The objective of this study is to determine the isothermal section at 400℃ of the Mgsingle bondCesingle bondSr system.In this study,the constitution of the Cesingle bondSr system and the Mgsingle bondCesingle bondSr system have been investigated over the entire composition range using X-ray diffraction(XRD),field emission scanning electron microscope(SEM)and energy dispersive spectroscopy(EDS).No any new binary compound has been found in the Cesingle bondSr system and no ternary compound has been found in the Mgsingle bondCesingle bondSr system also.Nine three-phase regions have been experimentally observed.Six binary phases Mg_(2)Sr,Mg_(23)Sr_(6),Mg_(38)Sr_(9),Mg_(17)Sr_(2),Mg_(12)Ce,Mg_(41)Ce_(5) are detected dissolving about 3-7 at.%the third element.This study first detected the experimental data of the Cesingle bondSr binary system and determined the isothermal section at 400℃ of the Mgsingle bondCesingle bondSr ternary system.
利用电弧离子镀技术在DSM11合金基体上制备含或不含扩散阻挡层(diffusion barrier,DB)的Ni Cr Al YSi涂层,对比研究2种涂层在900℃恒温热腐蚀行为和从900℃到室温的循环热腐蚀行为(表面混合盐质量分数为75%Na2SO4+25%K2SO4)。研究结果表明:在恒温热腐蚀条件下,含或不含扩散阻挡层的Ni Cr Al YSi涂层表面主要生成了α-Al2O3和γ/γ′相;腐蚀100 h后,Ni Cr Al YSi涂层出现了较多的Kirkendall孔洞,基体与涂层元素的互扩散明显。Ni Cr Al YSi/DB涂层的扩散阻挡层可有效地抑止基体与涂层的元素互扩散,防护效果比单一Ni Cr Al YSi涂层的效果好。在循环热腐蚀条件下,含或不含扩散阻挡层的Ni Cr Al YSi涂层表面主要生成α-Al2O3、尖晶石、Ti O2和γ/γ′相;腐蚀100 h后,Ni Cr Al YSi涂层内氧化和内硫化现象严重,Ni Cr Al YSi/DB涂层的扩散阻挡层界面易开裂,影响扩散阻挡层的效力,导致涂层体系比单一Ni Cr Al YSi涂层更快失效。
