【摘 要】
：
Silicon nitride ceramics were prepared by means of a hot-press sintering method. The ablation behavior was studied by plasma wind tunnel tests. The data suggested that, under low heat flux and stagnation pressure conditions, the ablation process was contr
【机 构】
：
Science and Technology on Thermostructural Composite Materials Laboratory, Northwestern Polytechnica
【出 处】
：
武汉理工大学学报（材料科学版）（英文版）
论文部分内容阅读
Silicon nitride ceramics were prepared by means of a hot-press sintering method. The ablation behavior was studied by plasma wind tunnel tests. The data suggested that, under low heat flux and stagnation pressure conditions, the ablation process was controlled by the atomic oxidation of Si3N4, leading to the elimination of Si3N4. By contrast, the erosion was mainly produced by the decomposition of Si3N4 under high heat flux and stagnation pressure conditions. Under these conditions, a fraction of Si phase, formed upon decomposition of Si3N4, was volatilized. The remained Si had melted due to high temperatures and scoured away from stagnation point area, generating mushroom-shaped samples.
其他文献
In the presence of titanium dioxide powder, cross-linking reaction between commercial polyvinyl alcohol (PVA)-based macromonomer and acrylic acid (AA) was initiated with potassium persulfate in an emulsifying system. As a result, PVA-AA/TiO2 composite gel
Catalytic direct decomposition of NO by perovskite-type catalysts has attracted much attention for the various possible components and the unique structure. LaCoO3 nanoparticles were precipitated on α-Al2O3 micro powders by rotary chemical vapor depositio
The influences of surfactant type and concentration on the content and uniformity of SiC particles in Ni-SiC deposit were studied in this paper. The electrochemical behavior of preparing Ni-SiC composite coating was investigated using the cyclic voltammet
A new hot mixed epoxy asphalt system was developed. The reaction process of epoxy resin was characterized by Fourier transform infrared spectroscopy (FTIR). The viscosity was investigated by Brinell viscometer when epoxy resin was mixed with asphalt. The
A simple strategy was developed to prepare a tough, self-healing, antibacterial and moldable hydrogel by introducing the natural polyphenolic compound tannic acid (TA) as a cross-linking center for hydrogen bonds. Polyvinyl alcohol (PVA)-TA hydrogel was p
Nano-spherical Co2+-doped FeS2 was synthesized through a simple solvothermal method. The products were investigated using XRD, FE-SEM, BET, ICP, EDS, TEM, HRTEM, XPS, and UV-vis spectroscopy. The results indicated that Co2+ ion could change the particle n
The La-Mg-Ni-Mn-based AB2-type La1-xCexMgNi3.5Mn0.5 (x = 0, 0.1, 0.2, 0.3, and 0.4) alloys were fabricated by melt spinning technology. The effects of Ce content on the structures and electrochemical hydrogen storage performances of the alloys were studie
Three different kinds of coatings were coated on the concrete surface, and the changes in appearance, surface roughness, microstructure and components of coatings in artificial sewage were investigated. In addition, the strength, micrograph, mineral compo
Polytetrafluoroethylene (PTFE) is a commonly used seal material for oil-free engine that is well known for its excellent tribological properties. In this work, the nano-ZrO2 particles were used as the friction modifiers to improve the friction and wear pe
Sapphire,belonging to hexagonal crystal system,is typically anisotropic which makes it direction-sensitive.To research the effects of growth directions on properties of sapphire,c-[0001]seed(c-sapphire)and a-[11-20]seed(a-sapphire)were used to prepare sap