Manufacture of iron-based, amorphous coatings with high fracture toughness

19th Chemnitz Seminar on Materials Engineering – 19. Werkstofftechnisches Kolloquium

Bobzin, K.^1 ; Öte, M.^1 ; Königstein, T.^1

Surface Engineering Institute of RWTH Aachen University, Kackertstr. 15, Aachen

52072, Germany^1

关键词: Amorphous structures;    Crystallization energy;    High velocity oxygen fuel spraying;    Indentation modulus;    Innovative approaches;    Linear relationships;    Thermal spraying technology;    Tribological performance;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/181/1/012012/pdf
DOI  :  10.1088/1757-899X/181/1/012012

来源: IOP

【 摘 要 】

Amorphous iron-based material have excellent corrosion behaviour, show good tribological performances and exhibit interesting thermophysical properties. The deposition as a coating system by thermal spraying technology is an innovative approach to manufacture these materials. In this study, the mechanical properties of three iron-based amorphous coatings with different chromium content xCr= 0, 5 and 15 at.% are presented deposited by means of High Velocity Oxygen Fuel Spraying. For the determination of the amorphous content the linear relationship between crystallization energy and amount of amorphous structures is used. Comparing the crystallization energies of amorphous ribbons manufactured by melt spinning to those of feedstock materials and free standing coatings, assumptions regarding the amorphous contents are drawn. The results show that the amorphous content in the feedstock material is influenced by the amount of chromium content. Furthermore, the amorphous content of all coatings do not exceed those of the feedstock materials. Powder xCr= 15 at.% and the corresponding coating exhibit smallest amount of amorphous structure, presumably due to a not fully melted state of the impacting particles. The values of fracture toughness of the coatings are determined by means of indentation and subsequent measurement of the crack lengths. Furthermore, values of indentation modulus and hardness are measured and compared to each other. While length of indentation cracks decreases with increasing chromium content, an increase in indention modulus and hardness is observed. In comparison to ceramic reference YSZ and the steel reference 1.4404, all amorphous coatings show promising properties such as low indentation crack lengths and high hardness.