Coated particles sintering

After gas-phase oxidation reaction finished, the reactor wall surfece was coated with a thick rough scale layer. The thickness of scale layer along axial direction was varied. The scale layer at front reactor was much thicker than that at rear. The SEM pictures were shown in Fig. 1 were scale layers stripped from the reactor wall surface. Fig. 1(a) was a cross sectional profile of scale layer collected from major scaling zone. Seen from right side of scale layer, particles-packed was loose and this side was attached to the wall surface. Its positive face was shown in Fig. 1(b). Seen from left side of scale layer, compact particles-sintered was tight and this side was faced to the reacting gases. Its local amplified top face was shown in Fig. 1(c). The XRD patterns were shown in Fig. 2(a) were the two sides of scale layer. Almost entire particles on sintered layer were characterized to be rutile phase. While, the particle packed layer was anatase phase. 

Proppants are solid particles used to hold open the fracture after conclusion of the well treatment. Criteria to choose the economically most effective proppant for a given set of formation conditions have been discussed (7 6). While sand is the most commonly used proppant because of its low cost, resin-coated sand, sintered bauxite, and A O particles have also been used because of their greater compressive strength and resistance to dissolution at high temperature and pH (55). While epoxy resins are most commonly used, the use of other resins such as phenol-formaldehyde has been described. 

Since the pigments are subjected to considerable thermal stress during this conversion, the FeOOH particles are stabiUzed with a protective coating against sintering (usually silicates [5.7], phosphates [5.8], chromates [5.9], or organic compounds such as fatty acids [5.10]). 

The sol-gel process is used to prepare dense, spherical particles of ThOa and (Th,U)02 for sphere-pac and coated-particle fuels. The thoria is dispersed in water from nitrate solutions by slow heating and steam denitration to form a stable sol from which spherical particles are produced. The sol droplets are injected at the top of a tapered glass column containing an upward flow of 2-ethylhexarol (2-EH). The water from the sol particles is slowly extracted by suspension in the 2-EH, and the gelled spheres drop out of the column. Coalescence of the particles is prevented with surfactants in the 2-EH. The sol-gel spheres are dried in steam and Ar at 220°C and sintered in H2 at ISOO C. 

Jagota A (1994) Simulation of the viscous sintering of coated particles. J Am Ceram Soc 77 2237-2239... 

The coats are sintered at a temperature in the range of 400-420 °C. The grain size of the PEEK powder has a mean grain size of about 20 xm. Suitable inert fillers are from the group of metal oxides, silica, mica particles, and flaked fillers. 

On the other hand, the USA adopts a block type fuel element in HTGRs. In this fuel element, coated particle fuel and graphite powder are mixed and sintered, then shaped into thin rods, and loaded and sealed into holes in a hexagonal column-shaped graphite block. The experimental... 

Korematsu A, Furuzono T, Yasuda S et al (2005) Nano-scaled hydroxyapatite/polymer composite III. Coating of sintered hydroxyapatite particles on poly(4-methacryloyloxyethyl trimeUitate anhydride)-grafted silk fibroin fibers. J Mater Sci Mater Med 16 67-71... 

Furuzono, T., Kishida, A., and Tanaka, J. (2004) Nano-scaled hy-droxyapatite/polymer composite 1. Coating of sintered hydroxyapatite particles on poly(y-methacrylopropyl trimethoxysilanej-grafted silk fibroin fibers through chemical bonding. J. Mater. Sci. - Mater. Med., 15, 19-23. 

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