Mechanical seal faces frequently operate under harsh and dynamic conditions, where maintaining stable and efficient lubrication remains a critical challenge. Surface texturing has emerged as an effective approach to improve the lubrication and tribological performance of sealing end faces. This study investigates the lubrication behavior and sealing characteristics of squamous textured mechanical sealing faces through a combination of sealing experiments and mixed lubrication modeling. The results indicate that during start-up, increasing rotational speed enhances the load-carrying capacity and reduces contact force, resulting in thicker lubricant films and lower friction coefficients. Consequently, the sealing interface gradually transitions from mixed to hydrodynamic lubrication. Moreover, with increasing medium pressure, both the critical rotational speed and duration required for this lubrication regime transition increase. Under various steady periods, smooth seal faces predominantly operate in the mixed lubrication regime, whereas textured faces maintain hydrodynamic lubrication, reducing the average friction coefficient and temperature rise by 69.5% and 51.8%, respectively. These findings provide crucial insights into the performance improvement and practical applications of squamous textures for high-efficiency, long-lifespan mechanical seals.

Combining surface texturing and solid lubricant coating is an effective approach to improve tribological performance and service life in surface engineering. However, few studies have systematically compared texture types and their adaptability to varying working conditions. In this work, a textured composite coating with a three-level gradient structure (interface texture-coating-surface texture) was prepared via plasma spraying and laser texturing. Reciprocating dry friction tests were carried out to compare the tribological properties of dimple, linear, and sinusoidal textures. The effects of normal load and sliding speed on friction and wear behavior were investigated. Results demonstrate that the average friction coefficients follow the order: non-textured coating > dimple-textured coating > linear-textured coating > sinusoidal-textured coating. The sinusoidal texture provides the lowest friction coefficient and superior debris capture and storage capacity, which effectively mitigate abrasive wear, adhesive wear, and fatigue spalling, leading to optimal friction reduction. Increasing the load moderately reduces the friction coefficient, but the coating fails rapidly due to severe plastic flow and adhesive tearing when the load exceeds 100 N. The textured composite coating presents favorable velocity adaptability with a friction coefficient reduced by 23.8%-41.3% relative to the non-textured coating. Yet the texture fails rapidly when the sliding speed exceeds 100 mm/s because of intensified adhesive wear and plastic deformation.

The adhesive bonding of high-pressure die-cast (HPDC) aluminum alloy AlSi10MnMg is extensively applied in the aerospace and automotive sectors. Surface pretreatment of HPDC aluminum prior to bonding is crucial for enhancing bonding strength and durability, as it regulates surface roughness, and chemical properties. Traditional multi-step surface treatments including chromic acid anodizing for HPDC AlSi10MnMg are hazardous, complex, and often fail to balance adhesive bonding durability and corrosion protection, limiting their industrial applicability. This study examined the impact of various chemical treatments on the adhesive bonding performance of an AlSi10MnMg aluminum alloy. The treated surfaces were bonded using a structural adhesive, and bonding performance was evaluated via wedge tests under pristine conditions and after accelerated aging. A scanning electron microscope (SEM) was used to study the surface morphology, chemical composition, and corrosion characteristics of the treated surfaces. Energy dispersive spectroscopy (EDS), electrochemical impedance spectroscopy (EIS), and potentiodynamic polarization measurements were employed. Excellent adhesion characteristics, dominated by the cohesive failure of the adhesive, were observed in H2O2-treated samples. The H2O2-treated samples exhibited the shortest initial crack length, indicating a superior baseline bonding quality, and showed minimal crack propagation (only slight extension) after aging under extreme environmental conditions (70 °C and 100% relative humidity for 4 weeks). Electrochemical measurements revealed that the SG200-treated sample achieved the lowest corrosion current density (0.25 ± 0.03 μA/cm2) with an excellent corrosion resistance, while sol–gel-treated samples generally suffered from a poor adhesion, with interfacial failure. This study proposes a simplified, single-step chemical treatment using an H2O2 solution that effectively achieves both a strong adhesive bonding and an excellent corrosion resistance, without the drawbacks of conventional methods. It offers a viable alternative to conventional multi-step hazardous surface treatments.

The novel application of laser surface texture as a method for enhancing the deposition of coatings on substrates has garnered significant interest. This study focuses on the use of atmospheric plasma-sprayed Mo–NiCrBSiCFe coating, which was applied to both laser surface textured and grit-blasted AISI 304 substrates. The coating powder was created by mechanically milling a mixture of 25 % molybdenum and 75 % NiCrBSiCFe powders, providing a unique combination of materials for the deposition coating. The analysis zeroed in on examining the effects of laser texture grooves on the microstructure, porosity, microhardness, and adhesion strength of the composite coating. The findings revealed that the composite coating primarily comprises MoO2, Mo, and Ni phases. In comparison to the grit-blasted substrate, the coating applied on the laser-textured groove substrate exhibited a porosity increase of 15.15 %, a pore size rise of 17.45 %, a notable 45.62 % improvement in adhesion strength, and a significant 23.57 % enhancement in scratch resistance. Furthermore, the coating on the laser-textured substrate exhibited fewer closed pores. The microhardness of the coating surface was higher than that of the coating cross-section within the grooves. Notably, the laser surface texture had a significant impact on the adhesion strength, microstructure, and hardness of the composite coating, surpassing the results achieved through traditional grit blasting. One novel observation from this study is that laser surface texturing can have a significant impact on the porosity of Mo–NiCrBSiCFe coatings. Another noteworthy finding is that laser surface texturing can enhance the hardness of Mo–NiCrBSiCFe coatings.

The structural adhesive bonding of aluminum is widely used in the aircraft and automotive industries. The surface preparation of aluminum prior to adhesive bonding plays a significant role in improving the bonding strength. Surface cleanliness, surface roughness, and surface chemistry can be controlled, primarily, by proper surface treatment methods. In this study, the effect of varying the chemical treatment period on the adhesive bonding characteristics was investigated. An epoxy adhesive was used to join the treated surfaces, and the bond strengths were evaluated via single lap-shear (SLS) tests in pristine, as well as degraded, conditions. The surface morphology, chemistry, and corrosion properties of the surfaces with chemical treatments were characterized using various surface analytical tools, such as scanning electron microscopy, an energy dispersive spectrometer (SEM/EDX), and an electrochemical workstation. Excellent adhesion characteristics, with the complete cohesive failure of the adhesive, were encountered on the surfaces of the H2O2-treated samples. The H2O2-treated samples exhibited the highest initial bond strength, reaching 22.5 ± 0.5 MPa, and showed a decrease of only 10% (to 18.1 ± 0.2 MPa) after aging under extreme humidity and temperature conditions (70 °C and 100% R.H. for 4 weeks). The chemical treatment reported in this work is a very simple method to produce durable joints.

The textured sealing surface increases opening force, but it is often accompanied by a high leakage rate. This study proposes a novel squamous texture and develops a fluid lubrication model to calculate its sealing performance, then optimizes the design parameters of the squamous texture by combining the response surface methodology and NSGA-II multi-objective optimization algorithm. The results indicate that the squamous texture has excellent hydrodynamic effect. The load-carrying capacity and leakage rate of the oil film both increase with the rise of the rotation speed. The depth of the squamous texture has a significant impact on the load-carrying capacity. Meanwhile, the depth, width, area proportion, and ratio of major and minor axes of the squamous texture sequentially affect the leakage rate. The multivariate equations for texture design parameters and sealing performance were obtained using the surface response methodology. At last the Pareto frontier solutions for high load-carrying capacity and low leakage rate were obtained through the NSGA-II multi-objective optimization.

The work focuses on the optimization of surface texturing and their geometrical characteristics to improve the sealing performance of mechanical seal. The hydrodynamic model is developed to predict the sealing performance of four textures, including dimple, triangle, chevron and squamous textures. Result indicates that the squamous texture exhibits better sealing performance with high ratio of load-carrying capacity to leakage and ratio of oil film stiffness to leakage at various angular speeds and pressures. Furthermore, the functions of squamous texture characteristics with the load-carrying capacity and leakage ratio are revealed by the response surface methodology. And the squamous texture is optimized with high load-carrying capacity and low leakage ratio through the multi-objective optimization algorithm NSGA-II to achieve the Pareto-optimal set.

Reasonable texture intervals can effectively generate a local dynamic pressure effect and promote the tribofilm formation. A friction experiment combined with simulation analysis is employed to investigate the effect mechanism of sinusoidal texture intervals on surface friction properties. The synergistic antifriction mechanism between the hydrodynamic pressure effect of texture and the tribofilm is discussed. The results display that synergistic texture lubrication has a beneficial effect on improving tribological properties. The surface with a textured area density of 25% displays the optimal tribological properties. Moreover, friction reduction mechanism under different working conditions is discussed. Higher sliding speed is beneficial to anti-friction property by promoting dynamic pressure lubrication, while larger load mainly facilitates the formation of surface friction film to reduce friction.

为提升设计专业学生学习自主性以及创新实践能力,解决课堂低头族、手机族问题,在"互联网+"背景下,将基于"惟真学堂+BOPPPS"的新型教学模式应用于设计类本科以及研究生课程实践教学中,探索如何充分利用移动互联网环境开展线上线下混合式教学实践,以促进设计类课程中实践教学部分的提升.以"文化创意产品设计"为例进行教学设计,对教学过程和教学效果进行总结反思.实践证明,基于"惟真学堂+BOPPPS"模式的教学设计可以激发学生学习动力,改善设计实践教学效果,为设计类课程实践教学改革提供借鉴.

Controlling surface wettability inspired by nano structure of lotus leaf has attracted much attention. The superhydrophobicity on the metals is significant for the applications including water repellence, self-cleaning, anti-corrosion, and reduction of drag. Herein a near superhydrophobic surface of 5051 aluminium has been fabricated by employing a combination of nanosecond laser texture and heat treatment, without using any toxic chemicals. The aluminium surface was textured by fibre nanosecond laser and then heat treated at 150 °C to create the near superhydrophobic surface. The evolution of heat treatment time with respect to contact angle measurements has been investigated. The contact angle became 0° when processed by two different kinds of laser textures (sinusoid pattern and grid pattern). The influence of heat treatment on the wettability of the laser textured aluminium surface was studied. The contact angle exhibits 134.88° and 136.97° for sinusoidal pattern and grid pattern with 72 hours heat treatment, respectively. The mechanism for fast wettability conversion time is discussed. This method is a rapid and environment-friendly process, which is feasible for fabrication.

Reasonable texture area density can effectively form continuous oil film and improve the surface tribological properties. The combination of friction experiment and simulation analysis studied the influence of sinusoidal texture surface density on the surface friction performance, and also discussed its influence on the surface oil retention behavior. The experimental results and simulation analysis show that the texture synergistic lubrication has a significant positive correlation with the tribological properties. Moreover, it is noticed that tribological properties are more sensitive when the smaller texture interval is employed. And when the texture interval is 0.216 mm, the effect of sinusoidal texture on surface wettability and dynamic pressure lubrication is more significant. The results of this research contribute to better understanding of sinusoidal texture friction mechanism.

Researchers have been concentrating on enhancing the surface tribological properties and minimizing wear on mechanical components during the oil starvation stage. In this work, a nanosecond laser was used to prepare sinusoidal textures of different amplitudes on the surface of 40Cr alloy steel, and then the obtained surfaces were pre-oxidized at 100 degrees C, 300 degrees C, and 500 degrees C, respectively. The results demonstrated that excessively large or small amplitude values would reduce the wear debris trapping ability of the textures, which ultimately affected the formation of the tribofilm. In addition, the numerical simulation results reveal that the texture pressure differ-ence is positively correlated with the texture amplitude, but excessively high or low amplitude leads to a sig-nificant micro-vortex effect within the texture. The tribological properties of the textured surfaces could be further enhanced by the pre-oxidation treatment. The experiment results indicated that the pre-oxidation treatment increased the degree of surface oxidation and promoted the formation of tribofilm. This work will pave the way to improve surface tribological properties by integrating sinusoidal textures and self-generated tribofilm.

Texture parameter was an important factor affecting tribological property. In this work, the friction experiments and orthogonal analysis method were combined to investigate the effects of texture parameters on the tribological properties of sinusoidal-textured Ni-based MoS2 coatings under dry conditions. Results showed that only the texture area ratio, width-depth ratio, and angular velocity have significant effects on the tribological properties, and the influence order was as follows: area ratio > angular velocity > width-depth ratio. Good tribological properties could be obtained when the texture area ratio was 9-10%, the angular velocity was 6 rad/ s, the width-depth ratio was 0.67-1.36, the amplitude was 0.1 mm, and the relative motion angle was 90 degrees.

高校专业课课程思政建设是构成完整的思政教育体系的必备途径,工业设计专业课程中蕴含了丰富的思政元素,OBE理念下,系统分析课程中的专业知识模块,制定相辅相成的教学目标和思政目标,并开展思政元素挖掘、承载与表达形式一体化的研究,建立从课上到课下、从理论到实践、从学生到教师的系统化、立体化全方位育人的长效机制,并推动教学方法、教学模式、课程考核等一系列教学改革创新.最后以《工业设计概论》为例,进行了课程思政改革实践,以期为工业设计专业课程思政融入提供经验.

针对深部煤层气井颗粒组分复杂且地温较高的特点,基于油气井砂沉降公式引入颗粒组分占比,综合考虑颗粒组分及井液温度的影响,推导出适用于深部煤层气井垂直井筒的颗粒沉降末速计算公式.并利用液携试验台进行试验,揭示深部煤层气井垂直井筒液流携带颗粒运移特性.结果 表明:煤层气并井筒中存在漂浮物形式的低密度煤质颗粒,该部分颗粒在井液流速很低时随井液排出井筒;随着井液流速增加泥质颗粒开始排出井筒,在流速达到0.05～0.06 m/s范围时,颗粒携带率达到稳定期;此后流速继续增大,较小的砂质和夹矸等颗粒随井液排出,当井液流速达到0.08 m/s时,颗粒携带率基本稳定.试验过程共出现3个稳定期,造成这种现象的原因是煤层气井煤质、泥质、砂质及不同比例混合颗粒导致颗粒组分复杂,这也正是煤层气井液携颗粒与油井携砂的主要区别.这为经济有效的解决煤层气井煤粉颗粒沉积问题、设计井筒排煤粉方案奠定了基础.

Continuous and proper oil lubrication between the friction pair can reduce wear and increase service life of mechanical components. In this paper, the friction experiment and finite element analysis method are combined to study the tribological properties and oil retention mechanism of sinusoidal textured under various width-depth ratios and oil supply. The results indicate that the sinusoidal texture can improve tribological property. ST-3 (the width-to-depth ratio is 1.35) has optimal oil retention property. Compared with untextured specimens (UT), the wear and friction coefficient of ST-3 are reduced by 74% and 7.7%, respectively. Furthermore, the maximum positive pressure is proportional to the non-friction area. This research provides a basis for the optimization design of texture.

针对深煤层地温较高的特点,综合考虑井液流速、管壁粗糙度及井液温度等因素的影响,对深部煤层管壁煤粉黏附机制进行分析,推导出深部煤层气井管壁黏附煤粉最大粒径计算公式,并进行煤粉黏附旋转挂片试验,以揭示深部煤层开发管壁煤粉黏附特性.结果表明:煤粉黏附特性主要受井液流速、管壁粗糙度、温度等因素影响,在其他条件不变时,井液流速增加到1.5 m/s及以上时粒径大于20μm的煤粉颗粒不再产生黏附现象;管壁粗糙度由32μm降到16μm可以使煤粉最大黏附粒径由40μm降到20μm;温度由40℃降至20℃可以使最大黏附粒径由26μm降到20μm.由此揭示深部煤层气井煤粉黏附更为严重的原因,可以为经济有效地解决管壁煤粉黏附问题,制定合理的排采策略奠定基础.

In this study, atmospheric plasma spraying was used to deposit molybdenum coatings on stainless steel substrates with laser-textured groove patterns and grit blasting substrate pretreatment. The groove depth and width were controlled by selecting the number of scans with a nanosecond pulse laser (1, 3, 5, and 7), while the groove spacing was 100 mu m, 150 mu m, and 200 mu m. The pull-off bonding strength and shear bonding strength parallel and perpendicular to the grooves of the coatings were analyzed using a pull-off and scratch instrument. Furthermore, optimal laser scan times of the groove opening angle were obtained. The results showed that the coating adhesion strength on the grooved substrate with a 100 mu m spacing and 5 scans was greater than the cohesive strength. On the other hand, the pull-off bonding strength of coatings on the substrates made with 5 and 3 scans was superior to that on the grit-blasted stainless steel substrate; furthermore, the shear bonding strength in parallel and perpendicular scratch directions of the coating made on the grooved substrate with 5 scans was greater than that on the grit-blasted substrate; for all textured substrate coatings, the shear bonding strength in the parallel direction higher than that in the perpendicular direction. Finally, the equations that correlate the groove width, opening angle, pull-off bonding strength, shear bonding strength, and scanning times were predicted. The study provides significant experimental findings and a theoretical basis about the bonding strength of the laser-textured substrate plasma spraying coatings.

目的 分析等离子喷涂熔滴在表面织构内的铺展、凝固规律,为了解表面织构化对等离子喷涂涂层结合机制的影响以提升涂层的结合强度提供理论辅助.方法 基于Flow 3D建立熔滴填充微织构的数值模型,研究等离子喷涂熔滴填充正弦形织构的温度场及铺展成形规律,并对比分析织构边缘凸起及织构形状的影响.同时,基于激光织构化表面等离子喷涂试验,分析不同织构对涂层形貌的影响.结果 无边缘凸起织构的散热速度比有边缘凸起织构的快约0.7μs,凹坑织构的散热速度最慢,计算结束时,其最高温依然高于熔滴液相线(1728.4 K)约44.7 K.基体最高温度约1680.5 K,其主要分布于织构边缘凸起顶端、基体平面与织构内壁的拐点以及织构内壁上的凸点位置.有边缘凸起正弦织构的凝固熔滴由中间向两侧逐渐变薄,熔滴在无边缘凸起织构外部呈规则的圆盘状,凹坑织构底部存在"空腔"特征.涂层截面形貌分析发现,有边缘凸起的织构表面的涂层形貌较优,凹坑织构涂层含有较多缺陷,形貌最差.结论 镍基涂层与织构化表面为机械结合.相比凹坑织构,正弦和直线织构更有利于提高涂层的质量.织构边缘凸起的存在对提高喷涂质量也是有利的.