A process layout for laser cladding of layers on substrates of titanium aluminides using state-of-theart and modified (additions of Si and TiB2) TiAl alloys is presented. The process involves a preheating of the samples to reduce thermal stresses and cladding in an inert gas atmosphere with an oxygen content lower than 30 ppm. These conditions lead to crack free layers and low surface oxidation. Microstructure and hardness of the layers are investigated. The abrasive wear resistance of the cladded layers in comparison to the base material is tested with promising results. Finally results of the oxidation behavior are shown and prove the increased performance of modified TiAl layers in comparison to the base material.

We present the theoretical concept of an optical isolator based on a resonance splitting in a silicon ring resonators covered by a magneto-optical polymer cladding. A polymer magneto optical cladding causing a 0.01 amplitude of the off-diagonal element of the dielectric tensor is assumed. Using a perturbation method it is shown that the resonance splitting of the clockwise and counter-clockwise modes increases for smaller ring radii. For the ring with a radius of approximately 1.5μm a 29GHz splitting is demonstrated. An optical isolator is proposed based on a critically coupled ring resonator. © (2011) Trans Tech Publications.