Interface Reaction Thermodynamics of AgCuTi Brazing Filler Metal and Alumina Ceramic

2014 ◽  
Vol 936 ◽  
pp. 1239-1246
Author(s):  
Hong Long Ning ◽  
Lin Feng Lan ◽  
Lei Wang ◽  
Jun Biao Peng ◽  
Zhi Jian Peng ◽  
...  
Keyword(s):  
Filler Metal ◽  
Interface Reaction ◽  
Liquid Solution ◽  
Product Formation ◽  
Influential Factor ◽  
Free Energies ◽  
The Real ◽  
Interface Reactions ◽  
Thermodynamics And Kinetics ◽  
Reaction Thermodynamics

In this work, the interface reaction between Al2O3 ceramic and Ag70.5Cu27.5Ti2 brazing filler metal at 845-860°C was investigated. Based on the data of thermodynamics and kinetics, the Gibbs free energies of the main interface reactions in the real brazing system condition were calculated. But the values of normal equilibrium reaction condition and the real interface reaction brazing system were different; and the main influential factor was the brazing temperature, and the system vacuum of brazing condition can lead the change of equilibrium constant (Kα). The results revealed that the high temperature and vacuum active brazing is a non-equilibrium interface reaction especially to titanium alloy, the vacuum and alloy liquid solution are beneficial to the brazing process, and the by-product formation of titanium-oxygen are affected by the diffusion process.

scholarly journals Interface Reactions Responsible for Run-Out in Active Brazing: Part 3

2021 ◽  
Vol 100 (12) ◽  
pp. 379-395
Author(s):  
PAUL T. VIANCO ◽  
◽  
CHARLES A. WALKER ◽  
DENNIS DE SMET ◽  
ALICE KILGO ◽  
...  
Keyword(s):  
Reaction Layer ◽  
Chemical Potential ◽  
Filler Metal ◽  
Sessile Drop ◽  
Interface Reaction ◽  
Base Material ◽  
Mitigation Strategies ◽  
Interface Reactions ◽  
Rate Kinetics ◽  
Sessile Drops

This study examined the interface reaction between sessile drops of the Ag-xAl filler metals having x = 0.2, 0.5, and 1.0 wt-% and KovarTM base material as an avenue to understand the run-out phenomenon observed in active filler metal braze joints. The brazing conditions were combinations of 965°C (1769°F) and 995°C (1823°F) temperatures and brazing times of 5 and 20 min. All brazing was performed in a vacuum of 10–7 Torr. Microanalysis confirmed that a reaction layer developed ahead of the filler metal to support spontaneous wetting and spreading activity. However, run-out was not observed with the sessile drops because the additional surface energy created by the sessile drop free surface constrained wetting and spreading. The value of z in the reaction layer composition, (Fe, Ni, Co)yAlz, increased with x of the Ag-xAl sessile drops for both brazing conditions. Generally, the values of z were lower for the more severe brazing conditions. Also, the reaction layer thickness increased with the Al concentration in the filler metal but did not increase with the severity of brazing conditions. These behaviors indicate that the interface reaction was controlled by the chemical potential rather than the rate kinetics of a thermally activated process. The determining metrics were filler metal composition (Ag-xAl) and brazing temperature. The findings of the present study provided several insights toward developing potential mitigation strategies to prevent run-out.

scholarly journals Interface Behavior of Brazing between Zr-Cu Filler Metal and SiC Ceramic

Crystals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 727
Author(s):  
Bofang Zhou ◽  
Taohua Li ◽  
Hongxia Zhang ◽  
Junliang Hou
Keyword(s):  
Interfacial Reaction ◽  
Reaction Layer ◽  
Chemical Potential ◽  
Filler Metal ◽  
Diffusion Constant ◽  
Interface Reaction ◽  
Diffusion Path ◽  
Interface Behavior ◽  
Interfacial Reaction Layer ◽  
Sic Ceramic

The interface behavior of brazing between Zr-Cu filler metal and SiC ceramic was investigated. Based on the brazing experiment, the formation of brazing interface products was analyzed using OM, SEM, XRD and other methods. The stable chemical potential phase diagram was established to analyze the possible diffusion path of interface elements, and then the growth behavior of the interface reaction layer was studied by establishing relevant models. The results show that the interface reaction between the active element Zr and SiC ceramic is the main reason in the brazing process the interface products are mainly ZrC and Zr2Si and the possible diffusion path of elements in the product formation process is explained. The kinetic equation of interfacial reaction layer growth is established, and the diffusion constant (2.1479 μm·s1/2) and activation energy (42.65 kJ·mol−1) are obtained. The growth kinetics equation of interfacial reaction layer thickness with holding time at different brazing temperatures is obtained.

Study on Interface Reactions between Nb-Si System In Situ Composite and Ceramics

2007 ◽  
Vol 546-549 ◽  
pp. 1495-1500
Author(s):  
Jing Jing Yu ◽  
Shu Suo Li ◽  
Ya Fang Han
Keyword(s):  
Elevated Temperature ◽  
Interface Reaction ◽  
Vacuum Arc ◽  
In Situ Composite ◽  
Interface Reactions ◽  
Arc Melting ◽  
Reaction Zones ◽  
C And N ◽  
Face Coat

A Nb-Si system in-situ composite Nb-16Si-24Ti-6Cr-6Al-2Hf(at%) was fabricated using vacuum arc melting method, and then was metallurgically reacted with four kinds of ceramics ZrO2, Y2O3 stabilized ZrO2, Y2O3, SiC+Si3N4 at elevated temperature. The microstructures in the interface reaction zones were investigated by SEM and EDS. The results showed that different extent chemical reactions between the composite and these four kinds of ceramics took place. It has been found that HfO2 riched layer formed near the interfaces between the Nb-Si in-situ composite and three ceramics of ZrO2, Y2O3 stabilized ZrO2 and Y2O3, and thickness of the reaction zones were about 100μm, 10μm, 1μm respectively. C and N elements in SiC+Si3N4 ceramic diffused to the composite at elevated temperature, and a new phase that rich of Ti, C and N elements appeared nearby the interface and accumulated inhomogenously. It may be concluded that the interface reactions of both ZrO2 and SiC+Si3N4 with Nb-Si composite were very violent, therefore they are not suitable as face-coat materials of shell molds for investment casting; the interface reaction of Y2O3 stabilized ZrO2 and Nb-Si composite was slighter than ZrO2 and SiC+Si3N4, and it can be used as face-coat material of shell molds, the interface reaction of Y2O3 and Nb-Si composite was very slight, and is recommended as an ideal face-coat materials of shell molds.

scholarly journals Interface Reactions Responsible for Run-Out in Active Brazing: Part 4

2022 ◽  
Vol 101 (1) ◽  
pp. 1-14
Author(s):  
PAUL T. VIANCO ◽  
◽  
CHARLES A. WALKER ◽  
DENNIS DE SMET ◽  
ALICE KILGO ◽  
...  
Keyword(s):  
Reaction Layer ◽  
Driving Force ◽  
Sessile Drop ◽  
Effective Means ◽  
Interface Reaction ◽  
Base Material ◽  
Test Sample ◽  
Interface Reactions ◽  
Braze Joint ◽  
Filler Metals

This study examined the interface reaction between Ag-xAl filler metals having x = 0.2, 0.5, or 1.0 wt-% and Kovar™ base materials. The present investigation used the braze joint test sample configuration. The brazing conditions were 965°C (1769°F), 5 min; 995°C (1823°F), 20 min, and a vacuum of 10–7 Torr. Run-out was absent from all test samples. Combining these results with those of the Part 2 study that used high-Al, Ag-xAl filler metals (x = 2.0, 5.0, and 10 wt-%) established these conditions for run-out: Ag-xAl filler metals having x ≥ 2.0 wt-% Al, which result in reaction layer compositions, and (Fe, Ni, Co)y Alz , having z ≥ 26 at.-% Al. The limited occurrences of run-out lobes resulted from the surface tension effect that quickly reduced the driving force for additional run-out events. The interface reactions were controlled by a driving force that was an expressed function of filler metal composition (Ag-xAl) and brazing temperature, as opposed to simply thermally activated rate kinetics. The differences of reaction layer composition and thickness confirmed that the interface reactions differed between the braze joint and sessile drop configurations. Collectively, the findings from the Parts 1–4 investigations concluded that the most-effective means to mitigate run-out is to place a barrier coating on the Kovar base material that will prevent formation of the (Fe, Ni, Co)y Alz reaction layer.

scholarly journals Effect of Brazing Parameters on the Microstructure and Properties of SiC Ceramic Joint with Zr-Cu Filler Metal

Crystals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 93
Author(s):  
Bofang Zhou ◽  
Jinfeng Wang ◽  
Keqin Feng ◽  
Yuchen Cai ◽  
Sitan Chen
Keyword(s):  
Shear Strength ◽  
Reaction Layer ◽  
Shear Test ◽  
Filler Metal ◽  
Interface Reaction ◽  
Fracture Morphology ◽  
Holding Time ◽  
Sic Ceramic ◽  
Maximum Shear Strength ◽  
Joint Reaction

The microstructure and mechanical properties of brazing SiC ceramic with Zr-Cu filler metal under different brazing parameters (brazing temperature, holding time) were investigated. The phase of the joint reaction interface between Zr-Cu filler metal and SiC ceramic was characterized by XRD, the microstructure and fracture morphology of the brazing SiC ceramic joint were analyzed by SEM with EDS, and the strength of the joint was evaluated by compression shear test. The results show that the brazing join between SiC ceramic and Zr-Cu filler metal can be realized at the brazing temperature of 1100 °C~1300 °C, and the main products of interface reaction are ZrC and Zr2Si. The shear strength of the joint increases with the brazing temperature, and reaches the highest at 1200 °C. The thickness of interface reaction layer increases with the increase of holding time at brazing temperature of 1200 °C. Thickness of the interface reaction layer is 2.9 μm when the joint is holding for 20 min, and the maximum shear strength of the corresponding brazed SiC ceramic joint is 57 MPa.

scholarly journals Thermodynamic Modeling of Ni-C, Co-C, and Ni-Co-C Liquid Alloys Using the Modified Quasichemical Model

2020 ◽  
Author(s):  
Junmo Jeon ◽  
Sun-Yong Kwon ◽  
Daniel Lindberg ◽  
Min-Kyu Paek
Keyword(s):  
Short Range ◽  
Interpolation Method ◽  
Liquid Solution ◽  
Pair Approximation ◽  
Strong Interactions ◽  
Free Energies ◽  
Quasichemical Model ◽  
Liquid Phases ◽  
Short Range Ordering ◽  
Co Alloys

Abstract The strong interactions between the metallic elements and C in liquid Ni, Co, and Ni-Co alloys have been thermodynamically analyzed. The liquid solution properties in Ni-C and Co-C systems showed significant asymmetry because of the short-range ordering of C exhibited in the liquid solution. Using the modified quasichemical model in the pair approximation, the Ni-C and Co-C systems were re-optimized to simultaneously reproduce the present experimental results of the C solubility and the reported thermodynamic properties in the liquid phases. In particular, the partial enthalpy data of C in liquid Ni and Co alloys were considered for the first time on the thermodynamic assessment of Ni-C and Co-C liquid solutions. The asymmetric interpolation method was introduced to evaluate the Gibbs free energy in the ternary system based on the binary Gibbs free energies in the Ni-C and Co-C systems. The C solubility data measured in the ternary Ni-Co-C alloy melt over a wide Co concentration range were successfully reproduced without any additional ternary model parameter by considering the short-range ordering of C.

Interfacial Reaction Thermodynamics between Sn-Cu-Ag Solder and Ni Substrate

2013 ◽  
Vol 433-435 ◽  
pp. 2020-2024 ◽  
Author(s):  
Hong Yan Xu ◽  
Hu Wu ◽  
Bing Sheng Xu ◽  
Yan Wu
Keyword(s):  
Mechanical Properties ◽  
Interfacial Reaction ◽  
Reaction Rate ◽  
Sessile Drop ◽  
Interface Reaction ◽  
Sessile Drop Method ◽  
Ni Substrate ◽  
Reaction Thermodynamics ◽  
Key Factor ◽  
Contour Evolution

Interfacial reaction during wetting and spreading of Sn-Ag-Cu solder on Ni substrate is a key factor in order to improve the mechanical properties of the joints and the weld quality. Therefore, it’s important to focus on the thermodynamic and kinetic analysis of this interface reaction. In this paper, the sessile drop method was used to study the spreading contour evolution. The Kissinger method was used to calculate thermo-kinetic parameters of reactions between Sn-Ag-Cu solder and Ni substrate based on DTA data. The results show that Cu reduces activation energy and reaction rate of Sn-Ag-Cu/Ni system. (Cu, Ni)6Sn5 phase mainly constitute the interface reaction layer of Sn-Ag-Cu/Ni. As the temperature increases, partial (Cu, Ni)6Sn5 phase is substituted by Ni3Sn4 phase.

Interface Reaction between DD6 Single Crystal Superalloy and Ceramic Core

2021 ◽  
Vol 1035 ◽  
pp. 297-304
Author(s):  
Jian Sheng Yao ◽  
Long Pei Dong ◽  
Li Li Wang ◽  
Shu Yang ◽  
Wei Yang ◽  
...  
Keyword(s):  
Reaction Time ◽  
Single Crystal ◽  
Interfacial Reaction ◽  
Interface Reaction ◽  
Ceramic Materials ◽  
Single Crystal Superalloy ◽  
Dense Layer ◽  
Ceramic Core ◽  
Interface Reactions ◽  
The Core

The interfacial reaction between alloys and ceramic materials is an important factor to influence the quality and service performance of the turbine blade. In this paper, three typical height sections of 120mm, 160mm and 210mm were selected, and the interface reactions between DD6 single crystal superalloy and silica based ceramic cores were investigated by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS). The results showed that the infiltration degree of the melt alloy increases with the increase of reaction time. The thickness of the reaction layer could be over 0.3mm when the reaction time increased up to 70min. The main reasons of forming the infiltration layer were the infiltration of the Al element and the interfacial reaction between the Al element and the ceramic core. There formed an aluminum deficient layer on the metal surface because of the interface reaction between the alloy and the ceramic core. The dense layer formed by interfacial reaction on the surface of the core will cause some difficulties for core leaching. Keywords: DD6 single crystal superalloy; Silica based ceramic core; Interface reaction

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