The water wettability of porous stainless steel specimens was enhanced via a nanoscaled silica coating for application to passive two-phase heat transfer devices. A combination of porous stainless steel and water has attracted attention in the area of the heat transfer devices. However, the water wettability of stainless steel is poor, limiting the performance of the devices. In the present study, the silica coating of the specimens was conducted via a reaction of tetraethyl orthosilicate (TEOS) after pretreatment using NaOH aq. or HCl aq. Energy-dispersive X-ray spectrometry revealed that the amount of silica deposited on the surface was dependent on the pretreatment conditions and the composition of the silica-coating solutions. Measurement of porous properties indicated that the silica coating did not affect pore diameter and gas permeability since the coating was in nanoscale. Microscale contact angles were directly evaluated using an environmental SEM. The specimens showed excellent water wettability when they were covered with numerous tiny silica bumps. When the specimen was pretreated with 2 M NaOH aq. and coated in weak alkaline TEOS solution, the contact angle of the porous stainless steel decreased from 87° to 54° after silica coating. The excellent water wettability originated from the relatively smooth surface and a sufficient coverage ratio, which resulted from the moderate strength of chemical etching of the NaOH aq. and the mild silica-coating condition in the weak alkaline solution.

多孔纳米不锈钢样品的水润湿性通过纳米级二氧化硅涂层得以增强，可应用于无源两相传热设备。多孔不锈钢和水的组合在传热装置领域引起了关注。但是，不锈钢的水润湿性差，限制了装置的性能。在本研究中，使用NaOH水溶液进行预处理后，通过原硅酸四乙酯（TEOS）的反应对样品进行二氧化硅涂层。或HCl水溶液 能量色散X射线光谱法表明，沉积在表面上的二氧化硅的量取决于预处理条件和二氧化硅涂布溶液的组成。多孔性能的测量表明，二氧化硅涂层不影响孔径和透气性，因为该涂层是纳米级的。使用环境SEM直接评估微尺度接触角。当样品被许多微小的二氧化硅凸起物覆盖时，它们显示出优异的水润湿性。当样品用2 M NaOH水溶液进行预处理时。并在弱碱性TEOS溶液中涂覆后，二氧化硅涂覆后多孔不锈钢的接触角从87°降至54°。优异的水润湿性源自相对光滑的表面和足够的覆盖率，这是由于NaOH水溶液的化学刻蚀强度中等所致。弱碱性溶液中的二氧化硅涂层条件温和。使用环境SEM直接评估微尺度接触角。当样品被许多微小的二氧化硅凸起物覆盖时，它们显示出优异的水润湿性。当样品用2 M NaOH水溶液进行预处理时。并在弱碱性TEOS溶液中涂覆后，二氧化硅涂覆后多孔不锈钢的接触角从87°降至54°。优异的水润湿性源自相对光滑的表面和足够的覆盖率，这是由于NaOH水溶液的化学刻蚀强度中等所致。弱碱性溶液中的二氧化硅涂层条件温和。使用环境SEM直接评估微尺度接触角。当样品被许多微小的二氧化硅凸起物覆盖时，它们显示出优异的水润湿性。当样品用2 M NaOH水溶液进行预处理时。并在弱碱性TEOS溶液中涂覆后，二氧化硅涂覆后多孔不锈钢的接触角从87°降至54°。优异的水润湿性源自相对光滑的表面和足够的覆盖率，这是由于NaOH水溶液的化学刻蚀强度中等所致。弱碱性溶液中的二氧化硅涂层条件温和。并在弱碱性TEOS溶液中涂覆后，二氧化硅涂覆后多孔不锈钢的接触角从87°降至54°。优异的水润湿性源自相对光滑的表面和足够的覆盖率，这是由于NaOH水溶液的化学刻蚀强度中等所致。弱碱性溶液中的二氧化硅涂层条件温和。并在弱碱性TEOS溶液中涂覆后，二氧化硅涂覆后多孔不锈钢的接触角从87°降至54°。优异的水润湿性源自相对光滑的表面和足够的覆盖率，这是由于NaOH水溶液的化学刻蚀强度中等所致。弱碱性溶液中的二氧化硅涂层条件温和。