Annealing stabilization

Chemically stabilized alloys such as Type 321 SS are available in a heat-treated condition known as stabilization annealed. In this condition, such alloys have maximum resistance to sensitization and its effects. Sensitization is discussed in Section 21.4. 

Special alloy composition requirements may be necessary to assure proper stabilization annealing [15]. These requirements limit the ratios of Ti/C in Type 321 stainless steel and of Cb/C in Type 347. The protection provided by a stabilization anneal can be partially destroyed by welding, since some chromium carbides may form. For full protection, welds made after the stabilization anneal should be restabilized. Type 321 SS is more susceptible to this welding effect than is Type 347. 

Several stabilized nickel-based high alloys (such as Alloy 825 (22Cr-42Ni-3Mo, Ti stabilized) (UNS N08825) are resistant to sensitization. They are usually furnished in the stabilization annealed condition but may be made susceptible to sensitization by subsequent PWHTs. The alloy manufacturer should be consulted before undertaking stress relief or PWHTs. 

After the anodization process, most of the time, a stabilization annealing at low temperature (below 500 °C) is performed in an O2 or in a N2 ambient. In some cases, an oxidation annealing is performed at higher temperature. Afterwards, a thin oxide cap layer is generally deposited to seal the pores and to ensure a complete DC isolation between the substrate and the device. Various metal layers can be used for the strips. To reduce the ohmic losses, low-resistivity metals must be used... 

Determine if a stabilized alloy, such as alloy 825 (UNS N08825), has received a proper stabilizing anneal. In this case a 677°C (1250°F)/1 h sensitization heat treatment... 

Solid-state C NMR techniques have been applied to the characterization of the different phases of several polybibenzoates [25,30], including P7MB, PDTMB and PTEB. The last two polymers offer the advantage of the stability of the mesophase at room temperature. The spectra corresponding to the pure mesophase of these samples only exhibited a broad component, while the spectra of the annealed samples were separated into two components crystal and noncrystal. The shapes of the mesophase and the noncrystal components are very similar, and only modest variations in the relaxation times were observed between these two components. The degree of crystallinity of these samples was determined... 

Sueh a behaviour of metastability has been reported in the systems Cu65Pt35 and CuAu3. It has been shown that for inereased annealing time or after meehanieal deformation LRO is obtained, whereas for too short annealing times in homogenised material only the variation of SRO with temperature is deteeted. This may lead to serious misinterpretation of alloy stability if not carefully enough investigated. 

Moreover, it was found that incorporation of nanoparticles about 8 nm in diameter in a-Si H led to improved properties, the most important one being enhanced stability against light soaking and thermal annealing [387]. A later study revealed a typical crystallite size of 2-3 nm. with a hexagonal close-packed structure [388]. Diamond structures can also be observed [389]. Hence the name polymorphous silicon is justified. 

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