SiO_2/CrO_x/CrN_y/Al太阳能选择性吸收涂层盐雾腐蚀性能分析

对SiO_2/CrO_x/CrN_y/Al型太阳能光谱选择性吸收涂层的盐雾腐蚀性能进行测试。在35℃下经质量分数为1%、3%、5%的NaCl盐雾处理一系列时间后采用UV、VIS、NIR、FTIR、SEM等方法表征该涂层腐蚀后光学性能及表面形貌的变化。结果表明经不同浓度的NaCl盐雾腐蚀后涂层出现表面粗糙度增加、白色斑点、起泡等缺陷。光学性能的衰减规律为:吸收比呈指数衰减,发射比初期迅速增加,然后进入钝化期,最后进入过钝化期而再次迅速增加。     

表面快速沉积选择性吸收涂层的抗腐蚀性能研究

利用表面快速沉积工艺在铝基材上制备选择性吸收涂层,并对涂层的太阳吸收比、红外发射比、耐盐雾性能测试及直接暴露在户外测试等性能进行评价。结果表明:该选择性吸收涂层具有高性能、高抗腐蚀等优点,太阳吸收比为0.938、红外发射比为0.154,盐雾288 h后涂层表面无变化,在户外裸露放置3个月无腐蚀。     

SnO_2/CrON/Cu太阳能选择性吸收涂层循环热冲击性能研究

采用DC磁控溅射法制备SnO_2/CrON/Cu太阳能光谱选择性吸收涂层并进行中低温循环热冲击试验。对所制备涂层循环热冲击试验前后的光学性能和热稳定性进行表征。该涂层沉积态的吸收比为0.927,100℃发射比为0.048,在25℃/300℃的中低温下经264.25 h的循环热冲后涂层表面粗糙度几乎不变,未出现明显的元素扩散。吸收比仅衰减为0.912,发射比仅增加为0.076。表明该涂层适用于中低温光热利用领域。     

盐雾腐蚀的吸热体样品发射比测定

对不同厂家选择性吸收涂层样品进行48h中性盐雾试验,给出了相关样品盐雾试验前、后的太阳吸收比、红外发射比等性能参数.试验表明,中性盐雾48h后,样品发生明显腐蚀,其发射比会增大到盐雾试验前的6～10倍.     

Cr-N-O型选择性吸收涂层制备及热稳定性研究

采用反应磁控溅射方法制备SiO_x/Cr-N-O/Al选择性吸收涂层,该涂层太阳吸收比为95.9%、发射比3.8%、吸收发射比25.2。结合光学显微镜微观形貌分析、X射线衍射结构分析(XRD)、X射线光电子能谱成分分析(XPS)探讨涂层在250和400℃大气环境下热稳定性机理:250℃大气热处理后,涂层保持较高光谱选择性,表面形貌与物相结构未出现明显变化,SiO_x层氧化程度增大导致太阳吸收比升高,金属Cr和金属Al相互扩散导致发射比升高;400℃大气热处理后,涂层光谱选择性降低,表面出现微米级孔洞,XRD及XPS结果表明Cr-N-O吸收层被氧化,导致太阳吸收比降低,金属Cr和金属Al相互扩散导致发射比明显升高。     

不同水质的NaCl溶液对太阳选择性吸收涂层耐盐雾性能的影响

采用去离子水、自来水及饮用纯净水为溶剂分别配制浓度5%wt的NaCl溶液,用这3种不同的盐雾介质对样片进行盐雾试验。分光光度计和热发射比测定仪测试膜层实验前后的光学性能变化情况,并根据表面外观的变化,分析3组实验不同实验结果产生的原因和盐雾对选择性吸收涂层的腐蚀机理。     

AlCrON太阳能选择性吸收涂层的制备及性能研究

采用直流反应磁控溅射及空气中300℃热处理法在Cu基底上制备Al Cr ON太阳能选择性吸收涂层。对所制备涂层的光谱选择性吸收性能和热稳定性能进行表征,涂层的吸收比和发射比分别为0.921和0.075。结果表明涂层具有较高的光学性能。另外,空气中300℃、100 h热处理后涂层的光学性能几乎不变,表明该涂层适用于平板太阳集热器。     

TiAlON太阳能吸收膜的制备及高温性能衰减分析

采用直流磁控溅射制备AlON/TiAlON(LMVF)/TiAlON(HMVF)/Cu型太阳能光谱选择性吸收薄膜,并对其光学性能及高温下的衰减机理进行研究。吸收膜沉积态的吸收比和发射比分别为0.951和0.045(100℃)。在500℃的大气气氛中热处理200 h后涂层的光学性能出现小幅衰减。主要的衰减机制为薄膜在高温下O、N和Cu发生轻微扩散及氧化。结果表明AlON/TiAlON(LMVF)/TiAlON(HMVF)/Cu型太阳能吸收膜具有良好的光学性能,可适用于CSP中高温发电及民用生活等方面。     

金属表面粗糙度对太阳能选择性吸收涂层性能的影响

对金属表面粗糙度与制备太阳能选择性吸收涂层性能(吸收比α(AM1.5),发射比ε_n(80℃))之间的关系进行实验,在对实验数据进行分析后得出,金属表面粗糙度与制备涂层发射比间存在线性关系,对制备涂层吸收比影响较小。实际生产中,选择粗糙度值在0.10μm较为合适。     

先进太阳选择性吸收涂层的发展

槽式抛物面太阳场运行温度的提高,由400℃至＞450℃,能增加总太阳发电效率和减小槽式抛物面发电厂的发电成本.当前的太阳选择性涂层不具备在较高工作温度所需的稳定性和工作性能.本文目的是开发更有效的太阳选择性涂层,在高于450℃时有高的太阳吸收比(α＞0.96)和低的热发射比(在450℃时,ε＜0.07),他们在高于450℃是热稳定的,在空气中是理想的,且具有改善了耐久性和生产制造性,因此减少了成本,利用计算机辅助光学设计软件,使多层太阳选择涂层具有超过目标的光学性能(吸收比为0.959,450℃时发射比为0.070)和比一般商业涂层有更低的热损失,那些具有高热稳定性的材料用计算机模型化了,这些超过设定的目标1％的发射比约等于1.2％吸收比.关键问题是沉积涂层的方法,为了沉积这单独的一层层薄膜,为了模型化的选择性多层结构的原型,使用由离子束辅助(IBAD)和电子束(电子束)共同沉积,这是由于它的灵活性和低的材料成本,实验工作聚焦在模型化的高温太阳选择性涂层;沉积一个个单层和模型化的涂层;测量光、热、形貌和成分等性质,并利用数据使模型化和沉积特性的有效性;涂层再优化;测量涂层工作性能和耐久性,将描述开发一个耐久的和先进的选择性涂层的过程.     

太阳光谱选择性吸收涂层制备工艺探讨

探讨粘结层、吸收层、减反射层的制备工艺及基底粗糙度状态对太阳选择性吸收涂层性能的影响。采用磁控溅射法,以SS/AlN涂层为例,制备太阳光谱选择性吸收涂层,并测试性能。结果表明：合适的制备工艺可以提高膜层的结合力和涂层的整体性能,胶带粘贴无脱落,吸收比96%,500℃发射比10.5%,并证实基底的粗糙度对涂层的发射率基本无影响。     

不同吸热涂层平板集热器的热性能衰减研究

为分析不同吸热涂层平板集热器的热性能衰减,以蓝膜、阳极氧化和黑铬集热器为研究对象,基于太阳集热器热性能测试平台,对集热器热性能及空晒老化性能进行测试。分别测试吸热涂层样品的吸收比和发射比,分析空晒前后平板集热器吸收比、发射比和瞬时效率的变化情况及影响因素。研究结果表明:在温度约为18℃的工况下,蓝膜集热器热性能为75.5%,黑铬为73.4%,阳极氧化为69.3%,吸热涂层的光学性能是影响平板集热器热性能的主要因素。平板集热器瞬时效率、吸收比和发射比变化情况的依存关系为Δη≈9.553Δα-1.213Δερ,该式可衡量平板集热器的热性能衰减度。通过空晒老化性能实验可知,提高平板集热器吸热涂层的抗腐蚀、抗氧化能力,可延长集热器的使用寿命。     

平板太阳能集热器热损系数及稳定性研究

为分析空晒对平板太阳能集热器热损的影响,通过准稳态的测试方法,得出3种涂层(蓝膜、黑铬、阳极氧化)集热器的热性能.此外,也分析了总热损系数随吸热板的平均温度、环温和风速等因素的变化趋势.分析结果表明,经过长期的空晒老化,蓝膜、黑铬和阳极氧化太阳能集热器的总热损系数分别为5.072、5.246和5.996 W/(m2·K...     

塔式外置式吸热器多区域涂层优化与性能分析

为减少塔式太阳能吸热器在高温下快速增加的辐射热损,基于聚光太阳辐射的空间分布不均匀特性,提出并优化一种在吸热器表面不同入射能流区域采用不同光谱选择性吸收涂层的多区域涂层设计方法,并与均一选择性吸收涂层和传统灰体涂层吸热器进行热损性能、全天适应性和全年性能的对比分析。结果表明：在中国帕里地区,吸热器进口温度为290 ℃、出口温度为800 ℃的条件下,多区域涂层对比传统灰体涂层和均一选择性吸收涂层吸热器在典型日12月21日中的辐射热损分别降低89.8%和75.7%,总热损分别降低63.9%和38.5%;全年光热转换效率可分别提升8.1%和2.4%。     

Time-dependent corrosion behavior of electroless Ni–P coating in H2S/Cl− environment

As a mature technology, electroless Ni–P alloy coating is widely applied in the protection of chemical equipment and pipelines owing to its excellent corrosion resistance, but its application and long-term service evaluation in the field of high-sulfur oil and gas are rare. Therefore, the time-dependent corrosion behavior of Ni–P coating, which was plated on the L360 steel surface, was investigated in a saturated H₂S medium by the method of surface analysis. The results indicate that Ni–P coating with a thickness of about 52.6 μm could significantly reduce the corrosion rate compared with uncoated pipeline steel. This is related to the structure of the dense, protective film on the surface. The uncoated pipeline steel suffered local corrosion during the immersion process, and then it developed into uniform corrosion with the formation of a large number of corrosion products. In comparison, Ni–P coatings corroded relatively mildly with only a thin corroded layer. However, during prolonged corrosion testing, the corrosive medium penetrated the coating/substrate interface at inherent defects, leading to severe local corrosion of the substrate.     

SiO2包覆对La-Ni-Al-Mn储氢合金抗毒化性能的影响研究

以LaNi_3.7Al_0.75Mn_0.55（La-Ni-Al-Mn）储氢合金为基体,采用低成本的气相二氧化硅溶胶包覆法对储氢合金进行抗毒化改性研究。制备的La-Ni-Al-Mn/SiO₂复合材料表现出良好的抗毒化性能和循环稳定性,经50次循环后,合金吸氢速率保持不变,吸氢容量达1.060%。复合材料抗毒化机理为：非晶态SiO₂包覆层在热处理过程中形成原子短程有序排布的渗氢点,有效阻挡O₂、N₂等大分子气体的透过。通过对复合材料热处理工艺的优化,最终获得其最佳的热处理工艺为200 ℃下热处理2 h。     

Computations of the optical properties of metal/insulator-composites for solar selective absorbers

Solar selective absorbers are very useful for photo thermal energy conversion. The absorbers normally consist of thin films (mostly composite), sandwiched between the antireflection layer and (base layer on) a metallic substrate, selectively absorbing in the solar spectrum and reflecting in the thermal spectrum. The optical performance of the absorbers depends on the thin film design, thickness, surface roughness and optical constants of the constituents. The reflectivity of the underlying metal and porosity of the antireflection coating plays important roles in the selectivity behavior of the coatings. Computer simulations, applying effective medium theories, have been used to investigate the simplest possible design for composite solar selective coatings. A very high solar absorption is achieved when the coating has a non-uniform composition in the sense that the refractive index is highest closest to the metal substrate and then gradually decreases towards the air interface. The destructive interference created in the visible spectrum has increased the solar absorption to 98%. This paper also addresses the optical performance of several metals/dielectric composites like Sm, Ru, Tm, Ti, Re, W, V, Tb, Er in alumina or quartz on the basis of their refractive indices. The antireflection coating porosity and surface roughness has been analyzed to achieve maximum solar absorption without increasing the thermal emittance. Antireflection layer porosity is a function of dielectric refractive index and has nominal effect on the performance of the coating. While, up to the roughness of 1×10⁻⁷ m RMS, the solar absorption increases and for higher roughness, the thermal emittance increases only.     

SnO2:F coated ferritic stainless steels for PEM fuel cell bipolar plates

Ferrite stainless steels (AISI441, AISI444, and AISI446) were successfully coated with 0.6 μm thick SnO₂:F by low-pressure chemical vapor deposition and investigated in simulated PEMFC environments. The results showed that a SnO₂:F coating enhanced the corrosion resistance of the alloys in PEMFC environments, though the substrate steel has a significant influence on the behavior of the coating. ICP results from the testing solutions indicated that fresh AISI441 had the highest dissolution rates in both environments, and coating with SnO₂:F significantly reduced the dissolution. Coating AISI444 also improved the corrosion resistance. Coating AISI446 steel further improved the already excellent corrosion resistance of this alloy. For coated steels, both potentiostatic polarizations and ICP results showed that the PEMFC cathode environment is much more corrosive than the anode one. More dissolved metallic ions were detected in solutions for PEMFC cathode environment than those in PEMFC anode environment. Sn²⁺ was detected for the coated AISI441 and AISI444 steels but not for coated AISI446, indicating that the corrosion resistance of the substrate has a significant influence on the dissolution of the coating. After coating, the ICR values of the coated steels increased compared to those of the fresh steels. The SnO₂:F coating seems add an additional resistance to the native air-formed film on these stainless steels.     

Comparative study on corrosion characteristics of Al2O3/316L and TiO2/316L stainless steel in supercritical water

Al₂O₃ and TiO₂ coatings were fabricated on 316L stainless steel by atmospheric plasma spraying to improve the corrosion resistance of 316L stainless steel in supercritical water. The corrosion characteristics of the samples were evaluated in a batch reactor at 500 °C and 25 MPa with an oxygen concentration of 1000 mg/L for 80 h. The adhesive strengths of the coated samples were tested, and the weight changes, morphologies and elements distributions of the fresh and corroded samples were analyzed. Results showed that the bond strength of TiO₂/316L was 1.5 times than that of Al₂O₃/316L (26.639 N/mm²). The surface morphology of Al₂O₃/316L showed gully erosion with much pores and cracks after exposed in SCW, which provided channels for oxygen and SCW to get into the substrate and also the elements in substrate to diffuse to the surface of the coating. The corroded Al₂O₃/316L suffered significant weight loss, and most of the coatings were peeled off. However, the surface morphology of TiO₂/316L was relatively dense and the thickness of the coating was not found to decrease obviously.