scholarly journals An Evaluation of Indentation and Finishing Properties of Bearing Grade Silicon Nitrides

1995 ◽  
Author(s):  
James F. Dill ◽  
Michael N. Gardos ◽  
Robert G. Hardisty
Keyword(s):  
Fracture Toughness ◽  
Silicon Nitride ◽  
Ceramic Materials ◽  
Initial Study ◽  
Indentation Hardness ◽  
Simple Relationship ◽  
Machining Performance ◽  
General Applicability ◽  
Load Dependence ◽  
Time Required

This paper describes the results of studies of the machining performance and the indentation hardness and fracture toughness of different silicon nitride materials as part of an effort to better define the optimum machining conditions for bearing components. This work builds on prior efforts by two of the authors, Gardos and Hardisty (1993) who formulated a simple relationship between diamond grinding performance of silicon nitride bearing balls and a wear equation first detailed by Evans and Wilshaw (1976). The goal of this present work was to determine the general applicability of such a relationship, i.e. could simple indentation studies be used to define finishing conditions for different silicon nitride materials. The availability of such a simple test would reduce the time required for developing an acceptable process when a supplier changes his formulation, or when a new material becomes available. Quicker development of optimum finishing conditions would eventually result in a lower-cost product for users. The initial study by Gardos and Hardisty (1993) was based on limited data taken at a fixed set of conditions. This study expanded the range of conditions evaluated and the number of ceramic materials studied in an effort to define the universality of the relationship between grinding wear, hardness and toughness. This study has shown that no simple relationship like that first envisioned by the authors exists. The results showed that the grinding wear of the individual silicon nitride materials increased at different rates as a function of load. Because of the differences found in the load dependence of grinding rates, no simple relationship between hardness, fracture toughness and grinding rate could be found which fit the data over the range of conditions studied. This work is part of an ARPA funded effort to provide a tribological performance database on ceramic bearing materials, including their grinding and finishing properties, and their interaction with standard bearing steels.

An Evaluation of Indentation and Finishing Properties of Bearing Grade Silicon Nitrides

1997 ◽  
Vol 119 (1) ◽  
pp. 196-199 ◽  
Author(s):  
J. F. Dill ◽  
M. N. Gardos ◽  
R. G. Hardisty
Keyword(s):  
Fracture Toughness ◽  
Silicon Nitride ◽  
Ceramic Materials ◽  
Initial Study ◽  
Indentation Hardness ◽  
Simple Relationship ◽  
Machining Performance ◽  
General Applicability ◽  
Load Dependence ◽  
Time Required

This paper describes the results of studies of the machining performance and the indentation hardness and fracture toughness of different silicon nitride materials as part of an effort to better define the optimum machining conditions for bearing components. This work builds on prior efforts by two of the authors, Gardos and Hardisty (1993) who formulated a simple relationship between diamond grinding performance of silicon nitride bearing balls and a wear equation first detailed by Evans and Wilshaw (1976). The goal of this present work was to determine the general applicability of such a relationship, i.e., could simple indentation studies be used to define finishing conditions for different silicon nitride materials? The availability of such a simple test would reduce the time required for developing an acceptable process when a supplier changes his formulation, or when a new material becomes available. Quicker development of optimum finishing conditions would eventually result in a lower-cost product for users. The initial study by Gardos and Hardisty (1993) was based on limited data taken at a fixed set of conditions. This study expanded the range of conditions evaluated and the number of ceramic materials studied in an effort to define the universality of the relationship between grinding wear, hardness, and toughness. This study has shown that no simple relationship like that first envisioned by the authors exists. The results showed that the grinding wear of the individual silicon nitride materials increased at different rates as a function of load. Because of the differences found in the load dependence of grinding rates, no simple relationship between hardness, fracture toughness, and grinding rate could be found that fit the data over the range of conditions studied. This work is part of an ARPA funded effort to provide a tribological performance database on ceramic-bearing materials, including their grinding and finishing properties, and their interaction with standard bearing steels.

Importance of chemistry in high-tech ceramics design

2002 ◽  
Vol 74 (11) ◽  
pp. 2137-2144 ◽  
Author(s):  
P. Šajgalík
Keyword(s):  
Fracture Toughness ◽  
Silicon Carbide ◽  
Silicon Nitride ◽  
Liquid Phase ◽  
Grain Boundary ◽  
Ceramic Materials ◽  
High Tech ◽  
Polycrystalline Ceramics ◽  
Sintered Silicon

This paper deals with the role of chemistry in the design of high-tech ceramic materials. Grain boundary composition of polycrystalline ceramics dictates the hardness fracture toughness and creep resistance of liquid-phase sintered silicon nitride and silicon carbide materials.

Electron Microscopy Techniques for the Microstructural Characterization of Silicon Nitride

1988 ◽  
Author(s):  
Kerry N. Siebein ◽  
Russell L. Yeckley
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Fracture Toughness ◽  
Silicon Nitride ◽  
Microstructural Characterization ◽  
Ceramic Materials ◽  
Processing Parameters ◽  
Bend Strength ◽  
Fracture Origin ◽  
Microscopy Techniques

It is well known that the mechanical properties of ceramic materials are directly dependent upon their microstructure with respect to the size, crystallinity, distribution and composition of the phases present. Our understanding of the microstructural details of silicon nitride was enhanced through the application of scanning electron microscopy (SEM) and scanning transmission electron microscopy (STEM). The SEM and STEM are necessary for analyzing the microstructure of silicon nitride because it is a fine grained material. The SEM is used to analyze the etched microstructure and fracture surfaces of bulk silicon nitride samples. Relationships between the grain size distribution, aspect ratio of the grains and fracture toughness of the material are summarized, as well as fracture origin identity and bend strength data. STEM is employed to analyze the crystallinity, distribution and composition of the phases present in a material. These features are related to the processing parameters, fracture toughness and bend strength of silicon nitride. This paper presents a short description of the microscopy techniques employed to characterize silicon nitride, the results obtained using the various techniques and the relationship between the microstructural features and mechanical properties.

scholarly journals Development of Ceramic Cutting Tools for Future Application on Dry Machining

2010 ◽  
Vol 660-661 ◽  
pp. 724-729
Author(s):  
Olivério Moreira Macedo Silva ◽  
José Vitor C. Souza ◽  
Maria do Carmo de Andrade Nono ◽  
G.V. Martins ◽  
M.V. Ribeiro ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Silicon Nitride ◽  
Cutting Tool ◽  
Mechanical Response ◽  
Cutting Tools ◽  
Ceramic Materials ◽  
Future Application ◽  
Dry Machining ◽  
Fine Grained ◽  
Potential Applications

Advanced ceramic materials constitute a mature technology with a very broad base of current and potential applications and a growing list of material compositions. Within the advanced ceramics category, silicon nitride based ceramics are wear-resistant, corrosion- resistant and lightweight materials, and are superior to many materials with regard to stability in high-temperature environments. Because of this combination the silicon nitride ceramics have an especially high potential to resolve a wide number of machining problems in the industries. Presently the Si3N4 ceramic cutting tool inserts are developed using additives powders that are pressed and sintered in the form of a cutting tool insert at a temperature of 1850 oC using pressureless sintering. The microstructure of the material was observed and analyzed using XRD, SEM, and the mechanical response of this array microstructure was characterized for hardness Vickers and fracture toughness. The results show that Si3N4/20 wt.% (AlN and Y2O3) gives the best balance between hardness Vickers and fracture toughness. The Si3N4/15 wt.% (AlN and Y2O3) composition allows the production of a very fine-grained microstructure with low decreasing of the fracture toughness and increased hardness Vickers. These ceramic cutting tools present adequate characteristics for future application on dry machining.

Examination of Fracture Interfaces in Silicon Nitride

1975 ◽  
Vol 33 ◽  
pp. 60-61
Author(s):  
Nancy J. Tighe
Keyword(s):  
Silicon Nitride ◽  
Grain Boundary ◽  
Crack Growth ◽  
Subcritical Crack Growth ◽  
Slow Crack Growth ◽  
Ceramic Materials ◽  
Grain Boundary Sliding ◽  
Boundary Phase ◽  
Turbine Engines ◽  
Boundary Sliding

Silicon nitride is one of the ceramic materials being considered for the components in gas turbine engines which will be exposed to temperatures of 1000 to 1400°C. Test specimens from hot-pressed billets exhibit flexural strengths of approximately 50 MN/m2 at 1000°C. However, the strength degrades rapidly to less than 20 MN/m2 at 1400°C. The strength degradition is attributed to subcritical crack growth phenomena evidenced by a stress rate dependence of the flexural strength and the stress intensity factor. This phenomena is termed slow crack growth and is associated with the onset of plastic deformation at the crack tip. Lange attributed the subcritical crack growth tb a glassy silicate grain boundary phase which decreased in viscosity with increased temperature and permitted a form of grain boundary sliding to occur.

Layer thickness optimization of ceramic composite for body armor by considering volume, weight, and cost

2021 ◽  
pp. 095440622110157
Author(s):  
Yuksel Palaci ◽  
Mustafa M Arikan
Keyword(s):  
Silicon Nitride ◽  
Boron Carbide ◽  
Layer Thickness ◽  
Ceramic Composite ◽  
Material Selection ◽  
Composite Layer ◽  
Ceramic Materials ◽  
Ternary Diagram ◽  
Body Armor ◽  
Volume Weight

This study investigates visualization of optimized layer thickness with a ternary diagram by considering Volume, Weight, and Cost priorities to determine the composite structure of alternative ceramics to use in body armor application by using the Digital Logic Method (DLM). Three criterion priorities (volume, weight, cost) have been investigated to help designers decide on optimum ceramic material for their applications. Alumina (Al2O3), silicon carbide (SiC), silicon nitride (Si3N4), and boron carbide (B4C) were analyzed and ranked to decide for material selection based on priorities. The analysis results showed that silicon nitride (Si3N4) had the maximum performance index (PI) point (80.0) based on the volume priority. On the other hand, while boron carbide (B4C) had the maximum PI point (76.4) in terms of the weight priority, alumina (Al2O3) was determined to be the best material according to the cost priority. PI point of alumina (Al2O3) was calculated as 100. A ternary diagram was developed for decision-makers to visualize material selection performances. The optimization of the ceramic composite layer thickness of the alternative ceramic materials is visualized by considering three criteria.

Grinding bodies from silicon nitride for fine milling of ceramic materials

1992 ◽  
Vol 49 (5) ◽  
pp. 239-240
Author(s):  
B. I. Kislov ◽  
L. V. Vodop'yanova
Keyword(s):  
Silicon Nitride ◽  
Ceramic Materials ◽  
Fine Milling

Indentation hardness and fracture toughness in single crystal TiC0.96

1996 ◽  
Vol 209 (1-2) ◽  
pp. 329-336 ◽  
Author(s):  
C. Maerky ◽  
M.-O. Guillou ◽  
J.L. Henshall ◽  
R.M. Hooper
Keyword(s):  
Fracture Toughness ◽  
Single Crystal ◽  
Indentation Hardness

Effect of α/β phase ratio on microstructure and mechanical properties of silicon nitride ceramics

2001 ◽  
Vol 16 (8) ◽  
pp. 2264-2270 ◽  
Author(s):  
Hirokazu Kawaoka ◽  
Tomohiko Adachi ◽  
Tohru Sekino ◽  
Yong-Ho Choa ◽  
Lian Gao ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Silicon Nitride ◽  
Phase Ratio ◽  
Phase Content ◽  
Sintering Process ◽  
Β Phase ◽  
Nitride Ceramics ◽  
Pulse Electric ◽  
Sintering Condition ◽  
Sintered Materials

Highly densed silicon nitride ceramics with various α/β phase ratios were produced by pulse electric current sintering process. The β-phase content of Si3N4 in sintered materials varied from 20 to 100 wt% depending on the sintering condition. The microstructure was observed by scanning electron microscopy and investigated by image analysis. Young's modulus, hardness, fracture toughness, and strength were strongly dependent on the α/β phase ratio. The fracture toughness increased from 4.6 MPa m1/2 for 20-wt% b-phase content to 8.2 MPa m1/2 for 95-wt% β-phase content, and the fracture strength showed a maximum value of about 1.6 GPa at 60-to-80-wt% β-phase content.

Effects of TiN Content on Mechanical Properties and Microstructure of ATN Materials

2013 ◽  
Vol 589-590 ◽  
pp. 590-593 ◽  
Author(s):  
Min Wang ◽  
Jun Zhao
Keyword(s):  
Mechanical Properties ◽  
Mechanical Property ◽  
Fracture Toughness ◽  
Vickers Hardness ◽  
Bending Strength ◽  
Sintering Temperature ◽  
Ceramic Materials ◽  
Hot Press ◽  
Hot Press Sintering ◽  
Tin Content

In order to investigate the effects of TiN content on Al2O3/TiN ceramic material (ATN), the ATN ceramic materials were prepared of TiN content in 30%, 40%, 50%, 60% in the condition of hot press sintering. The sintering temperature is 1700°C, the sintering press is 32MPa, and the holding time are 5min, 10min, 15min. The effects of TiN content on mechanical properties and microstructure of ATN ceramic materials were investigated by analyzing the bending strength, hardness, fracture toughness. The results show that ATN50 has the best mechanical property, its bending strength is 659.41MPa, vickers hardness is 13.79GPa, fracture toughness is 7.06MPa·m1/2. It is indicated that the TiN content has important effect on microstructure and mechanical properties of ATN ceramic materials.

Sign in / Sign up

Export Citation Format

Share Document