Aluminum stress

U. Basu, A. Basu, and G. J. Taylor, Differential exudation of polypeptides by roots of aluminum-resistant and aluminum-sensitive cultivars of Triticum aestivum L. in re.spon.se to aluminum stress. Plant Physiol. 706 151 (1994). 

S. J. Zheng, j. F. Ma, and H. Matsumoto, Continuous secretion of organic acid is related to aluminum resistance in relatively long-term exposure to aluminum stress. Phy.siol. Plant 703 209 (1998). 

Hudson M. J. and Sangster A. G. (2000) Aluminum localization in conifers growing on highly acidic soils in Ontario, Canada. In International Symposium on Impact of Potential Tolerance of Plants on the Increased Productivity Under Aluminum Stress. Research Instimte for Bioresources, Okayama University, pp. 103-106. 

Konishi S, Miyamoto S. Alleviation of aluminum stress and stimulation of tea pollen tube growth by fluorine. Plant Cell Physiol 1983 24 857-62. 

Wenzel P, Chaves AL, Patino GM, Mayee JE and Rao 1M (2002) Aluminum stress stimulates the accumulation of organic acids in root apices of Bra-chiaria species J Plant Nutr Soil Sci 165 582-588. 

Matsumoto H (2002) Plant roots under aluminum stress Toxicity and tolerance. In Waisel Y, Eshel A and Kafkafi U, eds. Plant roots the hidden half 3rd edn, pp. 821-838. Marcel Dekker, New York. 

Hutchinson, T.C., L. Bozie, and G. Munoz-Vega. 1986. Response of five species of conifer seedlings to aluminum stress. Water Air Soil Poll. 31 283-294. 

Nickel—Copper. In the soHd state, nickel and copper form a continuous soHd solution. The nickel-rich, nickel—copper alloys are characterized by a good compromise of strength and ductihty and are resistant to corrosion and stress corrosion ia many environments, ia particular water and seawater, nonoxidizing acids, neutral and alkaline salts, and alkaUes. These alloys are weldable and are characterized by elevated and high temperature mechanical properties for certain appHcations. The copper content ia these alloys also easure improved thermal coaductivity for heat exchange. MONEL alloy 400 is a typical nickel-rich, nickel—copper alloy ia which the nickel content is ca 66 wt %. MONEL alloy K-500 is essentially alloy 400 with small additions of aluminum and titanium. Aging of alloy K-500 results in very fine y -precipitates and increased strength (see also Copper alloys). 

Other alloys have been developed for use in particular corrosive environments at high temperatures. Several of these are age-hardenable alloys which contain additions of aluminum and titanium. Eor example, INCONEL alloys 718 and X-750 [11145-80-5] (UNS N07750) have higher strength and better creep and stress mpture properties than alloy 600 and maintain the same good corrosion and oxidation resistance. AHoy 718 exhibits excellent stress mpture properties up to 705°C as well as good oxidation resistance up to 980°C and is widely used in gas turbines and other aerospace appHcations, and for pumps, nuclear reactor parts, and tooling. 

Calcium—Silicon. Calcium—silicon and calcium—barium—siUcon are made in the submerged-arc electric furnace by carbon reduction of lime, sihca rock, and barites. Commercial calcium—silicon contains 28—32% calcium, 60—65% siUcon, and 3% iron (max). Barium-bearing alloys contains 16—20% calcium, 9—12% barium, and 53—59% sihcon. Calcium can also be added as an ahoy containing 10—13% calcium, 14—18% barium, 19—21% aluminum, and 38—40% shicon These ahoys are used to deoxidize and degasify steel. They produce complex calcium shicate inclusions that are minimally harm fill to physical properties and prevent the formation of alumina-type inclusions, a principal source of fatigue failure in highly stressed ahoy steels. As a sulfide former, they promote random distribution of sulfides, thereby minimizing chain-type inclusions. In cast iron, they are used as an inoculant. 

Shipment nd Stora.ge, Sulfur monochloride is minimally corrosive to carbon steel and iron when dry. If it is necessary to avoid discoloration caused by iron sulfide formation or chloride stress cracking, 310 stainless steel should be used. Sulfur monochloride is shipped in tank cars, tank tmcks, and steel dmms. When wet, it behaves like hydrochloric acid and attacks steel, cast iron, aluminum, stainless steels, copper and copper alloys, and many nickel-based materials. Alloys of 62 Ni—28 Mo and 54 Ni—15 Cr—16 Mo are useful under these conditions. Under DOT HM-181 sulfur monochloride is classified as a Poison Inhalation Hazard (PIH) Zone B, as well as a Corrosive Material (DOT Hazard Class B). Shipment information is available (140). 

Tellurium has been recommended as an additive to magnesium to increase corrosion resistance (see Corrosion and corrosion control). The addition is highly exothermic but can be controUed by adding one teUurium tablet at a time to a sufficiently large bath of Uquid magnesium. The addition to teUurium and chromium improves the stress-corrosion resistance of aluminum—magnesium aUoys. 

Titanium does not stress-crack in environments that cause stress-cracking in other metal alloys, eg, boiling 42% MgCl2, NaOH, sulfides, etc. Some of the aluminum-rich titanium alloys are susceptible to hot-salt stress-cracking. However, this is a laboratory observation and has not been confirmed in service. Titanium stress-cracks in methanol containing acid chlorides or sulfates, red Aiming nitric acid, nitrogen tetroxide, and trichloroethylene. 

Materials of Construction. GeneraHy, carbon steel is satisfactory as a material of construction when handling propylene, chlorine, HCl, and chlorinated hydrocarbons at low temperatures (below 100°C) in the absence of water. Nickel-based aHoys are chiefly used in the reaction area where resistance to chlorine and HCl at elevated temperatures is required (39). Elastomer-lined equipment, usuaHy PTFE or Kynar, is typicaHy used when water and HCl or chlorine are present together, such as adsorption of HCl in water, since corrosion of most metals is excessive. Stainless steels are to be avoided in locations exposed to inorganic chlorides, as stainless steels can be subject to chloride stress-corrosion cracking. Contact with aluminum should be avoided under aH circumstances because of potential undesirable reactivity problems. 

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