The ZrO2 ceranfic was successfully jointed to stainless steel by vacuum brazing with active filler metal. The AgCuTi active filler metal was used and the joining was performed at a temperature of 850 ℃ for 10 rain. T...The ZrO2 ceranfic was successfully jointed to stainless steel by vacuum brazing with active filler metal. The AgCuTi active filler metal was used and the joining was performed at a temperature of 850 ℃ for 10 rain. The microstructures of the joints were characterized by metallographic microscopy, scanning electron microscopy （SEM）, and energy dispersive spectroscopy （EDS）. Metallographic microscopy analysis shows that the morphology of the cross section was a sandwich structure and the TiO is observed in the surface of ZrO2/ stainless steel. The diffusion and enrichment of the elements are the key roles in the brazing of ZrO2 ceramic and stainless steel. The formation of TiCu compounds inhibited the further diffusion of titanium into stainless steel or the ZrO2 ceramic to form TiO compound. In the experimental conditions, the average tensile strength is 80MPa for the joint of ZrO2 ceramic / AgCuTi/ stainless steel systems. A complete joint is formed between the ZrO2 ceramic and stainless steel with the leakage rate at the degree of 10 ^-12 Pa · m^3/s.展开更多
Si3N4 ceramic was jointed to itself using a filler alloy of Cu76.5Pd8.5Ti15, and the mechanical properties of the jointwere measured and analyzed. By using a filler alloy of Cu76.5Pd8.5Ti15, the SisN4/SisN4 joints wer...Si3N4 ceramic was jointed to itself using a filler alloy of Cu76.5Pd8.5Ti15, and the mechanical properties of the jointwere measured and analyzed. By using a filler alloy of Cu76.5Pd8.5Ti15, the SisN4/SisN4 joints were obtained bybrazing at 1373～1473 K for 0.9～5.4 ks under a pressure of 2×10-3 MPa. The effect of brazing parameters on theshear strength of the joint was investigated. When the brazing temperature and holding time is 1423 K and 5.4 ksrespectively, the maximum shear strength of the Si3N4/Si3N4 joint is obtained to be 198 MPa.展开更多
As a structural and functional material with excellent properties,ceramics play an extremely important role in a wide range of industries,including life and production.To expand the range of applications for ceramic m...As a structural and functional material with excellent properties,ceramics play an extremely important role in a wide range of industries,including life and production.To expand the range of applications for ceramic materials,ceramics are often joined to metals and then used.Among the physical and chemical joining methods of ceramics to metals,the AMB method is efficient and simple,suitable for industrial applications,and has been a hot topic of research.However,due to the problems of residual stresses caused by the large difference in thermal expansion coefficients between ceramic and metal brazing,composite fillers have become a very worthwhile solution by regulating the physical properties of the brazing material and improving the weld structure.This review describes the wetting principle and application of Ag‒Cu‒Ti active metal filler in the field of ceramic joining,with emphasis on the current stage of composite filler,and discusses the influence on the former brazing properties and organization after the introduction of dissimilar materials.展开更多
Development of the technological process for brazing of heat-resistant copper alloy strengthened with Al2O3 oxide particles is an important task of fabrication of high-temperature application structures. As mechanical...Development of the technological process for brazing of heat-resistant copper alloy strengthened with Al2O3 oxide particles is an important task of fabrication of high-temperature application structures. As mechanical properties of the brazed joints directly depend on the structural factor and morphological peculiarities of the brazed seams, the latter are of technological interest in terms of making of permanent joints. This study gives results of X-ray spectral microanalysis of the brazed joints on dispersion-strengthened copper alloy （ Gridcop Al-25 ） produced by using the Ti-Cu system adhesion-active brazing filler alloy, different heat sources and temperature-time parameters of the brazing process. Shown are differences in formation of structure of the seams made by vacuum brazing using radiation and high-frequency heating. Vacuum brazing with radiation heating provides the homogeneous seams with crystallisation of the phases based on the CuTi and CuTi2 compounds in the form of discrete faceted particles 2 - 9μm in size against the background of the copper matrix. Based on investigation of structural peculiarities of the brazed seams, the temperature-time conditions of vacuum brazing with radiation heating were selected for manufacture of specimens for mechanical tests. Analysis of the results of strength tests of the butt brazed specimens proved the expediency of preliminary heat treatment of the base material, providing strength of the joints at a level of about 92% of that of the base material.展开更多
Applications like solid oxide fuel cells and sensors increasingly demand the possibility to braze ceramics to metals with a good resistance to high temperatures and oxidative atmospheres. Commonly used silver based ac...Applications like solid oxide fuel cells and sensors increasingly demand the possibility to braze ceramics to metals with a good resistance to high temperatures and oxidative atmospheres. Commonly used silver based active filler metals cannot fulfill these requirements, if application temperatures higher than 600℃ occur. Au and Pd based active fillers are too expensive for many fields of use. As one possible solution nickel based active fillers were developed. Due to the high brazing temperatures and the low ductility of nickel based filler metals, the modification of standard nickel based filler metals were necessary to meet the requirements of above mentioned applications. To reduce thermally induced stresses wide brazing gaps and the addition of A1203 and WC particles to the filler metal were applied. In this study, the microstructure of the brazed joints and the thermo-chemical reactions between filler metal, active elements and WC particles were analyzed to understand the mechanism of the so called wide gap active brazing process. With regard to the behavior in typical application oxidation and thermal cycle tests were conducted as well as tensile tests.展开更多
基金supported by the National Key R&D Program of China(Grant No.2017YFB0305700)
文摘The ZrO2 ceranfic was successfully jointed to stainless steel by vacuum brazing with active filler metal. The AgCuTi active filler metal was used and the joining was performed at a temperature of 850 ℃ for 10 rain. The microstructures of the joints were characterized by metallographic microscopy, scanning electron microscopy （SEM）, and energy dispersive spectroscopy （EDS）. Metallographic microscopy analysis shows that the morphology of the cross section was a sandwich structure and the TiO is observed in the surface of ZrO2/ stainless steel. The diffusion and enrichment of the elements are the key roles in the brazing of ZrO2 ceramic and stainless steel. The formation of TiCu compounds inhibited the further diffusion of titanium into stainless steel or the ZrO2 ceramic to form TiO compound. In the experimental conditions, the average tensile strength is 80MPa for the joint of ZrO2 ceramic / AgCuTi/ stainless steel systems. A complete joint is formed between the ZrO2 ceramic and stainless steel with the leakage rate at the degree of 10 ^-12 Pa · m^3/s.
文摘Si3N4 ceramic was jointed to itself using a filler alloy of Cu76.5Pd8.5Ti15, and the mechanical properties of the jointwere measured and analyzed. By using a filler alloy of Cu76.5Pd8.5Ti15, the SisN4/SisN4 joints were obtained bybrazing at 1373～1473 K for 0.9～5.4 ks under a pressure of 2×10-3 MPa. The effect of brazing parameters on theshear strength of the joint was investigated. When the brazing temperature and holding time is 1423 K and 5.4 ksrespectively, the maximum shear strength of the Si3N4/Si3N4 joint is obtained to be 198 MPa.
基金the National Natural Science Foundation of China(Grant Nos.51971204 and 52171081)the Zhejiang Provincial Natural Science Foundation of China(Grant Nos.LY19E010006 and LY21E010005).
文摘As a structural and functional material with excellent properties,ceramics play an extremely important role in a wide range of industries,including life and production.To expand the range of applications for ceramic materials,ceramics are often joined to metals and then used.Among the physical and chemical joining methods of ceramics to metals,the AMB method is efficient and simple,suitable for industrial applications,and has been a hot topic of research.However,due to the problems of residual stresses caused by the large difference in thermal expansion coefficients between ceramic and metal brazing,composite fillers have become a very worthwhile solution by regulating the physical properties of the brazing material and improving the weld structure.This review describes the wetting principle and application of Ag‒Cu‒Ti active metal filler in the field of ceramic joining,with emphasis on the current stage of composite filler,and discusses the influence on the former brazing properties and organization after the introduction of dissimilar materials.
文摘Development of the technological process for brazing of heat-resistant copper alloy strengthened with Al2O3 oxide particles is an important task of fabrication of high-temperature application structures. As mechanical properties of the brazed joints directly depend on the structural factor and morphological peculiarities of the brazed seams, the latter are of technological interest in terms of making of permanent joints. This study gives results of X-ray spectral microanalysis of the brazed joints on dispersion-strengthened copper alloy （ Gridcop Al-25 ） produced by using the Ti-Cu system adhesion-active brazing filler alloy, different heat sources and temperature-time parameters of the brazing process. Shown are differences in formation of structure of the seams made by vacuum brazing using radiation and high-frequency heating. Vacuum brazing with radiation heating provides the homogeneous seams with crystallisation of the phases based on the CuTi and CuTi2 compounds in the form of discrete faceted particles 2 - 9μm in size against the background of the copper matrix. Based on investigation of structural peculiarities of the brazed seams, the temperature-time conditions of vacuum brazing with radiation heating were selected for manufacture of specimens for mechanical tests. Analysis of the results of strength tests of the butt brazed specimens proved the expediency of preliminary heat treatment of the base material, providing strength of the joints at a level of about 92% of that of the base material.
文摘Applications like solid oxide fuel cells and sensors increasingly demand the possibility to braze ceramics to metals with a good resistance to high temperatures and oxidative atmospheres. Commonly used silver based active filler metals cannot fulfill these requirements, if application temperatures higher than 600℃ occur. Au and Pd based active fillers are too expensive for many fields of use. As one possible solution nickel based active fillers were developed. Due to the high brazing temperatures and the low ductility of nickel based filler metals, the modification of standard nickel based filler metals were necessary to meet the requirements of above mentioned applications. To reduce thermally induced stresses wide brazing gaps and the addition of A1203 and WC particles to the filler metal were applied. In this study, the microstructure of the brazed joints and the thermo-chemical reactions between filler metal, active elements and WC particles were analyzed to understand the mechanism of the so called wide gap active brazing process. With regard to the behavior in typical application oxidation and thermal cycle tests were conducted as well as tensile tests.
