PyC涂层厚度对T1000炭纤维拉伸性能的影响

本研究利用不同CVD时长制备了两种不同PyC涂层厚度的涂层炭纤维。研究了PyC涂层厚度对涂层炭纤维形貌、结构成分、精细结构以及拉伸性能的影响。研究表明:随着PyC涂层厚度增加,涂层炭纤维表面粗糙程度增加,炭材料的无定形含量减少,C有序度提高,石墨化度增加。与未涂层炭纤维相比,PyC涂层炭纤维丝束拉伸强度下降,厚度为1.99μm的PyC涂层炭纤维强度保有率为76.0%。     

什么是防腐蚀涂层的临界厚度

在各种腐蚀环境中使用的涂层,一定要达到必要的厚度,才能有效地发挥防腐蚀作用。习惯称这一必须达到的最小厚度为临界厚度。防腐蚀涂层的厚度通常比临界厚度要大,一般以150～200μm为宜。耐磨耐腐蚀涂层厚度在250～300μm为宜。     

涤纶金银丝用丙烯酸树脂涂料

一、前言真正的金银丝在我国古代就已经开始应用了。最近几年纺织工业掀起了用金银丝编织衣料的高潮,因此要求提供质量好,价格低廉的金银丝。目前国内外生产金银丝的方法,都是将涤纶薄膜真空镀铝,再以透明或有色热固性树脂涂料涂布,经分丝卷绕成丝卷,其颜色有金、银、大红、粉红、茶绿,     

涂层厚度对水性彩色反射涂料反射率影响的研究

以水为分散介质,用铁铬黑及红外反射颜料为主要颜料,以纯丙乳液为成膜物质,制成水性彩色太阳热反射涂料,有较高的反射率。颜料和成膜物质是影响涂层反射率的主要因素,除此之外,涂层厚度也对反射率产生影响。研究了水性彩色涂料反射率与涂层厚度和对比率的关系。结果表明,涂层反射率随涂层厚度和对比率的提高而增强。相同颜色涂料,当涂层透过率接近零时,涂层厚度对反射率影响随之减弱,涂层反射性能只与其表面反射率相关。     

金银丝保护层涂料中环氧交联助剂作用的研究

为改善金银丝保护层涂料的工艺,在涂料中添加了1种环氧交联助剂。通过正交试验对比了原涂料和现涂料的各项性能指标(耐酸碱蒸煮、耐有机溶剂、耐磨擦和有无柔韧性等)。采用电子扫描仪观察了涂层的表面结构。最后得出添加环氧交联助剂涂料的各项性能要好于前者而且使涂布工艺由原来的180℃×30 s降低到160℃×20 s。     

碳保护下钼金属表面MoSi_2涂层的可控制备及表征

采用活性碳粉为气氛保护介质,以NaF为催化剂,通过改良包埋渗硅工艺在钼金属表面原位反应制备MoSi_2抗氧化涂层。利用扫描电镜(SEM)、能谱分析(EDS)和X射线衍射仪(XRD)系统研究了热处理温度、热处理时间、催化剂含量和钼金属表面不同处理方式对涂层结构的影响,并分析了涂层制备机理。结果表明:采用碳保护下的改良包埋法在钼金属表面成功制备了MoSi_2涂层,涂层结构致密,且与基体之间的结合性良好。随着热处理温度的升高,涂层厚度急剧线性增加,涂层结构致密性明显提高,在1200℃得到的涂层质量最佳;随着热处理时间的延长,涂层厚度不断增加,当超过120 min后,涂层的厚度变化趋于平缓;增大钼金属表面粗糙度有利于涂层生长,可增加涂层厚度,但改变NaF用量对涂层结构和厚度的影响较小。     

镀银铜粉导电涂料的制备及性能

采用自制的镀银铜粉制备了导电涂料,研究了导电填料的用量和涂层厚度对涂层导电性的影响,以及导电涂层的抗电迁移和老化性能。结果发现,导电涂层的电阻率随导电填料的用量及涂层厚度的增加而逐渐下降,然后趋于平缓。适宜的镀银铜粉的用量为60%,涂层厚度为120μm。在100℃以内,涂层具有良好的导电性;超过100℃后,涂层电阻率急剧增大,导电性下降。含镀银铜粉的涂层较含纯银粉涂层具有明显的抗电迁移性。     

机械飞轮基体电泳沉积SiC涂层的研究

使用电泳技术在机械飞轮用30CrMo钢表面制备了SiC涂层,并研究了SiC的质量浓度对SiC涂层的厚度、表面形貌、硬度及耐蚀性的影响。结果表明:增加SiC的质量浓度有利于提高SiC涂层的厚度、硬度及耐蚀性。当SiC的质量浓度为35 g/L时,团聚作用和界面效应使得SiC涂层的厚度明显减小,表面裂纹增多,导致SiC涂层的硬度及耐蚀性大大降低。在SiC的质量浓度为30 g/L的条件下电泳沉积的SiC涂层具有最佳的硬度和耐蚀性。     

涂装涂层系统制造阶段的质量控制（Ⅳ）

6．7 湿/干涂层厚度的控制 （1）涂覆时湿膜涂层厚度的控制 一般隋况下,涂层厚度与保护寿命有近似正比例的关系,当然,需要将涂层厚度控制在合适的范围之内,否则会引起各种涂层弊病。为此,每道涂层喷涂前,要根据每层设计干膜厚度,算出湿膜厚度,然后在喷涂之前,在一块光滑平整的板上进行喷漆试验,测量出湿膜厚度的准确数,才能进行后续的喷涂工作。干、湿膜厚度的计算关系：     

正交试验法优化聚酰亚胺表面喷涂有机硅涂层的工艺参数

为了实现太阳能电池基板对原子氧的防护功能,以涂层表观形貌、最低厚度和厚度一致性作为质量评价指标,通过正交试验考察了几个主要的喷涂工艺参数对在聚酰亚胺表面制备有机硅涂层的影响。结果表明,喷嘴运行速率越快,涂层越薄;行间距越小,涂层厚度越均匀;空气压力越高,涂层表观形貌越好,但厚度一致性越差。经过第二次正交试验验证,得出优化的工艺参数为:喷嘴运行速率70～130 mm/s,雾化压力0.36～0.54 MPa,空气压力0.24～0.33 MPa,喷涂距离140～200 mm,行间距18～21 mm。在上述条件下可制得厚度为40～140μm的合格涂层。     

阳极功能层厚度对中温固体氧化物燃料电池电性能的影响

采用水系流延成型工艺,研究了阳极支撑型中温SOFC阳极功能层厚度对中温SOFC电性能的影响,运用电化学工作站对单电池的电性能进行了表征。结果表明,在相同的运行温度下,单电池的功率密度随着功能层厚度的增加而减小,而极化阻抗则相应增加;单电池的功率密度随着运行温度的提高而增大,对应的极化阻抗则减小。以H2＋3%水蒸气为燃料气,空气为氧化气,在750℃运行条件下,功能层厚度为25μm、30μm和35μm的单电池的功率密度分别为0.31 W/cm^2、0.10 W/cm^2和0.07 W/cm^2,相应的极化阻抗则分别为1.05Ωcm^2、2.41Ωcm^2和3.08Ωcm^2;阳极功能层厚度为25μm的单电池的测试温度在700℃、750℃和800℃,其功率密度分别为0.22 W/cm^2、0.31 W/cm^2和0.45 W/cm^2,对应极化阻抗分别为1.90Ωcm^2、1.05Ωcm^2和0.67Ω/cm^2。     

Ablation behavior of HfC coating with different thickness for carbon/carbon composites at ultra-high temperature

The thickness of the different HfC coatings from 20 μm to 50 μm were prepared on the surface of carbon/carbon (C/C) composites by low pressure chemical vapor deposition (LPCVD). The microstructure and thermal stress of the coatings after ablation were investigated, as well as the effect of thickness and thermal stress on the ablation resistance of the HfC coating was analyzed. After being ablated at a heat flux of 2.4 MW/m² for 60 s, the thermal stress gradually increased at first and then rapidly increased with the increasing thickness of coating. The results indicated that the moderate coating thickness can effectively release the thermal stress generated during the ablation process. The 40 μm-thick HfC coating showed the best ablation resistance with the mass ablation rate and line ablation rate were only 0.13 mg/s and 0.09 μm/s, respectively.     

Evaluation of the corrosion barrier properties of nano‐reinforced vinyl chloride/vinyl acetate coatings

A poly(vinyl chloride/vinyl acetate) copolymer (VYHH) with and without multiwalled carbon nanotubes (MWCNTs) as reinforcements were used as a coating for steel substrates to evaluate their barrier properties against corrosion. Electrical impedance and thermal properties of the coatings were evaluated. The coatings were formulated with 0.1% MWCNT, by weight. Neat and nano‐filled VYHH was used to coat polished, degreased steel substrates via a dipping method. The substrates were either dipped once, for a target coating thickness of 30–40 μm, or twice for a target coating thickness of 60–75 μm. The coated and uncoated control samples were submerged in a tank with a 5% NaCl solution for a 45‐day period. Electrochemical impedance spectroscopy (EIS) revealed that coating thickness plays a role in corrosion resistance. EIS also showed that nano‐reinforced VYHH had the highest charge transfer resistance within its coating thickness. Fourier transform infrared spectroscopy (FTIR) indicated that hydrolysis occurred in the single coatings for both the neat and nanoreinforced coatings. Differential scanning calorimetry (DSC) and thermo gravimetric analysis (TGA) both showed that the addition of MWCNTs improved the thermal stability of the VYHH. DSC thermograms revealed that the thermal properties of the nano VYHH were largely unchanged after 45 days of submersion as compared with the unaged nano VYHH. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

温度对化学镀Co-W-P合金镀层性能的影响

研究了温度对化学镀Co-W-P合金镀层的厚度、成分、表面形貌、耐蚀性和磁性能的影响。结果表明:适当升高温度有利于提高镀速和增加合金镀层的厚度,但当温度高于90℃时,镀液容易发生分解。随着温度的升高,合金镀层中钴的质量分数逐渐增大,而钨和磷的质量分数迅速降低,使得镀层的耐蚀性降低。Co-W-P合金镀层呈现出典型的颗粒结构,表面均匀、致密。高温下合金镀层表面粗糙度增大,使得矫顽力明显下降。     

Electron beam assisted physical vapor deposition of very hard TiCN coating with nanoscale characters

The work concerns electron beam assisted physical vapor deposition (EB-PVD) of titanium carbo-nitride (TiCN) on D2 tool steel. First, D2 steel substrate was heat treated to support and improve the load bearing capacity of the coating. To reduce the intrinsic gap between D2 substrate and TiCN coating and to improve the adhesive strength of the coating, a thin bond coat of Ti was EB-PV deposited on D2 steel prior to TiCN coating. The deposited coating was characterized in depth using XRD, SEM, AFM, profilometry and nanoindentation; its performance was assessed by the wear tests. The results demonstrated that EB-PVD process is successful in uniform deposition of nanograined (5.7 nm) TiCN coating; this character of the coating enhances its mechanical responses and cohesive strength. AFM topographic characterization confirms nanoscale smoothness of the TiCN coating which is a key factor in upgrading the wear resistance and tribological behavior of the coating. Nanoindentation results showed that the deposited coating is very hard; it is also tough enough. The hardness of the TiCN in this work is too much higher than those reported in the literature by similar works. AFM and nanoindentation results showed that a TiCN coating with thickness of 1.6 μm and roughness of 22 nm exhibits a hardness of 3552 HV which is much higher than those hardnesses reported in previous works. The wear tests showed that the deposited TiCN coating has a higher wear resistance than the D2 steel as well as TiN coating; this better performance is attributed to the modifications made in the coating process and its nanoscale characters.     

FPC保护膜用耐高温PSA胶带的研制

以丙烯酸-2-乙基己酯(2-EHA)、丙烯酸-2-羟乙酯(HEA)、丙烯酸(AA)和醋酸乙烯酯(VAc)为共聚单体,以环氧系列交联剂(E-5C)和苯二亚甲基二异氰酸酯交联剂(XDI)为复合交联剂,以偏苯三酸三辛酯(TOTM)为增塑剂,采用溶液共聚法制备溶剂型丙烯酸酯压敏胶(PSA);然后通过后期交联和增塑改性,制成柔性印刷电路板(FPC)保护膜用耐高温耐酸碱型PSA胶带。研究结果表明:当m(丙烯酸酯共聚溶液)∶m(E-5C)∶m(XDI)∶m(TOTM)=100∶15∶1.5∶3和干胶厚度为8～10μm时,相应PSA胶带的综合性能良好,其初始黏合力适中、耐高温性能和耐酸碱性能优异,并且其中试产品完全满足FPC加工过程的应用要求。     

Flexible graphite modified by carbon black paste for use as a thermal interface material

Polyol-ester-based carbon black pastes are used to either coat or penetrate flexible graphite, thereby increasing the thermal contact conductance of flexible graphite between copper surfaces. Paste penetration by up to an effective paste thickness (the volume of the penetrated paste divided by the geometric area of the flexible graphite) of 5 μm increases the conductance by up to 350%, 98% and 36% for thicknesses of 50, 130 and 300 μm, respectively. Paste coating up to 10 μm increases the conductance by up to 200%, 120% and 65% for thicknesses of 50, 130 and 300 μm, respectively. The paste penetration is more effective than the paste coating in enhancing the conductance, when the thickness is below 130 μm. At thickness ?130 μm, paste penetration and paste coating are similarly effective. These results stem from the relatively low interfacial thermal resistivity provided by paste penetration and the relatively high through-thickness thermal conductivity provided by paste coating. Paste penetration decreases the thermal conductivity of flexible graphite, but paste coating does not affect the conductivity. Both penetration and coating decrease the interfacial resistivity. The highest thermal contact conductance is 1.4 × 10⁵ W/m² K, as provided by paste-penetrated flexible graphite of thickness 26 μm.     

低温固化环氧阴极电泳涂料的制备

采用乙二醇单丁醚和甲乙酮肟对甲苯二异氰酸酯(TDI)进行全封闭,并将其加入到二乙醇胺改性的环氧树脂乳液中进行混合搅拌,制备了一种低温固化环氧阴极电泳涂料。研究了封闭反应温度、TDI用量和接枝反应温度对漆膜性能的影响,确定了适宜的工艺条件:甲乙酮肟封闭反应温度为40°C,接枝反应温度80°C,TDI质量分数为15%左右。在此条件下制备的漆膜可以在150°C/30min的条件下固化,所得漆膜厚度20μm,光泽70°,附着力1级,柔韧性1mm,铅笔硬度3H,冲击强度>50kg.cm,耐水性>800h,达到设计要求。     

Microstructure,adhesion, and tribological properties of conventional plasma-sprayed coatings on steel substrate

A variety of metallic and oxide coatings were deposited under various conditions on 1020 mild steel substrate by conventional plasma spraying. The coating thickness, microhardness, cohesion and adhesion failure loads, friction coefficient, and abrasive wear resistance were evaluated. The coatings were classified as follows, in order of decreasing microhardness and wear resistance: alumina, chromia, 316 stainless steel, Ni-5% Al, elemental aluminum and aluminum-polyester. Wear resistance increased with increasing microhardness and decreasing friction coefficient. The microhardness and wear resistance of high-velocity oxy-fuel (HVOF) diamond jet (DJ)-sprayed aluminum were found to be superior to those of plasma-sprayed aluminum. Plasma or flame-sprayed metallic coatings adhered well to the substrate. The cohesion, adhesion, microhardness, and wear resistance of alumina coatings exceeded those of equally thick chromia coatings.     

High performance environmental barrier coatings, Part I: Passive filler loaded SiCN system for steel

A novel environmental barrier coating system for steel consisting of a perhydropolysilazane (PHPS) bond coat and a polysilazane-based glass/ceramic composite top coat has been developed. After stabilising the coating slurries, double layers were applied on mild and stainless steel substrates by the dip-coating technique. Parameters like pre-treatment of the steel substrates, filler systems, particle size of the fillers or coating thickness were varied to optimize the coatings. The thermal treatment was performed in air at temperatures up to 800 °C. Microstructural analysis by SEM and XRD revealed the formation of a coating system consisting of a SiNO bond coat and a ZrO₂-filled glass/ceramic top coat. A uniform, well adherent, dense and crack-free coating system with a noteworthy thickness up to 100 μm was achieved. Even after cyclic oxidation tests on coated samples at 700 °C the coating system was still undamaged and no oxidation occurred on the mild steel substrates.