Ceramic dispersion strengthening

Aesthetic dental ceramics are essentially glass-matrix materials with varying volume fractions of crystalline fillers. Crystalline fillers are used in the glass matrix both for dispersion strengthening, usually at volume fractions of 40—70%, and for altering optical properties, usually at low volume fractions. Dental ceramics are generally manufactured from two distinct classes of materials, ie, beneficiated feldspathic minerals and glass—ceramics. 

Oxidative damage, role of ascorbic acid in preventing, 25 769 Oxidative degradation, 70 682 of gasoline, 72 399-400 Oxidative dehydrogenation, 23 342-343 Oxidative pyrolysis, 27 466 Oxidative stability, of olefin fibers, 77 229 Oxidative stability test, 72 400 Oxide crystal glass-ceramics, 72 641 Oxide-dispersion-strengthened alloys, 77 103-104... 

M. P. Borom, Dispersion-Strengthened Glass Matrices - Glass-Ceramics, A Case in Point, J. Am. Ceram. Soc. 60, 17-21 (1977). 

Particle reinforced composite systems can be either large particle or dispersion strengthened. If a composite is reinforced by large particles (larger than 0.1 [xm and equiaxed, which are harder and stiffer than the matrix), mechanical properties are dependent on volume fractions of both components and are enhanced by increase of particulate content. Concrete is a common large particle strengthened composite where both matrix and particulate phases are ceramic materials. 

An ability to build coded heat exchangers in a variety of nickel-based alloys, oxide dispersion strengthened alloys (ODS) and ceramic materials to address the temperature, life and corrosion issues associated with these demanding duties. 

In composites, different materials are combined to exploit favourable properties of each. That such combinations may be attractive was already shown in section 6.4.4 for particle strengthening of metals and in section 7.5 for dispersion-strengthened ceramics. 

Identify the main classes of stmctural materials for Generation-IV reactors steels oxide dispersion strengthened (ODS) steels refractory alloys ceramics composites. 

For such systems, metals, oxide dispersion-strengthened (ODS) alloys, ferritic-martensitic steels, and some superaUoys offer potential solutions but some require significant R D in terms of their properties and behavior under component conditions. Such systems may also require the deployment of nonmetallic materials (e.g., high-temperature fibrous insulation, composites, and ceramics) as alternatives to metals for different applications and components. The following sections provide a brief description of the six systems being considered within the GIF technology roadmap. 

D.P.H. Hasselman, R.M. Fulrath, Proposed Fracture Theory of a Dispersion Strengthened Glass Matrix,. Am. Ceram. Soc., 1966,... 

From the above evaluation, it seems that a good alternative may be a matrix of a metallic phase with high hydrogen permeability strengthened by a dispersion of ceramic particles (alternative ii). For this class of materials, flux densities have been measured to be of the order of 10-30 mL mim cm 2 using 1 atm total pressure with H2 as feed gas and He as sweep gas. In general, the flux in these materials increases with in the feed gas and is inversely proportional to the thick-... 

S. Sato, M. C. Chu, Y. Kobayashi and K. Ando, Strengthening of Mullite by Dispersion of Carbide Ceramics Particles (2nd Report, Effect of SiC grain Size and Heat Treatment), Jpn. Soc. Meek Eng., 61,1023-1030 (1995). (in Japanese)... 

To summarize, the effects of the addition of a second phase in the form of particles, as illustrated above, explain why small particles dispersed in a ceramic matrix are an integral part of the matrix strengthening of ceramic materials. 

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