Infiltration/Pyrolysis Processing of Fiber-Reinforced Silicon Nitride

1992 ◽  
Vol 287 ◽  
Author(s):  
Stuart T. Schwab ◽  
Renee C. Graef ◽  
Cheryl R. Blanchard ◽  
Yi-Ming Pan ◽  
David L. Davidson
Keyword(s):  
Silicon Nitride ◽  
Brittle Failure ◽  
High Temperature Strength ◽  
Fiber Reinforced ◽  
Southwest Research Institute ◽  
Resistance To Oxidation ◽  
Structural Applications ◽  
Complex Shapes ◽  
Near Net Shape ◽  
Manufacturing Techniques

ABSTRACTWhile its high-temperature strength, resistance to oxidation, and other properties make silicon nitride an attractive candidate for many advanced structural applications, its propensity for brittle failure has hindered its widespread adoption. One approach to avoiding brittle failure is through incorporation of continuous fiber-reinforcement; however, conventional (powderbased) methods of silicon nitride fabrication can degrade fibers and are not amenable to the production of complex shapes. The Southwest Research Institute has developed a number of polymeric precursors to silicon nitride which are available as thermosetting liquids, and we have shown that these materials can be used in combination with near net-shape manufacturing techniques to produce fiber-reinforced silicon nitride composites. Mechanical property tests conducted at room temperature suggest that these polymer-derived composites exhibit fracture behavior comparable to those produced through conventional techniques; micromechanical investigations conducted at 800°C indicate that non-brittle failure is maintained at elevated temperature.

Pip Processing, Microstructure and Properties of Si34N Fiber and Al2O3 Fiber Reinforced Silicon Nitride

1994 ◽  
Vol 365 ◽  
Author(s):  
Stuart T. Schwab ◽  
Richard A. Page ◽  
David L. Davidson ◽  
Renee C. Graef
Keyword(s):  
High Temperature ◽  
Silicon Nitride ◽  
Carbon Composite ◽  
Organic Polymer ◽  
High Temperature Strength ◽  
Fiber Reinforced ◽  
Southwest Research Institute ◽  
Structural Applications ◽  
Al2o3 Fiber ◽  
Manufacturing Techniques

ABSTRACTPolymer infiltration/pyrolysis (PIP) processing has the potential to become an affordable means of manufacturing continuous fiber-reinforced ceramic-matrix components. The PIP method is very similar to the well-known polymer-matrix and carbon-carbon composite manufacturing techniques, the major difference being the use of a preceramic polymer in place of the organic polymer or carbon precursor. To date, the majority of research in the field of preceramic polymers has centered on precursors to silicon carbide (SiC). The Southwest Research Institute (SwRI) has focused on the development of polymeric precursors to silicon nitride (Si3N4) because its high-temperature strength, resistance to oxidation, and other properties make it an attractive candidate for many advanced high-temperature structural applications. PIP Si3N4 composites with NICALON SiC fiber reinforcement have exhibited good fracture toughness (KIC ∼ 16MPa·m1/ 2). We report here processing, microstructure and preliminary mechanical properties of two new PIP Si3N4 composites. One is reinforced with Tonen Si3N4 fiber (plain weave) while the other is reinforced with ALMAX Al2O3 fiber (8 Harness satin weave).

Lattice Imaging of Grain Boundaries in Ceramics

1977 ◽  
Vol 35 ◽  
pp. 114-115
Author(s):  
D. R. Clarke ◽  
G. Thomas
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Silicon Nitride ◽  
Grain Boundaries ◽  
High Temperature Strength ◽  
Current Interest ◽  
Lattice Imaging ◽  
Special Significance ◽  
Structural Applications ◽  
Refractory Ceramics

Grain boundaries have long held a special significance to ceramicists. In part, this has been because it has been impossible until now to actually observe the boundaries themselves. Just as important, however, is the fact that the grain boundaries and their environs have a determing influence on both the mechanisms by which powder compaction occurs during fabrication, and on the overall mechanical properties of the material. One area where the grain boundary plays a particularly important role is in the high temperature strength of hot-pressed ceramics. This is a subject of current interest as extensive efforts are being made to develop ceramics, such as silicon nitride alloys, for high temperature structural applications. In this presentation we describe how the techniques of lattice fringe imaging have made it possible to study the grain boundaries in a number of refractory ceramics, and illustrate some of the findings.

Microwave and Millimeter wave Processing of Polymer-Derived Silicon Nitride

1996 ◽  
Vol 430 ◽  
Author(s):  
S. T. Schwab ◽  
S. F. Timmons ◽  
C. R. Blanchard ◽  
M. D. Grimes ◽  
R. C. Graef ◽  
...  
Keyword(s):  
Silicon Nitride ◽  
Millimeter Wave ◽  
Powder Processing ◽  
Cost Savings ◽  
Fiber Reinforced ◽  
Chemical Methods ◽  
Southwest Research Institute ◽  
Wave Heating ◽  
Polymer Infiltration ◽  
Matrix Precursor

AbstractChemical methods of processing ceramics have the potential to overcome many of the processing-related obstacles that have hindered widespread commercialization. The Southwest Research Institute (SwRI) has focused on the development of polymeric precursors to silicon nitride (Si3N4). One such precursor, perhydropolysilazane (or PHPS), has been shown to be a useful binder for Si3N4 powder processing, a useful matrix precursor for the polymer infiltration/pyrolysis (PIP) processing of fiber-reinforced Si3N4, and a useful ceramic coating precursor for the repair of oxidation protection coatings on carbon-carbon composites. While conventional, thermal pyrolyses of these preceramnics has been sufficient to demonstrate their potential, substantial cost savings could be realized if the polymer-to-ceramic conversion could be instigated with electromagnetic energy. We have investigated the use of millimeter wave heating as a means of converting PHPS into Si3N4, and report here the results of our efforts to produce bulk compacts, coatings, and fiber-reinforced ceramics.

Microstructure and microanalysis of silicon nitride ceramics in the Y-Si-Al-O-N and Y-Si-O-N systems

1990 ◽  
Vol 48 (4) ◽  
pp. 1072-1073
Author(s):  
Michael K. Cinibulk
Keyword(s):  
Silicon Nitride ◽  
Grain Boundary ◽  
Grain Boundary Sliding ◽  
Liquid Phase Sintering ◽  
Boundary Phase ◽  
Full Density ◽  
High Temperature Strength ◽  
Transmission Electron ◽  
Structural Applications ◽  
Nitride Ceramics

Silicon nitride ceramics are among the leading candidate materials for use in structural applications at high temperatures. Due to the highly covalent nature of the Si-N bond and therefore low self-diffusivity, processing Si3N4 to full density requires the use of additives to provide a medium for liquid-phase sintering. When exposed to temperatures above ∼1000°C the resulting amorphous grain-boundary phases soften, leading to grain-boundary sliding and the eventual failure of the ceramic. The objectives of this work were to modify the grain-boundary phase composition and then attempt to devitrify the resulting intergranular phase to a refractory crystalline phase, producing a sintered Si3N4 with improved high-temperature strength and oxidation resistance. Transmission electron microscopy (TEM) and energy-dispersive x-ray spectroscopy (EDS) were used to characterize these materials. This paper describes these results.

Electron Microscopy of Silicon Nitride-Based Ceramics

1991 ◽  
Vol 49 ◽  
pp. 926-927
Author(s):  
Gareth Thomas
Keyword(s):  
Electron Microscopy ◽  
High Temperature ◽  
Silicon Nitride ◽  
World Wide ◽  
Sintering Temperature ◽  
Liquid Phase Sintering ◽  
High Temperature Strength ◽  
Sintering Additives ◽  
Glass Forming ◽  
Dense Product

Silicon nitride and silicon nitride based-ceramics are now well known for their potential as hightemperature structural materials, e.g. in engines. However, as is the case for many ceramics, in order to produce a dense product, sintering additives are utilized which allow liquid-phase sintering to occur; but upon cooling from the sintering temperature residual intergranular phases are formed which can be deleterious to high-temperature strength and oxidation resistance, especially if these phases are nonviscous glasses. Many oxide sintering additives have been utilized in processing attempts world-wide to produce dense creep resistant components using Si3N4 but the problem of controlling intergranular phases requires an understanding of the glass forming and subsequent glass-crystalline transformations that can occur at the grain boundaries.

Phase transformation and layer evolution in molybdenum disilicide-silicon carbide nanolayered coatings

1994 ◽  
Vol 52 ◽  
pp. 538-539
Author(s):  
H. Kung ◽  
T. R. Jervis ◽  
J.-P. Hirvonen ◽  
M. Nastasi ◽  
T. E. Mitchell ◽  
...  
Keyword(s):  
Phase Transformation ◽  
High Temperature ◽  
Oxidation Resistance ◽  
Elevated Temperatures ◽  
Matrix Material ◽  
Molybdenum Disilicide ◽  
High Temperature Strength ◽  
Cross Sectional ◽  
Good Oxidation Resistance ◽  
Structural Applications

MoSi2 is a potential matrix material for high temperature structural composites due to its high melting temperature and good oxidation resistance at elevated temperatures. The two major drawbacksfor structural applications are inadequate high temperature strength and poor low temperature ductility. The search for appropriate composite additions has been the focus of extensive investigations in recent years. The addition of SiC in a nanolayered configuration was shown to exhibit superior oxidation resistance and significant hardness increase through annealing at 500°C. One potential application of MoSi2- SiC multilayers is for high temperature coatings, where structural stability ofthe layering is of major concern. In this study, we have systematically investigated both the evolution of phases and the stability of layers by varying the heat treating conditions.Alternating layers of MoSi2 and SiC were synthesized by DC-magnetron and rf-diode sputtering respectively. Cross-sectional transmission electron microscopy (XTEM) was used to examine three distinct reactions in the specimens when exposed to different annealing conditions: crystallization and phase transformation of MoSi2, crystallization of SiC, and spheroidization of the layer structures.

CARLSON 330

Alloy Digest ◽  
1992 ◽  
Vol 41 (11) ◽  
Keyword(s):  
Stainless Steel ◽  
High Temperature ◽  
Physical Properties ◽  
Tensile Properties ◽  
Heat Treating ◽  
High Temperature Strength ◽  
Corrosion Resistant ◽  
Nickel Chromium ◽  
Resistance To Oxidation ◽  
Chromium Stainless Steel

Abstract Carlson Alloy 330 is a heat and corrosion resistant austenitic nickel chromium stainless steel. It has good high temperature strength combined with resistance to oxidation and carburization. The alloy is popular in the heat treating industry. This datasheet provides information on composition, physical properties, and tensile properties. It also includes information on forming, heat treating, and joining. Filing Code: SS-537. Producer or source: G.O. Carlson Inc..

Information in United States Patents on works related to ‘Natural Fibers’: 2000-2018

2019 ◽  
Vol 12 (1) ◽  
pp. 4-76 ◽  
Author(s):  
Krittirash Yorseng ◽  
Mavinkere R. Sanjay ◽  
Jiratti Tengsuthiwat ◽  
Harikrishnan Pulikkalparambil ◽  
Jyotishkumar Parameswaranpillai ◽  
...  
Keyword(s):  
United States ◽  
Composite Materials ◽  
Natural Fiber ◽  
Comprehensive Evaluation ◽  
Natural Fibers ◽  
Fiber Reinforced Composites ◽  
Reinforced Composites ◽  
Fiber Reinforced ◽  
Macro Scale ◽  
Structural Applications

Background: This era has seen outstanding achievements in materials science through the advances in natural fiber-based composites. The new environmentally friendly and sustainability concerns have imposed the chemists, biologists, researchers, engineers, and scientists to discover the engineering and structural applications of natural fiber reinforced composites. Objective: To present a comprehensive evaluation of information from 2000 to 2018 in United States patents in the field of natural fibers and their composite materials. Methods: The patent data have been taken from the external links of US patents such as IFI CLAIMS Patent Services, USPTO, USPTO Assignment, Espacenet, Global Dossier, and Discuss. Results: The present world scenario demands the usage of natural fibers from agricultural and forest byproducts as a reinforcement material for fiber reinforced composites. Natural fibers can be easily extracted from plants and animals. Recently natural fiber in nanoscale is preferred over micro and macro scale fibers due to its superior thermo-mechanical properties. However, the choice of macro, micro, and nanofibers depends on their applications. Conclusion: This document presents a comprehensive evaluation of information from 2000 to 2018 in United States patents in the field of natural fibers and their composite materials.

scholarly journals Improvement of Performance Profile of Acrylic Based Polyester Bio-Composites by Bast/Basalt Fibers Hybridization for Automotive Applications

2021 ◽  
Vol 5 (4) ◽  
pp. 100
Author(s):  
Anjum Saleem ◽  
Luisa Medina ◽  
Mikael Skrifvars
Keyword(s):  
Hybrid Composites ◽  
Flexural Modulus ◽  
Basalt Fiber ◽  
Fiber Composites ◽  
Fiber Reinforced ◽  
Basalt Fibers ◽  
Bast Fiber ◽  
Bast Fibers ◽  
Resin Impregnation ◽  
Structural Applications

New technologies in the automotive industry require lightweight, environment-friendly, and mechanically strong materials. Bast fibers such as kenaf, flax, and hemp reinforced polymers are frequently used composites in semi-structural applications in industry. However, the low mechanical properties of bast fibers limit the applications of these composites in structural applications. The work presented here aims to enhance the mechanical property profile of bast fiber reinforced acrylic-based polyester resin composites by hybridization with basalt fibers. The hybridization was studied in three resin forms, solution, dispersion, and a mixture of solution and dispersion resin forms. The composites were prepared by established processing methods such as carding, resin impregnation, and compression molding. The composites were characterized for their mechanical (tensile, flexural, and Charpy impact strength), thermal, and morphological properties. The mechanical performance of hybrid bast/basalt fiber composites was significantly improved compared to their respective bast fiber composites. For hybrid composites, the specific flexural modulus and strength were on an average about 21 and 19% higher, specific tensile modulus and strength about 31 and 16% higher, respectively, and the specific impact energy was 13% higher than bast fiber reinforced composites. The statistical significance of the results was analyzed using one-way analysis of variance.

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