Solvothermal Modified Layers against High Temperature Corrosion

2015 ◽  
Vol 825-826 ◽  
pp. 621-627 ◽  
Author(s):  
Silke Wöllmer ◽  
Andrea Förg ◽  
Sebastian Schuster ◽  
Patrick J. Masset
Keyword(s):  
High Temperature ◽  
Driving Force ◽  
State Of The Art ◽  
Waste Incineration ◽  
High Temperature Corrosion ◽  
Self Healing ◽  
Waste Gas ◽  
Innovative Process ◽  
Lower Porosity ◽  
Nickel Based Alloy

Service and downtimes of waste incineration plants generate high expenses for their operators. State of the art is to protect high corrosion exposed components by cladding them with a nickel based alloy. The welded overlay is 2-3 mm thick and very expensive. It needs to be repaired at each service interval. An alternative coating consists of a thermal sprayed multilayer of a nickel based bondcoat and a ceramic topcoat. Thickness and costs of this multilayer are assumed to be in the range of about 10% of the currently used coating. A solvothermal treatment chemically densifies the coating. This leads to a significantly lower porosity whilst improving cohesion and hardness properties. This innovative process leads to a self-healing layer caused by the high temperature waste gas exposition as the driving force.

High-temperature corrosion resistance of SiO2-forming materials

2018 ◽  
Vol 36 (1) ◽  
pp. 65-74 ◽  
Author(s):  
Kazuya Kurokawa ◽  
Toto Sudiro ◽  
Tomonori Sano ◽  
Shoji Kyo ◽  
Osamu Ishibashi ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
High Temperature ◽  
Mechanical Strength ◽  
Corrosion Behavior ◽  
Driving Force ◽  
Operating Temperature ◽  
High Temperature Corrosion ◽  
High Mechanical Strength ◽  
Increasing Demand ◽  
Plant Efficiency

AbstractAn increasing demand for electricity and preserving the environment has become a great driving force for the development of advanced boilers for coal-fired plants to improve their plant efficiency by raising the operating temperature. To achieve this purpose, the development of materials that possess a high mechanical strength and excellent resistance against corrosion at high temperatures is required. Considering such situation, the high-temperature corrosion behavior of SiO2-forming materials such as CrSi2-Ni and CoNiCrAlY-Si alloys in atmospheres containing NaCl and Na2SO4 is introduced. The SiO2 scale plays a significant role in suppressing the inward diffusion of sulfur and chlorine, resulting in the remarkable suppression of the formation of sulfide and chloride at the scale/substrate interface and inside of the substrate. Based on such results, it is emphasized that SiO2-forming materials show outstanding corrosion resistance against atmospheres containing NaCl and Na2SO4.

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