scholarly journals A correlation between fracture toughness and cohesion strength of molybdenum thermal sprayed coatings

2018 ◽  
Vol 145 ◽  
pp. 02007 ◽  
Author(s):  
Alexandru Paraschiv ◽  
Gheorghe Matache ◽  
Cristian Puscasu ◽  
Mihaela Grigorescu
Keyword(s):  
Fracture Toughness ◽  
Steel Substrate ◽  
Atmospheric Plasma ◽  
Cohesion Strength ◽  
Indentation Fracture ◽  
Strength Tests ◽  
Indentation Fracture Toughness ◽  
Sprayed Coatings ◽  
Thermal Sprayed Coatings ◽  
Made In

The Molydenum thermal sprayed coatings on steel substrate using electric arc, atmospheric plasma spray and high velocity oxy-fuel spray were investigated. The tensile bond strength tests were made in order to examine the degree of adhesion/cohesion strength of coatings. The Vickers indentation fracture toughness tests were made on parallel and perpendicular direction to the coating-substrate interface in order to examine the fracture toughness of the material in relationship with the microstructure, indentation direction, hardness and the length of microcracks developed under different loads. It was found that the fracture toughness is influenced by the direction and load of indentation. It was established a correlation between the fracture toughness and cohesion strength of Mo coatings and a general trend was described

A Transparent and Tough β-Si3N4 Ceramic with a Whiskery Microstructure

2015 ◽  
Vol 655 ◽  
pp. 1-5
Author(s):  
Peng Xi Li ◽  
Hong Qiang Wang ◽  
Liu Cheng Gui ◽  
Jun Li ◽  
Hai Long Zhang ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Amorphous Phase ◽  
Hot Pressing ◽  
High Density ◽  
Indentation Fracture ◽  
Indentation Fracture Toughness ◽  
Resultant Material

The transparent β-Si3N4ceramic with a whisker-like microstructure was prepared by hot-pressing at 2000 °C for 26 h, with MgSiN2as an additive. The resultant material achieves the maximum transmittance of 70 % at the wavelength of about 2.5 μm and the transmittance value keeps higher than 60 % in the range of 700-4500 nm wavelength, which is attributed to the very small amount of the intergranular amorphous phase along with high density. The present transparent β-Si3N4ceramic exhibits an indentation fracture toughness of 7.2±0.3 MPa m1/2.

Pulsed Electric Current Sintered Cr2O3-rGO Composites

2016 ◽  
Vol 721 ◽  
pp. 419-424
Author(s):  
M. Erkin Cura ◽  
Vivek Kumar Singh ◽  
Panu Viitaharju ◽  
Joonas Lehtonen ◽  
Simo Pekka Hannula
Keyword(s):  
Fracture Toughness ◽  
Graphene Oxide ◽  
Electric Current ◽  
Chromium Oxide ◽  
High Hardness ◽  
High Wear Resistance ◽  
Carbide Formation ◽  
Indentation Fracture ◽  
Pulsed Electric Current ◽  
Indentation Fracture Toughness

Chromium oxide is a promising material for applications where excellent corrosion resistance, high hardness, and high wear resistance are needed. However, its use is limited because of low fracture toughness. Improvement of fracture toughness of chromium oxide while maintaining its afore mentioned key properties is therefore of high interest. In this communication we study the possibility of increasing the toughness of pulsed electric current sintered (PECS) chromium oxide by the addition of graphene oxide (GO). The indentation fracture toughness was improved markedly with the addition of graphene oxide. Materials prepared by direct chemical homogenization had better fracture toughness. In composites with 10 vol.% GO piling of thin graphene oxide layers resulted in the formation of graphite layers between Cr2O3 and in carbide formation, which were observed to be the main reasons for the degradation of the mechanical properties. The distribution of graphene oxide was more homogeneous, when the GO amount was 0.1 vol.% and the formation of graphitic layers were avoided due to lesser amount of GO as well as ultrasonic treatment following the ball milling.

Structure and Properties of Single Crystal Al2O3 Implanted with Chromium and Zirconium

1981 ◽  
Vol 7 ◽  
Author(s):  
C. J. Mchargue ◽  
H. Naramoto ◽  
B. R. Appleton ◽  
C. W. White ◽  
J. M. Williams
Keyword(s):  
Fracture Toughness ◽  
Single Crystal ◽  
Single Crystals ◽  
Solid Solutions ◽  
Rutherford Backscattering ◽  
Structure And Properties ◽  
Indentation Fracture ◽  
Surface Layers ◽  
Indentation Fracture Toughness

ABSTRACTSingle crystals of Al2O3 were implanted with chromium and zirconium to fluences of 1 × 1016 to 1 × 1017 ions cm−2. Rutherford backscattering-channeling studies showed the surface layers to be damaged but crystalline with the implanted ions randomly distributed. The microhardness and indentation fracture toughness were higher for the random solutions than for conventionally formed solid solutions. Changes in structure and properties caused by annealing in air at temperatures up to 1800°C were studied.

The Research of Thermal Arc Sprayed Coatings Tribological Properties by Using Rubber Wheel Test

2015 ◽  
Vol 220-221 ◽  
pp. 693-697 ◽  
Author(s):  
Justinas Gargasas ◽  
Algirdas Vaclovas Valiulis ◽  
Irmantas Gedzevicius ◽  
Hanna Pokhmurska
Keyword(s):  
Wear Resistance ◽  
Mass Loss ◽  
Tribological Properties ◽  
Steel Substrate ◽  
High Wear Resistance ◽  
Tribological Behaviour ◽  
Oxide Inclusions ◽  
Porosity Of Coatings ◽  
Sprayed Coatings ◽  
Thermal Sprayed Coatings

This paper present the result obtained from new experimental STEIN-MESYFIL 953 V; STEIN-MESYFIL 954 V coatings. The surfacing material was wires of 1.6 mm diameter. The tests aimed at determining wear resistance of coatings sprayed on steel substrate. The investigation shows that the tribological behaviour of new experimental thermal arc sprayed coatings is greatly affected by its microstructural constituents such as porosity, oxide inclusions, and microhardness of coatings. Results show that increasing porosity of coatings twice, it doubles the mass loss. Results for thermal sprayed coatings of all experiments showed their high wear resistance and are discussed.

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