Study on Erosion Wear Mechanism of SiC/(W,Ti)C Gradient Ceramic Nozzle Material

2008 ◽  
Vol 375-376 ◽  
pp. 440-444
Author(s):  
Li Li Liu ◽  
Jian Xin Deng
Keyword(s):  
Wear Resistance ◽  
Gradient Material ◽  
Gradient Structure ◽  
Erosion Wear ◽  
Indentation Fracture ◽  
Sand Blasting ◽  
Functionally Gradient ◽  
Test Conditions ◽  
Indentation Fracture Toughness ◽  
The Common

Idea of functionally gradient material (FGM) theory was used to the design of ceramic nozzle. The purpose was to increase the erosion wear resistance at the entrance of the nozzle in dry sand blasting processes. The SiC/(W,Ti)C gradient ceramic nozzles fabricated by conventional hot pressing. The erosion behavior of the SiC/(W,Ti)C gradient ceramic nozzles were investigated in comparison with the common homologous ceramic nozzles. The experimental results have shown that the ceramic nozzles with a gradient structure have superior erosion wear resistance to that of the common homologous ceramic nozzles under the same test conditions. It was shown that the mechanical properties of the gradient ceramic nozzle materials were greatly improved in comparison with that of the common homologous nozzles. The surface Vickers hardness and indentation fracture toughness of gradient ceramic nozzle were greatly improved compared with that of the common homologous nozzles. Therefore, it is indicated that gradient structures in ceramic nozzles is an effective way to improve the erosion wear resistance of the common homologous nozzles.

Erosion Wear and Design Model of Functionally Gradient Ceramic AJM Nozzle

2006 ◽  
Vol 315-316 ◽  
pp. 637-640
Author(s):  
Li Li Liu ◽  
Jian Xin Deng ◽  
Jun Zhou
Keyword(s):  
Maximum Stress ◽  
Gradient Material ◽  
Erosion Wear ◽  
Composition Distribution ◽  
Functionally Gradient Material ◽  
Abrasive Jet Machining ◽  
Functionally Gradient ◽  
Physical Composition ◽  
Stress States ◽  
Minimum Stress

The stress states of the ceramic nozzle in abrasive jet machining (AJM) process are analyzed. Results shown that the maximum stress appears in entrance area of the nozzle and minimum stress in middle area, while the stress of exit area was lower than entrance area and higher than middle area. It can interprets why the entrance and exit area of the nozzle were worn badly. The idea of functionally gradient material (FGM) theory was used to design of ceramic nozzle. The purpose was to reduce the stresses at the entrance and exit area of the nozzle during AJM processes. The physical, composition distribution, and property parameter models of the FGM nozzle were established.

scholarly journals High Velocity Oxygen Liquid-Fuel (HVOLF) Spraying of WC-Based Coatings for Transport Industrial Applications

Metals ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1675
Author(s):  
Janette Brezinová ◽  
Anna Guzanová ◽  
Jana Tkáčová ◽  
Jakub Brezina ◽  
Kristína Ľachová ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Wear Resistance ◽  
Cross Sections ◽  
Wear Test ◽  
Alloy Coating ◽  
Industrial Applications ◽  
Point Of View ◽  
Indentation Fracture ◽  
Indentation Fracture Toughness ◽  
Impact Angles

In this article, we analyse five types of coatings, in terms of their microstructure, hardness, porosity, and wear resistance, in the as-sprayed state. The coatings are WC-based (WC-FeCrAl, WC-WB-Co, and WC-NiMoCrFeCo), alloy-based (Co-MoCrSi), or nanoWC coating-based (nanoWC-CoCr). Two tests were applied to assess the wear resistance of the coatings: a dry-pot wear test with two impact angles and an abrasive test using an abrasive cloth with two grit sizes. Porosity was determined by image analysis. Vickers impression was performed on cross-sections of the coatings, in order to determine their indentation fracture toughness. The highest hardness of the tested coatings was recorded for the nanoWC coating, followed by the rest of the WC-based coatings; meanwhile, the lowest hardness was recorded for the alloy coating. Minimal porosity was achieved by the alloy coating, due to its different nature and the absence of hard particles with a higher melting point. The NanoWC coating and other WC-based coatings had a higher porosity; however, porosity did not exceed 1% for each coating. The best wear resistance was achieved by the nanoWC coating, followed by the other WC-based coatings, with the lowest obtained by the alloy coating. The same tendency was recorded when determining the indentation fracture toughness. From a microscopic point of view, the structure of the evaluated coatings is not compact; nevertheless, their properties are excellent, and they act as compact coatings under load.

Sand Erosion Performance of Gradient Ceramic Nozzles by Abrasive Air-Jets

2006 ◽  
Author(s):  
Jianxin Deng
Keyword(s):  
Wear Resistance ◽  
Abrasive Particle ◽  
Particle Impact ◽  
Erosion Wear ◽  
Apparent Increase ◽  
Air Jets ◽  
Air Jet ◽  
Sand Erosion ◽  
The Common ◽  
Compressive Residual Stresses

A SiC/(W,Ti)C ceramic nozzle with gradient structures was produced by hot pressing. The purpose is to reduce the tensile stress at the entry region of the nozzle in abrasive air-jet. The sand erosion performance of this kind gradient ceramic nozzle caused by abrasive particle impact was investigated by abrasive air-jets in comparison with the common one. Results showed that the gradient ceramic nozzles exhibited an apparent increase in erosion wear resistance over the common ceramic nozzles. The mechanism responsible was explained as the formation of compressive residual stresses in nozzle entry region in fabricating process of the gradient ceramic nozzles, which may partially counteract the tensile stresses resulting from external loadings. It is indicated that gradient structures in ceramic nozzles is an effective way to improve the erosion wear resistance of common ceramic nozzles.

scholarly journals Comparison of Different Cermet Coatings Sprayed on Magnesium Alloy by HVOF

Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1594
Author(s):  
Ewa Jonda ◽  
Leszek Łatka ◽  
Wojciech Pakieła
Keyword(s):  
Fracture Toughness ◽  
Wear Resistance ◽  
Magnesium Alloy ◽  
Wear Intensity ◽  
Instrumented Indentation ◽  
Indentation Fracture ◽  
Noticeable Effect ◽  
Cermet Coatings ◽  
Magnesium Alloy Az31 ◽  
Indentation Fracture Toughness

In the present study, two different cermet coatings, WC–CrC–Ni and Cr3C2–NiCr, manufactured by the high-velocity oxy-fuel (HVOF) method were studied. They are labeled as follows: WC–CrC–Ni coating—WC and Cr3C2–NiCr coating—CrC. These coatings were deposited onto a magnesium alloy (AZ31) substrate. The goal of the study was to compare these two types of cermet coating, which were investigated in terms of microstructure features and selected mechanical properties, such as hardness, instrumented indentation, fracture toughness, and wear resistance. The results reveal that the WC content influenced the hardness and Young’s modulus. The most noticeable effect of WC addition was observed for the wear resistance. WC coatings had a wear intensity value that was almost two times lower, equal to 6.5·10−6 mm3/N·m, whereas for CrC ones it was equal to 12.6·10−6 mm3/N·m. On the other hand, the WC coating exhibited a lower value of fracture toughness.

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.

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