Formation Of Borides Research Articles

Roles of Refractory Solutes on the Stability of Carbide and Boride Phases in Nickel Superalloys

Nickel-base superalloys contain high amounts of solutes like Cr, Mo, W, Nb, Ti, etc. These solutes promote the formation of different types of carbide and boride phases that may contain multiple elements. Researchers have mostly discussed the roles of primary elements responsible for the formation of a given carbide/boride phase, often ignoring the role of other solutes on its stability. In the present work, thermodynamic stability of carbide and boride phases in seven commercial superalloys, namely, Alloy 625, Alloy 690, Alloy 718, MAR M246, Rene 100, Udimet 710 and Nimonic 80A, has been studied using the CALPHAD based Thermo-Calc software. The aim of the study was to understand the role of different alloying elements on temperature stability and chemical compositions of equilibrium phases in superalloys. As the accuracy of CALPHAD based predictions depends upon the database used, a detailed examination of its inadequacies has also been carried out to ascertain the limitations of the predicted data. From the calculated equilibrium chemical compositions, major and minor constituents promoting the formation of carbides and borides have been identified. The individual effect of a given solute as well as the synergistic effect of two solutes on the relative thermodynamic stability of carbide/boride phases has been identified using property diagrams and isothermal sections of the temperature-composition diagrams. Most of the simulated results have been found to be consistent with the experimental data available in the literature. From a comparison of the experimental literature and the simulated data of the stable carbide and boride phases in the studied alloys, the interplay of different solutes has been deduced to define conditions under which these phases form, within the limitations of the database used. This study has helped in better understanding of general tendencies of solutes to form different carbide and boride phases in nickel-based superalloys.

Low-temperature fabrication of high-entropy rare earth hexaboride powders

Herein, we report a low-temperature method for synthesizing high-entropy rare earth hexaboride powders by reaction among rare earth oxides, B4C, and Al powders. Al was used as a reducing and decarburization agent in this process, which further reduced the Gibbs free energy change for the reaction of RexOy with B4C to form REB6. By investigating the influence of reacting temperature and amount of Al added on preparation of LaB6, the optimum experimental conditions of this method were determined to be 1300 °C and 2 times the stoichiometric ratio of Al. Theoretical supports were proposed to verify the feasibility for formation of high-entropy borides. Then, multicomponent hexaborides La0.5Ce0.5B6, La0.33Ce0.33Nd0.33B6, and La0.25Ce0.25Nd0.25Sm0.25B6 as well as high-entropy hexaboride La0.2Ce0.2Nd0.2Sm0.2Eu0.2B6 powders were successfully prepared by doping with Ce, Nd, Sm, and Eu on LaB6. RE elements with different radius were uniformly distributed in the multicomponent boride powders without obvious segregation. More importantly, the lattice distortion and stress induced by the element substitution contribute to the reduction of the average powder particle size. Finally, the DTA-TG curves show that rare earth hexaborides have good oxidation resistances when the temperature is below about 1000 °C.

Effect of Nb and B on the Precipitation Behaviors in Al-Ti-Nb Balanced-Ratio Ni-Based Superalloy: A Phase-Field Study

In this paper, quantitative two-dimensional (2-D) phase-field simulations were performed to gain insight into the effects of B and Nb for Al-Ti-Nb balanced-ratio GH4742 alloys. The microstructure evolution during the precipitation process was simulated using the MICRESS (MICRostructure Evolution Simulation Software) package developed in the formalism of the multi-phase field model. The coupling to CALPHAD (CALculation of PHAse Diagram) thermodynamic databases was realized via the TQ interface. The morphological evolution, concentration distribution, and thermodynamic properties were extensively analyzed. It is indicated that a higher Nb content contributes to a faster precipitation rate and higher amounts and the smaller precipitate size of the γ′ phase, contributing to better mechanical properties. The segregation of the W element in γ′ precipitate due to its sluggish diffusion effect has also been observed. Higher temperatures and lower B contents accelerate the dissolution of boride and reduce the precipitation of borides. With the increased addition of B, the formation of borides may have a pinning effect on the grain boundary to hinder the kinetic process. In addition, borides are prone to precipitate around the interface rather than in the bulk phase. Once the M3B2 borides nucleate, they grow in the consumption of γ′ phases.

Optimizing LPBF-parameters by Box-Behnken design for printing crack-free and dense high-boron alloyed stainless steel parts

Boron has almost null solubility in iron, and its addition to stainless steels leads to the formation of hard borides, beneficial for increasing the wear resistance. However, these boron-containing steels have poor printability, with the occurrence of pronounced cracking, high porosity and risk of delamination. In this work, Box-Behnken design coupled with analysis of variance (ANOVA) was used to optimize the LPBF (Laser Powder Bed Fusion) processing parameters of a highly boron-alloyed stainless steel reinforced with a boride network. The proposed models demonstrated to be accurate in determine the porosity percentage for the studied alloys, in which the laser power and scanning speed play the main role in the alloys’ densification, and absence of extensive defects. These results indicate that the use of design of experiments tools is essential to produce defect-free boron-modified stainless steel specimens with a relatively low number of experiments, identifying a narrow optimized processing window to build bulk composite materials.

Robust additive manufacturable Ni superalloys designed by the integrated optimization of local elemental segregation and cracking susceptibility criteria

To achieve an effective design of additively manufacturable Ni superalloys with decent service performance, a hybrid computational design model has been developed, where the strategy to tailor local elemental segregations was integrated within a scheme of minimizing the cracking susceptibility. More specifically, the phase boundary of primary NbC / γ matrix was introduced into the design routine to tune the spatial distribution of critical solutes at an atomic scale, thereby inhibiting the formation of borides and segregation-induced cracking. Based on the output of the design, new grades of Ni superalloy have been developed with excellent additive manufacturability, as confirmed by the robustness of printing parameters in fabricating low-defect-density samples. The capability of the phase boundaries to evenly distribute boron atoms was validated experimentally, and the cracking induced by uncontrolled boron segregation at grain boundaries was effectively prevented. The newly designed alloys showed good tensile properties and decent oxidation resistance at different service temperatures, which are comparable to those of conventionally produced superalloys. The finding that phase boundaries can be employed to prevent undesirable clustering of boron atoms can be extended to manipulate the distributions of other critical elements, which provides a new path for designing novel Ni superalloys with balanced printability and mechanical properties.

Gold and silver: Noble solvents for the synthesis of superconducting boron-doped diamonds

The synthesis of diamonds in traditional growth systems based on Fe, Co and Ni does not allow overcoming the semiconductor level of boron doping of diamond, presumably because of a high affinity of boron to boride-forming metals. For the first time, noble metals that do not form borides—silver and gold—are used as growth media for the synthesis of heavily boron-doped diamonds at 8–9 GPa. Gold and silver are not catalysts for the transformation of graphite to diamond, whereas elemental boron is catalytically active at eutectic melting temperatures above 2500 K. It is found that the synthesis of diamond in AgB and AuB growth media starts at temperatures close to the melting temperatures of Ag and Au, 1600 and 1800 K, respectively. Calculations show that molten Au and Ag dissolve boron atoms without a significant change in the electronic structure of the solution, suggesting that the metal melts serve as a carrier for the boron catalyst. The resulting polycrystalline diamond contains dispersed inclusions of Ag and Au, as well as traces of boron carbide; the formation of borides is not detected. The transport measurements of the diamond samples reveal a transition to a superconducting state in the temperature range from 4.5 to 2.5 K. Raman spectroscopy confirms the heavy boron doping of diamond. Thus, we show that melts of “non-catalytic” metals that do not form borides can be effectively used to synthesize boron-doped conductive/superconducting diamonds at relatively low temperatures.

Surface modification of die steels by liquid boriding

The research investigates the effect of liquid boriding on the microstructure, composition and microhardness of the surface layer on 5KhNM and 3Kh2V8F die steels. Boriding was carried out for 8 hours at 850 and 1000 °С in a melt based on sodium tetraborate and sodium salts. After high-temperature exposure during the boriding process, the samples were quenched in oil and tempered. Next, the samples were subjected to metallographic, X-ray spectral, X-ray diffraction and durometric analyses. As a result of processing, boride diffusion layers were obtained on the surface of 5KhNM and 3Kh2V8F steels up to 100 and 130 μm thick, respectively. It has been established that iron borides Fe2B and FeB are formed on the surface of both steels. In addition, chromium boride CrB is additionally formed on the surface of 5KhNM steel, increasing the maximum microhardness of the layer to 2130 HV. The maximum microhardness of 3Kh2V8F steel reaches 1709 HV due to the formation of borides and carbides in the layer. A study of the surface topography after boriding showed that the roughness parameter Ra of 5KhNM steel increased by 1.87 times, and of 3Kh2V8F steel by 1.78 times compared to the initial state.

Влияние ионной имплантации на свойства чугуна, используемого в конструкциях горнодобывающих машин и аппаратов

Introduction. Cast iron is a widely used material in mechanical engineering, mining and other industries. Modification of the surface properties of cast iron by ion implantation is of great interest. Research methods and materials. Samples of cast iron before and after implantation with C+, B+, N+ ions with dose D = 1017 ions/cm2 and energy of 40 keVwere taken for research. All samples were tested for wear resistance; microhardness was also measured and X-ray analysis was performed. Research results. It is shown that cast iron samples after ion implantation had higher wear resistance and microhardness in comparison with the initial state. The increase in hardness of all samples is apparently associated with the presence of a large number of specific radiation defects and the formation of dispersed phases (nitrides, borides, carbides). Discussion of the research results. The study of micro-hardness was carried out to determine the depth of the hardened layer after ion implantation with C+ , B+ , and N+ ions. The highest micro-hardness was detected at the surface of the sample after irradiation with N + ions. The lowest micro-hardness was obtained by B+ ions. X-ray analysis of cast iron samples after implantation by C+ , B+ , and N+ ions with dose D = 1017 ions/cm2 was the fine structure are observed. Conclusion. Ion implantation of cast iron with C+, B+, N+ ions has shown that irradiation leads to: Increased wear resistance of the material; A significant increase in micro-hardness; Changes in the fine structure of the implanted cast iron (mosaic block size and average dislocation density) and the formation of carbides, borides, and nitrides. Resume. The results of the research show that ion implantation of cast iron can significantly increase the wear resistance of various units of machines (parts) and other mining equipment, which ultimately increases their service life. Suggestions for practical application and direction of future research. The shown results allow us to propose the method of ion implantation as a hardening treatment of parts made of cast iron used, in particular, in the mining industry. In order to develop ion implantation as one of the hardening technologies, it would be advisable to continue studying various physical and chemical properties (for example, corrosion resistance) after exposure to ion implantation.

Dual-phase high-entropy carbide/boride ceramics with excellent tribological properties

Tribological characteristics of fine-grained dual-phase high-entropy carbide/boride ceramics were investigated using the ball-on-flat dry sliding method in air, applying linear reciprocation motion with SiC counterpart. Detailed fractographical analyses were used for the characterization of the deformation and damage mechanisms. The investigated system with composition (Ti0.14Zr0.2Nb0.2Hf0.2Ta0.26)C + (Ti0.38Zr0.18Nb0.22Hf0.115Ta0.105)B2 showed density with value 8.72 g/cm3 and very high hardness of HV1 29.4 ± 2.0 GPa. The friction coefficient at the test with 5 N was 0.56 and during the test with 10 N and 25 N loads were 0.48 and 0.5, respectively. The effective wear rates at the loads of 5 N and 25 N were very similar with values of 7.93 × 10−7 mm3/Nm and 6.63 × 10−7 mm3/Nm. At load 50 N the effective wear rate is significantly higher with a value of 9.11 × 10−6 mm3/Nm. Detailed fractography revealed that the dominant wear mechanisms at loads of 5 N and 25 N were an oxidation-driven tribochemical reaction and tribo-layer formation in boride grains and mechanical wear in carbide grains and at the load of 50 N fracture of boride and carbide grains and formation of chemically complex tribolayers.

Hardness and tribological behaviour of annealed electroless nickel phosphorus composite layers with incorporated boron particles

In this study, a possible alternative to hard chromium coatings is investigated. Amorphous boron particles have been incorporated in electroless nickel‑phosphorus (NiP) deposits, yielding a dispersion coating. The distribution of the particles is homogenous and the maximum mass fraction of particles embedded in the coating is 6.2 ± 0.2 wt%. Measurements of the zeta potential and particle size of amorphous boron particles in a diluted electrolyte showed that the particles withstood agglomeration until 120 days. Primary and secondary hardness maxima are observed after thermal annealing at 400 °C and 860 °C due to the formation of nickel phosphide, nickel boride and nickel boride phosphide phases. X-ray diffractometry shows an increase in nickel and nickel phosphide crystal size at 400 °C before levelling off at 600 °C. The annealing duration should be kept between 30 and 60 min for optimal hardness. The wear resistance increases when the coating is annealed at 400 °C. DSC measurements on nickel phosphorus incorporated with boron particles, Ni-P-B, bulk material with P-content (9.6 ± 0,6 wt%) and B-content (4.5 ± 0.8 wt%) showed that the solidus line lies at 926 °C, which is why a maximum annealing temperature of 860 °C was chosen to avoid melting of the material. The relative texture and phase coefficients, RTC and RPC, showed that the nickel phase is preferred in the NiP system at 400 °C and 600 °C while the Ni3P phase is preferred in the Ni-P-B system at the same annealing temperature. REM and EDX area analyses are used to show the areal distribution of nickel, phosphorus, and boron before and after the annealing process along the thickness of the coating. A diffusion layer between substrate and coating that contains iron nickel boride and iron nickel phosphide lamellar structure is observed.

Synthesis and Characterization of High-Purity, High-Entropy Diboride Ceramic Powders by a Liquid Phase Method

A nano-dual-phase powder with ultra-fine grain size was synthesized by the liquid precursor method at 1200 °C. A series of single-phase high-entropy ceramic powders ((Ti, Zr, Hf, Nb)B2, (Ti, Zr, Hf, Nb, Ta)B2, (Ti, Zr, Hf, Nb, Mo)B2, (Ti, Zr, Hf, Nb, Ta, Mo)B2) with high purity (C content less than 0.9 wt% and O content less than 0.7 wt%) and ultrafine (average grain sizes of 340–570 nm) were successfully synthesized at 1800 °C. The sample of (TiZrHfNbTa)B2 exhibited a hexagonal close-packed (HCP) structure, and the metal elements were uniformly distributed at the nanoscale, microscale, and macroscale. This method did not apply to the preparation of all high-entropy ceramic powders and was unfavorable for the formation of single-phase high-entropy borides when the size difference factor exceeded 3.9%. The present work provides a guide for the development of ceramic-based composites through precursor impregnation pyrolysis.

Adhesive wear behavior and microstructure of FeCr–FeMn–FeB–C coatings

Abstract This study employs a high-energy-density gas tungsten arc welding (GTAW) process to fabricate a surface coating on a substrate of 0.15 percent carbon steel, incorporating powders of FeCr, FeMn, FeB, and graphite. The investigation encompasses a multifaceted approach, utilizing X-ray diffraction (XRD), optical micrograph (OM) analysis, energy-dispersive X-ray analysis (EDS), scanning electron microscopy (SEM) imaging, microhardness testing, and adhesive wear testing, with the aim of examining the composite coating’s microstructural attributes, microhardness, and performance under dry-sliding wear conditions. The research findings reveal the formation of diverse carbides and borides, including Mn5C2, Fe3C, B8C, B4C, Fe3B, Fe7C3, FeB, and MnB on the coated surfaces. Notably, the graphite particles within the FeB–FeMn–FeCr–C composite TIG welding coatings exhibit a range of morphologies, varying from sheet-like to dendritic structures.

Alumino-Silico-thermic synthesis of high purity ferroboron alloy and its characterization

High purity ferroboron (Fe–B) alloy is used as an alloying agent for making special grades of steels, Nd-Fe-B magnets etc. In this study, alumino-silico-thermic co-reduction of Fe2O3 and B2O3 was attempted to prepare high purity Fe–B. Extensive differential thermal analysis (DTA) studies were carried out to understand the reduction behaviour of Fe2O3 and B2O3 by Al and Si. DTA exothermic peaks indicated three step reduction of Fe2O3 (Fe2O3→Fe3O4→FeO→Fe) when reacted with Al and Si separately. B2O3–Si system did not show exothermic peaks while heating indicating sluggish or no reduction, however, B2O3–Al DTA peaks indicated two step reduction behaviour. Differential thermal analysis of Fe2O3–B2O3–Al–Si indicated completion of reduction of oxides, and formation of different intermediate phases. Specially designed reduction reactors were used to produce ferroboron alloy in bulk quantities. Thermal analysis results suggested that the formation of aluminium and silicon borides could be avoided using sub-stoichiometric amount of Al and Si, which was further confirmed from the bulk thermit product. Si acted as reducing agent as well as forming low melting slag comprising of Al(Si)–B–O type oxides. Inductively coupled plasma-atomic emission spectroscopy (ICP-AES) and Particle Induced Gamma-ray Emission (PIGE) analysis confirmed the presence of 12 wt% boron in the alloy product with lower content (<1 %) of impurity elements like Al and Si. The relationship between the chemical homogeneity with the thermit process parameters was established. Microstructure and mechanical properties confirmed the formation of Fe2B and FeB phase in the thermit alloy.

Boosting the Catalytic Performance of NiMoO4 Nanorods in H2 Generation upon NH3BH3 Hydrolysis via a Reduction Process.

Although a range of noble metal catalysts, including Ru, Rh, Pd, Pt, and Au, have been developed for efficient H2 generation upon NH3BH3 hydrolysis at room temperature, this is a highly urgent need for exploring earth-abundant metal nanocatalysts for H2 generation upon NH3BH3 hydrolysis. Herein, a NaBH4 reduction strategy was developed to boost the catalytic performance of NiMoO4 nanorods in H2 generation upon NH3BH3 hydrolysis. Indeed, the pristine NiMoO4 nanorods were catalytically inert in NH3BH3 hydrolysis. Significantly, the reduced NiMoO4 nanorods presented excellent catalytic activity in H2 generation upon NH3BH3 hydrolysis, with a turnover frequency (TOF) of 31.2 L(H2)·gcat-1·h-1. Interestingly, the TOF of NH3BH3 hydrolysis over reduced NiMoO4 nanorods significantly increased from 31.2 to 53.6 L(H2)·gcat-1·h-1 under 0.3 M NaOH. The boosting catalytic performance of NiMoO4 nanorods via NaBH4 reduction in H2 generation might be attributed to the higher content of Oads and the formation of nickel boride in the reduced NiMoO4 nanorods. In this work, NH3BH3 hydrolysis over reduced NiMoO4 nanorods was not only used for safe H2 generation but also for its in situ tandem hydrogenation in organic chemistry.

Magnetic properties and structure of the Fe63.5Mn10Cu1Nb3Si13.5B9 alloy nanocrystallized under tensile stresses

The influence of introduction of 10 at. % Mn for Fe in the classical Finemet (Fe73.5Cu1Nb3Si13.5B9) on its magnetic properties, magnetic anisotropy, and structure is studied after nanocrystallization annealing at 520°C with varying duration from 10 min to 4 h in the presence of tensile stresses (σ = 200 MPa) (SA) and without them (NA). It is established that in the Fe63.5Mn10Cu1Nb3Si13.5B9 alloy (Mn10-alloy), just as in the classical Finemet, SA results in the induction of transverse magnetic anisotropy, yet, the constant of induced magnetic anisotropy is decreased by a factor of 4. The coercivity of the Mn10-alloy grows with increasing annealing time upon both SA and NA, while that of Finemet virtually does not change. Unlike Finemet, in the Mn10-alloy, along with the α-Fe(Si, Mn) solid solution and Fe3Si phase, there form borides already after 10-min treatment. This results in the change in the volume fractions of structure components with a negative magnetostriction, α-Fe(Si, Mn) and Fe3Si, which are responsible for the induction of transverse magnetic anisotropy, and positive magnetostriction, FeB, Fe2B, Fe3B, and hence, most likely, causes decrease in the constant of IMA of the Mn10-alloy. Besides, unlike Finemet, the average grain size in the alloy with Mn increases with the time of annealing, which, together with the formation of borides, increases the coercivity.

Thermochemical Study of the Formation of Silicides, Borides, and Carbides in an Fe–Ni–Cr–Cu–Si–B–C Alloy

Thermochemical Study of the Formation of Silicides, Borides, and Carbides in an Fe–Ni–Cr–Cu–Si–B–C Alloy

Combustion synthesis of ultra-high-temperature solid solutions (ZrxNb1-x)B2. Part 1: The mechanisms of combustion and structure formation

The self-propagating high-temperature synthesis (SHS) in Zr–Nb–B system has been thoroughly investigated with a focus on its macrokinetics and phase formation mechanisms. The activation energies were determined by analyzing the relationship between the combustion rate and temperature. For compositions NbB2–40%ZrB2 and NbB2–50%ZrB2, the increase in the initial temperature has resulted in a significant change in combustion rate's dependence on temperature, signifying a possible shift in the reaction mechanisms. The quenched combustion front technique (QCF) method in conjunction with thermodynamic and ab initio calculations were used to analyze the sequence of phase formation events, including the formation of niobium and zirconium borides through gas transport reactions involving volatile boron suboxide BO in the heating zone, followed by the emergence of a zirconium-boron melt in the combustion zone and formation of main fraction of niobium and zirconium borides. Interactions between the primary niobium and zirconium borides and the melt result in the formation of solid solutions; however, at sub-optimal combustion conditions multiple non-equilibrium solid solutions are retained in the products. To address this issue, a machine learning model was developed, attaining coefficients of determination (R2) of 89% for combustion temperature and rate predictions, thus enabling the fine-tuning of macrokinetic parameters of the SHS process in the system.

Characterization of a 2205 Duplex Steel Modified with Boron Obtained via Powder Metallurgy

Stainless steels are commonly used when a good balance between mechanical properties and corrosion resistance is required. Usually, to increase wear resistance, hard particles are added (carbides, borides, nitrides, and others) to the more ductile matrix (ferrite or austenite). The addition of boron to steels leads to the formation of primary and eutectic borides, which harden the material as solidified. Therefore, herein, the viability to prepare a modified 2205 duplex steel with 2.5 wt% of boron through powder metallurgy is investigated. The boron addition is performed in the atomization step. In addition, the effect of temperature in the sintering process is investigated, as well as the characterization of microstructure formation, phase transformations, and mechanical properties. The specimens are prepared from a prealloyed metal powder with three different granulometries: thick (250–500 μm), medium (106–180 μm), and thin powders (&lt;45 μm). Shaping is conducted by cold uniaxial compaction with sintering in a controlled Ar atmosphere. An optimal sintering temperature of 1200 °C is identified for all granulometries studied. However, the highest densification of &gt;85% is observed with medium powder with an increase of nearly 40% in microhardness in comparison to the reference 2205 steel.

Development and characterization of boride-reinforced CoCrFeNi composites

CoCrFeNi is a face-centered cubic (FCC) high entropy alloy (HEA) that exhibits high ductility both at room temperature and at cryogenic temperatures but has limited strength. The present study is focused on addition of TiB2 to the CoCrFeNi HEA with the goal of developing materials with better combinations of strength and ductility. HEA composites with varying amounts of TiB2 were prepared by arc melting under an argon atmosphere. The resulting alloys were subjected to chemical, microstructural, and mechanical characterization. Interaction of TiB2 with chromium in the HEA matrix during melting resulted in its decomposition, leading to in-situ formation of chromium borides with plate morphology. A eutectic mixture, consisting of a hard phase (chromium boride) and a tough phase (the FCC matrix) was also developed with the amount of the eutectic mixture increasing with increasing amount of TiB2 added to the HEA. Mechanical characterization of the developed composites revealed a very wide range of mechanical properties, including yield strengths ranging from 180 MPa to 1282 MPa, hardness values ranging from 200 to 750 HV, and elongation ranging from 3.4% to more than 60%. Outstanding combinations of mechanical properties could also be obtained, for example the HEA composite developed by addition of 6 wt% TiB2, exhibited very high hardness (400 ± 10 HV) and very high yield strength (918 MPa), along with very good values of elongation before fracture (30%). The results in this study demonstrate that development of ceramic-reinforced HEA composites can help in obtaining alloys with excellent combinations of strength and ductility.

Standstill corrosion of the BNi-2/316L brazing joints in a stirling engine

A stirling engine was stored for about two years. When the engine was started, the cooler in the engine was found leaked, which affects the normal operation of the entire equipment. After dismantling, brazing seems between the cooling tubes and the cylinder were detected leaked by air pressure tests. The leaked sites were further determined at the diffusion zones of the brazing joints by the X-ray tomography and microscopic inspections. The crevice penetrated the diffusion zones, where chromium in the matrix depleted due to the formation of chromium borides. Considering the storage environment and the corrosion characteristics, the cause of the leakage is confirmed at the combined effect of standstill corrosion and crevice corrosion in the Cl- containing water. In addition to the failure cause, the wide brazing clearance and formation of nitrogen borides are considered to be two factors that promoted corrosion. Based on the above analysis, suggestions are proposed to prevent recurrence of corrosion and improve the corrosion resistance of the BNi-2/316L brazing joint.