Mark Parish - Academia.edu (original) (raw)

Papers by Mark Parish

The dispersibility of four commercial grade barium titanate (BaTiO3) powders in 21 pure organic l... more The dispersibility of four commercial grade barium titanate (BaTiO3) powders in 21 pure organic liquids with various functional groups, five alcohol-organic surfactant solutions, and water was investigated. Effects on sediment volumes were observed as a function of moisture, total mass, applied force, particle concentration, and particle size distribution. Dispersibility was attributed to the formation of an electrical double layer resulting from the surface-liquid interactions. Sediments in the best dispersed systems were uniform and dense (up to 48.3 % measured powder density), yet still displayed the ability to flow. Of the liquids tested, those with acid, alcohol, and aldehyde functional groups dispersed the BaTiOs powders better than esters, ethers, ketones, hydrocarbons, and water. Concentrations up to 30 vol% showed little effect on sediment densities. However, centrifugation resulted in more dense compacts. Powders with a narrow size

CeraNova Corporation has developed a ceramic piezoelectric actuator/sensor array embedded in a co... more CeraNova Corporation has developed a ceramic piezoelectric actuator/sensor array embedded in a composite. The array will enable the intelligent actuation and control of the smart composite at discrete locations to achieve greatly reduced vibration modes and increased aerodynamic efficiency leading to reduced fatigue in critical structural components. The array is composed of miniature ceramic piezoelectric tubes produced by powder processing. Vibration control was successfully demonstrated by 3 5 db vibration damping of a cantilever beam.

The dispersibility of four commercial grade barium titanate (BaTiO3 ) powders in 21 pure organic ... more The dispersibility of four commercial grade barium titanate (BaTiO3 ) powders in 21 pure organic liquids with various functional groups, five alcohol-organic surfactant solutions, and water was investigated. Effects on sediment volumes were observed as a function of moisture, total mass, applied force, particle concentration, and particle size distribution. Dispersibility was attributed to the formation of an electrical double layer resulting from the surface-liquid interactions. Sediments in the best dispersed systems were uniform and dense (up to 48.3% measured powder density), yet still displayed the ability to flow. Of the liquids tested, those with acid, alcohol, and aldehyde functional groups dispersed the BaTiOs powders better than esters, ethers, ketones, hydrocarbons, and water. Concentrations up to 30 vol% showed little effect on sediment densities. However, centrifugation resulted in more dense compacts. Powders with a narrow size distribution settled to very dense cakes ...

Although the Y{sub 1}Ba{sub 2}Cu{sub 3}O{sub 7-{delta}} (YBCO) high-temperature superconductors a... more Although the Y{sub 1}Ba{sub 2}Cu{sub 3}O{sub 7-{delta}} (YBCO) high-temperature superconductors are known to possess superior flux pinning properties at high temperatures and in a large magnetic fields, the development of practical conductors has been severely limited by the existence of ``weak links`` at the grain boundaries. It is now established that strongly-linked, high J{sub c} YBCO materials can be produced in the form of bulk masses by a variety of melt-processing techniques. Here we describe a technique that couples a continuous fiber spinning process with zone-melt-processing, resulting in long lengths of high quality YBCO filaments that have microstructures and high-temperature electrical transport properties similar to those of melt-textured bulk materials.

Window and Dome Technologies and Materials XV

Transparent ceramics are finding increasing use in optical applications with demanding operating ... more Transparent ceramics are finding increasing use in optical applications with demanding operating conditions. Polycrystalline ceramics provide a unique combination of mechanical, dielectric and optical properties for sensor window applications that were previously not possible. The mechanical strength of CeraNova’s transparent alumina and spinel was measured by an equibiaxial strength test method. The results of the tests and their analysis, included those at elevated temperatures for transparent alumina, will be presented.

Window and Dome Technologies and Materials XV

Samples of fine-grain, transparent polycrystalline alumina (CeraNova Corp) and multispectral zinc... more Samples of fine-grain, transparent polycrystalline alumina (CeraNova Corp) and multispectral zinc sulfide (Cleartran) were tested to determine mechanical strength and slow crack growth parameters. Mechanical strength measurements of coupons were fit to a Weibull equation that describes the material strength and its distribution. Slow crack growth parameters were calculated using the procedure set forth by Weiderhorn.1 This paper describes the derivation of Weibull and slow crack growth parameters from strength measurements over a range of stress rates and how these parameters are used to predict window lifetime under stress. Proof testing is employed to ensure that a window begins its life with a known, minimum strength.

Window and Dome Technologies and Materials XV

The refractive index of fully dense, infrared-transparent polycrystalline alumina (PCA) with a me... more The refractive index of fully dense, infrared-transparent polycrystalline alumina (PCA) with a mean grain size of ∼0.6 μm is reported for the wavelength range 0.85 to 5.0 μm over the temperature range T ¼ 296 to 498 K. The temperature-dependent Sellmeier equation is n 2 − 1 ¼ ðA þ B½T 2 − T 2 o Þλ 2 ∕½λ 2 − ðλ 1 þ C½T 2 − T 2 o Þ 2 þ Dλ 2 ∕ðλ 2 − λ 2 2 Þ, where λ is expressed in μm, T o ¼ 295.15 K, A ¼ 2.07156, B ¼ 6.273 × 10 −8 , λ 1 ¼ 0.091293, C ¼ −1.9516 × 10 −8 , D ¼ 5.62675, λ 2 ¼ 18.5533, and the root-mean square deviation from measurements is 0.0002. This paper describes how to predict the refractive index of fully dense isotropic PCA with randomly oriented grains using the ordinary and extraordinary refractive indices (n o and n e) of sapphire spatially averaged over the surface of a hemisphere. The refractive index of alumina at 296 and 470 K agrees within AE0.0002 with the predicted values. Similarly, the ordinary and extraordinary optical constants k o and k e are used to predict the absorption coefficient of alumina. The refractive indices n o and n e of sapphire grown at Rubicon Technologies by the Kyropoulos method were measured at 295 K and agree with published Sellmeier equations for sapphire grown by other methods within AE0.0002.

Pres~tlksd by ANSI Std. Z]g.IS 3n-91

Window and Dome Technologies and Materials XI, 2009

CeraNova's transparent polycrystalline alumina (CeraLuminTM)a has sub-micron grain size (300-... more CeraNova's transparent polycrystalline alumina (CeraLuminTM)a has sub-micron grain size (300-500nm) and high transmittance in the mid-wave infrared (>85% in the 3-5µm MWIR region). The fine, uniform grain size imparts high hardness, high strength, and high thermal shock resistance. Polycrystalline alumina is a viable alternative to sapphire for domes, particularly for aerodynamic shapes which are readily fabricated by powder processing. Both hemispheric and ogive domes (sub-scale and full-size) have been successfully molded and densified to transparency. Hemispheric domes have been optically finished. Current efforts include a focus on scale-up, fabrication, and metrology of aerodynamic domes. This paper presents recent analyses of microstructure, optical properties, and mechanical properties.

Window and Dome Technologies and Materials IX, 2005

Polycrystalline alumina (PCA) has great potential for providing performance comparable to or bett... more Polycrystalline alumina (PCA) has great potential for providing performance comparable to or better than single-crystal sapphire, yet offers the opportunity for low-cost powder based manufacturing. CeraNova has demonstrated transparent PCA, by processing the material to simultaneously achieve 100% density and sub-micron grain size. CeraNova PCA displays low scatter in the infrared, with high transmittance (>85%) in the 3.0-4.0μm region, comparable to sapphire. In addition, the sub-micron grain size leads to high hardness, high strength and high thermal shock resistance. This fine-grain PCA is a viable sapphire replacement for dome applications, including those that require aerodynamic shapes readily possible by powder processing. Such shapes present not only processing challenges, but also surface finishing issues. Results from a current program to address these issues in creating an ogive dome of PCA are discussed.

SPIE Proceedings, 2013

Transparent ceramics are finding applications in demanding optical applications were traditional ... more Transparent ceramics are finding applications in demanding optical applications were traditional mineral salts and amorphous materials are limited and single crystals are not practical. Polycrystalline ceramics offer a unique combination of mechanical, electrical and optical properties that allow window and dome applications and possibilities that were previously not possible. Transparent ceramics are being developed for use in a number of applications with each material possessing a distinctive set of properties that address a particular application. The current status of CeraNova’s fine grain transparent ceramic programs for dome and window applications will be presented with emphasis on their exceptional material properties for specific applications.

SPIE Proceedings, 2011

Transparent ceramics are finding applications is demanding optical applications were traditional ... more Transparent ceramics are finding applications is demanding optical applications were traditional mineral salts and amorphous materials are limited and single crystals are not practical. Polycrystalline ceramics offer a unique combination of mechanical, electrical and optical properties that allow window and dome applications and possibilities that were previously not possible. Transparent ceramics are being developed for use in a number of applications with each material possessing a distinctive set of properties that address a particular application. The current status of CeraNova's fine grain transparent ceramic programs for dome and window applications will be presented with emphasis on their exceptional properties for specific applications.

Smart Structures and Materials 1999: Smart Materials Technologies, 1999

Lead Zirconate Titanate (PZT) active fibers, from 80 to 250 micrometers in diameter, are produced... more Lead Zirconate Titanate (PZT) active fibers, from 80 to 250 micrometers in diameter, are produced for the AFOSR/DARPA funded Active Fiber Composites Consortium (AFCC) Program and commercial customers. CeraNova has developed a proprietary ceramics-based technology to produce PZT mono-filaments of the required purity, composition, straightness, and piezoelectric properties for use in active fiber composite structures. CeraNova's process begins with the extrusion of continuous lengths of mono-filament precursor fiber from a plasticized mix of PZT-5A powder. The care that must be taken to avoid mix contamination is described using illustrations form problems experiences with extruder wear and metallic contamination. Corrective actions are described and example microstructures are shown. The consequences of inadequate lead control are also shown. Sintered mono- filament mechanical strength and piezoelectric properties data approach bulk values but the validity of such a benchmark is questioned based on variable correlation with composite performance measures. Comb-like ceramic preform structures are shown that are being developed to minimize process and handling costs while maintaining the required mono-filament straightness necessary for composite fabrication. Lastly, actuation performance data are presented for composite structures fabricated and tested by Continuum Control Corporation. Free strain actuation in excess of 2000 microstrain are observed.

Pres~tlksd by ANSI Std. Z]g.IS 3n-91

Lead Zirconate Titanate (PZT) active fibers, from 80 to 250 micrometers in diameter, are produced... more Lead Zirconate Titanate (PZT) active fibers, from 80 to 250 micrometers in diameter, are produced for the AFOSR/DARPA funded Active Fiber Composites Consortium (AFCC) Program and commercial customers. CeraNova has developed a proprietary ceramics-based technology to produce PZT mono-filaments of the required purity, composition, straightness, and piezoelectric properties for use in active fiber composite structures. CeraNova's process begins with the

The dispersibility of four commercial grade barium titanate (BaTiO3) powders in 21 pure organic l... more The dispersibility of four commercial grade barium titanate (BaTiO3) powders in 21 pure organic liquids with various functional groups, five alcohol-organic surfactant solutions, and water was investigated. Effects on sediment volumes were observed as a function of moisture, total mass, applied force, particle concentration, and particle size distribution. Dispersibility was attributed to the formation of an electrical double layer resulting from the surface-liquid interactions. Sediments in the best dispersed systems were uniform and dense (up to 48.3 % measured powder density), yet still displayed the ability to flow. Of the liquids tested, those with acid, alcohol, and aldehyde functional groups dispersed the BaTiOs powders better than esters, ethers, ketones, hydrocarbons, and water. Concentrations up to 30 vol% showed little effect on sediment densities. However, centrifugation resulted in more dense compacts. Powders with a narrow size

CeraNova Corporation has developed a ceramic piezoelectric actuator/sensor array embedded in a co... more CeraNova Corporation has developed a ceramic piezoelectric actuator/sensor array embedded in a composite. The array will enable the intelligent actuation and control of the smart composite at discrete locations to achieve greatly reduced vibration modes and increased aerodynamic efficiency leading to reduced fatigue in critical structural components. The array is composed of miniature ceramic piezoelectric tubes produced by powder processing. Vibration control was successfully demonstrated by 3 5 db vibration damping of a cantilever beam.

The dispersibility of four commercial grade barium titanate (BaTiO3 ) powders in 21 pure organic ... more The dispersibility of four commercial grade barium titanate (BaTiO3 ) powders in 21 pure organic liquids with various functional groups, five alcohol-organic surfactant solutions, and water was investigated. Effects on sediment volumes were observed as a function of moisture, total mass, applied force, particle concentration, and particle size distribution. Dispersibility was attributed to the formation of an electrical double layer resulting from the surface-liquid interactions. Sediments in the best dispersed systems were uniform and dense (up to 48.3% measured powder density), yet still displayed the ability to flow. Of the liquids tested, those with acid, alcohol, and aldehyde functional groups dispersed the BaTiOs powders better than esters, ethers, ketones, hydrocarbons, and water. Concentrations up to 30 vol% showed little effect on sediment densities. However, centrifugation resulted in more dense compacts. Powders with a narrow size distribution settled to very dense cakes ...

Although the Y{sub 1}Ba{sub 2}Cu{sub 3}O{sub 7-{delta}} (YBCO) high-temperature superconductors a... more Although the Y{sub 1}Ba{sub 2}Cu{sub 3}O{sub 7-{delta}} (YBCO) high-temperature superconductors are known to possess superior flux pinning properties at high temperatures and in a large magnetic fields, the development of practical conductors has been severely limited by the existence of ``weak links`` at the grain boundaries. It is now established that strongly-linked, high J{sub c} YBCO materials can be produced in the form of bulk masses by a variety of melt-processing techniques. Here we describe a technique that couples a continuous fiber spinning process with zone-melt-processing, resulting in long lengths of high quality YBCO filaments that have microstructures and high-temperature electrical transport properties similar to those of melt-textured bulk materials.

Window and Dome Technologies and Materials XV

Transparent ceramics are finding increasing use in optical applications with demanding operating ... more Transparent ceramics are finding increasing use in optical applications with demanding operating conditions. Polycrystalline ceramics provide a unique combination of mechanical, dielectric and optical properties for sensor window applications that were previously not possible. The mechanical strength of CeraNova’s transparent alumina and spinel was measured by an equibiaxial strength test method. The results of the tests and their analysis, included those at elevated temperatures for transparent alumina, will be presented.

Window and Dome Technologies and Materials XV

Samples of fine-grain, transparent polycrystalline alumina (CeraNova Corp) and multispectral zinc... more Samples of fine-grain, transparent polycrystalline alumina (CeraNova Corp) and multispectral zinc sulfide (Cleartran) were tested to determine mechanical strength and slow crack growth parameters. Mechanical strength measurements of coupons were fit to a Weibull equation that describes the material strength and its distribution. Slow crack growth parameters were calculated using the procedure set forth by Weiderhorn.1 This paper describes the derivation of Weibull and slow crack growth parameters from strength measurements over a range of stress rates and how these parameters are used to predict window lifetime under stress. Proof testing is employed to ensure that a window begins its life with a known, minimum strength.

Window and Dome Technologies and Materials XV

The refractive index of fully dense, infrared-transparent polycrystalline alumina (PCA) with a me... more The refractive index of fully dense, infrared-transparent polycrystalline alumina (PCA) with a mean grain size of ∼0.6 μm is reported for the wavelength range 0.85 to 5.0 μm over the temperature range T ¼ 296 to 498 K. The temperature-dependent Sellmeier equation is n 2 − 1 ¼ ðA þ B½T 2 − T 2 o Þλ 2 ∕½λ 2 − ðλ 1 þ C½T 2 − T 2 o Þ 2 þ Dλ 2 ∕ðλ 2 − λ 2 2 Þ, where λ is expressed in μm, T o ¼ 295.15 K, A ¼ 2.07156, B ¼ 6.273 × 10 −8 , λ 1 ¼ 0.091293, C ¼ −1.9516 × 10 −8 , D ¼ 5.62675, λ 2 ¼ 18.5533, and the root-mean square deviation from measurements is 0.0002. This paper describes how to predict the refractive index of fully dense isotropic PCA with randomly oriented grains using the ordinary and extraordinary refractive indices (n o and n e) of sapphire spatially averaged over the surface of a hemisphere. The refractive index of alumina at 296 and 470 K agrees within AE0.0002 with the predicted values. Similarly, the ordinary and extraordinary optical constants k o and k e are used to predict the absorption coefficient of alumina. The refractive indices n o and n e of sapphire grown at Rubicon Technologies by the Kyropoulos method were measured at 295 K and agree with published Sellmeier equations for sapphire grown by other methods within AE0.0002.

Pres~tlksd by ANSI Std. Z]g.IS 3n-91

Window and Dome Technologies and Materials XI, 2009

CeraNova's transparent polycrystalline alumina (CeraLuminTM)a has sub-micron grain size (300-... more CeraNova's transparent polycrystalline alumina (CeraLuminTM)a has sub-micron grain size (300-500nm) and high transmittance in the mid-wave infrared (>85% in the 3-5µm MWIR region). The fine, uniform grain size imparts high hardness, high strength, and high thermal shock resistance. Polycrystalline alumina is a viable alternative to sapphire for domes, particularly for aerodynamic shapes which are readily fabricated by powder processing. Both hemispheric and ogive domes (sub-scale and full-size) have been successfully molded and densified to transparency. Hemispheric domes have been optically finished. Current efforts include a focus on scale-up, fabrication, and metrology of aerodynamic domes. This paper presents recent analyses of microstructure, optical properties, and mechanical properties.

Window and Dome Technologies and Materials IX, 2005

Polycrystalline alumina (PCA) has great potential for providing performance comparable to or bett... more Polycrystalline alumina (PCA) has great potential for providing performance comparable to or better than single-crystal sapphire, yet offers the opportunity for low-cost powder based manufacturing. CeraNova has demonstrated transparent PCA, by processing the material to simultaneously achieve 100% density and sub-micron grain size. CeraNova PCA displays low scatter in the infrared, with high transmittance (>85%) in the 3.0-4.0μm region, comparable to sapphire. In addition, the sub-micron grain size leads to high hardness, high strength and high thermal shock resistance. This fine-grain PCA is a viable sapphire replacement for dome applications, including those that require aerodynamic shapes readily possible by powder processing. Such shapes present not only processing challenges, but also surface finishing issues. Results from a current program to address these issues in creating an ogive dome of PCA are discussed.

SPIE Proceedings, 2013

Transparent ceramics are finding applications in demanding optical applications were traditional ... more Transparent ceramics are finding applications in demanding optical applications were traditional mineral salts and amorphous materials are limited and single crystals are not practical. Polycrystalline ceramics offer a unique combination of mechanical, electrical and optical properties that allow window and dome applications and possibilities that were previously not possible. Transparent ceramics are being developed for use in a number of applications with each material possessing a distinctive set of properties that address a particular application. The current status of CeraNova’s fine grain transparent ceramic programs for dome and window applications will be presented with emphasis on their exceptional material properties for specific applications.

SPIE Proceedings, 2011

Transparent ceramics are finding applications is demanding optical applications were traditional ... more Transparent ceramics are finding applications is demanding optical applications were traditional mineral salts and amorphous materials are limited and single crystals are not practical. Polycrystalline ceramics offer a unique combination of mechanical, electrical and optical properties that allow window and dome applications and possibilities that were previously not possible. Transparent ceramics are being developed for use in a number of applications with each material possessing a distinctive set of properties that address a particular application. The current status of CeraNova's fine grain transparent ceramic programs for dome and window applications will be presented with emphasis on their exceptional properties for specific applications.

Smart Structures and Materials 1999: Smart Materials Technologies, 1999

Lead Zirconate Titanate (PZT) active fibers, from 80 to 250 micrometers in diameter, are produced... more Lead Zirconate Titanate (PZT) active fibers, from 80 to 250 micrometers in diameter, are produced for the AFOSR/DARPA funded Active Fiber Composites Consortium (AFCC) Program and commercial customers. CeraNova has developed a proprietary ceramics-based technology to produce PZT mono-filaments of the required purity, composition, straightness, and piezoelectric properties for use in active fiber composite structures. CeraNova's process begins with the extrusion of continuous lengths of mono-filament precursor fiber from a plasticized mix of PZT-5A powder. The care that must be taken to avoid mix contamination is described using illustrations form problems experiences with extruder wear and metallic contamination. Corrective actions are described and example microstructures are shown. The consequences of inadequate lead control are also shown. Sintered mono- filament mechanical strength and piezoelectric properties data approach bulk values but the validity of such a benchmark is questioned based on variable correlation with composite performance measures. Comb-like ceramic preform structures are shown that are being developed to minimize process and handling costs while maintaining the required mono-filament straightness necessary for composite fabrication. Lastly, actuation performance data are presented for composite structures fabricated and tested by Continuum Control Corporation. Free strain actuation in excess of 2000 microstrain are observed.

Pres~tlksd by ANSI Std. Z]g.IS 3n-91

Lead Zirconate Titanate (PZT) active fibers, from 80 to 250 micrometers in diameter, are produced... more Lead Zirconate Titanate (PZT) active fibers, from 80 to 250 micrometers in diameter, are produced for the AFOSR/DARPA funded Active Fiber Composites Consortium (AFCC) Program and commercial customers. CeraNova has developed a proprietary ceramics-based technology to produce PZT mono-filaments of the required purity, composition, straightness, and piezoelectric properties for use in active fiber composite structures. CeraNova's process begins with the