Oxide coatings on AM60B magnesium alloy were prepared using the microarc oxidation(MAO) technique in silicate-KOH electrolyte with addition of 0-6.0 g/L Na2WO4. The MAO processes in base electrolyte with different con...Oxide coatings on AM60B magnesium alloy were prepared using the microarc oxidation(MAO) technique in silicate-KOH electrolyte with addition of 0-6.0 g/L Na2WO4. The MAO processes in base electrolyte with different concentrations of Na2WO4 were studied. The microstructure, compositions and mechanical tribological characteristics of the oxide coatings were also investigated by SEM, XRD, XPS, microhardness analysis and ball-on-disc friction testing, respectively. It is found that the addition of Na2WO4 into the base electrolyte has direct effect on the characteristics of voltage—time curves and breakdown voltage in MAO process. The number of micropores at top of the coating surface is increased by the addition of Na2WO4. The fraction of forsterite Mg2SiO4 in the oxide coating increases with increasing concentration of Na2WO4 in base electrolytes. Furthermore, the microhardness and wear resistance of oxide coatings are enhanced as well.展开更多
基金Projects(50432020, 50575218) supported by the National Natural Sicence Foundation of China
文摘Oxide coatings on AM60B magnesium alloy were prepared using the microarc oxidation(MAO) technique in silicate-KOH electrolyte with addition of 0-6.0 g/L Na2WO4. The MAO processes in base electrolyte with different concentrations of Na2WO4 were studied. The microstructure, compositions and mechanical tribological characteristics of the oxide coatings were also investigated by SEM, XRD, XPS, microhardness analysis and ball-on-disc friction testing, respectively. It is found that the addition of Na2WO4 into the base electrolyte has direct effect on the characteristics of voltage—time curves and breakdown voltage in MAO process. The number of micropores at top of the coating surface is increased by the addition of Na2WO4. The fraction of forsterite Mg2SiO4 in the oxide coating increases with increasing concentration of Na2WO4 in base electrolytes. Furthermore, the microhardness and wear resistance of oxide coatings are enhanced as well.
文摘采用新颖的微弧氧化法(Microarc oxidation,MAO)在钛合金表面制备氧化钛基含钙磷的多孔复合生物陶瓷涂层.用扫描电镜(SEM)、电子能谱(EDAX)和X射线衍射(XRD)表征涂层的微观形貌、元素与相组成.采用纳米压痕仪(Nano Indenter)测试涂层的力学性能,并通过在模拟体液(Simulated body fluid,SBF)中培养对陶瓷涂层的生物活性进行了初步研究.结果表明,微弧氧化时间、电解液配比与电参数是影响涂层结构与Ca/P比值的关键工艺参数.涂层主要由锐钛矿和金红石相TiO2及钙磷化合物组成.涂层内层为致密的氧化钛层,并与钛合金基底成微冶金结合.涂层外层主要为含钙磷的化合物层,且涂层表面呈多微孔结构,有利于骨组织的长入并改善骨与植入体的结合.涂层的硬度为5.9GPa,弹性模量为102.5GPa.优化工艺参数下(氧化时间5min,占空比8%)制备的涂层,在模拟体液中培养8周有明显的羟基磷灰石沉积.羟基磷灰石在微孔内或孔边缘位置首先形核并长大,并逐渐向周边扩展生成羟基磷灰石层,体现了多孔含钙磷生物陶瓷涂层良好的诱骨生长特性.
