Robust super‐hydrophobic ceramic coating on alumina with water and dirt repelling properties

Abstract

Artificial super‐hydrophobic surfaces are required for various applications. The super‐hydrophobic surfaces are usually made by applying a low surface‐energy organic coating on a highly textured substrate. A major problem with the as‐created surfaces is their poor durability. This problem is even severer for the surfaces created by applying the organic coating on inorganic substrates. The present study reports for the first time the all‐inorganic super‐hydrophobic surface created by modifying the inorganic substrates with polymer‐derived inorganic coating. A polydimethylsiloxane (PDMS) film was applied to an alumina substrate having flower‐like hierarchal micro‐nano surface texture, and then subjected to pyrolysis at 400°C in a nonoxidizing atmosphere. As a result, a SixCyOz ceramic coating with low‐surface energy methyl groups was formed on the alumina substrate. The as‐modified alumina exhibited super‐hydrophobicity with a water contact angle of 170° and a sliding angle of 5°. The super‐hydrophobicity was well retained after abrasion with sandpaper and exposure to boiling water and acidic solution. The super‐hydrophobic alumina demonstrated desired water repelling and self‐cleaning function. The method explored in this study could also be used for super‐hydrophobic surface modification of other inorganic materials such as glass and metals.

Synthesis of coatings on SiC fibers and their effects on microstructure and mechanical properties of SiCf/SiBCN composites

“…[7][8][9]40,41 A survey of the published literature shows that process modeling of CMCs has been studied by a number of researchers. Processes that have been modeled include RMI, 15,16 CVD, 17,18 CVI, [19][20][21][22] and Sol-Gel Infiltration. 23 Impregnation of alumina matrix in eight-harness satin Nextel 610 fabric has been studied numerically in Ref.…”

“…SiO + 2CO = SiC + CO 2 ΔG < 0, above 920 • C. A survey of the published literature modeling of CMCs has been studied by a n ers. Processes that have been modeled CVD, 17,18 CVI, [19][20][21][22] and Sol-Gel Infiltrat of alumina matrix in eight-harness satin has been studied numerically in Ref. [ proaches used in the above work general ing the flow of a high viscosity resin thr and modeling the chemical reactions and during processing.…”

“…[10][11][12][13] It is, thus, of great significance to tune and optimize the interfacial structure of fibers and SiBCN matrix so as to take the maximum advantages of the fiber-toughening effects. [14][15][16][17][18] Pyrolytic carbon (PyC), which has a layered crystal structure, is the common coating for SiC fibers (SiC f ). [19][20][21][22] In this regard, He et al have fabricated the SiC nanowires/ pyrocarbon (SiCnws/PyC) core-shell structure by chemical liquid vapor deposition process.…”

Surface modification of ceramic coating for enhanced hydrophobicity and wear properties

“…All have good results. The commonly used methods for constructing rough structures include template method, etching method, and laser processing, etc., which are complicated in operation, unfriendly to the environment, and high in cost 14–16 . Since the curing process of the phosphate coating requires high temperature, it is very convenient to directly decompose the pore‐forming agent by high temperature during this process, leaving a rough surface structure.…”

“…The commonly used methods for constructing rough structures include template method, etching method, and laser processing, etc., which are complicated in operation, unfriendly to the environment, and high in cost. [14][15][16] Since the curing process of the phosphate coating requires high temperature, it is very convenient to directly decompose the pore-forming agent by high temperature during this process, leaving a rough surface structure. Hao et al used polymethyl methacrylate microspheres as pore-forming agent and prepared sizecontrollable porous aluminum-calcium-aluminate ceramics by a combination of gel sintering and pore-forming agent.…”