响

以硅酸钾溶液和苯丙乳液作为成膜剂,通过控制颜填料和膨胀防火助剂的添加量,以提高无机膨胀型防火涂料的理化性能和防火性能,且通过热重(TG-DTG)、X射线衍射(XRD)、红外光谱(FT-IR)分析涂层的防火机理。结果表明:制备无机膨胀型防火涂料的最佳工艺参数是以5%的滑石粉、4%的钛白粉和6%玻璃粉作为颜填料,膨胀防火助剂白云石、氢氧化铝和可膨胀石墨添加量分别为5%、20%、2%。涂层防火性能测试后质量损失仅36.87%,且形成了新的陶瓷相。涂层在耐火1 h后,其背板最高温度为286℃,灼烧后可膨胀9.2倍左右,极大地提升了硅酸钾无机膨胀型防火涂料的理化性能和防火性能。

TEOS对有机硅基耐高温热控涂层的性能影响

目的研究不同组分有机硅基耐高温热控涂层的微观结构及光谱吸收/发射性能的演变规律,揭示涂层成分对涂层性能的影响机制。方法以正硅酸四乙酯、甲基三乙氧基硅烷、二甲基二乙氧基硅烷、3-(异丁烯酰氧)丙基三甲氧基硅烷为基料原料,以TiO_(2)、云母为功能颜料,采用溶胶-凝胶法通过有机、无机杂化得到一种耐高温热控涂层,并对涂层的物相、表面微观结构、光学性能和热稳定性进行了测试表征。结果所制得的热控涂层均具有较低的太阳吸收比以及较高的半球发射率,当TEOS物质的量比为8时,涂层具有最低的太阳吸收比和最高的半球发射率,其值分别为0.209和0.901。涂层在600℃高温下,Si—O—Si转变为SiO_(2),部分涂层表面出现微裂纹,但未与基体脱落。TEOS物质的量比为8的涂层经高温处理后的太阳吸收比最小,半球发射率最大,其值分别为0.169和0.894。结论室温固化后涂层的太阳吸收比和半球发射率与TEOS的含量有关,太阳吸收比随着TEOS含量的增多而减少,半球发射率随着TEOS含量增多而增大。并且涂层的热稳定性随着TEOS含量的增多而增大。

硅酸钾水性无机涂料的贮存稳定性及耐水性能的研究

主要研究了不同模数的硅酸钾和不同种类的有机乳胶对涂料贮存稳定性和耐水性能的影响。通过对比实验制备了涂料样品,并对涂料的黏度、耐水性、贮存稳定性等进行了表征。实验结果表明:硅酸钾模数为3.5的无机涂料贮存稳定性最好,硅酸钾模数在3.5~3.9的耐水性能较为优异;对比了纯丙乳胶、苯丙乳胶和硅丙乳胶对涂料性能的影响,结果发现使用苯丙乳胶的硅酸钾水性无机涂料贮存稳定性最好,且苯丙乳胶和硅丙乳胶的耐水性能均优于纯丙乳胶。本实验使用3.5模数硅酸钾和苯丙乳胶所制备的硅酸钾水性无机涂料性能满足TCSTM 00632.3—2022《建筑涂饰工程用涂料产品技术要求第3部分:无机建筑涂料体系》的标准要求。

无机建筑涂料的高分子有机物含量的测试方法——热失重法

无机建筑涂料的高分子有机物含量的测试,可以使用灰分法或热失重法。本文讨论了无机建筑涂料的组分的热失重特点,建立了无机建筑涂料的高分子有机物含量的热失重测试方法,并通过一组试验证明了高分子有机物含量与无机建筑涂料中的乳液添加量成正比。