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Buckley, Donald H.

Publications and source records attributed to Buckley, Donald H..

17 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1989

Deformation and fracture of single-crystal and sintered polycrystalline silicon carbide produced by cavitation

An investigation was conducted to examine the deformation and fracture behavior of single-crystal and sintered polycrystalline SiC surfaces exposed to cavitation. Cavitation erosion experiments were conducted in distilled water at 25 C by using a magnetostrictive oscillator in close proximity (1 mm) to the surface of SiC. The horn frequency was 20 kHz, and the double amplitude of the vibrating disk was 50 microns. The results of the investigation indicate that the SiC (0001) surface could be deformed in a plastic manner during cavitation. Dislocation etch pits were formed when the surface was chemically etched. The number of defects, including dislocations in SiC (0001) surface, increased with increasing exposure time to cavitation. The presence of intrinsic defects such as voids in the surficial layers of the sintered polycrystalline SiC determined the zones at which fractured grains and fracture pits (pores) were generated. Single-crystal SiC had superior erosion resistance to that of sintered polycrystalline SiC.

Miyoshi, Kazuhisa↗
NASA NTRS1989

Tribological properties of structural ceramics

The tribological and lubricated behavior of both oxide and nonoxide ceramics are reviewed in this chapter. Ceramics are examined in contact with themselves, other harder materials and metals. Elastic, plastic and fracture behavior of ceramics in solid state contact is discussed. The contact load necessary to initiate fracture in ceramics is shown to be appreciably reduced with tangential motion. Both friction and wear of ceramics are anisotropic and relate to crystal structure as has been observed with metals. Grit size effects in two and three body abrasive wear are observed for ceramics. Both free energy of oxide formation and the d valence bond character of metals are related to the friction and wear characteristics for metals in contact with ceramics. Surface contaminants affect friction and adhesive wear. For example, carbon on silicon carbide and chlorine on aluminum oxide reduce friction while oxygen on metal surfaces in contact with ceramics increases friction. Lubrication increases the critical load necessary to initiate fracture of ceramics both in indentation and with sliding or rubbing. Ceramics compositions both as coatings and in composites are described for the high temperature lubrication of both alloys and ceramics.

Buckley, Donald H.↗
NASA NTRS1988

Tribology - A Survery Of The Science

Compendium presents six papers on tribology study of adhesion, friction, wear, and lubrication of solid materials in contact: collection of papers covering theory, practice, history, and research.

Buckley, Donald H.↗
NASA NTRS1987

Tribological Properties of Structural Ceramics

Paper discusses tribological properties of structural ceramics. Function of tribological research is to bring about reduction in adhesion, friction, and wear of mechanical components; to prevent failures; and to provide long, reliable component life, through judicious selection of materials, operating parameters, and lubricants. Paper reviews adhesion, friction, wear, and lubrication of ceramics; anisotropic friction and wear behavior; and effects of surface films and interactions between ceramics and metals. Analogies with metals are made. Both oxide and nonoxide ceramics, including ceramics used as high temperature lubricants, are dicussed.

Buckley, Donald H.↗
NASA NTRS1987

Adhesion, friction, and deformation of ion-beam-deposited boron nitride films

The tribological properties and mechanical strength of boron nitride films were investigated. The BN films were predominantly amorphous and nonstoichiometric and contained small amounts of oxides and carbides. It was found that the yield pressure at full plasticity, the critical load to fracture, and the shear strength of interfacial adhesive bonds (considered as adhesion) depended on the type of metallic substrate on which the BN was deposited. The harder the substrate, the greater the critical load and the adhesion. The yield pressures of the BN film were 12 GPa for the 440C stainless steel substrate, 4.1 GPa for the 304 stainless steel substrate, and 3.3 GPa for the titanium substrate.

Miyoshi, Kazuhisa↗
NASA NTRS1987

Mechanical strength and tribological behavior of ion-beam deposited boron nitride films on non-metallic substrates

An investigation was conducted to examine the mechanical strength and tribological properties of boron nitride (BN) films ion-beam deposited on silicon (Si), fused silica (SiO2), gallium arsenide (GaAs), and indium phosphide (InP) substrates in sliding contact with a diamond pin under a load. The results of the investigation indicate that BN films on nonmetallic substrates, like metal films on metallic substrates, deform elastically and plastically in the interfacial region when in contact with a diamond pin. However, unlike metal films and substrates, BN films on nonmetallic substrates can fracture when they are critically loaded. Not only does the yield pressure (hardness) of Si and SiO2 substrates increase by a factor of 2 in the presence of a BN film, but the critical load needed to fracture increases as well. The presence of films on the brittle substrates can arrest crack formation. The BN film reduces adhesion and friction in the sliding contact. BN adheres to Si and SiO2 and forms a good quality film, while it adheres poorly to GaAs and InP. The interfacial adhesive strengths were 1 GPa for a BN film on Si and appreciably higher than 1 GPa for a BN film on SiO2.

Miyoshi, Kazuhisa↗
NASA NTRS1987

Deformation and fracture of single-crystal and sintered polycrystalline silicon carbide produced by cavitation

An investigation was conducted to examine the deformation and fracture behavior of single-crystal and sintered polycrystalline SiC surfaces exposed to cavitation. Cavitation erosion experiments were conducted in distilled water at 25 C by using a magnetostrictive oscillator in close proximity (1 mm) to the surface of SiC. The horn frequency was 20 kHz, and the double amplitude of the vibrating disk was 50 microns. The results of the investigation indicate that the SiC (0001) surface could be deformed in a plastic manner during cavitation. Dislocation etch pits were formed when the surface was chemically etched. The number of defects, including dislocations in the SiC (0001) surface, increased with increasing exposure time to cavitation. The presence of intrinsic defects such as voids in the surficial layers of the sintered polycrystalline SiC determined the zones at which fractured grains and fracture pits (pores) were generated. Single-crystal SiC had superior erosion resistance to that of sintered polycrystalline SiC.

Miyoshi, Kazuhisa↗
NASA NTRS1987

Mechanical strength and tribological behavior of ion-beam-deposited boron nitride films on non-metallic substrates

An investigation was conducted to examine the mechanical strength and tribological properties of boron nitride (BN) films ion-beam deposited on silicon (Si), fused silica (SiO2), gallium arsenide (GaAs), and indium phosphide (InP) substrates in sliding contact with a diamond pin under a load. The results of the investigation indicate that BN films on nonmetallic substrates, like metal films on metallic substrates, deform elastically and plastically in the interfacial region when in contact with a diamond pin. However, unlike metal films and substrates, BN films on nonmetallic substrates can fracture when they are critically loaded. Not only does the yield pressure (hardness) of Si and SiO2 substrates increase by a factor of 2 in the presence of a BN film, but the critical load needed to fracture increases as well. The presence of films on the brittle substrates can arrest crack formation. The BN film reduces adhesion and friction in the sliding contact. BN adheres to Si and SiO2 and forms a good quality film, while it adheres poorly to GaAs and InP. The interfacial adhesive strengths were 1 GPa for a BN film on Si and appreciably higher than 1 GPa for a BN film on SiO2.

Miyoshi, Kazuhisa↗
NASA NTRS1986

Friction and wear of ceramics

The adhesion, friction, wear, and lubricated behaviors of both oxide and non-oxide ceramics are reviewed. Ceramics are examined in contact with themselves, other harder materials, and metals. Elastic, plastic, and fracture behavior of ceramics in solid state contact is discussed. The contact load necessary to initiate fracture in ceramics is shown to be appreciably reduced with tangential motion. Both friction and wear of ceramics are anisotropic and relate to crystal structure as with metals. Grit size effects in two and three body abrasive wear are observed for ceramics. Both the free energy of oxide formation and the d valence bond character of metals are related to the friction and wear characteristics for metals in contact with ceramics. Surface contaminants affect friction and adhesive wear. For example, carbon on silicon carbide and chlorine on aluminum oxide reduce friction while oxygen on metal surfaces in contact with ceramics increases friction. Lubrication increases the critical load necessary to initiate fracture of ceramics both in indentation and with sliding or rubbing.

Buckley, Donald H.↗
NASA NTRS1961

Effect of Inert, Reducing, and Oxidizing Atmospheres on Friction and Wear of Metals to 1000 F

Experiments were conducted in inert, reducing, and oxidizing atmospheres to determine their influence on the friction and wear properties of various metals. Nitrogen, argon, forming gas (10 volume percent H2, 90 volume percent N2), and various concentrations of oxygen in nitrogen were used. A 3/16-inch-radius hemispherical rider under a load of 1000 grams contacted the flat surface of a rotating disk. The surface speed employed was 35 feet per minute. The presence of surface oxides is vitally important to the protection of metals in sliding contact. Extremely high friction and excessive wear were encountered in the absence of these oxides. In some instances (electrolytically pure copper), the removal of the surface oxides resulted in mass welding of the specimens in sliding contact. Extremely small quantities of oxygen are sufficient to provide protection of metal surfaces; for example, with 440-C stainless steel, 0.03 volume percent oxygen was found to be adequate.

Buckley, Donald H.↗
NASA NTRS1961

Friction, Wear, and Evaporation Rates of Various Materials in Vacuum to 10(exp -7) mm Hg

The requirements for bearings and seals to operate in the environment of space dictate a new area for lubrication research. The low ambient pressures encountered in space can be expected to influence the behavior of oil, grease, and solid-film lubricants. The property of these materials most significantly affected by low ambient pressures is the evaporation rate. Various investigators have therefore measured the evaporation rates of oils and greases in vacuum as one method of establishing their relative merit for space applications (1-3). The results of this work have given some indication as to the oils and greases with the greatest stability at reduced ambient pressures. Only limited experimental work, however, has been reported in the literature for inorganic solids and soft metals which have potential use as solid lubricant films or coatings for hard alloy substrates [e.g. Reference ( 4 )]. In general, the evaporation rates of these materials would be lower than those of oils and greases. These films might therefore be very attractive as lubricants for high vacuum service.

Buckley, Donald H.↗
NASA NTRS1960

Halogen Containing Gases as Lubricants for Crystallized Glass Ceramic Metal Combinations at Temperatures to 1500 F

Pyroceram 9608 (a crystallized glass ceramic) has been considered for use in high-temperature bearing and seal applications. One of the problems encountered with Pyroceram is the lack of availability of lubricants for the temperature range in which this material becomes practical. Experiments were conducted with Pyroceram sliding on various nickel- and cobalt-base alloys using reactive halogen-containing gases as lubricants. Friction and wear data were obtained as a function of sliding velocity and temperature. Studies were made with a hemispherical rider (3/16-in. rad., Pyroceram 9608) sliding in a circumferential path on the flat surface of a rotating disk (2(1/2) in. diam., nickel- or cobalt-base alloys). The specimens were run in an atmosphere of the various gases with a load of 1200 grams, a sliding velocity of 3200 feet per minute, and temperatures from 75 to 1500 F. The gas CF2Br-CF2Br was found to be an effective lubricant for Pyroceram 9608 sliding on Hastelloy R-235 and Inconel X up to 1400 F. The gas CF2Cl-CF2Cl provided effective lubrication for Pyroceram sliding on various cobalt-base alloys at 1000 F.

Buckley, Donald H.↗
NASA NTRS1960

Ignition of a Combustible Atmosphere by Incandescent Carbon Wear Particles

A study was made to determine whether carbon wear particles from carbon elements in sliding contact with a metal surface were sufficiently hot to cause ignition of a combustible atmosphere. In some machinery, electric potential differences and currents may appear at the carbon-metal interface. For this reason the effect of these voltages and currents on the ability of carbon wear particles to cause ignition was evaluated. The test specimens used in the investigation were carbon vanes taken from a fuel pump and flat 21-inch-diameter 2 metal disks (440-C stainless steel) representing the pump housing. During each experiment a vane was loaded against a disk with a 0.5-pound force, and the disk was rotated to give a surface speed of 3140 feet per minute. The chamber of the apparatus that housed the vane and the disk was filled with a combustible mixture of air and propane. Various voltages and amperages were applied across the vane-disk interface. Experiments were conducted at temperatures of 75, 350, 400, and 450 F. Fires were produced by incandescent carbon wear particles obtained at conditions of electric potential as low as 106 volts and 0.3 ampere at 400 F. Ignitions were obtained only with carbon wear particles produced with an electric potential across the carbon-vane-disk interface. No ignitions were obtained with carbon wear particles produced in the absence of this potential; also, the potential difference produced no ignitions in the absence of carbon wear particles. A film supplement showing ignition by incandescent wear particles is available.

Buckley, Donald H.↗
NASA NTRS1960

Use of Less Reactive Materials and More Stable Gases to Reduce Corrosive Wear When Lubricating with Halogenated Gases

The gases CF2Cl-CF2Cl, CF2Cl2, and CF2Br-CF2Br were used to lubricate metals, cermets, and ceramics in this study. One of the criteria for determining the effectiveness of a reactive-gas-lubricated systems is the stability of the halogen-containing gas molecule. The carbon-to-halogen bond in the ethane molecule has extremely good thermal stability superior to the methane analogs (CF2Cl2 and CF2Br2) used in earlier research. For this reason, the ethane compounds CF2Cl-CF2Cl and CF2Br-CF2Br were considered as high-temperature lubricants. Friction and wear studies were made with a hemisphere (3/16-in. rad.) rider sliding in a circumferential path on the flat surface of a rotating disk (21/2-in. diam. ). The specimens of metal alloys, cermets, and ceramics were run In an atmosphere of the various gases with a load of 1200 grams, sliding velocities from 75 to 8000 feet per minute, and temperatures from 75 to 1400 F. The gas CF2Cl-CF2Cl was found to be an effective lubricant for the cermet LT-LB (59.0 Cr, 19.0 Al2O3, 20.0 Mo, 2.0 Ti) and the ceramic Al2O3 sliding on Stellite Star J (cobalt-base alloy) at temperatures to 1400 F. The bromine-containing gas CF2Br-CF2Br was found to give friction and wear values that can be considered to be in a region of effective boundary lubrication for the cermet K175D (nickel-bonded metal carbide) sliding on the metal Hastelloy R-235 (nickel-base alloy) at temperatures to 1200 F.

Buckley, Donald H.↗
NASA NTRS1960

The Influence of Silicon Additions on Friction and Wear of Nickel Alloys at Temperatures to 1000 Degrees Fahrenheit

Small additions of silicon have considerable beneficial effect on performance on slider alloys. This effect has most frequently been attributed to increased hardness. The research reported was conducted to consider a hypothesis that the primary role of silicon in slider alloys is one of supporting the formation of protective surface films. Friction and wear data were obtained at temperatures from 75 to 1000 degrees Fahrenheit with a series of binary silicon-nickel alloys containing up to 10 percent silicon. Pertinent hot hardness, metallurgical and surface-film analysis data are included. Atmospheres used were air, mixtures of oxygen and argon, a mixture of hydrogen and nitrogen, and a halogenated methane gas lubricant. The results show the role of silicon as a film former to be of great importance in success of silicon-containing alloys as slider materials for extreme temperatures. The range of variables studied gave friction coefficients from 0.05 to greater than 10.00 depending on film formation tendencies. Alloys with 5 percent or more silicon having a duplex structure showed the best results. Film formation resulted from surface reactions or the smearing of the softer phase from the alloys having duplex structure.

Buckley, Donald H.↗
NASA NTRS1959

Halogen-Containing Gases as Boundary Lubricants for Corrosion-Resistant Alloys at 1200 F

The extreme temperatures anticipated for lubricated parts in advanced flight powerplants dictate the consideration of unconventional methods of lubrication such as solid lubricants and the reactive gases described in the present research. These halogen-containing "reactive" gases such as dichlorodifluoromethane, CF2Cl2, are among the most stable of organic molecules. The high "flash" temperatures generated at the contacting asperities as a result of frictional heat are sufficient to cause local decomposition of the halogen-containing gases. The active atoms thus released (e.g., chlorine) then react with the metal to be lubricated to form halides capable of effective lubrication. The presence of small amounts of a sulfur-containing gas (e.g., 1 percent sulfur hexafluoride, SF6) was found to catalyze the formation of metal halides. Friction and wear studies were made with a hemisphere (3/16-in. rad.) rider sliding in a circumferential path on the flat surface of a rotating disk (2 1/2-in. diam.). The specimens of corrosion-resistant 2 alloys were run in an atmosphere of the various gases with a load of 1200 grams, a sliding velocity of 120 feet per minute, and temperature from 75 to 1200 F. An effective lubricant for ferritic materials (M-1 tool steel) was CF2Cl2, but significant corrosion occurred above 600 F. Corrosion evaluation in CF2Cl2 suggested a number of nickel- and cobalt-base alloys for additional lubrication study. Several combinations of gases and these metals were found to lubricate to 1200 F without excessive corrosion. The gases were CF2Cl2 Plus 1 percent SF6, monobromotrifluoromethane CF3Br plus 1 percent SF6, dibromodifluoromethane CF2Br2, iodotrifluoromethane, CF3I, and I2. Careful selection of metals and gas are necessary for successful lubrication over specific temperature ranges. Optimum combinations give friction coefficients as low as 0.05 without

Buckley, Donald H.↗