| Tube baking machine is one of critical equipments in the production line offluorescent tube, and its primary parts (steel tubes) are made of 316L stainless steel. Since thesteel tube serves at high temperature around 1000°C and undergoes cyclically thermal load, itis prone to oxidation and thermal fatigue failure, resulting in shutdown and equipmentscrapping. Moreover, natural gas often acts as the heat source of tube baking machine, and theheat dissipation from stainless steel surface is more efficient due to rather high heatconductivity of stainless steel itself. If no thermal barrier coatings are clad to the surface ofstainless steel tube, it will consume more natural gas, waste energy and emit more greenhousegases. Therefore, it is urgent for researchers to solve the problem of surface shield for the keyparts of tube baking machine. In this paper, air plasma spraying technique was employed toprepare the nano-zirconia ceramic thermal barrier coatings on 316L stainless steel surface,and that would be hopeful to improve the properties and life period of stainless steel tubegrea tly.In this paper, plasma-sprayed nano-zirconia ceramic thermal barrier coating on 316Lstainless steel by using nano-materials technology and air plasma spraying technology. Theplasma spray procedure factors and the plama spray power have great impact on properties ofthe nano-structured zirconia thermal barrier coating. Through orthogonal test, the procedurefactors were optimized. And successfully use the best procedure factors on tube bakingmachine. The main achievements are drowning as following:1. Nano-zirconia ceramic thermal barrier coating was successfully fabricated byatmospheric plasma spraying technique. The nano-zirconia ceramic coating is composed ofmajor tetragonal (t-ZrO2).2. Compared with the micron zirconia ceramic thermal barrier, the surface ofnano-zirconia ceramic thermal barrier coating is much smoother and denser, and its pores andmicrocracks are smaller. Nano-zirconia ceramic thermal barrier coating is composed of fullymelted region and partially melted region.3. The plasma spray procedure factors and the percentage of Y2O3 take great effect on properties of the nano-structured zirconia thermal barrier coating.The results showed that thenano-zirconia ceramic thermal barrier coating have best thermal shock resistance when thespray power is 40KW, the spraying distance is 75mm, the main gas flow is 34L/min and thepreheat temperature is 200℃.4. Plasma spray nano-zirconia ceramic thermal barrier coating was used on tube bakingmachine successfully. It has important significance to the modern industrial production. Inorder to achieve industrial production, we need to continue to practice and innovationin plasma spraying systems. |
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