Heat treatment conditions

Z varies from -0.23 to - 0.64 over the heat treatment temperature range 2673 to 3273 K, and the term (e +Z) in Eq. (5) therefore varies from 0 to -0.4 over the same temperature range. Equation (6) was then substituted back into eq. (5) which was used to refit the data to determine the relationship between X and the heat treatment conditions (time and temperature, Eqs. 7 and 8). The empirical parameter X in Eq. (5) was found to be given by... 

BSI Designation Alloy Elements Heat Treatment Condition Mechanical Properties Tensile Strength Hardness (N/mm2) (DPN) ... 

These values are roughly constant across a range of electrolyte environments except where noted but the variations between alloys, heat treatment conditions, etc. creates a range for each metal. For some metals such as iron and steel the range is low ( 100 mV), but for lead, nickel, stainless steels a range is given. The corrosion potential is reported with respect to the saturated calomel reference electrode. 

Steiner, A., Effect of Phosphorous Level on General and Intercrystalline Corrosion in 18/8 Type Steel , Pr. Inst. Hutn., 24, 255 (1972) C.A., 80, 6185n Anisimova, M. S. and Chikurova, A. A., Effects of Heat-treatment Conditions and Structure of Khl8N9TL Cast Steel on its Susceptibility to Intercrystalline Corrosion , Optimiz Met. Protsessov, 6, 163 (1972)... 

Fig. 8.24 Influence of heat-treatment conditions on the sub-critical stress corrosion growth rate of a nickel-bearing SS as a function of stress intensity. In the as-quenched condition, the steel shows much faster crack grown rates (after Spaehn )...

Al-Mg (5000 Series) and Al-Mg-Si (6000 Series) In the binary alloy system strength is obtained mainly by strain hardening. Stress corrosion is thought to be associated with a continuous grain boundary film of Mg,Alg which is anodic to the matrix . Air cooling prevents the immediate formation of such precipitates, but they form slowly at ambient temperatures. Thus only low Mg alloys are non-susceptible (Al-3% Mg). Widespread precipitation arising from plastic deformation with carefully controlled heat-treatment conditions can lower susceptibility. Al-5Mg alloys of relatively low susceptibility are subjected to such treatments. Mn and Cr... 

Sonochemical synthesis of nanostmctured anatase and study of the kinetics among phase transformation and coarsening as a function of heat treatment conditions. J Eur Ceramic Soc 28 1585-1594... 

Aluminas are amphoteric, hence, they possess acidic and basic properties that are controlled by the surface groups or ions which terminate the microcrystallites [91]. The acidic and basic properties of these materials can be modified by the heat treatment conditions and by incorporating additives, such as halogen or alkali. 

To arrange NC or nanoparticles into an assembly is inevitable in order to utilize them for practical purposes. An assemblage in a finely regulated manner is always desired. It is therefore developed to control the interparticle separation. One of the most interesting methods, very rational but not too complicated, is the use of the thermal change in the state of surfactants adsorbed on the surface of nanoparticles. Kotov et al. (30) showed that the interparticle separation of titania NC of 2.0 0.5 nm could be controlled from 0.9 nm to 0.2 nm depending on the heat treatment condition, from 90 min at 70°C to 120 min at 90°C. 

Heat Treatment Conditions. Because of very finite process constraints In the food processing Industry, the heat treatment required for gel formation Is extremely critical when assessing the applicability of a given protein to a specific food formulation. For example, replacement of myosin (which has relatively low gel temperature requirement) In a hot dog formulation with a protein preparation requiring extremely high temperature for comparable gelation would not be desirable. 

While gelation temperature Is usually considered a characteristic property of a given protein system, the heating conditions required for gel formation may be Interrelated to all of the previously mentioned factors. It has been observed that WPG dispersions In 0.2 M NaCl will gel at 75 C while a temperature of 90 C Is required to gel WPG dispersions In distilled water (1). Heating time, at a specific temperature, required to form a protein gel structure Is generally considered to decrease with Increased protein concentration. Alteration of heat treatment conditions affects the gel s macroscopic and microscopic structural attributes. This has been dramatically shown by Tombs (A) with electromlcroscoplc evaluation of bovine serum albumin gels. 

In the process of photocatalysis, the electrons and holes produced on photoirradiated Ti02 powders are trapped at the particle surface to form unpaired-electron species (step (4) in Fig.D.3). Photocatalytic reactions are actually the reactions of these radicals with reactant molecules at the Ti02 surface. Electron spin resonance (ESR) spectroscopy has been used for the detection of the photoproduced radicals on Ti02 at low temperatures such as 77 K. It has been reported that photoproduced electrons are trapped at various different sites titanium atoms on the surface or inside the particles, or oxygen molecules adsorbed on the surface. On the other hand, photoproduced holes are trapped at lattice OAygen atoms near the particle surface or at surface hydroxyl groups. We analyzed these radical species for several Ti02 photocatalysts that are commercially available, and found that the differences in the photoproduced radicals resulted from different heat-treatment conditions and the reactivity with several molecules.17)... 

Figure 10.6 XRD patterns (a) As-obtained Sm2FeI7 ingot (powdered), and (b-d) Samples heated at various temperatures (573-873 K). Heat treatment conditions CH4-N2-H2 (molar ratio = 1 1 4), 1 X 105 Pa (atmospheric pressure), and 2 h.24...

POSTER TITLE Partitioning behavior of AI2Ca and eutectic Si modification with varying heat treatment conditions in AI-7Si-0.4Mg alloy with AI2Ca (PAPER ID 8826)... 

Nickel-copper alloys The physical properties ate foi annealed material. Both the tensile strength and hardness can vary with form and heat treatment condition. 

Yajima T, Itai S, Takeuchi H, Kawashima Y. Optimum heat treatment conditions for masking the bitterness of clarithromycin wax matrix. Chem Pharm Bull 2003 51(11) 1223-1226. 

Figure 3. X-ray diffraction patterns of arc-melted silicon boride (B=90mol%) after heat-treatment. The heat-treatment conditions are (a) 1538K, 5hr (b) 1538K, 40hr (c) 1673K, 0.5hr (d) 1673K, 2hr.

From the surface chemistry studies, it is seen that the titanium-water vapor surface reaction rate is very fast. The reaction rate constant kc at room temperature is of the order of 10 Pa s and supports the transport controlled for crack growth. (Although there is a slower additional reaction, its contribution to crack growth appears to be small, and no further consideration was given to it.) Conformance of the data to the model for transport controlled crack growth is shown in Fig. 9.13 at two AK levels and two heat treatment conditions. 

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