Mn-doped black pigments CuMnxCr2-xO4(x=0, 0.05, 0.10, 0.15, 0.20 and 0.25) were synthesized by precursor coprecipitation method, and characterized by TG-DTA, XRD, FTIR and colorimetric analysis. The TG-DTA curves showed the crystal transition temperature was at about 800°C and mass loss ended at about 450°C. The infrared spectra displayed vibrations of spinel phase. XRD patterns displayed the characteristic peaks of the tetragonal phase spinel structure and proved that Mn substituted Cr in the spinel crystal lattice. L*a*b* analysis showed that all samples are black pigments with blue intensity, and Mn-doping could strengthen the black intensity and weaken the blue intensity of such black pigments.
In order to increase the ignition performance and combustion performance of B/PTFE fuel-rich propellant,Li-Al alloy is used to increase the sensitivity of B/PTFE fuel-rich propellant.The impact sensitivity、friction sensitivity、 combustion temperature、 burning rate combustion heat and TGA are tested.The results showed that the sensitivity、combustion heat and ignition performance increase much.The burning rate increased 30~50% and the combustion temperature was relatively stable about 800°C.
Metal ions doped complex cobalt blue pigments are prepared by homogeneous precipitation, to investigate the effects of doping ions Zn2+,Mg2+,Ni2+and Y3+on some properties of the doped complex cobalt blue pigments, such as crystal structure, color, shading power and temperature resistance. Studies have shown that doping have little effect on the spinel crystal type and temperature resistance of the pigments ; ionic radius differences between doping ions and Co2 +cause lattice distortion and changes of lattice constant , thus affecting the ligand state spaces of Co2 +ion, color and shading power of complex cobalt blue pigment. The lattice constant of Zn2 +doped complex cobalt blue becomes larger with the increasing amount of Zn2 +; while doping Mg2 +and Ni2 +, the crystal lattice constants become smaller; when doping with Y3 +, Y3 +ions enter into CoAl2O4lattice, replacing some hexa-coordinate octahedral gap of Al3 +, ionic radius differences between Y3 +and Al3+cause lattice distortion, when doping amount of Y3 +increases to a certain extent, the phase in the form of Y2O3will be generated and it will maybe form a kind of CoYxAl2-xO4- Y2O3solid solution instead of the complete spinel structure.
The Co1-xNixCr2O4(x=0.1, 0.2 and 0.3) solid solutions were successfully synthesized by low-temperature combustion synthesis method. The crystal structure and optical properties of the samples were investigated. The samples displayed single phase spinel structure with 30 nm in grain size. Infrared absorption peaks at about 525 and 630 cm-1 corresponded to the vibration of octahedron group ([CrO6] / [NiO6]) and tetrahedron group ([CoO4] / [NiO4]) respectively. Due to the electronic transition of 4A2(F) → 4T1(P) of Co2+, 4A2g → 4T2g of Cr3+, 3T1g(F) → 3T1g(P) and 3A2g(F) → 3T1g(F) of Ni2+, absorption peaks at about 578, 618 and 670 nm were observed in the visible region, making the color center be green. The degree of lightness, greenness and chroma increased, whereas the degree of blueness decreased, making the color of the samples transit from pale green to brilliant green as x value increased.
A convincing interpretation to hexagonal prism ordered-arrangement and self-ordering cell in porous anodic alumina (PAA) is absent up to now. Based on the growth model of oxygen bubble mould effect (OBME) for PAA, a satisfactory explanation for the growth process of hexagonal cells is proposed. The columnar pores and hexagonal cells result from the oxide growth embracing oxygen bubbles. The avalanche electron multiplication at critical thickness dc leads to electronic current which gives rise to the evolution of oxygen gas under anion-contaminated alumina (ACA) layer. The holes on the surface are usually irregular whereas the pores under the surface layer (ACA layer) are big and regular. The thickness of the barrier oxide layer remains constant due to continuous releasing of the oxygen bubbles at the critical thickness. The self-ordering of cell arrangement and the ordered morphology are related to the dissolving process of the ACA layer on PAA surface.
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