Formation mechanism and supersonic flame erosion behavior of SiC and SiC-SiCnano single-layer oxidation protective coatings for carbon materials by reactive melt infiltration (RMI) method

Effect of processing parameters on microstructure and ablation behavior of SiC/ZrB2 coating for graphite

“…Based on the changes in the morphology and color of the coating surface, the ablated surface can be divided into three regions (Figure ): Central ablation region (region C): In this region, in a location where the flame collides with the sample surface, the highest degree of coating erosion occurs due to the high velocity and high pressure of the flame. Also, due to the high pressure of the flame, a part of the glassy phase flows toward the outer regions. Transitional ablation region (region T): This region is created adjacent to the central region and the effects of heat and pressure of the flame in this region are less than the central region.…”

“…The free Si in the coating exhibits active oxidation under the conditions of the ablation test. In other words, it is oxidized to the gaseous SiO rather than SiO 2 . This causes a large amount of SiO gas to be produced during the ablation test and exits the coating which results in severe denudation of the coating.…”

“…However, even if the Si present in the coating does not exit the system in the form of SiO, it will melt during the ablation test and reduce the adhesion of the coating to the substrate. The existence of the molten phase in the system and the reduction of adhesion of the coating to the substrate initiate the denudation of coating/substrate interface, therefore the protective layer (SiC) will be easily removed from the surface due to the pressure caused by high velocity flame . Also, according to Shi et al, SiO 2 and Si could react with each other at a high temperature, according to the reaction () that is a possibility of producing SiO gas …”

“…On the other hand, the materials response to large heat fluxes, high pressure, and high velocity (usually supersonic velocity) flame are evaluated. 12,17 However, up to now, few researchers have reported the influence of preparation temperature and holding time on the ablation behavior of SiC coatings in detail especially on the graphite substrate. Thus, the main purpose of this study is the evaluation of infiltration temperature and holding time effects on supersonic ablation behavior of SiC-coated graphite.…”

Enhancing the Stability of Passive Film on 304 SS by Chemical Modification in Alkaline Phosphate–Molybdate Solutions

“…Various methods have been developed to enhance the stability of this passive film, including chemical modification [14,15], electroless plating [16,17], electroplating [18], diffusion and infiltration technology [19], laser surface modification [20], and ion implantation [21]. Of these, the chemical modification method is favored for its flexibility and minimal consumption of electrical energy.…”