Abstract
	The creep resistance of two MoSi2 based materials containing SiC and HfO2 particles, respectively, in ambient atmosphere was studied at temperatures 1000 - 1400°C under a stress of 100 MPa.  The microstructure and its response to high temperature load were investigated by TEM using thin foil technique. Comparison of the creep resistance of both materials at each particular testing temperature show that the performance of MoSi2 -15 % HfO2 are about one order of magnitude better opposite of MoSi2 - 15 % SiC.
	The analysis of the experimental results demonstrate that the creep properties of the both materials (MoSi2 - 15 % HfO2 a MoSi2 - 15 % SiC) confirm relatively good deformation resistance composites during creep testing. The creep resistance of the system MoSi2 - 15 % HfO2 is higher than a creep resistance of the system MoSi2 - 15 % SiC. From the microstructure analysis of the material MoSi2 - HfO2 found, that the structure consists of MoSi2 grains of the matrix (medium-sized ~ 5 ?m), amorphous SiO2 of two kategories (~ 0,5, resp. 1 ?m) and the HfO2 particle (medium-sized 10 resp. 200 nm), which produce clusters mostly on the grain boundary of the matrix. The values of the activation energy (~430 kJ/mol) and analyses of the microstructure demonstrate, that probable majority mechanism of the creep are a diffusion processes.