耐高温厌氧胶的油面粘接性能改进

以乙氧化双酚A二甲基丙烯酸酯(BPA 2EODPT)、环氧丙烯酸酯(EA)和甲基丙烯酸羟丙酯(HPMA)为主体材料,BMI为耐热改性剂,添加SiO 2等无机填料以及Span 85等表面活性剂,制备出油面粘接性好的耐高温厌氧胶。结果表明,以破坏扭矩、平均拆卸扭矩、油面粘接强度损失率为考查指标,当w(SiO2)=4%~6%、w(Span 85)=0.4%时,油面粘接性能较优。     

Joining zirconia with nickel-based superalloys for extreme applications by using a pressure-free high-temperature resistant adhesive

In order to meet the high demand for joining ceramic/superalloy composite structure in extreme environments, a novel high-temperature resistant adhesion technique was developed for joining ZrO₂ and Inconel 625 by applying an aluminum phosphate emulsion/zirconium sol based adhesive. With increasing temperature, a series of reactions occurred in adhesive, and its high-temperature bonding was attributed to the formation of a composite structure containing various ceramics and intermetallics. The adhesive after RT curing could find direct applications in extreme environments, and provide bonding strength no less than 2.5 MPa in the temperature range of RT-1100 °C. The bonding strength was higher than 4 MPa in the temperature range of 800–1000 °C, which was further attributed to the formation of an effective CTE-gradient relationship among ZrO₂, adhesive and Inconel 625, as well as the interfacial reactions between the two substrates. The work broadened the application of adhesion technique and brought new ideas for joining dissimilar engineering materials.     

环氧树脂胶粘剂工程应用研究

采用某种型号的环氧树脂(EP)胶粘剂胶接LY12-CZ铝合金试片,在110～170℃范围内加热4 h后测定胶接件的剪切强度,并对该胶接件的不同加载速率与拉伸剪切强度的关系进行了研究。结果表明:短时高温加热对该胶粘剂的剪切强度没有影响,这有利于飞机组件的整体修复;拉伸剪切强度随着加载速率的增加而增大,这又为探讨加载速率对不同胶粘剂性能的影响提供了试验依据。     

Advanced high-temperature (RT-1100°C) resistant adhesion technique for joining dissimilar ZrO2 ceramic and TC4 superalloys based on an inorganic/organic hybrid adhesive

To meet the high demand for ceramic/superalloy composite structural components in various fields, an advanced high-temperature adhesion technique was firstly developed by preparing a novel inorganic/organic hybrid adhesive suitable for ZrO₂ and TC4. Chemical bonding started to work at ～600°C, and became the crucial bonding mechanism at elevated temperatures. The formation of ZrSiO₄ and Ti₅Si₃ at the interfaces of two substrates not only increased the interfacial connection strength, but also formed two gradient layers with a size of ～2 μm to effectively alleviate the difference of composition and performance between the adhesive and substrates. In the temperature range of 500–900°C, the matching degree of CTE among ZrO₂, adhesive and TC4 is higher, and the maximum difference does not exceed 3×10^-6 K^-1. Meanwhile, the formation of a composite structure containing various ceramics (ZrO₂, SiC and ZrB₂) and intermetallics (Ni–Si, Al–Ni), and the improvement of structural compactness of adhesive from 500 to 900°C greatly improved the bonding strength to the maximum value of 31.4 MPa at 900°C. Also, the adhesive pretreated at 900°C showed good thermal cycling resistance, and the strength was still higher than 15 MPa after 50 cycles. For cured adhesive, when used directly in an extreme environment, it can provide bonding strength not less than 5 MPa in the whole temperature range, indicating that the adhesive possessed potential emergency repair convenience. This work significantly broadened the application of high-temperature-resistant adhesion technology in the connection of dissimilar ceramics and alloys.     

Fabrication of in-situ self-reinforced Si3N4 ceramic foams for high-temperature thermal insulation by protein foaming method

To meet demand for lightweight and high-strength ceramic foams, in-situ self-reinforced Si₃N₄ ceramic foams, with compressive strength of 13.2–45.9 MPa, were fabricated by protein foaming method combined with sintered reaction-bonded method. For comparison, ordinary protein foamed ceramics with irregular block microstructure were fabricated via reaction-bonded method, which had compressive strength of 3.6–20.5 MPa. Physical properties of these two types of samples were systematically compared. When open porosity was about 80%, both types of Si₃N₄ ceramic foams had excellent thermal insulation properties (<0.15 W m^?1 K^?1), while compressive strength of in-situ self-reinforced samples increased by more than 158% compared with ordinary samples. Under high-temperature oxidation conditions, microstructures of both types of samples were deformed with increase in oxidation temperature. Moreover, after oxidation temperature was increased to 1400 °C, oxidation weight gain decreased from 18.07% for ordinary samples to only 2.18% for self-reinforced samples. Thus, high-temperature oxidation resistance of Si₃N₄ ceramic foams was greatly improved.     

Graphene modified phosphate-based metal/ceramic composite coating for corrosion protection in the high-temperature marine environment

Graphene-modified phosphate-based metal/ceramic composite coatings were prepared for corrosion protection in the high-temperature marine environment. The morphology and structure of the coating were observed by SEM, and the high-temperature anticorrosion performance of the coating was analyzed by electrochemical measurement and salt spray-high temperature cycle test. The results showed that the addition of 0.1 wt% graphene could bridge the aluminum particles inside the composite coating and extend the sacrificial anode protection time of the coating in the 3.5 wt% NaCl solution from less than 4 days to more than 8 days, thus avoiding the local failure of the coating and improving the anticorrosion performance. Besides, the addition of graphene nanosheets at low content also enhanced the physical barrier effect of the coating and prolonged the penetration path of the corrosive medium without destroying the structure of the composite coating.     

磷酸结合的锆英石捣打料在陶瓷熔块池炉中的应用

采用磷酸结合锆英石捣打料捣制锆英石流出口砖和捣打池炉底，明显地提高了池炉底和流出口的抗熔体侵蚀性能，延长了熔块池炉的大修周期，不但保证了所熔制的陶瓷熔块质量，而且降低了产品成本。     

高温熔烧法制备金属基陶瓷涂层的研究

以玻璃熔块、氧化铬粉、粘土粉和硅酸锆微粉为原料制成的涂料,用滚涂法将其均匀涂覆在不锈钢管上,经高温(1000~1050℃保温20min)熔烧制备出了耐磨、抗高温氧化的陶瓷涂层。对陶瓷涂层的耐磨性、抗高温氧化性、抗热震性等性能进行了测试,并对影响涂层性能的因素进行了研究。结果表明:引入具有较大热膨胀系数的玻璃熔块料有利于提高涂层结合性;加涂层的试样均能明显改善基体的耐磨性和抗高温氧化性。涂层的耐磨性随硅酸锆微粉加入量的增加而提高,加入量为15%时耐磨性和抗热震性最好,其热震循环(1000℃空冷)可达22次。