Pub Date : 1988-11-01DOI: 10.1111/J.1551-2916.1988.TB00282.X
A. Saigal, N. Das
Silicon carbide coatings have been deposited on graphite specimens by thermal decomposition of dichlorodimethylsilane. The effects of flow variables, substrate temperature and gas composition, on the tensile strength of chemically vapor deposited silicon carbide coatings are discussed. The ratio H{sub 2}:(CH{sub 3}){sub 2}SiCl{sub 2} was varied from 4:1 to 6:1 at substrate temperatures of 1,100{degree}, 1,150{degree}, 1,200{degree}, and 1,250{degree}C. The strength of VCD SiC coatings was strongly dependent on the substrate temperature and the gas composition. Highest strength values were obtained at low temperatures (1,100{degree}) and low concentration ratios (4:1) of carrier/precursor gas. At 1,150{degree} and 1,200{degree}C, the curves tend to exhibit minimum strength at a specific ratio of carrier to precursor gas. The effects of substrate temperature and gas composition on the stoichiometry and structure of the SiC and its relation with the strength of the coatings are also discussed.
{"title":"Effect of deposition parameters on the strength of CVD. beta. -SiC coatings","authors":"A. Saigal, N. Das","doi":"10.1111/J.1551-2916.1988.TB00282.X","DOIUrl":"https://doi.org/10.1111/J.1551-2916.1988.TB00282.X","url":null,"abstract":"Silicon carbide coatings have been deposited on graphite specimens by thermal decomposition of dichlorodimethylsilane. The effects of flow variables, substrate temperature and gas composition, on the tensile strength of chemically vapor deposited silicon carbide coatings are discussed. The ratio H{sub 2}:(CH{sub 3}){sub 2}SiCl{sub 2} was varied from 4:1 to 6:1 at substrate temperatures of 1,100{degree}, 1,150{degree}, 1,200{degree}, and 1,250{degree}C. The strength of VCD SiC coatings was strongly dependent on the substrate temperature and the gas composition. Highest strength values were obtained at low temperatures (1,100{degree}) and low concentration ratios (4:1) of carrier/precursor gas. At 1,150{degree} and 1,200{degree}C, the curves tend to exhibit minimum strength at a specific ratio of carrier to precursor gas. The effects of substrate temperature and gas composition on the stoichiometry and structure of the SiC and its relation with the strength of the coatings are also discussed.","PeriodicalId":7260,"journal":{"name":"Advanced Ceramic Materials","volume":"74 1","pages":"580-583"},"PeriodicalIF":0.0,"publicationDate":"1988-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86933236","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1988-11-01DOI: 10.1111/J.1551-2916.1988.TB00281.X
A. Ayral, J. Phalippou
A new manufacturing procedure for pure submicrometer alumina powder is presented. This process allows the physical characteristics of the powder to be controlled. The starting compound is an organic solution of aluminum alkoxide. Particles of aluminum acetate are produced by controlling the nucleation stage from an homogeneous solution. This aluminum acetate yields alumina powder after decomposition and firing. The decomposition treatment decreases the particle size. The final particle size of the alumina powder ranges between 0.1 and 0.2 {mu}m depending on the synthesis parameters. The shaping and sintering of these powders are studied.
{"title":"Submicrometer alumina powders","authors":"A. Ayral, J. Phalippou","doi":"10.1111/J.1551-2916.1988.TB00281.X","DOIUrl":"https://doi.org/10.1111/J.1551-2916.1988.TB00281.X","url":null,"abstract":"A new manufacturing procedure for pure submicrometer alumina powder is presented. This process allows the physical characteristics of the powder to be controlled. The starting compound is an organic solution of aluminum alkoxide. Particles of aluminum acetate are produced by controlling the nucleation stage from an homogeneous solution. This aluminum acetate yields alumina powder after decomposition and firing. The decomposition treatment decreases the particle size. The final particle size of the alumina powder ranges between 0.1 and 0.2 {mu}m depending on the synthesis parameters. The shaping and sintering of these powders are studied.","PeriodicalId":7260,"journal":{"name":"Advanced Ceramic Materials","volume":"37 1","pages":"575-579"},"PeriodicalIF":0.0,"publicationDate":"1988-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74560517","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1988-11-01DOI: 10.1111/J.1551-2916.1988.TB00277.X
D. Partlow
A composite having low dielectric constant and displaying nonbrittle failure was prepared using a cordierite-based matrix reinforced with boron aluminosilicate fibers. Since these fibers are normally chemically attacked by an oxide matrix during composite consolidation at high temperatures, good composite behavior required the application of a barrier/debonding coating on the fibers prior to composite fabrication. A boron nitride coating was applied using a known process, in which B{sub 2}O{sub 3} within the fiber diffuses to the surface and is nitrided. Fiber tensile testing showed that the coating process did not significantly lower the fiber strength, and the composite prepared with fibers coated by this process showed better mechanical properties than composites in which the barrier coating was either BN or carbon applied by chemical vapor deposition.
{"title":"A ceramic-ceramic composite with low dielectric constant and nonbrittle failure","authors":"D. Partlow","doi":"10.1111/J.1551-2916.1988.TB00277.X","DOIUrl":"https://doi.org/10.1111/J.1551-2916.1988.TB00277.X","url":null,"abstract":"A composite having low dielectric constant and displaying nonbrittle failure was prepared using a cordierite-based matrix reinforced with boron aluminosilicate fibers. Since these fibers are normally chemically attacked by an oxide matrix during composite consolidation at high temperatures, good composite behavior required the application of a barrier/debonding coating on the fibers prior to composite fabrication. A boron nitride coating was applied using a known process, in which B{sub 2}O{sub 3} within the fiber diffuses to the surface and is nitrided. Fiber tensile testing showed that the coating process did not significantly lower the fiber strength, and the composite prepared with fibers coated by this process showed better mechanical properties than composites in which the barrier coating was either BN or carbon applied by chemical vapor deposition.","PeriodicalId":7260,"journal":{"name":"Advanced Ceramic Materials","volume":"22 1","pages":"553-556"},"PeriodicalIF":0.0,"publicationDate":"1988-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72831162","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1988-11-01DOI: 10.1111/J.1551-2916.1988.TB00288.X
G. Sung, C. Kim
From the analysis of selected-area electron diffraction patterns through transmission electron microscopy, the crystallographic orientation of anisotropic ZnO grain growth by the addition of TiO{sub 2} to the varistor system ZnO-Bi{sub 2}O{sub 3}-MnO was determined to be the (10{anti 1}0) and ({anti 2}110) directions. The behavior of anisotropic grain growth was interpreted by the epitaxial growth of prism planes (resulting from the favorable atomic arrangement on these planes compared with other planes) and the increase in reactivity of the Bi-rich liquid phase toward the ZnO grain by the addition of TiO{sub 2}.
通过透射电镜对选择区电子衍射图的分析，确定了在ZnO- bi {sub 2}O{sub 3}-MnO中加入TiO{sub 2}后，各向异性ZnO晶粒生长的晶体取向为(10{anti 1}0)和({anti 2}110)方向。各向异性晶粒生长的行为可以通过棱镜平面的外延生长(由于这些平面上的原子排列比其他平面有利)和添加TiO{sub 2}提高富bi液相对ZnO晶粒的反应性来解释。
{"title":"Anisotropic Grain Growth of ZnO Grain in the Varistor System ZnO-Bi2O3-MnO-TiO2","authors":"G. Sung, C. Kim","doi":"10.1111/J.1551-2916.1988.TB00288.X","DOIUrl":"https://doi.org/10.1111/J.1551-2916.1988.TB00288.X","url":null,"abstract":"From the analysis of selected-area electron diffraction patterns through transmission electron microscopy, the crystallographic orientation of anisotropic ZnO grain growth by the addition of TiO{sub 2} to the varistor system ZnO-Bi{sub 2}O{sub 3}-MnO was determined to be the (10{anti 1}0) and ({anti 2}110) directions. The behavior of anisotropic grain growth was interpreted by the epitaxial growth of prism planes (resulting from the favorable atomic arrangement on these planes compared with other planes) and the increase in reactivity of the Bi-rich liquid phase toward the ZnO grain by the addition of TiO{sub 2}.","PeriodicalId":7260,"journal":{"name":"Advanced Ceramic Materials","volume":"59 1","pages":"604-606"},"PeriodicalIF":0.0,"publicationDate":"1988-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89430527","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1988-11-01DOI: 10.1111/J.1551-2916.1988.TB00276.X
M. Cauchetier, O. Croix, M. Luce
Ultrafine silicon carbide powders have been synthesized from mixtures of silane and hydrocarbons (with one to four carbon atoms) irradiated with an unfocused, high-power (1 kW), continuous-wave industrial CO{sub 2} laser. The chemistry of the reaction has been determined by analysis of the gaseous phase, either by infrared spectroscopy or by combined-gas chromatography-mass spectrometry; reaction yields have been determined. A silicon carbide production rate of 30 g/h with a yield > 99% was obtained from silane and acetylene mixtures with a 600-W laser power. An attempt to approach a production rate of 100 g/h at laboratory scale has been successful. Powder characteristics, such as particle size (10 to 50 nm), crystallinity, and stoichiometry can be controlled through optimization of laser intensity, gas pressure, and flow rate. The powders consist of equiaxed particles which exhibit a narrow size distribution.
{"title":"Laser synthesis of silicon carbide powders from silane and hydrocarbon mixtures","authors":"M. Cauchetier, O. Croix, M. Luce","doi":"10.1111/J.1551-2916.1988.TB00276.X","DOIUrl":"https://doi.org/10.1111/J.1551-2916.1988.TB00276.X","url":null,"abstract":"Ultrafine silicon carbide powders have been synthesized from mixtures of silane and hydrocarbons (with one to four carbon atoms) irradiated with an unfocused, high-power (1 kW), continuous-wave industrial CO{sub 2} laser. The chemistry of the reaction has been determined by analysis of the gaseous phase, either by infrared spectroscopy or by combined-gas chromatography-mass spectrometry; reaction yields have been determined. A silicon carbide production rate of 30 g/h with a yield > 99% was obtained from silane and acetylene mixtures with a 600-W laser power. An attempt to approach a production rate of 100 g/h at laboratory scale has been successful. Powder characteristics, such as particle size (10 to 50 nm), crystallinity, and stoichiometry can be controlled through optimization of laser intensity, gas pressure, and flow rate. The powders consist of equiaxed particles which exhibit a narrow size distribution.","PeriodicalId":7260,"journal":{"name":"Advanced Ceramic Materials","volume":"30 1","pages":"548-552"},"PeriodicalIF":0.0,"publicationDate":"1988-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80635529","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1988-09-01DOI: 10.1111/J.1551-2916.1988.TB00256.X
M. Santella
A technique for brazing Si{sub 3}N{sub 4} with metallic alloys was evaluated. The process involved vapor coating the ceramic with a 1.0-{mu}-thick layer of titanium before the brazing operation. The coating improved wetting of the Si{sub 3}N{sub 4} surfaces to the extent that strong bonding between the solidified braze filler metal and the ceramic occurred. Braze joints of Si{sub 3}N{sub 4} were made with Ag-Cu, Au-Ni, and Au-Ni-Pd alloys at temperatures of 790{degree}, 970{degree}, and 1,130{degree}C. Silicon nitride specimens were also brazed with a Ag-Cu alloy to the molybdenum alloy TZM, titanium, and A286 steel at 790{degree}C. Residual stresses resulting from mismatch of thermal expansion coefficients between the Si{sub 3}N{sub 4} and the metals caused all of the ceramic-to-metal joints to spontaneously crack in the Si{sub 3}N{sub 4} upon cooling from the brazing temperature.
{"title":"Brazing of titanium-vapor-coated silicon nitride","authors":"M. Santella","doi":"10.1111/J.1551-2916.1988.TB00256.X","DOIUrl":"https://doi.org/10.1111/J.1551-2916.1988.TB00256.X","url":null,"abstract":"A technique for brazing Si{sub 3}N{sub 4} with metallic alloys was evaluated. The process involved vapor coating the ceramic with a 1.0-{mu}-thick layer of titanium before the brazing operation. The coating improved wetting of the Si{sub 3}N{sub 4} surfaces to the extent that strong bonding between the solidified braze filler metal and the ceramic occurred. Braze joints of Si{sub 3}N{sub 4} were made with Ag-Cu, Au-Ni, and Au-Ni-Pd alloys at temperatures of 790{degree}, 970{degree}, and 1,130{degree}C. Silicon nitride specimens were also brazed with a Ag-Cu alloy to the molybdenum alloy TZM, titanium, and A286 steel at 790{degree}C. Residual stresses resulting from mismatch of thermal expansion coefficients between the Si{sub 3}N{sub 4} and the metals caused all of the ceramic-to-metal joints to spontaneously crack in the Si{sub 3}N{sub 4} upon cooling from the brazing temperature.","PeriodicalId":7260,"journal":{"name":"Advanced Ceramic Materials","volume":"44 1","pages":"457-462"},"PeriodicalIF":0.0,"publicationDate":"1988-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83711633","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1988-09-01DOI: 10.1111/J.1551-2916.1988.TB00261.X
Z. Zhuang, M. J. Haun, S. Jang, L. Cross
In the course of the development of a phenomenological theoretical model for the whole lead zirconate-titanate solid-solution system, it was found that some of the required experimental information was missing. To permit these required measurements, pure homogeneous ceramic samples of specific PZT compositions were fabricated from sol-gel derived powders. This paper describes the preparation and characterization of these required compositions. High-purity lead acetate, titanium isopropoxide, and zirconium n-propoxide were used as precursors to form PZT powders using a sol-gel technique. Powder XRD was used to study in effect of calcining time and temperature from 400 to 900{degree}C. The submicrometer calcined powders were sintered at temperatures from 1,000{degree} to 1,250{degree}C, depending on the composition, into high-density (96% to 97% of the theoretical density) ceramic bodies with uniform microstructure. Excess lead oxide was included in the starting powders to control the lead stoichiometry and to act as a transient liquid phase to facilitate grain growth and densification by eliminating the porosity in the ceramics during sintering.
{"title":"Fabrication and Characterization of Pure Homogeneous PZT Ceramics from Sol-Gel Derived Powders","authors":"Z. Zhuang, M. J. Haun, S. Jang, L. Cross","doi":"10.1111/J.1551-2916.1988.TB00261.X","DOIUrl":"https://doi.org/10.1111/J.1551-2916.1988.TB00261.X","url":null,"abstract":"In the course of the development of a phenomenological theoretical model for the whole lead zirconate-titanate solid-solution system, it was found that some of the required experimental information was missing. To permit these required measurements, pure homogeneous ceramic samples of specific PZT compositions were fabricated from sol-gel derived powders. This paper describes the preparation and characterization of these required compositions. High-purity lead acetate, titanium isopropoxide, and zirconium n-propoxide were used as precursors to form PZT powders using a sol-gel technique. Powder XRD was used to study in effect of calcining time and temperature from 400 to 900{degree}C. The submicrometer calcined powders were sintered at temperatures from 1,000{degree} to 1,250{degree}C, depending on the composition, into high-density (96% to 97% of the theoretical density) ceramic bodies with uniform microstructure. Excess lead oxide was included in the starting powders to control the lead stoichiometry and to act as a transient liquid phase to facilitate grain growth and densification by eliminating the porosity in the ceramics during sintering.","PeriodicalId":7260,"journal":{"name":"Advanced Ceramic Materials","volume":"38 1","pages":"485-490"},"PeriodicalIF":0.0,"publicationDate":"1988-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73141785","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1988-09-01DOI: 10.1111/J.1551-2916.1988.TB00265.X
M. Brun, Raj N. Singh
A modified indentation technique has been used to measure the interfacial shear stress in a number of ceramic matrices containing silicon carbide fibers. It was shown that the frictional component of interfacial stress was essentially zero when matrix thermal expansion was lower than that of the fiber and increased linearly with thermal expansion mismatch when matrix thermal expansion was higher. The interfacial shear stress was lowered when the fibers were coated with BN. Lower matrix shear stresses resulted in a more extensive fiber pullout during the composite fracture.
{"title":"Effect of thermal expansion mismatch and fiber coating on the fiber/matrix interfacial shear stress in ceramic matrix composites","authors":"M. Brun, Raj N. Singh","doi":"10.1111/J.1551-2916.1988.TB00265.X","DOIUrl":"https://doi.org/10.1111/J.1551-2916.1988.TB00265.X","url":null,"abstract":"A modified indentation technique has been used to measure the interfacial shear stress in a number of ceramic matrices containing silicon carbide fibers. It was shown that the frictional component of interfacial stress was essentially zero when matrix thermal expansion was lower than that of the fiber and increased linearly with thermal expansion mismatch when matrix thermal expansion was higher. The interfacial shear stress was lowered when the fibers were coated with BN. Lower matrix shear stresses resulted in a more extensive fiber pullout during the composite fracture.","PeriodicalId":7260,"journal":{"name":"Advanced Ceramic Materials","volume":"34 1","pages":"506-509"},"PeriodicalIF":0.0,"publicationDate":"1988-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86996569","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1988-09-01DOI: 10.1111/J.1551-2916.1988.TB00264.X
S. Hirano, K. Kato
Homogeneous and stoichiometric LiNbO{sub 3} films were prepared on substrates from double alkoxide solutions by a dip-coating method. Structural control of the double alkoxide solution is critical in synthesizing crystalline stoichiometric LiNbO{sub 3} films. The coordination states of alkoxides in solution were monitored by Ir and NMR spectroscopy. A viscosity of the double alkoxide solution was adjusted to a value of 6 {times} 10{sup {minus}3} to 7 {times} 10{sup {minus}3} N{center dot}s/m{sup 2} (6 to 7 cP) by partial hydrolysis and the concentration of the solution. Amorphous LiNbO{sub 3} films prepared on Si- or sapphire-single-crystal substrates from controlled alkoxide solutions began to crystallize at temperatures as low as 250{degree}C. Films on sapphire substrates crystallized with the preferred orientation along each orientation, such as (001), (110), and (012) but not on Si(100) and Si(111) substrates. The crystallinity of the initial thin-film coating of LiNbO{sub 3} significantly influenced the crystallization of films deposited subsequently.
{"title":"Preparation of crystalline LiNbO sub 3 films with preferred orientation by hydrolysis of metal alkoxides","authors":"S. Hirano, K. Kato","doi":"10.1111/J.1551-2916.1988.TB00264.X","DOIUrl":"https://doi.org/10.1111/J.1551-2916.1988.TB00264.X","url":null,"abstract":"Homogeneous and stoichiometric LiNbO{sub 3} films were prepared on substrates from double alkoxide solutions by a dip-coating method. Structural control of the double alkoxide solution is critical in synthesizing crystalline stoichiometric LiNbO{sub 3} films. The coordination states of alkoxides in solution were monitored by Ir and NMR spectroscopy. A viscosity of the double alkoxide solution was adjusted to a value of 6 {times} 10{sup {minus}3} to 7 {times} 10{sup {minus}3} N{center dot}s/m{sup 2} (6 to 7 cP) by partial hydrolysis and the concentration of the solution. Amorphous LiNbO{sub 3} films prepared on Si- or sapphire-single-crystal substrates from controlled alkoxide solutions began to crystallize at temperatures as low as 250{degree}C. Films on sapphire substrates crystallized with the preferred orientation along each orientation, such as (001), (110), and (012) but not on Si(100) and Si(111) substrates. The crystallinity of the initial thin-film coating of LiNbO{sub 3} significantly influenced the crystallization of films deposited subsequently.","PeriodicalId":7260,"journal":{"name":"Advanced Ceramic Materials","volume":"88 1","pages":"503-506"},"PeriodicalIF":0.0,"publicationDate":"1988-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85599129","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1988-09-01DOI: 10.1111/J.1551-2916.1988.TB00255.X
J. H. Steele, R. Engel
Microstructural characterization of commercially hot-pressed boron nitride (BN) using SEM and mercury porosimetry are described. Commercial material consits of varying amounts of B{sub 2}O{sub 3} (2% to 9%) and fine porosity (2% to 7%) within a bonded three-dimensional network of BN particles. The platelike BN particle morphology, which forms an aggregate by bonding along particle edges, is displayed. A layered structure present within individual BN particles is shown to consist of fine porous layers (<30 nm in thickness), which separate BN regions (100 to 200 nm in thickness) in the plane of the platelets. Size and dispersion of the pores and the continuous B{sub 2}O{sub 3} phase are estimated with mercury porosimetry and with SEM after leaching and filling with a liquid bismuth-tin (Bi-Sn) alloy.
{"title":"Microstructural characterization of commercial hot-pressed boron nitride","authors":"J. H. Steele, R. Engel","doi":"10.1111/J.1551-2916.1988.TB00255.X","DOIUrl":"https://doi.org/10.1111/J.1551-2916.1988.TB00255.X","url":null,"abstract":"Microstructural characterization of commercially hot-pressed boron nitride (BN) using SEM and mercury porosimetry are described. Commercial material consits of varying amounts of B{sub 2}O{sub 3} (2% to 9%) and fine porosity (2% to 7%) within a bonded three-dimensional network of BN particles. The platelike BN particle morphology, which forms an aggregate by bonding along particle edges, is displayed. A layered structure present within individual BN particles is shown to consist of fine porous layers (<30 nm in thickness), which separate BN regions (100 to 200 nm in thickness) in the plane of the platelets. Size and dispersion of the pores and the continuous B{sub 2}O{sub 3} phase are estimated with mercury porosimetry and with SEM after leaching and filling with a liquid bismuth-tin (Bi-Sn) alloy.","PeriodicalId":7260,"journal":{"name":"Advanced Ceramic Materials","volume":"90 1","pages":"452-456"},"PeriodicalIF":0.0,"publicationDate":"1988-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76668318","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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