Research on the Microstructure and the Growth Mechanism of Oxidation Film of T91 Steels after Service

2012 ◽  
Vol 476-478 ◽  
pp. 144-150
Author(s):  
Wan Li Zhong ◽  
Zheng Gang Li ◽  
Wei Wang ◽  
Bing Yang
Keyword(s):  
Oxide Layer ◽  
Transition Zone ◽  
Layer Structure ◽  
Alloy Element ◽  
Testing Methods ◽  
Intergranular Oxidation ◽  
Double Layer Structure ◽  
Superheater Tube ◽  
Outer Oxide Layer ◽  
Original Metal

The character of structure and the micro-area elements of inner oxidation film were investigated by using metallographic microscope, electron microscopy, energy spectrum analysis and other testing methods based on samples of superheater and reheater tube cutting from three units. The results showed that the inner wall oxide layer of T91 steel superheater tube after running exhibited a double-layer structure, including inner and outer layer, and the interface between the two layers is the original metal surface. There exists a transition zone between the inner oxide film and metal matrix. A concentration gradient of alloy element in transition zone can be observed and the intergranular oxidation is present. The Fe-rich outer oxide layer does not contain Cr, which consists of Fe3O4, and the internal oxidation layer is composed of (Fe,Cr)3O4.

Ignition model of boron particle based on the change of oxide layer structure

2019 ◽  
Vol 37 (3) ◽  
pp. 3033-3044 ◽  
Author(s):  
Xu Hu ◽  
Yihua Xu ◽  
Wen Ao ◽  
Zhuoxiong Zeng ◽  
Chunbo Hu ◽  
...  
Keyword(s):  
Oxide Layer ◽  
Layer Structure ◽  
Boron Particle

Modification of Tribolayers of a Titanium Alloy Sliding against a Steel

2018 ◽  
Vol 140 (4) ◽  
Author(s):  
Y. Zhou ◽  
W. Jiang ◽  
W. Chen ◽  
X. L. Ji ◽  
Y. X. Jin ◽  
...  
Keyword(s):  
Titanium Alloy ◽  
Layer Structure ◽  
Frictional Coefficient ◽  
Tribological Performance ◽  
Wear Loss ◽  
Multilayer Graphene ◽  
Double Layer Structure ◽  
Sustainable Protection ◽  
Wear Transition ◽  
Sliding Distance

The nonprotective tribolayers of the titanium alloy were modified into additives-containing tribolayers through an artificial addition of multilayer graphene (MLG), Fe2O3 nanomaterials, or their mixtures with various proportions on the titanium alloy/steel sliding interface. The sustainability of the modified tribolayers under a high load was evaluated by the critical sliding distance for a mild-to-severe wear transition. The modified tribolayers were found to significantly improve or deteriorate tribological performance of the titanium alloy, which was decided by their ingredients. The pure MLG- or Fe2O3-containing tribolayers, because of their lacking load-bearing or lubricant capacity, presented poor sustainability and readily lost protection to cause high wear loss or frictional coefficient. However, for the addition of various mixtures of MLG and Fe2O3, the modified tribolayers possessed a double-layer structure consisting of friction-reducing MLG- and wear-resistant Fe2O3-predominated layers. They presented a sustainable protection, thus remarkably improving the tribological performance of the titanium alloy.

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