Expansion behavior support material

A listing of the thermal conductivity and thermal expansion values for various support materials has been given in Tables 3.6 and 3.8, respectively. Since most support materials at cryogenic temperatures have thermal conductivities and thermal expansion coefficients whose temperature dependence behavior is unpredictable, Eq. (7.57) must be integrated either numerically or graphically. 

Second, the use of a supporting sub-layer such as titanium and chromium with high adhesion may improve the stability of the palladium sensing layer. Different materials have proved effective for this purpose including nickel (Butler 1994), VOx (Smith et al. 2002), (Liu et al. 2002), CaF (Fedtke et al. 2004), and MgF (Chtanov and Gal 2001). For example, Fedtke et al. 2004 found that structures with CaFj buffer layers and palladium cap showed a better time stability and behavior up to 6% H. Palladium-polymer nano-composite thin films allowed the accommodation of the palladium lattice expansion during hydrogen exposure up to 10% Liu et al. (2002) have shown that PdA jO,... 

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