Research On Fabrication And Properties Of Plasam Sprayed Nanostructural Al₂O₃-13wt.%TiO₂ Coatings

A new method of plasma spraying in which the feed for the plasma spraying, Al₂O₃-13wt.%TiO₂(13AT) is prilled by nanopaticles, is provided in this search. A new field for plasma spraying is introduced. The study covers the dispersing of nanomatcrial, the preparation of nanostructrured feedstock for plasma spraying ,decision of parameters for plasma spraying pracess.The influence proportion of nanoparticles on the coating is investigated . The conclusion are drawn as following:1. The experiments show that nanoparticles are homogeneously diopersed in water under the cooperation effect of ultrasonic and punchy stirring. After dispersing, nanometer hydrosol is blended by conbentional sparying powders, which is often call green slurry. Subsequently green slurry is dehydrated, pressed, sintered, porphyrized and sifted. Eventually the nanostructured of micronmeter size is preparated by namometer particles and the feed powder can be used for plasma spraying. The process parameters are basically equal to the conventional ones, but the former efficency was been improved.2. The results show that, the optimized parameters of sintering-breaking process are binder content 4.5Wt%,isostatic pressing 280 MPa, sintering temperature 1200℃, Sintering time 2h.3. The exprements show that the optimal process of plasma spraying is spray power 40kW and spray distance 100mm.Compared with the coating of the conventional powders for plasma spray ,the microrigidity and the fracture toughness property have separatedly raised 55.5% and 75%. The volum loss of coating declined to 40% . At the same time, the friction factor between coating and GCrl5 grinded-loop decreases from 0.58 to 0.45,and the fracture from of the coating changes from brittle intergranular fracture to flexible transgranular fracture.5. Through analyzing the test data, the toughened mechanics and abrasion mechanics of nanostructrued coating were presented.Through the study of the application of nanomaterial to plasma spraying , a method that can improve the performance of the coating by preparating namostructured powders for spraying.