To investigate the evolution of microstructure and wear behavior of TiSiN coatings with the variation of Si in targets and lays the foundation for its controllable mass production, Ti1-xSixN composite coatings were de...To investigate the evolution of microstructure and wear behavior of TiSiN coatings with the variation of Si in targets and lays the foundation for its controllable mass production, Ti1-xSixN composite coatings were deposited onto Si(100) and cemented carbide substrates using TiSi targets with different Si content by cathodic arc ion plating. The influences of Si on the microstructure and mechanical properties were studied. Nano-amorphous composite structure appeared in the Ti1-xSixN coatings when Si content in TiSi target was higher than 5 at%. However, further increase of Si content in TiSi target exhibited a negligible effect on the microstructure of Ti1-xSixN coatings. Hardness and deformation resistance were correlated to the content of Si in TiSi targets. Maximum hardness was obtained as the Si content in target increased up to 20 at%. Friction coefficient and wear rate significantly decreased with addition of Si in TiN coating, and then dually increased with the increase of Si content in targets.展开更多
A temperature stable Li2Zn0.95(SrxCa1-x)0.05Ti3O8(0≤x≤1)ceramics were fabricated using a conventional solid-state route sintered at 1100℃for 4 h.The XRD results indicate that the main phase Li2ZnTi3O8 and secondary...A temperature stable Li2Zn0.95(SrxCa1-x)0.05Ti3O8(0≤x≤1)ceramics were fabricated using a conventional solid-state route sintered at 1100℃for 4 h.The XRD results indicate that the main phase Li2ZnTi3O8 and secondary phase including SrxCa1-xTiO3(0≤x≤1)solid solution and TiO2 co-exist in composite and form a stable composite system when the(CaxSr1-x)(0≤x≤1)substitutes for Zn of Li2ZnTi3O8 ceramic.As x is increased from 0 to 1,the relative permittivity(εr)increases from 26.65 to 27.12,and the quality factor(Q×f)increases from 63300 to 66600 GHz.With the increased of x,the temperature coefficient of resonant frequency(τf)increases from 0.27 to 8.23 ppm/℃,and then decreases to 3.51 ppm/℃.On the whole,the Li2Zn0.95(SrxCa1-x)0.05Ti3O8(0≤x≤1)ceramics show excellent comprehensive properties of middleεr=25-27,higher Q×f≥60000 GHz andτf≤±8.5 ppm/℃.展开更多
The oxidation behaviors of bulk Ti3Si(1-x)AlxC2 prepared by hot pressing were investigated. The results show that the isothermal oxidation behavior of Ti3SiC2 obeys a parabolic law between 900 and 1 100℃and follows a...The oxidation behaviors of bulk Ti3Si(1-x)AlxC2 prepared by hot pressing were investigated. The results show that the isothermal oxidation behavior of Ti3SiC2 obeys a parabolic law between 900 and 1 100℃and follows a two-step parabolic rate law between 1 200℃and 1 300℃. The cyclic oxidation behavior of material is assumed to obey a three-step parabolic rate law at 1 100℃and 1 200℃. The calculated activation energy of isothermal oxidation is 101.43 kJ/mol. The oxide layers which consist of a mass ofα-Al2O3 and little TiO2 and SiO2 are observed on Ti3SiC2 as a dense and adhesive protect scale. The oxidation mechanism varies with the additive aluminum that greatly improves the oxidation resistance of Ti3SiC2.展开更多
采用钛酸四丁酯[Ti(OC_4H_9)_4]水解和900℃高温烧结工艺制得不同Ti^(4+)含量掺杂下的Li[Li_(0.2)Mn_(0.54)Ni_(0.13)Co_(0.13)]_(1-x)Ti_xO_2正极材料。采用XRD、SEM等表征方法对Ti^(4+)掺杂前后的Li[Li_(0.2)Mn_(0.54)Ni_(0.13)Co_(0....采用钛酸四丁酯[Ti(OC_4H_9)_4]水解和900℃高温烧结工艺制得不同Ti^(4+)含量掺杂下的Li[Li_(0.2)Mn_(0.54)Ni_(0.13)Co_(0.13)]_(1-x)Ti_xO_2正极材料。采用XRD、SEM等表征方法对Ti^(4+)掺杂前后的Li[Li_(0.2)Mn_(0.54)Ni_(0.13)Co_(0.13)]O_2颗粒的微观结构、表面形貌进行分析研究,发现掺杂前后材料的结构并未明显变化。电化学测试结果表明,虽然Ti^(4+)表现为非电化学活性,使得掺杂有Ti^(4+)的正极材料其首次充放电比容量有所降低,但是在高倍率性能及循环性能测试中,Ti^(4+)掺杂改性效果表现明显。其中当Ti^(4+)掺杂量为x=0.02时,其倍率性能及循环性能最佳。在5C高倍率下放电,Li[Li_(0.2)Mn_(0.54)Ni_(0.13)Co_(0.13)]_(0.98)Ti_(0.02)O_2样品的放电比容量要比未掺杂样品高出约20 m A·h/g。而且经过100次循环后,Li[Li_(0.2)Mn_(0.54)Ni_(0.13)Co_(0.13)]_(0.98)Ti_(0.02)O_2样品的放电比容量仍有187.9 m A·h/g,容量保持率高达96.8%。而未掺杂样品的100次循环后容量保持率仅有91.2%。展开更多
基金Funded by the National Natural Science Foundation of China(U1832127)
文摘To investigate the evolution of microstructure and wear behavior of TiSiN coatings with the variation of Si in targets and lays the foundation for its controllable mass production, Ti1-xSixN composite coatings were deposited onto Si(100) and cemented carbide substrates using TiSi targets with different Si content by cathodic arc ion plating. The influences of Si on the microstructure and mechanical properties were studied. Nano-amorphous composite structure appeared in the Ti1-xSixN coatings when Si content in TiSi target was higher than 5 at%. However, further increase of Si content in TiSi target exhibited a negligible effect on the microstructure of Ti1-xSixN coatings. Hardness and deformation resistance were correlated to the content of Si in TiSi targets. Maximum hardness was obtained as the Si content in target increased up to 20 at%. Friction coefficient and wear rate significantly decreased with addition of Si in TiN coating, and then dually increased with the increase of Si content in targets.
基金Funded by the Open Project Program of Key Laboratory of Inorganic Functional Materials and Devices,Chinese Academy of Sciences(No.KLIFMD201606)the Open Fund of National Innovation Platform(No.2017YJ163)+1 种基金the National Natural Science Foundation of China(Nos.51502220,51521001,and 51672197)the Open Foundation of Hubei Key Laboratory of Theory and Application of Advanced Materials Mechanics(Wuhan University of Technology)(No.TAM201802)。
文摘A temperature stable Li2Zn0.95(SrxCa1-x)0.05Ti3O8(0≤x≤1)ceramics were fabricated using a conventional solid-state route sintered at 1100℃for 4 h.The XRD results indicate that the main phase Li2ZnTi3O8 and secondary phase including SrxCa1-xTiO3(0≤x≤1)solid solution and TiO2 co-exist in composite and form a stable composite system when the(CaxSr1-x)(0≤x≤1)substitutes for Zn of Li2ZnTi3O8 ceramic.As x is increased from 0 to 1,the relative permittivity(εr)increases from 26.65 to 27.12,and the quality factor(Q×f)increases from 63300 to 66600 GHz.With the increased of x,the temperature coefficient of resonant frequency(τf)increases from 0.27 to 8.23 ppm/℃,and then decreases to 3.51 ppm/℃.On the whole,the Li2Zn0.95(SrxCa1-x)0.05Ti3O8(0≤x≤1)ceramics show excellent comprehensive properties of middleεr=25-27,higher Q×f≥60000 GHz andτf≤±8.5 ppm/℃.
基金Project (KF200505) supported by the Key Laboratory of Heavy Ion Physics (Peking University), Ministry of Education
文摘The oxidation behaviors of bulk Ti3Si(1-x)AlxC2 prepared by hot pressing were investigated. The results show that the isothermal oxidation behavior of Ti3SiC2 obeys a parabolic law between 900 and 1 100℃and follows a two-step parabolic rate law between 1 200℃and 1 300℃. The cyclic oxidation behavior of material is assumed to obey a three-step parabolic rate law at 1 100℃and 1 200℃. The calculated activation energy of isothermal oxidation is 101.43 kJ/mol. The oxide layers which consist of a mass ofα-Al2O3 and little TiO2 and SiO2 are observed on Ti3SiC2 as a dense and adhesive protect scale. The oxidation mechanism varies with the additive aluminum that greatly improves the oxidation resistance of Ti3SiC2.
文摘采用钛酸四丁酯[Ti(OC_4H_9)_4]水解和900℃高温烧结工艺制得不同Ti^(4+)含量掺杂下的Li[Li_(0.2)Mn_(0.54)Ni_(0.13)Co_(0.13)]_(1-x)Ti_xO_2正极材料。采用XRD、SEM等表征方法对Ti^(4+)掺杂前后的Li[Li_(0.2)Mn_(0.54)Ni_(0.13)Co_(0.13)]O_2颗粒的微观结构、表面形貌进行分析研究,发现掺杂前后材料的结构并未明显变化。电化学测试结果表明,虽然Ti^(4+)表现为非电化学活性,使得掺杂有Ti^(4+)的正极材料其首次充放电比容量有所降低,但是在高倍率性能及循环性能测试中,Ti^(4+)掺杂改性效果表现明显。其中当Ti^(4+)掺杂量为x=0.02时,其倍率性能及循环性能最佳。在5C高倍率下放电,Li[Li_(0.2)Mn_(0.54)Ni_(0.13)Co_(0.13)]_(0.98)Ti_(0.02)O_2样品的放电比容量要比未掺杂样品高出约20 m A·h/g。而且经过100次循环后,Li[Li_(0.2)Mn_(0.54)Ni_(0.13)Co_(0.13)]_(0.98)Ti_(0.02)O_2样品的放电比容量仍有187.9 m A·h/g,容量保持率高达96.8%。而未掺杂样品的100次循环后容量保持率仅有91.2%。
