Boron Nitride Ceramic Composite Obtained by High Pressure and High Temperature Sintering

2012 ◽  
Vol 727-728 ◽  
pp. 736-739 ◽  
Author(s):  
Ana Lucia D. Skury ◽  
Carlos A. Oliveira Monteiro ◽  
Guerold Sergueevitch Bobrovinitchii ◽  
Sérgio Neves Monteiro
Keyword(s):  
Mechanical Properties ◽  
High Pressure ◽  
Composite Material ◽  
High Temperature ◽  
Boron Nitride ◽  
Chemical Reactions ◽  
Ceramic Composite ◽  
Sintering Process ◽  
Polycrystalline Structure ◽  
Binding Agents

In the present work, by selecting Si3N4, TiB2 and Al2O3 as binding agents as well as La3O2 as an additive, sintered wBN composites were studied. By modifying the number of sintering cycles, the composites processed at 4.5GPa and 1800°C showed improved mechanical properties. The degree of transformation of the wBN, as well as the chemical reactions during the sintering process were discussed. This new composite material was found to present polycrystalline structure that provides superior cutting properties. Moreover, owing to superior properties, the wBN composite sharpens itself during cutting.

Microstructures and Mechanical Properties of β-Sialon-cBN Composites

2016 ◽  
Vol 697 ◽  
pp. 515-520
Author(s):  
Xin Ze Wu ◽  
Yi Wu ◽  
Jin Long Han ◽  
Tian Yu Shen
Keyword(s):  
Mechanical Properties ◽  
Computer Simulation ◽  
High Pressure ◽  
High Temperature ◽  
Boron Nitride ◽  
Oxygen Content ◽  
Cubic Boron Nitride ◽  
Test Results ◽  
Microstructure And Mechanical Properties ◽  
Z Value

β-Sialon-cubic boron nitride (cBN) composites were prepared by the high temperature (1700°C) and high pressure (5GPa) sintering. β-Sialon chemical general composition can be represented as Si6-zAlzOzN8 –z (Z is the number of Al atoms which are substituted by Si atoms, and the range of z value is usually between 0-4.2[1].).The effects of different formula with corresponding to z values on microstructure and mechanical properties of β-Sialon-cBN composites were studied. The relative test results were verified by computer simulation. The study result showed: with the z values of β-Sialon increasing, the aluminum and oxygen content increased. The densification and mechanical properties of β-Sialon-cBN composites decreased gradually.

Microstructural Study of Diamond Deformed Under High Pressure and Temperature

1985 ◽  
Vol 43 ◽  
pp. 230-231
Author(s):  
E. F. Koch
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Lattice Structure ◽  
Diamond Particle ◽  
Polycrystalline Diamond ◽  
Sintering Process ◽  
Ion Milling ◽  
Sintered Compact ◽  
Transmission Electron ◽  
High Pressure Sintering

Because of the extremely rigid lattice structure of diamond, generating new dislocations or moving existing dislocations in diamond by applying mechanical stress at ambient temperature is very difficult. Analysis of portions of diamonds deformed under bending stress at elevated temperature has shown that diamond deforms plastically under suitable conditions and that its primary slip systems are on the ﹛111﹜ planes. Plastic deformation in diamond is more commonly observed during the high temperature - high pressure sintering process used to make diamond compacts. The pressure and temperature conditions in the sintering presses are sufficiently high that many diamond grains in the sintered compact show deformed microtructures.In this report commercially available polycrystalline diamond discs for rock cutting applications were analyzed to study the deformation substructures in the diamond grains using transmission electron microscopy. An individual diamond particle can be plastically deformed in a high pressure apparatus at high temperature, but it is nearly impossible to prepare such a particle for TEM observation, since any medium in which the diamond is mounted wears away faster than the diamond during ion milling and the diamond is lost.

Cubic Boron Nitride as a New Semiconductor for Optoelectronics: Luminescence Properties and Potentialities

1989 ◽  
Vol 162 ◽  
Author(s):  
Koh Era ◽  
Osamu Mishima
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Boron Nitride ◽  
Room Temperature ◽  
Cubic Boron Nitride ◽  
Visible Region ◽  
Vibrational Structure ◽  
Luminescence Properties ◽  
Optoelectronic Applications ◽  
P Type

ABSTRACTIn cubic boron nitride made by high pressure and high temperature technique in our institute, we have found three luminescence bands in the ultraviolet and the short visible region at room temperature by cathode-ray excitation. They are: a band having vibrational structure and ascribable to undoped state of the crystal, a band ascribable to p-type doping and a band ascribable to n-type doping. Discussion is made on differences between the injection luminescence and the cathodoluminescence. Potentialities and difficulties in realizing the potentialities of cBN for optoelectronic applications are discussed.

Microstructure, mechanical properties, and thermal stability of γ-Nb5Si3 under high temperature and high pressure

2021 ◽  
Vol 130 (13) ◽  
pp. 135104
Author(s):  
Juwei Wang ◽  
Haihua Chen ◽  
Zhengang Zhang ◽  
Bin Wang ◽  
Hongtao Ma ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
High Pressure ◽  
High Temperature ◽  
Thermal Stability Of

Mechanical Properties and Oxidation Behavior of Si3N4/BN Laminated Ceramics

2007 ◽  
Vol 280-283 ◽  
pp. 1869-1872
Author(s):  
Cui Wei Li ◽  
Chang An Wang ◽  
Yong Huang
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Silicon Nitride ◽  
Boron Nitride ◽  
Oxidation Behavior ◽  
Elevated Temperatures ◽  
Testing Procedure ◽  
No Oxidation ◽  
Temperature Oxidation ◽  
High Temperature Oxidation Behavior

Laminated ceramics with high mechanical properties were fabricated in the Si3N4/BN system. The mechanical properties at elevated temperatures were tested, and the oxidation behavior during tested procedure was studied at the same time. The flexure strength of the Si3N4/BN laminated ceramics changed a little below 1000°C. The displacement-load curves appeared non-linear characteristic even at high temperature. During testing procedure at high temperature, oxidation behavior of silicon nitride and silicon carbide happened, and no oxidation product of boron nitride was found. The silicon nitride layers were oxidized to form a protective silicate scale, which prevented oxidation of the boron nitride interlayers. The stability of boron nitride was beneficial to the boron nitride interlayer to partition the silicon nitride matrix layers at high temperature.

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