Dense metallic membranes chemical vapor deposition

The manufacture of dense metal membranes or thin films can be effected by a number of processes casting/rolling, vapor deposition by physical and chemical means, electroplating (or electroforming) and electroless plating. By far, casting in combination with rolling is the predominant preparation and fabrication technique. It is noted that many of these processes have been demonstrated with palladium and its alloys because of their low oxidation propensity. Preparation of dense metal membranes is summarized in some detail as follows. 

Perovskite-structured membranes, in the form of thin films supported on porous ceramic or metal substrates, have been studied extensively in the past decade. Thin films offer several advantages including reduced material cost, improved mechanical strength and possibly higher H2 flux. Chemical vapor deposition (CVD) [99], electrochemical vapor deposition (EVD) [100] and sputtering [101] represent typical methods. However, dense films have been difficult to obtain by these methods. It was found that the continuity and gas-tightness of the deposited films were very sensitive to the morphologies and pore size of substrates. 

In the last decade, a variety of porous substrates were proposed for supporting the dense membranes, such as ceramics, metals, and alloys [42-44]. In those studies, special attention was paid to the LSCF coating on metallic substrates by using physical methods such as plasma spray physical vapor deposition and magnetron sputtering as an alternative to the wet chemical deposition methods [43,44]. When considering ceramic substrates, besides the elastic behavior and the thermal expansion of the perovskites, other properties such as toughness... 

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