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A series of silicon-aluminum oxynitride-glass compositions containing selected rare-earth (RE) additions were prepared to examine the effects of specific RE, as well as Si:Al:RE and N:O ratio, on properties. The properties that were characterized included density, thermal expansion coefficient (␣), glasstransition temperature (T g ), hardness (H), and Young's modulus (E). The compositions (in equivalent percent) selected included: 55 Si-20 RE-25 Al oxide and 80 O-20 N oxynitride, and 45 Si-30 RE-25 Al oxide and 70 O-30 N glasses. The results show that the density increased significantly with an increase in the RE atomic mass and slightly with an increase in N:O ratio. For each of the fixed Si-Al-RE-O-N compositions, the E, H, and T g values were each increased by substituting smaller RE ions, whereas the ␣ value was decreased. For each specific cation composition and RE, increasing the N:O ratio systematically led to a decrease in the ␣ values but an increase in the E, H, and T g values. The observed response in the glass properties to changes in composition appears to reflect modifications in the bonding within the glass network. I. BackgroundT HE manner in which the composition of oxynitride glasses influences their properties is of considerable interest for at least two reasons. First, such glasses exhibit various properties that could be of interest for numerous applications. For example, the Si-Al-Y-O-N glasses (1) are very refractory, with a glass-transition temperature (T g ) Ͼ900°C, (2) have E values higher than those of oxide glasses, and (3) exhibit a range of ␣ values. 1-5 Indeed, the properties apparently can be readily modified by tailoring the compositions. Studies 6 -10 have shown that the substitution of lanthanide-series ions for yttrium can be used to modify elastic and thermal properties, as well as glass viscosity. Shelby and Kohli 11 observed an increase in ␣ values and a decrease in T g values as the rare-earth (RE) ion size increased in 50 Si-25 RE-25 Al oxide glasses. Ohashi et al. 9 found that both the E and T g values increased with increases in the RE cationic field strength (valence/ (r 3ϩ ) 2 , where r 3ϩ is the radius of RE 3ϩ in sixfold coordination) in oxynitride glasses with a composition of 64 Si-36 RE-20 N-80 O. In 56 Si-28 RE-16 Al-17 N-83 O glasses, Ramesh et al. 10 observed a decrease in ␣ and an increase in H and T g with an increase in cationic field strength of the RE. Increases in T g with decreases in the RE ionic radius were found in both 51 Si-11 RE-38 Al-23 N-77 O and 40 Si-23 RE-37 Al-100 O glasses, and E increased with RE size in the latter glass. 7,8 In addition, the oxidation resistance of the Si-Al-RE-O-N glasses increased with decreases in the radius of the RE ion. 8 Finally, the refractive index (n) and magneto-optical properties of 50 Si-25 RE-25 Al oxide glasses were functions of the specific RE ion size (e.g., n ϰ 1/r 3ϩ ) and content. 11,12 Currently, considerable effort is underway to improve silicon devices by developing thin (Ͻ3 nm) film gate oxide films...

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Implants containing antimicrobial metals may reduce morbidity, mortality, and healthcare costs associated with medical device-related infections. We have deposited diamondlike carbonsilver (DLC-Ag), diamondlike carbon-platinum (DLC-Pt), and diamondlike carbon-silverplatinum (DLC-AgPt) thin films using a multicomponent target pulsed laser deposition process.Transmission electron microscopy of the DLC-silver and DLC-platinum composite films revealed that the silver and platinum self-assemble into nanoparticle arrays within the diamondlike carbon matrix. The diamondlike carbon-silver film possesses hardness and Young's modulus values of 37 GPa and 331 GPa, respectively. The diamondlike carbon-metal composite films exhibited passive behavior at open-circuit potentials. Low corrosion rates were observed during testing in a phosphate-buffered saline (PBS) electrolyte. In addition, the diamondlike carbon-metal composite films were found to be immune to localized corrosion below 1000 mV (SCE). DLC-silver-platinum films demonstrated exceptional antimicrobial properties against Staphylococcus bacteria. It is believed that a galvanic couple forms between platinum and silver, which accelerates silver ion release and provides more robust antimicrobial activity.Diamondlike carbon-silver-platinum films may provide unique biological functionalities and improved lifetimes for cardiovascular, orthopaedic, biosensor, and implantable microelectromechanical systems.