溶液前驱体等离子喷涂制备三氧化钼涂层  

Molybdenum trioxide coating prepared by solution precursor plasma spraying

作　　者：罗成[1] 沈培智[1] 张军[1] 

机构地区：[1]湖北汽车工业学院材料科学与工程学院,十堰442002

出　　处：《粉末冶金材料科学与工程》2017年第4期518-524,共7页Materials Science and Engineering of Powder Metallurgy

基　　金：湖北省科技支撑项目(2014BAA065)

摘　　要：通过溶液前驱体等离子喷涂制备三氧化钼涂层。通过TG和DSC热分析,以及SEM和XRD分析前驱体四水合钼酸铵加热分解过程中微观组织结构和物相组成的转变。结果表明,在加热过程中前驱体逐步脱水、脱氨,400℃下完全转变为稳定的α-MoO_3。在等离子喷涂过程中,前驱体溶液经历汽化、沉淀、分解,释放气体导致涂层出现孔洞和裂纹。喷涂距离影响液滴飞行过程中的热分解和涂层结构。喷涂距离70 mm时前驱体分解充分,涂层结构致密,喷涂距离90 mm时涂层开裂明显,喷涂距离50 mm时前驱体分解不充分。喷涂距离50 mm的涂层经过350℃退火后形貌与喷涂距离70 mm相似;经700℃退火后涂层转变为针状组织。Molybdenum trioxide coating was prepared by solution precursor plasma spraying with ammonium molybdate tetrahydrate as precursor. Thermal analysis was conducted by TG and DSC, and microstructures and phase structure were performed by SEM and XRD respectively to evaluate the decomposition of the precursor. The results show that the precursor undergoes dehydration and deamination when being heated in low temperature and is converted to alpha molybdenum trioxide completely before 400 ℃. Vaporization, precipitation and pyrolysis occured for the in-flight droplet of the precursor solution sequentially, resulting in pores and cracks in the coating by the released gases. The spray standoff distance impacts on the heating and decomposition degree. The solution precursor was fully decomposed to obtain a dense coating with a standoff distance of 70 mm while incompletely decomposition happened when the standoff distance was 50 mm and cracks were formed at a 90 mm standoff distance. With standoff distance of 50 mm, the similar coating was acquired when annealing for 1 hour at 350 ℃, and needlelike microstructure is gained after annealing at 700 ℃.

关 键 词：四水合钼酸铵 三氧化钼 溶液前驱体等离子喷涂 微观形貌 物相 

分 类 号：TG174.4[金属学及工艺—金属表面处理]