Simultaneous Boronizing and Carburizing of Titanium via Spark Plasma Sintering

Karimoto, Takato; Nishimoto, Akio

doi:10.2320/matertrans.l-m2019838

Cited by 7 publications

(4 citation statements)

References 41 publications

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“…These results indicate that the use of SPS accelerated the reaction and shortened the processing time. It has been observed that in the boronizing process using SPS, the boron source powder becomes active when an electric current is applied, and the reaction is accelerated owing to a decrease in the activation energy of the boronizing reaction [20,21]. In this study, the reaction was promoted in the same manner, and it can be considered that a boride layer of the same thickness could be obtained in a shorter time than that of the boronizing treatment using the general powder packing method.…”

Section: Cross-sectional Hardnessmentioning

confidence: 99%

“…Using this method, a hard layer with excellent adhesion can be formed. One of the diffusion coating methods is boronizing (boron immersion) treatment, which can form borides with an excellent hardness and wear resistance [18][19][20][21], and this could help overcome the aforementioned limitations associated with HEA. However, in conventional boronizing treatment, the deterioration of the mechanical properties of the base material owing to high temperatures and prolonged treatment is an issue that needs to be addressed [22,23].…”

Section: Introductionmentioning

confidence: 99%

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Boronizing of CoCrFeMnNi High-Entropy Alloys Using Spark Plasma Sintering

Nakajo

Nishimoto

2022

JMMP

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In this study, we investigated the formation of a protective coating on a face-centered cubic high-entropy alloy (HEA). The coating was formed by a diffusion coating method. In the conventional diffusion coating method, the degradation of the mechanical properties of the base material owing to prolonged high-temperature treatment is a major issue. Therefore, we formed a ceramic layer using spark plasma sintering (SPS), which suppresses grain growth with rapid heating and enables fast, low-temperature processing. The objective of this study was to form borides on the surface of CoCrFeMnNi HEAs using the SPS method and to investigate their properties. A CoCrFeMnNi HEA prepared by the casting method was used as the base material, and a powdered mixture of B4C and KBF4 was used as the boron source. The analysis of the surfaces of the SPS-treated samples revealed the formation of M2B, MB, and Mn3B4-type borides on the HEA surface. The surface hardness was 2000–2500 HV owing to the formation of a ceramic layer on the HEA surface, and elemental analysis showed that certain elements exhibited characteristic diffusion behaviors.

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Section: Cross-sectional Hardnessmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Boronizing of CoCrFeMnNi High-Entropy Alloys Using Spark Plasma Sintering

Nakajo

Nishimoto

2022

JMMP

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“…It can be combined with B 4 C to form a composite material that results in inhibition of grain growth, lower sintering temperature and improved mechanical properties [11][12][13][14][15][16][17] . When sintered at high temperature, the overall performance of nanoscale Ti and B 4 C powders is weaker than that of pure B 4 C [18] .…”

Section: Introductionmentioning

confidence: 99%

“…It can be combined with B 4 C to form a composite material that results in inhibition of grain growth, lower sintering temperature, and improved mechanical properties. [13][14][15][16][17][18][19] When sintered at high temperature, the overall performance of nanoscale Ti and B 4 C powders is weaker than that of pure B 4 C. [20] Additionally, Ti is easily oxidized into Ti-O phase, or Ti-B-O and Ti-C-O solid solutions. Nanoscale Ti powers are usually unstable, so they are too difficult to handle.…”

Section: Introductionmentioning

confidence: 99%

Properties of B₄C-TiB₂ ceramics prepared by spark plasma sintering*

et al. 2021

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By doping titanium hydride (TiH2) into boron carbide (B4C), a series of B4C + x wt% TiH2 (x = 0, 5, 10, 15, and 20) composite ceramics were obtained through spark plasma sintering (SPS). The effects of the sintering temperature and the amount of TiH2 additive on the microstructure, mechanical and electrical properties of the sintered B4C-TiB2 composite ceramics were investigated. Powder mixtures of B4C with 0–20 wt% TiH2 were heated from 1400 °C to 1800 °C for 20 min under 50 MPa. The results indicated that higher sintering temperatures contributed to greater ceramic density. With increasing TiH2 content, titanium diboride (TiB2) formed between the TiH2 and B4C matrix. This effectively improved Young’s modulus and fracture toughness of the composite ceramics, significantly improving their electrical properties: the electrical conductivity reached 114.9 S⋅cm−1 at 1800 °C when x = 20. Optimum mechanical properties were obtained for the B4C ceramics sintered with 20 wt% TiH2, which had a relative density of 99.9 ± 0.1%, Vickers hardness of 31.8 GPa, and fracture toughness of 8.5 MPa⋅m1 / 2. The results indicated that the doping of fine Ti particles into the B4C matrix increased the conductivity and the fracture toughness of B4C.

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