超低压等离子喷涂喷嘴设计与喷枪特性  

The Characteristic of Plasma Torch Designed for the Very Low-Pressure Plasma Spraying

作　　者：高阳[1] 杨德明[1] 

机构地区：[1]大连海事大学热喷涂研究中心,大连116026

出　　处：《热喷涂技术》2011年第3期65-70,共6页Thermal Spray Technology

基　　金：国家自然基金项目(51172033)

摘　　要：相比大气等离子喷涂(APS),超低压等离子喷涂(VLPPS)在喷嘴出口处的自由区域对粉末的加热能力较低。目前,大多数超低压等离子喷涂设备采用大功率等离子喷枪,电弧电流高达2500A,以补偿加热能力较低的缺点,然而这样对等离子喷枪及其辅助设备要求较高。根据低压环境下的等离子体特性,设计了内送粉变径阳极等离子喷枪。本研究使用热焓探针系统测量了低压以及超低压状态下等离子体内部压力变化。在真空室压力为1000Pa,电流为500～600A,电压为50V时,制备了SUS316不锈钢涂层。结果表明:在适当的条件下涂层呈现类似结构材料的等轴晶组织。In contrast with the atmosphere plasma spraying （APS）, the very low pressure plasma spraying （VLPPS） exhibited lower heating ability for the feed materials at plasma freoe region exit of nozzle. Most very low pressure plasma spraying at the present usually are adopted a high power plasma gun which operated at great arc currents up to 2500A to remedy a lower heating ability, thus result in a series problems not only for the plasma torch but also for associated facility. According to the characteristic of plasma spray in the low pressure environment we designed a plasma torch with separating anode and nozzle, and the powder injected to the plasma jets is from inside nozzle intake. In this study, the pressures in the plasma gases intake, nozzle intake and out of the plasma torch were measured by enthalpy probe, respectively. For the practice, SUS 316 stainless steel coatings were prepared at plasma currents of 500-600A and arc voltage of 50V and the chamber pressure of 1000 Pa, the results indicated that the coatings with the equiaxed microstructure could deposited in the appropriate conditions.

关 键 词：低压等离子喷涂 等离子射流 等轴晶组织 喷嘴 

分 类 号：TG174.4[金属学及工艺—金属表面处理]