This paper presents the experiments on the synthesis of zirconium carbide (ZrC) using carbothermal reduction of zirconia (ZrO 2 ). The ratio of ZrO 2 :C is used to adapt ZrC x O y with x < 1 or ZrC + C. The modification of ZrC x O y and the total carbon amount allows the use of pressureless sintering method in combination with sintering temperatures ≤ 2000 ℃. Fully densified ZrC products are obtained. The relevant details of ZrC formation are investigated by X-ray diffraction (XRD). The sintered products are characterized by XRD, field emission scanning electron microscopy (FESEM), as well as mechanical and electrical methods. XRD and FESEM investigations show that ZrC x O y is formed during the manufacturing process. The grain size and additional zirconia or carbon are related to the ZrO 2 :C ratio of the starting powder mixture. Bending strength up to 300 MPa, Young's modulus up to 400 GPa, fracture toughness up to 4.1 MPa·m 1/2 , and electrical resistance at room temperature around 10 4 Ω·cm are reached by the pressureless sintered ZrC.

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The performance of carbon fibers depends on the quality of the precursor and the conditions of the thermal treatment. In detail, for a PAN precursor fiber the viscosity of a spinning dope and the draw ratio during the spinning process needs to be considered. Through wet spinning, different types of PAN precursor fibers with defined spinning parameters, including solid content, solvent content in a bath, and especially draw ratio resulting in defined cross section diameters, were fabricated and analyzed with tensile tests, density investigations, SEM, TGA-MS, FTIR, and XRD. The results show that the mechanical properties of the fibers correlate to crystallinity. The cross section diameter is strongly related to the morphology of the fibers after thermal treatment. By extending the postdrawing of PAN fibers high tenacities were obtained at the cost of the cross section shape. In addition, TGA measurements reveal trapped residues of the wet spinning process as well as show several chemical reactions takes place at the same time at different temperatures