CAJ | 학술논문

目的：制备等离子喷涂NiCoCrAlY/Al2 O3高温固体润滑耐磨涂层,并研究该涂层的摩擦性能和磨损机理。方法采用喷雾造粒、化工冶金包覆和固相合金化技术制备NiCoCrAlY/Al2 O3复合粉体,用等离子喷涂技术在45#钢表面制备NiCoCrAlY/Al2 O3复合涂层。用SEM和XRD等手段分析粉体和涂层的显微结构和物相组成,研究涂层从室温到800℃的摩擦磨损性能,探讨NiCoCrAlY/Al2 O3复合涂层在室温和高温下的磨损机理。结果 Al2 O3颗粒表面均匀包覆着一层致密的NiCoCrAlY合金,包覆层厚度大约为3~5μm；等离子喷涂NiCoCrAlY/Al2 O3复合涂层呈典型的层状结构,涂层各层间结合良好,涂层中孔隙率约为2.84%,主晶相为NiCrAl合金相和Al2 O3相。涂层的摩擦系数随温度的升高逐渐降低,在室温下约为0.64,800℃时在0.4以下。高温下,金属氧化物的形成是摩擦系数降低的主要原因。涂层的磨损率随温度的升高先升高后降低。涂层在低温下为脆性断裂和磨粒磨损,高温下为氧化磨损、磨粒磨损、塑性变形和金属氧化物的转移。结论等离子喷涂NiCoCrAlY/Al2 O3复合涂层是一种性能优良的高温固体润滑耐磨涂层。
목적：제비등리자분도NiCoCrAlY/Al2 O3고온고체윤활내마도층,병연구해도층적마찰성능화마손궤리。방법채용분무조립、화공야금포복화고상합금화기술제비NiCoCrAlY/Al2 O3복합분체,용등리자분도기술재45#강표면제비NiCoCrAlY/Al2 O3복합도층。용SEM화XRD등수단분석분체화도층적현미결구화물상조성,연구도층종실온도800℃적마찰마손성능,탐토NiCoCrAlY/Al2 O3복합도층재실온화고온하적마손궤리。결과 Al2 O3과립표면균균포복착일층치밀적NiCoCrAlY합금,포복층후도대약위3~5μm；등리자분도NiCoCrAlY/Al2 O3복합도층정전형적층상결구,도층각층간결합량호,도층중공극솔약위2.84%,주정상위NiCrAl합금상화Al2 O3상。도층적마찰계수수온도적승고축점강저,재실온하약위0.64,800℃시재0.4이하。고온하,금속양화물적형성시마찰계수강저적주요원인。도층적마손솔수온도적승고선승고후강저。도층재저온하위취성단렬화마립마손,고온하위양화마손、마립마손、소성변형화금속양화물적전이。결론등리자분도NiCoCrAlY/Al2 O3복합도층시일충성능우량적고온고체윤활내마도층。
ABSTRACT:Objective To prepare the atmospheric plasma-sprayed NiCoCrAlY/Al2 O3 wear-resistant coatings and study the tribo-logical properties and tribological mechanism of the coating. Methods The NiCoCrAlY/Al2 O3 composite powder was prepared by the technology of spray granulation, chemical and metallurgical coating and solid state alloying. The NiCoCrAlY/Al2 O3 composite coating was prepared by atmospheric plasma-spray technology using the prepared powder on the surface of 45# steel. The micro-structure and phase composition of the powder and coating were studied by SEM and XED. The tribological properties and tribologi-cal mechanism of the APS sprayed NiCoCrAlY/Al2 O3 composite coatings were investigated. Results The surface of Al2 O3 particles was evenly coated with NiCoCrAlY alloy and the thickness of NiCoCrAlY alloy was 3~5 μm. The composite coatings consisted of elongated lamellae and they integrated with each other very well. The phase compositions of composite powder were NiCrAl and Al2 O3 . The friction coefficient of the coating decreased with the increase of temperature. The friction coefficient of the coating was 0. 64 at room temperature and decreased to below 0. 4 at 800 ℃, which was due to the formation of metallic oxide. The wear rate of the coating first increased and then decreased with the increase of temperature. The abrasive mechanism of the NiCoCrAlY/Al2 O3 composite coatings was dominated by mixed brittle crack and abrasive at low temperature, and it was characterized by oxida-tion, abrasive, plastic deformation and as well as coating transfer to the coupled pin at high temperature. Conclusion The atmos-pheric plasma-sprayed NiCoCrAlY/Al2 O3 composite coating exhibited excellent wear-resistant performance by high temperature self-lubrication.